Dissertations / Theses on the topic 'Active antenna'
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Scattone, Francesco. "Phased array antenna with significant reduction of active controls." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S168/document.
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L'objectif de cette thèse est d'exploiter les phénomènes des ondes de fuite pour améliorer les performances des antennes classiques à ouverture pour les applications spatiales. Ici, nous considérons des configurations planaires où les ondes de fuite sont excitées entre un plan de masse et un superstrat partiellement réfléchissant. Des réseaux de petites ouvertures sur le plan de masse sont utilisés pour alimenter les antennes considérées. Les structures avec superstrat sont développées en configuration réseaux simples ou réseaux à commande de phase, considérées intéressantes en termes de flexibilité du système pour des liens satellitaires de nouvelle génération.Pour étudier efficacement ces antennes, nous avons développé un outil d'analyse basé sur une approche spectrale avec fonction de Green. Cet outil permet d'analyser les structures proposées en prenant en compte l'impact du couplage mutuel entre les éléments sur les performances de rayonnement avec une réduction du temps de calcul et d'utilisation de mémoire.L'augmentation du gain des structures à ondes de fuite peut ouvrir la voie à la réduction du nombre d'éléments des réseaux associés, et donc des commandes en amplitude et phase. Dans une configuration à ondes de fuite, chaque élément du réseau rayonne avec une ouverture équivalente plus grande, augmentant ainsi l'espacement entre les éléments sans affecter le gain global de la structure. Comme largement expliqué dans le manuscrit, les solutions à ondes de fuite représentent par conséquent un avantage majeur pour les antennes du segment utilisateur.En plus de l'amélioration du gain, la technologie à ondes de fuite peut être efficacement exploitée pour synthétiser le diagramme de rayonnement, en choisissant correctement les paramètres de conception de l'antenne. Cette caractéristique peut être utilisée dans les réseaux à commande de phase, pour produire un diagramme d'élément qui minimise les pertes par dépointage et qui filtre les lobes de réseaux. Une procédure de synthèse pour des antennes réseaux raréfiés à ondes de fuite est ainsi présentée dans le manuscrit, ainsi qu'une nouvelle configuration de réseaux avec superstrat irrégulier. Ce dernier permet de réduire les lobes secondaires de l'antenne en utilisant une excitation uniforme. Cette dernière configuration montre clairement que la capacité de modifier le diagramme de rayonnement est la caractéristique la plus attrayante des antennes planaires à ondes de fuite, pour être utilisée dans des solutions de réseaux à commande de phaseThe objective of this thesis is to exploit the leaky-wave phenomena to enhance the performance of classical aperture antennas for space applications. Here, we consider planar configurations where the leaky modes are excited between a ground plane and a partially reflective superstrate. Arrangements of small apertures opening on the ground plane are used to feed the antennas under study. The superstrate-like leaky-wave structures are developed in array or phased array configurations, considered of interest in terms of flexibility of the system for next generation satellite links. In order to efficiently study planar leaky-wave arrays, we have developed an analysis tool based on a Green's function spectral approach. The developed tool allows to precisely analyze the proposed structure by taking into account the impact of the mutual coupling among the elements on the radiation performance of the whole antenna. In addition, it can handle extremely large structures in terms of wavelengths with a small computational effort with respect to commercial tools. In particular, the gain enhancement of leaky-based structures can pave the way to the reduction of the number of elements of the associated phased arrays. In a leaky-wave configuration each element of the array will radiate with a larger equivalent aperture allowing a larger spacing among elements without affecting the final gain of the whole structure. This aspect is particularly important in the case of phased arrays, where phase shifters and control cells are, typically, the most expensive components of the system. As extensively explained in the manuscript, antennas for user segment might find the highest benefit by using leaky-wave solutions. Besides the gain enhancement, the leaky-wave technology can be effectively exploited to conveniently shape the radiation pattern by properly engineering the design parameters of the antenna. This capability can be used in phased arrays to generate a convenient element pattern to minimize the scan losses and filter the grating lobes appearing in the visible space when dealing with periodicities larger than a wavelength. Therefore, a synthesis procedure for thinned leaky-wave arrays is presented in the manuscript. Also, a novel array configuration, the irregular superstrate array, is presented. The irregular superstrate allows the reduction of the side lobes of the antenna below -20 dB in the considered 2.5 % band, using a uniform excitation. This last configuration clearly shows that the shaping capability of leaky-wave antennas is the most appealing feature to be used in phased array solutions
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A, Rahim Mohamad Kamal. "Wideband active antenna." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404129.
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Adaniya, Hana L. "Wideband active antenna cancellation." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/47896.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (leaf 91).
There exists a simultaneous transmit and receive antenna system where the transmitted signal is creating wideband interference of the receiver. To resolve this interference problem, the isolation between the transmit antenna and the receive antenna must be increased. This thesis analyzes and discusses various strategies for antenna isolation and demonstrates the feasibility of an adaptive filtering approach on active signal cancellation. The final system design demonstrates that, with a broadband interference source in close proximity to a receiver, it is possible to provide 30 dB of isolation by using active cancellation.
by Hana L. Adaniya.
M.Eng.
4
Lin, Yuanzhi. "Active Antenna Oscillator Array." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1231873914.
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Cummings, Nathan Patrick. "Active Antenna Bandwidth Control Using Reconfigurable Antenna Elements." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/29990.
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Reconfigurable antennas represent a recent innovation in antenna
design that changes from classical fixed-form, fixed-function antennas
to modifiable structures that can be adapted to fit the requirements
of a time varying system. Advances in microwave semiconductor
processing technologies have enabled the use of compact, ultra-high
quality RF and microwave switches in novel aspects of antenna design.
This dissertation introduces the concept of reconfigurable antenna
bandwidth control and how advances in switch technology have made
these designs realizable. Specifically, it details the development of
three new antennas capable of reconfigurable bandwidth control. The
newly developed antennas include the reconfigurable ring patch, the
reconfigurable planar inverted-F and the reconfigurable parasitic
folded dipole. The relevant background work to these designs is
described and then design details along with computer simulations and
measured experimental results are given.Ph. D.
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Ventas, Muñoz de Lucas Jesus. "Active- integrated aperture lens antenna." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-303003.
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Luneburg lens antennas are gaining popularity in new communication systems, as increasingly higher frequencies are being used. Broadband fully- metallic implementations of Luneburg lenses, such as Rinehart- Luneburg lenses, constitute simple, cheap and efficient beamformers. However, Luneburg lenses need to have one amplifier per port, which constrains the maximum power that can be transmitted and increases the cost of the system. In this thesis, an investigation to integrate amplifiers within the aperture of Luneburg lenses is conducted. This concept allows for increasing the maximum transmitted power with reduced costs. Special attention has been paid to the design principles. Active integration without altering the Luneburg lens functionality has been a key task in this work. A design in Kaband (2640 GHz) has been also exemplified in order to show the feasibility of the concept. The final design includes transitions to a PCB in the aperture of the Luneburg lens, where amplifiers can be mounted. Good results were obtained in terms of directivity and side- lobe levels, and the antenna achieves a scanning range up to ±64° with reasonable scan losses.Luneburgs linsantenner blir alltmer populära i nya kommunikationssystem eftersom högre frekvenser används. Det finns bredbandiga Luneburg- linser som är helt metallicof, som Rinehart- Luneburg- linsen, vilket gör den till en enkel, billig och effektiv strålformare. Luneburg- linser måste dock ha en förstärkare per port, vilket begränsar den maximala sändningseffekten och ökar kostnaden för systemet. I den här avhandlingen undersöks hur man kan integrera förstärkare, monterade på ett PCB, i Luneburg- linsernas öppning. Detta tillvägagångssätt gör det möjligt att öka den maximala överförda effekten och minska kostnaderna. Särskild uppmärksamhet har ägnats åt konstruktionsprinciperna. Att hitta en geometri som gör det möjligt att integrera förstärkare inuti utan att ändra Luneburg- linsens strålningsegenskaper har varit en viktig uppgift i detta arbete. En specifik konstruktion för Ka- bandet (2640 GHz) har också utvecklats för att visa att konceptet är genomförbart. Den slutliga utformningen omfattar övergångar till ett kretskort i Luneburg- linsens öppning, där förstärkare kan monteras. Resultaten visar på rimliga värden för riktverkan och sidolobnivåer, och antennen har ett avläsningsområde på upp till ±64°.
Las lentes de Luneburg se están haciendo cada vez más populares en los nuevos sistemas de comunicaciones, debido al uso de frecuencias cada vez más altas. Existen implementaciones totalmente metálicas y de banda ancha de las lentes de Luneburg, como las lentes de Rinehart- Luneburg, lo que las convierte en conformadores de haz simples, baratos y eficientes. Sin embargo, las lentes de Luneburg necesitan tener un amplificador en cada uno de sus puertos, lo que limita la máxima potencia que se puede transmitir e incrementa el coste del sistema. En este trabajo de fin de Máster se lleva a cabo una investigación que busca la integración de amplificadores, montados en una PCB, dentro de la apertura de las lentes de Luneburg. Este enfoque permite transmitir potencias mayores y además reduce costes. Se ha puesto especial atención en los principios de diseño. Encontrar una geometría que permite integrar amplificadores dentro sin alterar las características de radiación de la lente de Luneburg ha sido uno de los puntos clave de este trabajo. También se ha desarrollado un diseño específico en banda Ka (2640 GHz) para mostrar la viabilidad de la idea. El diseño final incluye transiciones a un PCB en la apertura de la lente, donde se pueden incluir los amplificadores. Los resultados muestran valores razonables de directividad y lóbulos secundarios, y la antena permite un rango de escaneo de hasta ±64°.
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Lindberg, Peter. "Wideband Active and Passive Antenna Solutions for Handheld Terminals." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7445.
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Qin, Yi. "Broadband high efficiency active integrated antenna." Thesis, Northumbria University, 2007. http://nrl.northumbria.ac.uk/79/.
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Active integrated antenna (MA) is a very popular topic of research during recent decades. This is mostly due to its advantages, such as compact size, multiple functions and low cost, etc. The MA system can be regarded as an active microwave circuit which the output or input port is free space instead of a conventional 50-ohm interface. The major drawbacks of the conventional MA include narrow bandwidth, low efficiency, etc. An experimental investigation on broadband slot-coupled antenna is carried out, which results an impedance bandwidth of 50 % is achieved by both a ring slot- coupled and square ring slot-coupled patch antenna. An improved design technique for broadband class-E power amplifier (PA) design, based on the theoretical analysis done by Mader [2], is introduced to calculate the circuit parameters. The technique is applied to a RF microwave class-E power amplifier design (PA) that results a bandwidth of 12 % power added efficiency (PAE) greater than 60 % is achieved. The aim of this work is to design broadband high efficiency linearly polarized (LP) and circularly polarized (CP) MA and arrays that will be useful for mobile communication system. The MA does not need conventional matching network between the amplifier and the antenna, because the antenna serves as both a harmonics-tuning network and a radiator. A novel high efficiency broadband LP MA is demonstrated using a ring slot-coupled patch antenna with a class-E PA. It exhibits a PAE over 50 % within a 14.6 % bandwidth. For the first time, a high efficiency broadband CP MA is designed using a class-E PA integrated with a broadband CP antenna. The CP AIA achieves a PAE over 50 % within a 14 % bandwidth. The axial ratio of the CP MA is below 3 dB over a 9 % bandwidth. For further improve the performance, a novel L-shaped slot-coupled broadband CP MA is employed in a 2x2 array. The array consists of four sequentially rotated broadband CP antenna elements with an element spacing of half a free space wavelength. The antenna was designed to operate in the 3G band around 2 GHz. A bandwidth of 22.7 % PAE greater than 50 % is achieved together with a peak PAE of 71.35%. A bandwidth of 27 % axial ratio below 3 dB is resulted.
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Drew, Stephen Arthur. "Active microstrip antenna modelling and characterisation." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.482798.
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Ismail, Widad. "Active integrated antenna (AIA) with image rejection." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412555.
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Humphrey, Denver Edward Johnston. "Coupled active antenna oscillator analysis and characterisation." Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337012.
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Sancheti, Sandeep. "Active microstrip antenna self-detecting oscillator characterisation." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295427.
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Zhao, Jun. "Development of Integrated "Chip-Scale" Active Antennas for Wireless Applications." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34695.
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With the rapid expansion of wireless communication services, ultra-miniature, low
cost RF microsystems operating at higher carrier frequencies (e.g. 5-6 GHz) are in
demand for various applications. Such applications include networked wireless sensor
nodes and wireless local area data networks (WLANs). Integrated microstrip antennas
coupled directly to the RF electronics, offer potential advantages of low cost,
reduced parasitics, simplified assembly and design flexibility compared to systems
based on discrete antennas. However, the size of such antennas is governed by physical
laws, and cannot be arbitrarily reduced. The critical patch antenna dimension
at resonance needs to be ~λg/2 (where λg is the guided wavelength given by λg
=λ/sqrt(er) . Several methods are available to reduce the physical size of the antenna
to enable on-chip integration. A high dielectric constant substrate reduces the guided
wavelength. Grounding one edge of the microstrip patch enables the resonant antenna
length to be further reduced to ~λg/4. However, these techniques result in degraded
antenna efficiency and bandwidth. Nonetheless, such antennas still have potential for
use in low power/short range applications.
In this work, "electrically small" (small with respect to λo) square-shaped microstrip
patch antennas, grounded on one edge by shorting posts, have been investigated. The
antenna input impedance depends on the feed position; by adjusting the feed point,
the antenna can be tuned to match a 50 â ¦ or other system impedance. The antennas
were designed on a GaAs substrate, with a high dielectric constant of 12.9. The size of the patch antenna is further reduced by utilizing shorted through substrate vias
along one edge. The size of the antenna is about 4.2mm à 4.2mm, which is ~1/13 of
λo at ~5.6GHz. The antennas are practical for integration on chip. Due to the size
reduction, the simulated peak gain of the antenna is only â 10.2 dB ( ~3.2% radiation
efficiency). However, this may be acceptable for short-range wireless communications
and distributed sensor network applications.
Based on the above approach, integrated GaAs "chip-scale" antennas with matching power amplifiers have been designed and fabricated. Class A tuned MESFET
power amplifiers (PAs) were designed with outputs directly matched to the antenna
feed point. The antenna is fabricated on the backside of the chip through backside
patterning; the PA feeds the antenna through a backside via. The structure is then
mounted such that the antenna faces up, and is compatible with flip-chip technology.
The measurement of a 50 â ¦ passive (no PA) antenna indicates a gain of -12.7dB on
boresight at 5.64 GHz, consistent with the antenna size reduction. The measurement
of one active antenna (50 â ¦ system) shows a gain of -4.3dB on boresight at 5.80
GHz. The other version of active antenna (22.5 â ¦system) shows a gain of -2.9 dBi
on boresight at 5.725 GHz. The active circuitry (PA) contributes an average of ~9
dB gain in the active antenna, reasonable close to the designed PA gain of 12.7dB.
The feasibility of direct integration of a PA with an on-chip antenna in a commercial
GaAs process at RF frequencies was successfully demonstrated.Master of Science
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Khoshniat, Ali. "A Linearly and Circularly Polarized Active Integrated Antenna." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/881.
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This thesis work presents a new harmonic suppression technique for microstrip patch antennas. Harmonic suppression in active integrated antennas is known as an effective method to improve the efficiency of amplifiers in transmitter side. In the proposed design, the antenna works as the radiating element and, at the same time, as the tuning load for the amplifier circuit that is directly matched to the antenna. The proposed active antenna architecture is easy to fabricate and is symmetric, so it can be conveniently mass-produced and designed to have circular polarization, which is preferred in many applications such as satellite communications.
The antenna simulations were performed using Ansoft High Frequency System Simulator (HFSS) and all amplifier design steps were simulated by Advanced Design System (ADS). The final prototypes of the linearly polarized active integrated antenna and the circularly polarized active integrated antenna were fabricated using a circuit board milling machine. The antenna radiation pattern was measured inside Utah State University's anechoic chamber and the results were satisfactory. Power measurements for the amplifiers' performance were carried out inside the chamber and calculated by using the Friis transmission equation. It is seen that a significant improvement in the efficiency is achieved compared to the reference antenna without harmonic suppression.
Based on the success in the single element active antenna design, the thesis also presents a feasibility of applying the active integrated antenna in array configuration, in particular, in scanning array design to yield a low-profile, low-cost alternative to the parabolic antenna transmitter of satellite communication systems.
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Tunio, Irfan Ali. "Study of impedance matching in antenna arrays." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT4055.
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La désadaptation d'impédance dans les réseaux d'antennes est un problème important, en particulier lorsqu'un grand nombre d'éléments rayonnants sont placés côte à côte. Cette désadaptation est généralement due au couplage mutuel entre les éléments d'antenne. Le phénomène de couplage mutuel peut cependant provenir des ondes de surface, du rayonnement de champ proche ou du rayonnement de champ lointain. Le phénomène de désadaptation se révèle néanmoins important lorsque l'ensemble du réseau est réglé pour rayonner même temps même si le couplage est faible. Dans cette thèse, nous concentrons nos travaux sur l'effet du rayonnement total en champ lointain. En mettant les antennes en réseau, l'impédance d'entrée de chaque élément du réseau d'antennes change par rapport à celle de l'élément unique lorsqu’il n’est pas en réseau. En d'autres termes, la valeur de l'impédance d'entrée des éléments rayonnants individuels change en fonction du nombre d’éléments et de la position de l'antenne. Ce travail propose en outre un aspect important de l'évaluation des paramètres S actifs dans les réseaux d'antennes. Il a été montré que les paramètres S actifs obtenus en utilisant la matrice de distribution passive ne correspondent pas aux valeurs réelles obtenues lors d'une excitation simultanée de tous les éléments. Enfin, cette étude a fait un pas de plus vers deux nouvelles méthodes de découplage afin de valider la théorie du rayonnement total et l'évaluation des paramètres S actifs. Les résultats théoriques sont complétés par des simulations 3D et des mesuresImpedance mismatching in antenna arrays is an important issue especially when a huge number of antenna elements are placed side by side. This mismatch is generally blamed to exist because of mutual coupling between antenna elements. The phenomenon of mutual coupling, however, may result due to surface waves, near field radiation or far field radiation. The phenomenon of mismatch, nevertheless, reveals itself strongly when the whole array is set to radiate even in presence of less significant coupling. In this thesis, we focus our work to the effect of total radiation due to far field radiation only. It says that by arraying the antennas the input impedance of each element of the antenna array changes as compared to that of the single element which is not arrayed. In other words, the value of the input impedance of individual antenna elements changes versus antenna number and position. This work further proposes an important aspect of the evaluation of active S-parameters in antenna arrays. It has been shown that the active S-parameters obtained by using the passive scattering matrix do not correspond to the actual values obtained during a simultaneous excitation of all the elements. Finally, this study has taken a step further towards two novel decoupling methods in order to validate the theory of total radiation and evaluation of active S-parameters. Theoretical results are complemented with 3D simulations and measurements
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Ali, N. T., Abubakar S. Hussaini, Raed A. Abd-Alhameed, Mark B. Child, Jonathan Rodriguez, Neil J. McEwan, and E. A. El-Khazmi. "Explanation of DC/RF Loci for Active Patch Antennas." Springer for the ICST, 2010. http://hdl.handle.net/10454/4483.
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YesA characteristic loop locus of dc power versus RF output power was observed as the frequency was varied around the optimum point of an operational active antenna. A new technique was introduced into the simulation, plotting the dependence of parameters such as supply current, efficiency or output power on internal impedance as seen by the naked transistor. It is now clear that the loop was formed as a consequence of the interaction of the transistor packaging elements with the patch impedances.
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Douvalis, Vassileios. "Monolithic millimetre-submillimetre wave active conical horn antenna arrays." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414468.
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Van, Wyk M. D. "An active receiving antenna for borehole pulsed radar applications." Thesis, Stellenbosch : University of Stellenbosch, 2002. http://hdl.handle.net/10019.1/2521.
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Thesis (MEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2002.An efficient radiating strucllire was needed for borehole pulsed radar applications in the 10-100 MHz frequency band. Both resistively loaded and insulated wire antennas were investigated and an active antenna is proposed as a fmal solution. The study proceeded from the characterization of the origin of radiation on a conductive dipole wire antenna when excited with a transient. Different radiation mechanisms were identified when the antenna was excited with a current or voltage source. The wire antenna in insulated surroundings was modelled using transmission line theory to simulate the antenna in the borehole environment. The transmission line model proved to be useful for investigating conducting and resistively loaded antennas for the dimensions associated with borehole surveys. From the modelling results, it became apparent that the asymmetric resistively loaded antenna might provide the best practical solution. This antenna displays reasonably stable input impedance and low far-field variations for different theta angles across the desired frequency band. Different percentage Wu-King resistive profiles were studied to show that a 50% reduction in the normal Wu-King resistor values will add only a little ringing but have better amplitude response than the 100% Wu-King loading. The asymmetric resistively loaded antenna has better sensitivity to receiving transients when combined with a high impedance source load than when symmetrically loading the antenna. An active antenna incorporating the asymmetric resistively loaded antenna and a low noise current feedback front end amplifier was built and measured in an air environment. The results show that the active antenna has a flat transfer function and reacts as a wide band electric field probe with better resolution than in the conventional 50 Q loaded case
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Jacmenovic, Dennis, and dennis_jacman@yahoo com au. "Optimisation of Active Microstrip Patch Antennas." RMIT University. Electrical and Computer Engineering, 2004. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20060307.144507.
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This thesis presents a study of impedance optimisation of active microstrip patch antennas to multiple frequency points. A single layered aperture coupled microstrip patch antenna has been optimised to match the source reflection coefficient of a transistor in designing an active antenna. The active aperture coupled microstrip patch antenna was optimised to satisfy Global Positioning System (GPS) frequency specifications. A rudimentary aperture coupled microstrip patch antenna consists of a rectangular antenna element etched on the top surface of two dielectric substrates. The substrates are separated by a ground plane and a microstrip feed is etched on the bottom surface. A rectangular aperture in the ground plane provides coupling between the feed and the antenna element. This type of antenna, which conveniently isolates any circuit at the feed from the antenna element, is suitable for integrated circuit design and is simple to fabricate. An active antenna design directly couples an antenna to an active device, therefore saving real estate and power. This thesis focuses on designing an aperture coupled patch antenna directly coupled to a low noise amplifier as part of the front end of a GPS receiver. In this work an in-house software package, dubbed ACP by its creator Dr Rod Waterhouse, for calculating aperture coupled microstrip patch antenna performance parameters was linked to HP-EEsof, a microwave computer aided design and simulation package by Hewlett-Packard. An ANSI C module in HP-EEsof was written to bind the two packages. This process affords the client the benefit of powerful analysis tools offered in HP-EEsof and the fast analysis of ACP for seamless system design. Moreover, the optimisation algorithms in HP-EEsof were employed to investigate which algorithms are best suited for optimising patch antennas. The active antenna design presented in this study evades an input matching network, which is accomplished by designing the antenna to represent the desired source termination of a transistor. It has been demonstrated that a dual-band microstrip patch antenna can be successfully designed to match the source reflection coefficient, avoiding the need to insert a matching network. Maximum power transfer in electrical circuits is accomplished by matching the impedance between entities, which is generally acheived with the use of a matching network. Passive matching networks employed in amplifier design generally consist of discrete components up to the low GHz frequency range or distributed elements at greater frequencies. The source termination for a low noise amplifier will greatly influence its noise, gain and linearity which is controlled by designing a suitable input matching network. Ten diverse search methods offered in HP-EEsof were used to optimise an active aperture coupled microstrip patch antenna. This study has shown that the algorithms based on the randomised search techniques and the Genetic algorithm provide the most robust performance. The optimisation results were used to design an active dual-band antenna.
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Caldwell, Dwight D. (Dwight Douglas). "Design and analysis of the ICRF antenna with active cooling." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/42516.
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Bertulli, Scott. "MATLAB-Based Dipole Array Simulator Tool For MIT Haystack Observatory." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050505-104840/.
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Zhou, Dawei. "Development of active integrated antennas and optimization for harmonic suppression antennas : simulation and measurement of active antennas for amplifiers and oscillators and numerical solution on design and optimization of active patch antennas for harmonic suppression with adaptive meshing using genetic algorithms." Thesis, University of Bradford, 2007. http://hdl.handle.net/10454/4763.
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The objectives of this research work are to investigate, design and implement active integrated antennas comprising active devices connected directly to the patch radiators, for various applications in high efficiency RF front-ends, integrated oscillator antennas, design and optimization of harmonic suppression antennas using a genetic algorithm (GA). A computer-aided design approach to obtain a class F operation to optimizing the optimal fundamental load impedance and designing the input matching circuits for an active integrated antenna of the transmitting type is proposed and a case study of a design for 1.6 GHz is used to confirm the design principle. A study of active integrated oscillator antennas with a series feed back using a pseudomorphic high electronmobility transistor (PHEMT) confirms the design procedure in simulation and measurement for the oscillator circuit connected directly to the active antenna. Subsequently, another design of active oscillator antenna using bipolar junction transistor (BJT) improves the phase noise of the oscillation and in addition to achieve amplitude shift keying (ASK) and amplitude modulation (AM) modulation using the proposed design circuit. Moreover, the possibility of using a sensor patch technique to find the power accepted by the antenna at harmonic frequencies is studied. A novel numerical solution, for designing and optimizing active patch antennas for harmonic suppression using GA in collaboration with numerical electromagnetic computation (NEC), is presented. A new FORTRAN program is developed and used for adaptively meshing any planar antenna structure in terms of wire grid surface structures. The program is subsequently implemented in harmonic suppression antenna design and optimization using GA. The simulation and measurement results for several surface structures show a good agreement.
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Kaverine, Evgueni. "Contribution à la conception d'antennes MF, HF et VHF miniatures pour des applications mobiles, terrestres et maritimes." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S152.
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Les objectifs de ce travail concernent l'étude, la conception et la caractérisation d'antennes miniatures actives ou passives, large bande ou bande étroite fonctionnant en bandes MF, HF et VHF. Le manuscrit est divisé en cinq parties : La première partie présente un système de caractérisation d'antennes qui a été développé, validé et utilisé pour tous les aériens conçus. Ce système, basé sur une cellule à plaque parallèles (PPC), permet un large spectre de mesures telles que la mesure du gain, du point de compression, de l'intermodulation et de la sensibilité via une méthode rayonnée, particulièrement intéressante dans le cas des antennes actives intégrées. La deuxième partie concerne les antennes solénoïdales sur ferrite. L'utilisation de simulateurs électromagnétiques 3D a permis d'obtenir des résultats qui sont comparés à la théorie proposée dans la littérature. Les principaux systèmes d'adaptation d'impédance sont également étudiés. La troisième partie met en avant la possibilité de concevoir des antennes à substrat ferromagnétique de géométrie non conventionnelle en utilisant des matériaux composites. Deux antennes miniatures fabriquées et fonctionnant en bande VHF permettent d'illustrer ce point. Dans la quatrième partie, nous présentons un concept d'antennes à substrat ferromagnétique partiellement saturé. L'utilisation d'une source de champ magnétique statique associée à un matériau initialement dispersif permet de constater un certain nombre de phénomènes intéressants, tels que l'amélioration de l'efficacité tout en préservant l'adaptation de l'antenne ou bien la création de directivité sur des antennes électriquement très compactes. La dernière partie présente la valorisation du travail à travers un projet de télécommunication hertzienne longue portée s'inscrivant dans le cadre de la navigation maritimeThe objectives of this work concern the study, the design and the measurement of miniaturized passive and active, broadband and narrowband antennas for MF, HF and VHF frequency bands. The thesis is divided into five parts : The first part deals with a measurement system, which has been developed, validated and used for all conceived aerials. The system is based on a parallel plate cell (PPC) and allows an evaluation of the gain, the compression point, the interception point and the sensitivity using a radiative method particularly useful in the case of active integrated antennas. The second part concerns solenoidal ferrite antennas. The results obtained from electromagnetic 3D simulators were compared to the state of the art theory. Main matching technics have also been studied. The third part put the light on the possibility of development of arbitrary shaped antennas on a ferromagnetic substrate using a composite material. Two antennas developed for the VHF band, confirm this point. In the fourth part, we present a concept of antennas on a partially saturated ferromagnetic substrate. A static magnetic field associated with an initially lossy material brings up some interesting phenomena such as an increased efficiency without a degradation of the impedance matching or the directivity with very small antennas. The last part presents an application of the work across a project dedicated to long distance telecommunications in marine navigation
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Sittakul, Vitawat. "Study of photonic active integrated antenna based systems for radio-over-fibre applications." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504230.
Full textAbstract:
The thesis introduces the concept of the Photonic Active Integrated Antenna (PhAIA) where optical devices are integrated with planar antennas to produce very compact, low cost modules. PhAIAs are applied to the Radio-over-Fibre application area which is a promising approach to improve the coverage of Wireless Local Area Networks (WLANs). Results show that our systems can operate within a room scale without the use of amplification and at much larger wireless ranges with the use of integrated amplifiers chips. Initially, laboratory based setups are developed which prove the system concept and this is followed by the development of fully portable systems which have under gone field trials using live WiFi access points. Initially unamplified systems are developed to understand the fundamental properties of the radio-over-fibre system and impedance matching of the optical devices directly to the antennas has been implemented- To further improve the impedance matching, lossless matching circuits are implemented, in particular for the photodiode which has a large capacitive part to its input impedance. Following this, a fully modular system was developed using packaged lasers and photodiodes which resulted a fully portable. rugged system suitable for a number of commercial applications. Finally the concept of Power-over-Fibre, where by electrical energy is transferred to a remote location via an optical fibre, is used to power the remote PhAIA module. In this case simultaneous transmission of WLAN data and energy was used for the first time.
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Petersson, Björn. "Modeling of a Retrodirective Channel With Active Antenna Arrays for Cross-Eye Jamming." Licentiate thesis, KTH, Elektroteknisk teori och konstruktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217232.
Full textAbstract:
Cross-Eye (CE) jamming is a technique aimed at inducing false target angles in radar measurements. The potential to deceive monopulse radar, a radar type commonly used due to its angular accuracy and resilience against jamming, has captured the interest of Electronic Warfare (EW) system manufacturers. CE jamming may increase the capability of self-defense against radar guided missiles. In this thesis, a CE jammer, based on the retrodirective channel design, for use in an EW systems is modeled and analyzed. The focus of the analysis is on the non-reciprocal Active Electronically Scanned Arrays (AESA). An electrical model of the jammer system and the AESA, including variations in the electrical properties, together with three different system correction methods are used. A simulation procedure, using single frequency (CW) signals, is defined and used for estimating total level of reciprocity, which is a primary contributor to jammer performance. Reciprocity error sensitivity for variations in model parameters is simulated to indicate which AESA aspects are essential for performance. Further, the influence of characterization and calibration noise is investigated. The usability of the model is demonstrated in different types of simulations, which highlights the differences between the system correction methods. Simulations show that a relatively high level of reciprocity can be achieved when using system correction, if measurement noise and model limitations are disregarded. The expected degradation in reciprocity from differences in electrical properties between the reception and transmission branch of the AESA has been confirmed. The effect of characterization and calibration noise, for realistic levels of noise, seems to be a dominating factor in the total reciprocity error. A significant increase in reciprocity error can likely be expected when non-CW signals are used and when realistic levels of noise and non-linear effects are added.Cross-eye (CE) är en störprincip som har potential att inducera vinkelmätfel i radar. Dess möjlighet att störa monopulsradar, en vanligt förekommande typ av radar som är motståndskraftig mot många störformer, har skapat ett intresse för metoden hos tillverkare av system för elektronisk krigföring (EW-system). Användning av CE störning i ett EW-system skulle kunna öka möjligheten till självskydd vid attack från en monopulsradarstyrd robot. Avhandlingen analyserar en modell av en retrodirektiv CE störare som är avsedd för integration i ett multifunktionellt EW-system. Fokus i analysen är på de aktiva gruppantennerna (AESA) som används i systemet. En elektrisk modell av systemet används, vilken inkluderar variationer i parametrar hos AESA samt tre olika systemkorrektionsmetoder. En simuleringsprocedur som ger möjlighet att uppskatta reciprocitetsfel och känslighet för parametervariationer i AESA är definierad. Vidare undersöks inverkan av karaktäriserings och kalibreringsbrus. Modellens användningsområden visas i olika typer av prestandasimulering där effekter av de olika systemkorrektionsmetoderna tydliggörs. Simuleringsresultat för enkelfrekvens (CW) signaler visar en relativt hög nivå av reciprocitet om brus och olinjäriteter ignoreras. Det förväntade resultatet, att elektriska skillnader mellan mottagar- och sändargrenarna orsakar en försämring i reciprocitet, bekräftas. Inverkan av karaktäriserings och kalibreringsbrus verkar vara en dominerande faktor i det totala reciprocitetsfelet då rimliga brusnivåer används. En signifikant höjning av reciprocitetsfelet kan sannolikt förväntas då signaler med en viss bandbredd används och då rimliga nivåer av brus samt olinjäriteter inkluderas.
QC 20171102
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Gholami, Mehrdad. "A C-Band Compact High Power Active Integrated Phased Array Transmitter Module Using GaN Technology." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36045.
Full textAbstract:
In this research, an innovative phased array antenna module is proposed to implement a high-power, high-efficient and compact C-band radio transmitter. The module configuration, which can be integrated into front-end circuits, was designed as planar layers stacked up together to form a metallic cube. The layers were fabricated by using a Computer Numerical Control (CNC) milling machine and screwed together. The antenna parts and the amplifier units were designed at two opposite sides of the cube to spread the dissipated heat produced by the amplifiers and act as a heat sink. Merging the antenna parts with the amplifier circuits offers additional advantages such as decreasing the total power loss, mass, and volume of the transmitter modules by removing the extra power divider and combiner networks and connectors between them as well as reducing the total signal path.
To achieve both a maximum possible radiation efficiency and high directivity, the aperture waveguide antenna was selected as the array element. Four antenna elements have been located in a cavity to be excited equally and the cavity is excited through a slot on its underside so a compact subarray is formed. Antenna measurements demonstrated a 15.5 dBi gain and 20 dB return loss at 10 % fractional bandwidth centered around 5.8 GHz and with more than 98% radiation efficiency. The total dimensions of the subarray are approximately 8*12*4 cm3.
The outcoming signal from the amplifiers is transferred into the slot exciting the subarray through a microstrip-to-waveguide transition (MWT). A novel and robust MWT structure was designed for the presented application. The MWT was also integrated with a microstrip coupler to monitor the power from the amplifier output. The measured insertion loss of the MWT along with the microstrip coupler was less than 0.25 dB along with more than 20 dB return loss within the same bandwidth of the subarray. The microstrip coupler shows 38 dB of coupling and more than 48 dB of isolation with negligible effects on the amplifier output signal and the insertion/return loss of the MWT.
The amplifier subcomponents consist of power combiners/dividers (PCDs), high power amplifiers (HPAs) and bias circuitry. A Monolithic Microwave Integrated Circuit (MMIC) three-stage HPA was designed in a commercially available 0.15 um AlGaN/GaN HEMT technology provided by National Research Council Canada (NRC) and occupies an area of 4.7*3.7 mm2. To stabilize the HPA, a novel inductive degeneration technique was successfully used. To the best of the author’s knowledge, this is the first time this technique has been used to stabilize HPAs. Careful considerations on input/output impedances of all HEMTs were taken into account to prevent parametric oscillations. Other instability sources, i.e. odd-mode, even-mode, and low frequency (bias circuit) oscillations were also prevented by designing the required stabilization circuits. The electromagnetic simulation of the HPA shows 35 W (45.5 dBm) of saturated output power, 26 dB large signal gain and 29% power added efficiency within the same operating bandwidth as the subarray. The output distortion is less than 27 dB, indicating that the HPA is highly linear. The PCD was designed by utilizing a novel, enhanced configuration of a Gysel structure implemented on Rogers RT-Duroid5880. The insertion loss of the Gysel is less than 0.2 dB while return loss and isolation are greater than 20 dB over the entire bandwidth. The same subarray area (8*12 cm2) has been used for the amplifier circuits and up to eight HPAs can be included in each module. All the above parts of the transmitter module were fabricated and measured, except the MMIC-HPA.
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Raei, Mohammed. "The Shape Synthesis of Antenna Decoupling Surfaces." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42252.
Full textAbstract:
Although multi-element antenna (MEA) systems are already used in some modern wireless communication systems, the issue of mutual coupling between elements remains a challenge during MEA system design. Indeed, communications engineers continue to bemoan the fact that that the antenna elements are often still designed with such coupling as an afterthought. Thus, some authors have used the decoupling surface (DS) idea, whereby a separate DS is added to the MEA systems to reduce the above coupling. Whereas a DS may indeed lower the coupling levels between the elements of a given MEA system, it usually changes the other performance parameters as well, and in an undesirable way. Thus, this design route is a complicated one that is not easily affected. In this thesis we propose, for the first time, a new design process for MEA systems based on shape synthesis. The MEA system performance indicators are combined into an objective that sets the goal of the shape synthesis procedure. The application of the proposed design process is illustrated for three different geometrical arrangements of patch antennas and decoupling surfaces. This confirms the efficacy of the new design method.
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Wu, Xunxun. "Design of Passive UHF RFID Tag Antennas and Industry Application." Thesis, Högskolan i Gävle, Institutionen för teknik och byggd miljö, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-8052.
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Nowadays, there is a growing demand for reliable assets security and management in various industries. The company SolarWave is eager to implement a comprehensive security system to produce active protection for their expensive product: solar panels. This security system is not only including assets tracking, monitoring but also combined with a control system, which is used to binary control a switch of solar panel to be on in presence of the correct ID and off in absence of the correct ID. One of the technologies that made this concept viable is known as Radio Frequency Identification (RFID). The thesis project is a sub-project in the development project whose content is mentioned as above. It contains two main parts. One is the system solution for the company. The other is RFID tag design which is in parallel with the company solution in order to reach a scientific level of a master thesis. In this thesis, I systematically analyze the operating mechanism and characteristics of RFID, and propose both active and passive RFID solutions for the company. And I also suggest an alternative radio technology ZigBee which can be used instead or as a complement to RFID. Meanwhile, I propose two designs of RFID tag according to the specification of the solar panel. One is modified meandering antenna. This kind of antenna is very effective and popular in RFID tag design in order to minimize the size of antenna. The other is inductively coupled loop antenna. It is a very useful method for conjugate matching in RFID tag antenna. The required input resistance and reactance can be achieved separately by choosing appropriate geometry parameters. It makes the antenna easier to match to the tag chips. Both the RFID antenna designs are simulated on Ansoft HFSS 12.
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Liu, Chuan-Chang. "Design, Analysis and Implementation of Fully-Integrated Millimeter-Wave Coupled-Oscillator Antenna Array." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452240824.
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Huang, Caijin. "Optical nano-antennas : passive properties and active control." Thesis, Dijon, 2010. http://www.theses.fr/2010DIJOS011/document.
Full textAbstract:
Les nano-antennes optiques sont de nouveaux éléments, généralement métalliques, permettant d’améliorer les interactions électromagnétiques entre le rayonnement lumineux et un objet sub-longueur d’onde. Ces dispositifs innovants, fonctionnant dans une gamme de longueur d’onde correspondant au spectre visible et proche infrarouge, répondent à certaines contraintes inhérentes à l’optique lorsque les échelles d’interactions relèvent du nanomètre. En particulier, les propriétés des antennes optiques métalliques sont régies par l’apparition de résonances plasmons qui permettent, d’une part de confiner le champ électromagnétique dans des volumes très inférieurs aux limites imposées par la diffraction, et d’autre part d’exalter fortement les processus optiques à faibles sections efficaces. L’objectif de cette thèse est de comprendre par l’expérience quels sont les paramètres clés qui caractérisent une nano-antenne optique afin d’en contrôler son fonctionnement. Ces paramètres ont été accessibles expérimentalement grâce au développement d’une microscopie adaptée basée sur une illumination diascopique à faible ouverture numérique avec soit une détection coronographique confocale ou conoscopique. Cet appareillage nous a permis de mesurer la capacité d’une antenne optique unique à diffuser un rayonnement lumineux. Les études ont débutées avec des systèmes modèles simples (nanoparticules) pour évoluer vers des antennes couplées (dimères). Par analogie avec le domaine radiofréquences, les paramètres importants d’une antenne optique que sont la plage fréquentielle, le désaccord, le gain et le diagramme de rayonnement ont été définis et mesurés. L’influence des caractéristiques morphologiques de l’antenne sur ces paramètres a complété l’étude. Toujours par comparaison avec les antennes radiofréquences, nous avons introduit le concept de tuner optique. Le principe est de modifier la réponse optique de la charge de l’antenne, c’est-à-dire le milieu dans lequel elle émet son rayonnement. Dans ce but, nous avons utilisé un milieu anisotrope composé des molécules de cristal liquide dont l’orientation de l’ellipsoïde des indices peut être commandée par un champ électrostatique. Le fonctionnement du tuner, c’est-à-dire l’accord de l’antenne à une fréquence de travail, a été démontré pour des antennes optiques coupléesOptical nanoantennas are a new class of optical devices, generally constituted of metal nanoparticles, used for enhancing the interaction between an electromagnetic wave and a nano-scale object. These components are operating in the visible to near infra-red part of the spectrum and are offering solutions for the inherent limitations of optics at the nanometer scale. In particular, the properties of optical antennas are governed by the surface plasmon resonances of the underlying structure. These resonances are associated with a large field confinement, beyond the diffraction limit, and an enhancement of the local electromagnetic response that is used to amplify weak optical processes. The objective of this doctoral thesis is to understand by an experimental approach what are the key parameters characterizing an optical antenna with the aim to control its operation. Through the development of an original microscopy based on a low numerical aperture diascopic illumination and a subsequent spatial filtering, the scattering characteristics of a single optical nano-antenna were successfully measured. Our approach was first tested with simple model antennas (nanoparticles) before investigating multi-element coupled antennas (dimers). In analogy to radiofrequency theory, we have defined and measured important antenna characteristics: operating frequency, detuning factor, gain and emission diagram. We have studied the influence of the morphology of the antenna on these characteristics. Continuing the comparison with microwave antennas, we have introduced the concept of an optical tuner. The operating principle is to modify the medium in which the antenna is emitting its radiation i.e. the load of the device. To this aim, we have employed anisotropic liquid crystal molecules. With this load medium, the orientation of the anisotropy can be controlled by a static electric field. The operation of the optical tuner, i.e. tuning of the antenna to a broadcasting frequency, is demonstrated for electromagnetically coupled antennas
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Ben, abdallah Essia. "Conception conjointe d’antenne active pour futurs modules de transmissions RF miniatures et faible pertes." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT104/document.
Full textAbstract:
L’évolution des différentes générations de systèmes de télécommunications cellulaires a entraîné une complexité du frontal des terminaux mobiles caractérisés notamment par la multiplication des chaînes RF qui le constituent. Chaque chaîne est dédiée à un standard, ce qui n’est pas optimale ni du point de vue du coût, ni de l’encombrement. Afin d’optimiser les performances et la consommation du transmetteur radiofréquence, l’approche retenue dans cette thèse consiste à concevoir de façon globale différents blocs afin de partager les contraintes. Dans cette thèse, l’approche globale de la co-conception est organisée en deux sous études. Celles-ci sont destinées à terme à être intégrées dans un même frontal RF entièrement configurable.La première étude aborde la problématique de la conception conjointe entre une antenne et un amplificateur de puissance (PA) qui sont traditionnellement conçus séparément. Nous avons tout d’abord déterminé les spécifications de l’antenne permettant de maximiser le transfert d’énergie entre ces deux blocs. Ensuite, nous avons conçu l’antenne en partageant les contraintes d’impédance à la fois dans la bande utile et aux harmoniques entre cette dernière et le PA afin de relâcher les spécifications sur le réseau d’adaptation d’impédance. Cette approche permet de maintenir la linéarité du PA à des niveaux de puissances supérieures par rapport au cas où l’antenne est adaptée sur 50 Ω.La seconde étude s’intéresse à la conception conjointe d’antennes et de composants agiles. Nous avons réparti l’effort de miniaturisation et les pertes ohmiques associées entre la structure d’antenne et le composant agile (capacité commutable numériquement). Les développements présentés se sont appuyés sur des simulations électromagnétiques, des modélisations, des caractérisations système (linéarité et temps de commutation) et des mesures en rayonnement (efficacité) de prototypes d’antennes miniatures dans les bandes basses 4G. Nos études ont abouti à la conception d’une antenne fente reconfigurable fonctionnant sur la bande instantanée maximale autorisée par la 4G. Pour une intégration sur smartphone, l’élément rayonnant n’occupe que 18 x 3 mm2 de surface soit λ_0/30×λ_0/180 à 560 MHz. La fréquence de résonance de l’antenne varie entre 560 MHz et 1.03 GHz et l’efficacité totale varie entre 50% et 4%. Un banc de mesure de la linéarité a été implémenté afin d’évaluer la linéarité des antennes agiles. La spécification de linéarité exigée par le standard est maintenu jusqu’à une puissance de 22 dBmThe recent development of cellular communication standards has led to an increasing RF front-end complexity due to the ever increasing number of RF needed paths. Each RF path is dedicated to a frequency bands group which might not be optimal for cost and occupied space area. Consequently, in order to optimize the RF performances and energy consumption, the approach used in this thesis is to share the constraints between the PA and the antenna of the front-end: this is called co-design. In this thesis, the considered co-design approach is twofold and in near future both results should be simultaneously considered and integrated into one fully reconfigurable RF front-end design.The first study addresses the co-design of an antenna and its associated power amplifier (PA), which are traditionally designed separately. We first determine the antenna impedance specifications to maximize the tradeoff between the energy transfer and PA linearity. Then, we propose to remove the impedance matching network between antenna and PA, while demonstrating that a low impedance antenna can maintain the RF performances. Contrarily to the classical approach where the antenna is matched to 50 Ω, the proposed co-design shows the possibility to keep the linearity of the PA even for high power levels (> 20 dBm).The second study focuses on the co-design of an antenna and tunable components. We are sharing the miniaturization effort and the resistive losses between the antenna structure and the tunable capacitor (DTC). The achieved developments are based on electromagnetic simulations, modeling, system characterization (linearity and switching time) and radiation measurements (efficiency) of miniature reconfigurable antenna prototypes in the 4G low bands. The considered studies have led to the design of a frequency reconfigurable antenna addressing the maximum instantaneous available bandwidth authorized by 4G. The radiator occupies only 18 x 3 mm2 (λ0/30 x λ0/180 at 560 MHz), and thus it is extremely suitable for a possible integration onto smartphones. The antenna resonance frequency is tuned between 560 MHz and 1030 MHz and the total efficiency varies between 50% and 4%. For the first time, the impact of SOI DTC implemented on the antenna radiating structure on linearity is measured with a dedicated test bench. The linearity specified by 4G is maintained up to 22 dBm of transmitted power
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Liu, Lei. "Investigation of aperture coupled microstrip antenna to obtain a high efficient active integrated antenna by using Class F and Inverse Class F power amplifiers." Thesis, Northumbria University, 2013. http://nrl.northumbria.ac.uk/21425/.
Full textAbstract:
In wireless communications and radar systems, there are requirements for high efficiency, small size, low cost, and wide bandwidth of transmitter front –end usage for commercial and also military applications. Active integrated antenna (AIA) could satisfy almost all the requirements. The overall objective of the proposed research is to model, optimise, and design a compact and high efficient AIA using an aperture coupled microstrip antenna (ACMA) by integrating with a power amplifier (PA). Research on ACMA has been focused on the transmissions line (TL) model (TLM) and full wave electromagnetic (EM) model analysis. The full wave investigation is rigorous and elegant but because the dimension of the physical model and the value of the circuit elements are interdependent, the design of the antenna is still difficult. TLM analysis has lower accuracy but easier to analysis and optimise than full wave EM model analysis. To increase the accuracy, the challenge is the coupling ratios between feed/slot, and slot/patch where no unique solution at the moment exists. In this thesis, a novel and simplified method has been produced to investigate these ratios using Scattering (S) parameters. A dual frequency ACMA has been designed to verify these results. Research on the class F and inverse class F PAs is carried out by a novel and simplified load/pull method. A new design method of harmonic load matching network has been presented using lump elements and TLs. Both linear and nonlinear modelling has been investigated. High power added efficiency (PAE) and high gain which are up to 60% and 12dB have been obtained. Finally AIAs have been produced based on previous investigation on class F, inverse class F PAs and a broadband circular polarized ACMA design with 350 MHz bandwidth and 8.5 dB gain at 2 GHz.
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Caba, Wilson Ariel. "Application of antenna synthesis and digital signal processing techniques for active millimeter-wave imaging systems." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4532.
Full textAbstract:
Millimeter-wave imaging has gathered attention in recent years for its ability to penetrate clothing, thin layers of soils, and certain construction materials. However, image quality remains a challenge that needs to be addressed. One way of improving image quality is by increasing the dimensions of the collecting aperture. A sparse array can be used to synthesize a larger aperture with a limited set of relatively small detectors. In this research we design, build, and test a test-bed having an active source at 94 GHz and an array of coherent detectors, mounted on arms that extend radially on a rotary table. Using this test bed a circular area with a maximum diameter of 900 mm can be scanned. The signal is down-converted using heterodyne receivers with digital in-phase and quadrature detection. Signal correlation is performed using the digitized data, which is stored for post-processing, electronic focusing, and image reconstruction. Near-field imaging using interferometric reconstructions is achieved using electronic focusing. Imaging tests show the ability of the system to generate imagery of concealed and unconcealed objects at distances between 400 and 700 mm. A study of the effects of redundant and non-redundant configurations on image quality for 4 common detector configurations is presented. In this document we show that an active sparse-aperture imaging system using digital correlators is a viable way to generate millimeter-wave images.ID: 029050356; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references (p. 125-129).
Ph.D.
Doctorate
Optics and Photonics
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Wang, Chien-Jen, and 王健仁. "Nonel Active Leaky-Wave Antenna and Commercial Chip Antenna." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/37998832448944644458.
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博士國立交通大學
電信工程系
88
This thesis consists of two parts: The development of active frequency-scanning leaky-wave antennas (LWA) and compact microstrip chip antennas. In the first part of the dissertation, three types of the microstrip active frequency-scanning leaky-mode antennas that employ the first higher order mode (the space wave) of odd symmetry in their leaky wave region are presented. In order to excite the first higher order mode, the antennas are fed asymmetrically. These antennas includes the topologies of leaky-wave antenna (LWA) arrays, a two-terminal feeding LWA and a single feeding LWA integrated with a self-oscillating doubler. The antenna arrays are integrated one, two and four microstrip leaky-wave antenna elements with a single varactor-tuned HEMT VCO as an active source. Using the symmetric configuration of this leaky-wave antenna array not only can effective reduce the reflected wave coming from the open end of a finite-length LWA, but it also can increase the power gain. A two-terminal feeding LWA is integrated with a varactor-tuned HEMT VCO. This design creates a dual-beam radiation pattern and has the advantages of the double scanning covered region and the suppression of the reflected wave. A new method which can enhance the scanning angle and elevate the operating frequency for the active LWA is proposed. We demonstrate an asymmetrically feeding LWA integrated with a self-oscillating doubler on a RT/Duriod substrate. The self-oscillating doubler generates the signal source at the second-harmonic frequency. The operating frequency 2FX (the second harmonic frequency) and the double frequency variation 2ΔFX are twice ΔFX at the fundamental band FX . This feature, combined with the advantage of no external injection power, is useful for millimeter-wave applications of the LWA and to obtain a wider scanning angle. In the second part of the dissertation, a new design of miniaturized microstrip helical antennas is proposed for the mobile communication. The antenna-size reduction is achieved by folding the microstrip line around a substrate. We use the RT-Duriod microwave substrate, the dielectric constant = 10.2 and the height H = 25 mil to fabricate a small microstrip monolithic antenna for the PCS and cellular phones. For the other sample, we use the Low Temperature Co-fired Ceramic (LTCC) technology to fabricate a compact dual-band chip antenna. We have carried out experimental studies on these antennas, which have the large bandwidth and the multiple frequency resonant bands. The chip antenna is suitable for the applications of the wireless network communication and the bluetooth system. In order to increase the resonant bandwidth, the antennas support the helical mode and the monopole mode. The radiation pattern in the E plane of the antenna is quasi-omnidirectional and the characteristic is like as the monopole.
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Kishor, Krishna. "An Active Reconfigurable Reflectarray Antenna." Thesis, 2010. http://hdl.handle.net/1807/24591.
Full textAbstract:
This thesis focuses on a type of antenna known as the reflectarray antenna. In particular, it looks at the design of an active reconfigurable reflectarray antenna, which has not received much attention in the reflectarray community. Potential applications include deployment as a high gain, reconfigurable antenna for communication links, and as a spatial power combiner. The reflectarray element is an aperture-coupled patch that accepts a linearly polarized wave, phase shifts and amplifies the guided-waves in the
transmission lines, and then re-radiates an orthogonally polarized wave. Stability analysis of the element, experimental results of the designed phase shifter and simulation and experimental results of the element are presented. Fabrication details of a 48 element reflectarray and challenges faced during experimental characterization of the elements are also discussed. The two dimensional beamforming capability and amplifying nature of the array are successfully demonstrated and veri fied, indicating robustness to phase errors and oscillating elements.
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lee, Chun-Sheng, and 李春生. "Studies of Planar Active Antenna." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/91036356096855393850.
Full textAbstract:
碩士大葉大學
電機工程研究所
90
In this thesis, an amplifier-type active microstrip antenna to be operated in the frequency range of 1.53GHz to 1.62GHz is proposed. This amplifier-type active microstrip antenna consists of an active element and a passive element. The active element is a power amplifier or a low noise amplifier and the passive element is a microstrip antenna. First, we design a low noise amplifier and a 3-dB, 90-degree coupler to construct a semi-balance type amplifier. Next, we design a circularly polarized rectangular microstrip antenna with dual feeds. Finally, we integrate the semi-balance type amplifier with the rectangular microstrip antenna. The fabricated amplifier-type active microstrip antenna exhibits an antenna gain of 10dBi to 14dBi and an axial-ratio lower than 2dB over the frequency range of interest, whose bandwidth is about 90MHz. Such performance is well suited to GPS related application.
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Lin, Yu-Cheng, and 林育正. "Self_Oscillating Active Leaky-Mode Antenna." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/51146018863585784307.
Full textAbstract:
碩士國立交通大學
電信研究所
85
In this thesis, a HEMT-based differential amplifier integrated with a shortmicrostrip line is present for an self-oscillating active leaky-mode antenna.First, a differential feed short leaky-mode antenna with dual-beam radiationpattern is designed. This four-port element ( differential inputs and outputs)can be used in the active antenna as a radiating element. Secondly, weemploy a microstrip leaky-mode antenna and a feedback oscillator to design anoscillator type active antenna. The short microstrip line serves as a feedback network of the oscillator as well as a radiating element. Two highimpedance microstrip lines are used for interconnecting the differentialamplifier and the leaky-mode antenna feedback loop. The self-oscillating active antenna has been developed at 11.8 GHz and 10.74 dBm output power.Finally, we present a nonlinear transmission line (NLTL) used in the circuitas a phase-controlling element to tune the oscillation frequency with tuningbandwidth about 300 MHz.
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Hu, Cheng-Chi, and 胡政吉. "X-band Active Antenna Array." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/10079025376179420618.
Full textAbstract:
碩士國立交通大學
電信工程研究所
84
Solid-state devices can not generate large power at very high frequencies,it is necessary to combine many solid-state devices to obtain high power. In this thesis, the quasi-optical X-band active antenna arrays are designed. The fabrication and measurement are also presented. The project is based on the circuit designed by Prof. Itoh's group. A planar periodic HEMT power-combining array is designed and fabricated in X-band.A microstrip transmission line is periodically connected to HEMT devices driving a linear microstrip antenna array. The power combining is achieved byphasing locking the oscillators. In order for only the desired power-combiningmode to oscillate, appropriate resistors are introduced at the midpoints of thecoupling lines between the active antennas. An experiment for the active antenna arrays has been carried out. The oscillation frequency is measured at about 9.7GHz. An effective radiation power(ERP) of 32mW, 226mW, and 1102mW is obtained for single-unit, two-unit, and four-unit active antenna array.
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Lin, Chi-Huang, and 林佶篁. "Study of Compact Active Antenna." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/w53z3f.
Full textAbstract:
碩士南台科技大學
電子工程系
94
The purpose of this study is focused on the active antenna with miniaturization. In recent years, the technology of MIC&MMIC have been advanced, the products of wireless communication are gradually miniaturize as well. Due to those are requested to be as small as possible in nowadays, the antenna which is conformed this condition will have wide application in the future. Furthermore, the dimension of the antenna is confined by the different requirement of the products whose dimension and operation frequency. Therefore, it is a factor deserved to discuss how to display the highest efficiency at the least dimension of antenna. In this research, we use an active antenna that combines microstrip antenna (MSA) with oscillator on the same substrate. As a result of it is made out of one-piece substrate, which can greatly reduce the loss of transmission line. First, in terms of the need of the operation frequency, we can calculate the dimension of MSA and the specification for the oscillating circuit by circuit theory. Moreover, we use the simulation software (Serenade) to prove its accuracy. The active antenna is constructed by using the process of manufacturing for printed circuit board (PCB). Then , we measured its characteristics at the chamber. In addition, we aimed at the active antenna with miniaturization by transforming the configuration of oscillating circuit to reduce the area of the active antenna substantially. Finally, we made the two-sided compact active antenna with coplanar waveguide (CPW), so that the antenna is just completed by using the area of the active antenna and the radiation power is not decreased.
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Min-Hsi, Chuang. "Dielectric-Resonator- Fed Active Horn Antenna." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2207200517210100.
Full text
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Chuang, Min-Hsi, and 莊閔旭. "Dielectric-Resonator- Fed Active Horn Antenna." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/51237064680284375827.
Full textAbstract:
碩士國立臺灣大學
電信工程學研究所
93
In this thesis, a high directivity active horn antenna is designed and analyzed, and which is implemented by integrating the horn antenna, dielectric resonator and power amplifier. Using DRs in the stripline-to-waveguide transition, signals can couple to stripline or waveguide efficiently. An 8 \% impedance bandwidth and better radiation patterns in the $E$-plane radiation is observed. By integrating power amplifiers into the horn antenna, antenna gain is increased by 7.1 dB without increasing the circuit volume. Chokes are used to reduce the backward radiation. Finally, dual horn antennas are designed and implemented. Sum and difference patterns are also observed as expected. The invention can be applied in many fields such as satellite communication, short term communication, microwave detection system, and signal detector, etc. They can be moduled for extensive application.
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chaw, cheng-chung, and 趙正中. "An Active Double Ring Microstrip Antenna." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/38758734584284119236.
Full textAbstract:
碩士中正理工學院
電機工程研究所
86
Recently,the communication equipments are widely used in the development of global communication. In application, these equipments adopt the microwave band for operation. Thus, the microwave circuits play a important role in modern microwave communication. Mainly, a small-size,low-cost higher-frequency and low-loss microwave circuit are necessary in practice. Generally, simplified the microwave circuit are available for small-size and low-cost. In this thesis, we proposed a method to have an alternative microstrip antenna designated active microstrip antenna. It can represent the LNA, OSC and Mixer of the conventional superheterdyn receiver in all. It is found the present method can be applied in radar and microwave systems.
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Cheng, Wen-Kai, and 鄭文凱. "Interference Control for Active Antenna Systems." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/4d7ua6.
Full textAbstract:
碩士國立中正大學
通訊工程研究所
102
By using beamforming, the multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) system combining with an active antenna system (AAS) can increase antenna gain effectively and improve the interference rejection of other beams. In this thesis, in order to perform the interference control of each beam-channel in the same beam-group, three kinds of precoding schemes, namely, the zero forcing (ZF), the joint leakage suppression (JLS), and the block diagonalization (BD) schemes, are employed. The sum-rate performance of the proposed precoding techniques at the base-station are evaluated and compared with different size of antenna arrays. Simulation results show that the sum-rate capacity is proportional to the number of antennas at the base-station. By using the BD precoding design, a superior sum-rate performance can be achieved in downlink.
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Nien-An, Kao, and 高念安. "Active Aperture-Coupled Leaky-Wave Antenna." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/86577771140409809941.
Full textAbstract:
碩士國立交通大學
電信工程系
87
This thesis will investigate the active aperture-coupled leaky-wave antennas and the multi-beam aperture-coupled leaky-wave antenna, including design, fabrication and measurement. To excite the microstrip first higher mode, the aperture-fed structure is utilized and a sequence of covered wire is added in the center of this antenna to suppress the dominant mode. The leaky-wave antenna offers beam-steering capability, high gain and narrow main beam. In addition, the aperture-fed structure reduces the circuit size and offers an excellent shielding between active and radiation elements. We produce two kinds of active aperture-coupled leaky-wave antennas-side-fed with a single main beam and center-fed with a dual-beam. The side-fed one provides a 16°scanning angle in H-plane from 8.97 GHz to 9.5 GHz and its maximum EIRPs are 21.98±1.59 dBm. The center-fed one provides a 20°scanning angle in H-plane from 8.97 GHz to 9.5 GHz and its maximum EIRPs are 18.56±0.33 dBm for the right beam and 18.9±0.13 dBm. Theses antennas are suitable for active phase antenna array applications or other microwave transceiver system. On the other hand, we utilized the aperture-fed leaky-wave antenna to develop a multi-beam antenna. Its transmitting and receiving radiation patterns are observed their scanning angles as 22°and 16°~18°respectively. This antenna has a developmental potential in transmit/receive modules such as smart antenna systems because both modules employ use only one antenna.
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Huang, Yun-Fang, and 黃韻芳. "Multi Function Active Antenna System-Design and Analysis of Antenna Array." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/52317016904699299767.
Full textAbstract:
碩士元智大學
通訊工程學系
98
This thesis investigates the Multi Function Active Antenna System with the Design and Analysis of the Antenna Array by using the electromagnetic simulation and the real model implement. The antenna design for this Active Antenna System will “improve the 2.4GHz WLAN throughput rate and transmission distance” while it can automatically choices the antenna radiation pattern which will adapt the environment scenario requirement by the portfolio of the algorithm in the system. The radiation terminal of the system is so called a symmetrical array antenna, and by using the traditionally method of the multi-angle radiation for the array antenna is not easy to implement due to the complex impedance system control. This thesis offer an significant view point that using the common grounding system and floating coupling approach for the antenna radiation angle switching without the impedance modification for the radio frequency input from the feeding system. The structure of the antenna array design has one main radiation mono-pole type antenna with 6 switching quarter wavelength mechanisms around the main radiation mono-pole type antenna with quarter wavelength distance. By the switching control for the grounding and floating of the 6 mechanism the complete antenna array system offers 12 different radiation patterns which cover the 0 degree to 360 degree. The benefit of the controllable high gain antenna radiation system is not only to provide the good signal strength for the link system but can reduce the network loading depend on the multi-path environment with more than one base-station and more than one subscriber. The application can be used for not only the terrestrial wireless infrastructure but hand-held equipment after minimize the antenna dimension for the suitable application to have better wireless communication performance in the different scenario.
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Li, Chien-Hua, and 李建樺. "Design of Dual-Band Printed Dipole Antennas and Study of Active Antenna Systems." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/29361580965275499214.
Full textAbstract:
碩士國立臺灣大學
電信工程學研究所
93
In this thesis, we have designed two antennas, one is double step-type microstrip line fed rectangular slot dipole antenna operated at the band of IEEE 802.11b, the other is the microstrip line fed dual-band printed dipole antenna operated at the band of IEEE 802.11a/b/g. Full-wave simulation software IE3D & HFSS used in this thesis, the resonant frequencies, bandwidth, return loss, input impedance and radiation pattern are studied completely by various antenna size parameter. Step-type MS line feeding enhances the bandwidth, the bandwidth covering 2GHz~3GHz is about 41.2%.Furthermore,we try to reduce ground size, and then we trade-off between size and bandwidth. MS line fed dual-band printed dipole antenna are studied to cover 2.4GHz~2.4835GHz, 5.15GHz~5.35GHz, 5.725GHz~ 5.825GHz for all WLAN IEEE802.11a/b/g. Finally, we combine with the low noise amplifier and the double step-type microstrip line fed rectangular slot dipole antenna, and then we measure the radiation pattern for this active antenna module. The total noise figure of all receivers is discussed. The research of the RF receiving system will be mentioned in this thesis, too.
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Tsai, Jyh-Horng, and 蔡志鴻. "Design of An Active Antenna Amplifying Array Using Patch-Coupling Microstrip Antenna." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/31474524424604371094.
Full textAbstract:
碩士國立交通大學
電信工程系
88
This paper presents the design of an active antenna amplifying array using patch-coupling microstrip antennas. In the array each element was linked by the coupled transmission lines placed next to the patch. The required power in the excitations of the individual patches of the array was achieved by adjusting the levels of coupling energy and amplifier gain. To control the levels of coupling energy precisely, the effects of different coupled-line’s lengths, gaps, and the port orientations are investigated. Experiments show good results of the antennas and the arrays. The proposed amplifying array has the following advantages over the conventional ones: a single input port, no power divider required, higher transmission gain, good and controllable radiation patterns, ease of bias, and compactness.
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柯承志. "Design and analysis of broadband active antenna." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/09576032413213564502.
Full textAbstract:
碩士大葉大學
電機工程研究所
90
Due to the trend of faster speed and higher frequency demands on electronic and telecommunication systems, there is an increasing problem for the electromagnetic compatibility (EMC) and also the trouble on the measuring electromagnetic interference signals. The measurement problem arose from the nature of cable loss in the high frequency ranges (greater than GHz). Because the strength of received signal attenuates rapidly along the cable between the receiving antenna and receiver, it is difficult and impractical to detect and analyze the high frequency signal (even install an pre-amplifier in front of receiver). The thesis investigates the design of broadband active antenna with moderate gain over the frequency range 1GHz — 6 GHz, and thus to solve the measurement problem for high frequency EMI and RF Tests. The works of the thesis is first to implement the S-parameters of amplifier module from manufacturer (Mini-Circuit), then use the microwave amplifier design principles and utilize the microwave circuit design software (Microwave Office 2000) to simulate and analyze the low noise amplifier (LNA), finally use the lump elements and microstrip lines to match the impedances, and therefore fine-tune the LNA performance on the printed circuit board (FR4). After the LNA circuit is finished, it is mounted on the dedicated horn antenna to measure the S-parameters and antenna patterns of the integrated active antenna system. The system measurement is conducted in the CSIST and proved to be effective for the high frequency measurements.
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Chuang, Che-yi, and 莊哲一. "An active Beam-Switching Transmitting Antenna Array." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/49180429201185142768.
Full textAbstract:
碩士國立交通大學
電信工程系
90
This thesis presents the architecture and circuit design of a high power active beam-steering antenna array for 28GHz Video-Relay System. The antenna array is composed of eight RF transmitters connected with inset-fed patch antennas. Each RF transmitter includes an MMIC power amplifier, a driver amplifier and a sub-harmonic Mixer with image rejection filter. The active array utilizes these 8 MMIC power amplifiers to transmit high power. On the other hand, the IF circuitry distributes to the IF signal into eight way so each way passing through phase shifter connects to the mixer in RF transmitter. Thus, the antenna array could switch beam by controlling phase shifter. Then, describing three antenna designs (cavity-backed aperture coupled patch antenna, cavity-backed slot antenna, Insert-fed patch antenna) applied for 28GHz video-relay system. Finally, discussing why using Insert-fed patch antenna for this transmitting antenna array.
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Chi, Tsai Tsung, and 蔡宗祺. "Design of Active Antenna for 930MHz Pager." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/07723552314483474184.
Full textAbstract:
碩士大葉大學
電信工程學系碩士班
93
ABSTRACT In this paper, an amplifier active antenna to be operated in 930MHz for the pager . This active antenna consists of an active element and a passive element . The active element is a low noise amplifier and passive element is a loop antenna. First, we design a loop antenna which is operated in 930MHz , measure pattern and antenna gain .Next, we design a low noise amplifier, measure noise figure、isolation and gain. Finally, by combine the two and fabricate the active antenna , measure pattern、antenna gain and average gain . The active antenna gain is 3.5dBi, active antenna average gain is 0.6dBi, such performance is suitable for the pager receive. Key Word：Active antenna；Pager；Loop antenna