Дисертації з теми "Antenna models"
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Su, Tao. "Characterization of antenna radiation and receiving properties in complex environments based on physical models." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3023561.
Повний текст джерелаShekhar, Hemabh. "Multi-antenna physical layer models for wireless network design." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22681.
Повний текст джерелаCommittee Chair: Ingram, Mary Ann; Committee Member: Andrew, Alfred; Committee Member: Copeland, John; Committee Member: Owen, Henry; Committee Member: Sivakumar, Raghupathy.
Licul, Stanislav. "Ultra-Wideband Antenna Characterization and Modeling." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29487.
Повний текст джерелаPh. D.
Cracraft, Michael Andrew. "Mobile array designs with ANSERLIN antennas and efficient, wide-band PEEC models for interconnect and power distribution network analysis." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/mcthesis20070623_09007dcc80374999.pdf.
Повний текст джерелаVita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 134-136).
Bengtsson, Mats. "Antenna array signal processing for high rank data models." Doctoral thesis, KTH, Signaler, sensorer och system, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2903.
Повний текст джерелаGrimm, Markus [Verfasser]. "Analytic on-body antenna and propagation models / Markus Grimm." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1176105191/34.
Повний текст джерелаGlenn, Dickins, and glenn dickins@dolby com. "Applications of Continuous Spatial Models in Multiple Antenna Signal Processing." The Australian National University. Research School of Information Sciences and Engineering, 2008. http://thesis.anu.edu.au./public/adt-ANU20080702.222814.
Повний текст джерелаHerring, Keith 1981. "Propagation models for multiple-antenna systems : methodology, measurements and statistics." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43027.
Повний текст джерелаIncludes bibliographical references (leaves 219-223).
The trend in wireless communications is towards utilization of multiple antenna systems. While techniques such as beam-forming and spatial diversity have been implemented for some time, the emergence of Multiple-Input Multiple-Output (MIMO) communications has increased commercial interest and development in multiple-antenna technology. Given this trend it has become increasingly important that we understand the propagation characteristics of the environments where this new technology will be deployed. In particular the development of low-cost, high-performance system architectures and protocols is largely dependent on the accuracy of available channel models for approximating realized propagation behavior. The first contribution of this thesis is a methodology for the modeling of wireless propagation in multiple antenna systems. Specifically we consider the problem of propagation modeling from the perspective of the protocol designer and system engineer. By defining the wireless channel as the complex narrow-band channel response h e C between two devices, we characterize the important degrees of freedom associated with the channel by modeling it as a function of its path-loss, multipath/frequency, time stability, spatial, and polarization characteristics. We then motivate this model by presenting a general set of design decisions that depend on these parameters such as network density, channel allocation, and channel-state information (CSI) update rate. Lastly we provide a parametrization of the environment into measurable factors that can be used to predict channel behavior including link-length, Line-Of-Sight (LOS), link topology (e.g. air-to-ground), building density, and other physical parameters. The second contribution of this thesis is the experimental analysis and development of this modeling space.
(cont) Specifically we have gathered a large database of real wireless channel data from a diverse set of propagation environments. A mobile channel-data collection system was built for obtaining the required data which includes an eight-channel software receiver and a collection of WiFi channel sounders. The software receiver synchronously samples the 20-MHz band centered at 2.4 GHz from eight configurable antennas. Measurements have been carried out for both air-to-ground and ground-to-ground links for distances ranging from tens of meters to several kilometers throughout the city of Cambridge, MA. Here we have developed a collection of models for predicting channel behavior, including a model for estimating the path-loss coefficient a in street environments that utilizes two physical parameters: P1 = percentage of building gaps averaged over each side of the street, P2= percentage of the street length that has a building gap on at least one side of the street. Results show a linear increase in a of 0.53 and 0.32 per 10% increase in P1 and P2, respectively, with RMS errors of 0.47 and 0.27 a for a's between 2 and 5. Experiments indicate a 10dB performance advantage in estimating path-loss with this multi-factor model over the optimal linear estimator (upper-bound empirical model) for link lengths as short as 100 meters. In contrast, air-to-ground links have been shown to exhibit log-normal fading with an average attenuation of a ; 2 and standard deviation of 8dB. Additionally we provide exhaustive evidence that the small-scale fading behavior (frequency domain) of both Non-Line-Of-Sight (NLOS) air-to-ground and ground-to-ground links as short as tens of meters is Rayleigh distributed. More specifically, fading distributions across a diverse set of environments and link lengths have been shown to have Rician K-factors smaller than 1, suggesting robust performance of the Rayleigh model.
(cont) A model is also presented that defines a stochastic distribution for the delay-spread of the channel as a function of the link-length (do), multipath component (MPC) decay-rate ( ... attenuation per unit delay ... ), and MPC arrival-rate (q = MPCs per unit delay ... periments support the use of this model over a spectrum of link-lengths (50m-700m) and indicate a dense arrival-rate (q) (on the order of 1 MPC) in ground-to-ground links. In this range the frequency structure of the channel is insensitive to q, which reduces the modeling complexity to a single unknown parameter, P. We provide estimators for 3 over a variety of environment types that have been shown to closely replicate the fade width distribution in these environments. The observed time-coherence length (tc) of MPCs tend to be either less than 300ms (high-frequency) or 5 seconds and longer (low-frequency), resulting in a Rician-like distribution for fading in the time domain. We show that the time characteristics of the channel are accurately modeled as the superposition of two independent circularly symmetric complex gaussian random variables corresponding to the channel response due to a set of stable and unstable MPCs. We observe the S-factor, defined as the ratio of average power in stable to unstable MPCs (distinct from the Rician K-factor), which ranges between 0-30dB depending on environment and link length, and can be estimated with an rms error of 3dB in both ground-to-ground and air-to-ground link regimes. Experiments show improved performance of this model over the Rician fading model which has been shown to underestimate high fade events (tails) in the time domain, corresponding to cases where the stable MPCs destructively combine to form a null. Additionally, the Kronecker MIMO channel model is shown to predict channel capacity (of a 7x7 system) with an rms error of 1.7 ... (at 20dB SNR) over a diverse set of observed outdoor environments.
(cont) Experiments indicate a 3dB performance advantage in this prediction when applied to environments that are not dominated by single-bounce propagation paths (Single-bounce: 2.1 ... rms, Multi-bounce: 1 ... rms).
by Keith T. Herring.
Ph.D.
Sherkat, Navid. "Approximation of Antenna Patterns With Gaussian Beams in Wave Propagation Models." Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-14437.
Повний текст джерелаPapou, Uladzislau. "Conformal and reconfigurable sparse metasurfaces : advanced analytical models and antenna applications." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASC027.
Повний текст джерелаThis PhD thesis deals with electromagnetic metasurfaces for wavefront manipulation represented by arrays of scatterers engineered at subwavelength scale. The manuscript develops novel analytical and numerical models that allow one to solve the inverse scattering problem by taking into account all interactions between elements of a metasurface. Specifically, the manuscript focuses on sparse arrays, periodic or not, of structured wires for the application to electronically reconfigurable antennas. The manuscript is divided into two main parts, one on periodic arrangements of wires called metagratings and one on sparse metasurfaces when there is no periodicity imposed. Each part is endorsed by experiments performed at microwave frequencies. In the first part, theoretical conditions for arbitrary control of the diffraction patterns with metagratings, whose period is composed of multiple individually-engineered wires, are established and importance of the near-field regulation is highlighted. Moreover, an analytical retrieval technique is developed and allows one to consider, with the help of full-wave simulations, arbitrarily structured wires for metagratings operating from microwave to optical domains. In the second part of the thesis, the analytical model of metagratings is generalized, from planar periodic, to arbitrarily-shaped non-periodic distributions of wires by means of numerical calculation of a Green’s function. The concept is applied to design sparse metasurfaces in Fabry-Perot cavity and semi-cylindrical antenna configurations. Finally, the approach is applied to design a reconfigurable planar sparse metasurface. A fabricated sample is exploited to experimentally demonstrate dynamic control of the far-field radiation pattern and the near-field intensity distribution. As such beam-steering, multi-beam manipulation and subdiffraction focusing are shown
Lyberopoulos, George L. "Numerical models of new HF shipboard communication antenna systems for improved survivability." Thesis, Monterey, California: U.S. Naval Postgraduate School, 1986. http://hdl.handle.net/10945/22007.
Повний текст джерелаTakamizawa, Koichiro. "Analysis of Highly Coupled Wideband Antenna Arrays Using Scattering Parameter Network Models." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/11099.
Повний текст джерелаPh. D.
Choi, Il Yong. "Design of survivable shipboard HF mast antenna models using the numerical electromagnetics code." Thesis, Monterey, California: U.S. Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22739.
Повний текст джерелаHe, Xin, and 何鑫. "Probabilistic quality-of-service constrained robust transceiver designin multiple antenna systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48199527.
Повний текст джерелаpublished_or_final_version
Electrical and Electronic Engineering
Master
Master of Philosophy
Sonkki, M. (Marko). "Wideband and multi-element antennas for mobile applications." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526201085.
Повний текст джерелаTiivistelmä Väitöskirjassa esitetään uusia laajakaistaisia ja monielementtiantenneja matkaviestimiin. Väitöskirja koostuu neljästä pääalueesta: pintavirtojen muototeoria, laajakaistaiset antennit, monielementtiantennit sekä laajakaistaiset monielementtiantennit. Teoriaosassa säteilykenttiä on aluksi tutkittu pallon pinnalla sekä skalaaripotentiaaleina että pintavirtavektoreina, jonka jälkeen niitä on verrattu mobiilin laitteen maatason ominaispintavirtojen synnyttämiin säteilykenttiin. Teoriaosassa osoitetaan, että pallon pinnalla sekä tasomaisella suorakaiteen muotoisella pinnalla on mahdollista herättää samat säteilykentät. Myöhemmin väitöskirjassa esitettävien uudenlaisten antennirakenteiden ominaisuuksia verrataan teoriaosassa esitettyihin pintavirtoihin ja säteilykenttiin. Teoriaosuuden jälkeen osoitetaan miten säteilevä sähkömagneettinen kenttä saadaan herätettyä laajalla taajuusalueella. Tähän on otettu kaksi eri lähestymistapaa, joista ensimmäisessä esitellään ja tutkitaan kvasikomplementaarista antennirakennetta (QCA). Kvasikomplementaarisessa antennirakenteessa sisääntuloimpedanssin imaginaariosa kompensoidaan yhdistämällä sähköinen johde ja magneettinen rako samaan antenniin. Samanaikaisesti perusmuoto herätetään laajalla taajuusalueella, jolla varmistetaan antennin hyvät säteilyominaisuudet koko toimintataajuusalueella. Toisessa lähestymistavassa käytetään kahta symmetrisesti asetettua antennielementtiä, joita syötetään symmetrisesti samalla amplitudilla ja vaiheella. Kun sähkömagneettinen kenttä herätetään symmetrisesti, korkeamman kertaluvun muotojen herättäminen voidaan välttää laajalla taajuusalueella. Symmetrisesti syötetyillä antennirakenteilla saavutettu -6 dB suhteellinen impedanssikaistanleveys on 37.5–80 %. Useita syöttöelementtejä käytettäessä voidaan mobiilin laitteen maatasossa herättää yhdellä pistetaajuudella monta toisistaan riippumatonta säteilykenttää. Koska herätetyt kentät ovat toisistaan riippumattomia, on niiden välinen korrelaatio myös pieni. Kyseisellä rakenteella on mahdollista toteuttaa säteilykuviodiversiteetti erittäin pienessä tilassa, kuten matkapuhelimessa. Toisaalta, kun yhdistetään kaksi QCA-elementtiä yhdeksi monielementtiratkaisuksi, voidaan toteuttaa laajakaistainen diversiteettiantenni, jonka suhteellinen -6 dB impedanssikaistanleveys on 87.5 %. Vastaavasti kahdella laajakaistaisella QCA-elementillä toteutetulla MIMO-ratkaisulla päästään 95 % suhteelliseen -6 dB impedanssikaistanleveyteen. Molemmilla ratkaisuilla on erittäin hyvät säteilyominaisuudet sekä alhainen korrelaatio ja pieni keskinäiskytkentä antennielementtien välillä. Suunniteltaessa toimivaa laajakaistaista antennirakennetta, on tärkeää ottaa huomioon antennisyötön impedanssisovitus, jotta antennin suorituskyky ei heikkenisi. Lisäksi balansoidussa rakenteissa tulee olla laajakaistainen baluni, jolla vältetään säteilykuvion vääristyminen. Väitöskirjan syöttöratkaisuissa on käytetty kaupallisia sähkömagneettisia simulaattoreita, joilla antennirakenne voidaan mallintaa kolmiulotteisesti, ja joilla laajakaistainen syöttö saadaan optimoitua haluttuun antenniin. Suurin osa esitellyistä antennirakenteista on simulointien lisäksi myös mitattu, jolloin niiden toimivuus käytännössä pystytään todentamaan rakentamalla prototyyppiantenni. Yleisesti väitöskirjassa esitellään tasomaisia antenniratkaisuja johtavassa maatasossa, joissa säteilevät pintavirrat herätetään mahdollisimman laajalla taajuusalueella. Ideana on löytää laajakaistaisia antenni- ja syöttörakenteita, joilla saadaan herätettyä perusmuoto tai jokin muu haluttu muoto. Ajatuksena on välttää korkeamman kertaluvun muotojen herättäminen, jotka voivat pilata antennin suorituskyvyn. Väitöskirjassa osoitetaan myös, että pienikokoisella antennilla on mahdollista herättää korkeamman kertaluvun muotoja pistetaajuudella käyttämällä useita heräte-elementtejä
Hebelka, Vladimír. "Antény pro bezdrátové sítě pracující v blízkosti lidského těla." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-234369.
Повний текст джерелаJan, Naeem A. "Anomalous Nature Of Metamaterial Inclusion and Compact Metamaterial-Inspired Antennas Model For Wireless Communication Systems. A Study of Anomalous Comportment of Small Metamaterial Inclusions and their Effects when Placed in the Vicinity of Antennas, and Investigation of Different Aspects of Metamaterial-Inspired Small Antenna Models." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/16003.
Повний текст джерелаElghannai, Ezdeen Ahmed. "NOVEL METHOD TO CONTROL ANTENNA CURRENTS BASED ON THEORY OF CHARACTERISTIC MODES." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471871173.
Повний текст джерелаPirkl, Ryan J. "Measurement-based investigations of radio wave propagation: an exposé on building corner diffraction." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33961.
Повний текст джерелаJaafar, Hussein. "Antennes miniatures, large bande et superdirectives à charges optimisées par l'analyse des modes caractéristiques." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S031/document.
Повний текст джерелаThe rapid evolution in the wireless communication systems requires more miniaturization of various electronic components in addition to the major element of the wireless technology: the antenna. In this case, an antenna occupying a limited space should be miniaturized in order to operate at the desired communication bands. However, as the electrical size of the antenna decreases, its performance degrades dramatically and it becomes limited in bandwidth, efficiency, and directivity. Classical size reduction techniques with material loading and geometry shaping of the antenna suffer from narrow bandwidth and low radiation efficiency. On the other hand, attempts to increase the directivity of small antennas using superdirective arrays are also associated with low radiation efficiency and very narrow bandwidth. To overcome these drawbacks, we propose boosting the performance of compact antennas using embedded reactive loads. By properly placing loads (active or passive) inside the antenna, it is possible to control the currents to significantly enhance the antenna performance in terms of bandwidth and directivity. Yet, for a successful loading criteria, it is mandatory to analyze the modes that are naturally supported by the antenna under study. These are called the characteristic modes, which provide deep physical insights about the behaviour of the antenna and its radiating modes. By combining this theory with and optimization algorithm, it becomes possible to optimally manipulate the currents inside the antenna using reactive loads to achieve wideband, superdirective and efficient designs
Lambert, Kevin M. "An environmental model for calculating the antenna temperature of earth based microwave antennas /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487327695622938.
Повний текст джерелаPresse, Anthony. "Conception d'antennes souples et de conducteurs magnétiques artificiels en bande UHF." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S087/document.
Повний текст джерелаThe invention of antennas was the base of wireless communications appearance at the dawn of the twentieth century. Originally metal objects for transmitting and receiving electromagnetic waves, antennas have steadily become more complex to meet the impressive development of wireless communications. It is in this context that the concept of wearable antennas was born less than two decades ago opening a new field of research namely flexible antennas. It is in this framework that this thesis is dedicated to the design of flexible antennas for UHF band.A first study enabled the design of a flexible antipodal Vivaldi antenna [150-900 MHz] for Technical Section of the Army. Six of these antennas are intended to be placed under a balloon inflated with helium for receiving RF signals.A second study was conducted in collaboration with the company Syrlinks and CNES. The objective of the project is to design flexible antennas for tracking people with ARGOS system (401 and 466 MHz). The selected solution is a planar PIFA which width is smaller than lambda/3. This antenna has the advantage of being thin and light. The flexible material used is a silicone rubber and it was selected among several others due to some dielectric characterizations. However, the drawback of this antenna is that it has a quasi-omnidirectional radiation pattern. Since it was not possible to use a reflector metal plane due to size constraints, it was decided to design a flexible artificial magnetic conductor (AMC). However, the design of AMCs in the lower UHF band is challenged with the miniaturization difficulties. Two concepts of small size (compared to the wavelength) AMCs unit cells were developed to work around this problem. The first solution uses interdigitated capacitors and the second a double layer structure. For these two concepts, a circuit model is proposed and validated by experimental measurements. The measurement of the AMC associated antenna demonstrates a bandwidth sufficient for ARGOS applications and a radiation pattern mostly directed in the direction opposite to that of the AMC
Surittikul, Nuttawit. "Pattern reconfigurable printed antennas and time domain method of characteristic modes for antenna analysis and design." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1143225860.
Повний текст джерелаObeidat, Khaled Ahmad. "Design Methodology for Wideband Electrically Small Antennas (ESA) Based on the Theory of Characteristic Modes (CM)." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274730653.
Повний текст джерелаRaines, Bryan Dennis. "Systematic Design of Multiple Antenna Systems Using Characteristic Modes." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306951104.
Повний текст джерелаSmierzchalski, Maciej. "Characterization methods for metamaterials : directive antennas using space eigen-mades." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S126/document.
Повний текст джерелаThe work presented in this thesis concerns two parts: characterisation methods for metamaterials and directive antennas using space eigen-modes. The first one describes the homogenisation methods of metamaterials to retrieve the constitutive parameters from scattering parameters of the metamaterial's slab. We investigated the metamaterials which present the most common properties of media: bi-isotropic metamaterials (chiral), anisotropic metamaterials (BC-SRR), uni-axial bi-anisotropic metamaterials (double omega medium) and bi-axial bi-anisotropic metamaterials (EC-SRR). The transverse and longitudinal constitutive parameters characterising the anisotropic and bi-anisotropic require to examine the media at normal and oblique incidences. In the analysis we considered to distinguish continuous media restricted to long wave limit and resonating particles lattice which are out of long wave limit. The application of continuous media approach to the resonating particle lattice with size not satisfying the long wave limit can leads to violation of causality and passivity laws. The main different between proposed two approaches is interpretation of boundary conditions (Maxwellian/non-Maxwellian) for the metamaterial slab. The inclusions of lattice we ascribe as electric and magnetic dipole moments to develop an homogeneous resonating particles lattice and to retrieve the constitutive parameters. We validated the proposed approaches and compared the retrieved constitutive parameters according to physical laws. We found that the application of Bloch admittance and equivalence to electric and magnetic dipole moments provides the physical constitutive parameters. The second part of the thesis refers to directive antenna using space eigen-modes. The directivity of the antennas is limited to the size of the antenna or number of elements in an array. In common with keeping small sizes of the array the space between radiation elements has to be minimised. The proposed directive antenna considers the radiation elements determine by the orthogonal modes, i.e. each radiator of the array corresponds to unique space eigen-mode. This allows to ensure small distance between the array elements without introduction of high mutual coupling between them. The original approach refers to superposition of spherical modes however it is not practical. Instead of spherical modes we propose superposition of cylindrical modes which are easy to be realised. For the constructive summation of cylindrical modes and maximisation of directivity in end-fire plane we determine amplitudes of the cylindrical modes excited by electric and/or magnetic vector potentials. The cylindrical modes we obtain by the annular ring antennas and miniaturised annular rings. The superposition of cylindrical modes is achieved with a stacked antenna of annular rings and a coplanar cylindrical annular rings antenna. The both antennas we realised and measured
Liu, Lingjia. "On delay-sensitive communication over wireless systems." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2725.
Повний текст джерелаDiallo, Alpha Ousmane. "Modélisation hyperfréquence de problèmes multi-échelles appliquée au cas des antennes à métamatériaux diélectriques." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066356/document.
Повний текст джерелаThis work focuses on the improvement of the antennas compactness used primarily for embedded systems while respecting the performance and competitiveness requirements. The approach explored consists in using artificial materials operating in transmission and designed by structuring the dielectric material on a scale smaller than the wavelength (sub-wavelength). This structuring makes it possible in practice to achieve a variation in the effective refractive index in order to produce diffractive elements capable of performing a microwave function. However, the particularity of this type of structured element is to mix several physical scales generating complexity in their study. The largest dimension of a structured component can reach several tens of wavelength, for example 20λ, while the minimum size of the sub-wavelength structures may be less than a fraction of the wavelength, as than λ / 20. This multi-scale aspect increases the simulation times of antenna devices integrating these structured elements, thus preventing any possibility of multi-parameter optimization in reasonable times. In order to exploit fully the potential of these structured materials, a numerical model of computation has been developed on the basis of optical paths. This model gives results on the maximum gain of structured diffractive lens antennas with an accuracy of 0.5 dB. The computation time of the model is of the order of the minute compared to more than 6 hours for a complete simulation with the electromagnetic calculation software CST Microwave Studio. The speed and precision of this model have been used to optimize the design of a structured diffractive lens. To illustrate the relevance of this structured approach, its performances were compared with those of Fresnel lens antenna and hyperbolic lens antenna. This comparison was carried out under identical footprint conditions with a length to diameter ratio L / D of 0.5. The gain of the structured lens was found to be 1.6 dB higher than the Fresnel lens and 2.7 dB higher than the hyperbolic lens
Paiva, Jordan Silva de. "Modelagem tensorial para estimaÃÃo de parÃmetros em arranjos de antenas polarimÃtricas." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11393.
Повний текст джерелаIn this dissertation, we propose methods based on tensor signal processing for the parameter estimation in electric vector (Tripole) antenna arrays, considering different structures of arrays (ULA, L-shape and UPA). Initially, using a L-shape array, we develop a third order (3-D) tensor model for the received data. Based on this model, a trilinear alternating least squares (T-ALS) algorithm is used for the blind estimation of the sourceâs parameters. Then, under supervised transmission an alternative method is proposed by resorting to the SVD decomposition, which is compared to the T-ALS algorithm. A second approach is proposed, which is based on a uniform planar array antenna (UPA). In this case a fourth-order (4-D) tensor model is obtained, and the Q-ALS (Quadrilinear Alternating Least Squares) algorithm is used for parameter estimation. An alternative method is also proposed, which exploits the factorization of the Khatri-Rao product. Considering the supervised case, a new algorithm called Nested-SVD is proposed and a comparative study with Q-ALS, T-ALS and SVD algorithms is carried out. The performance of the proposed methods is evaluated through Monte Carlo simulations in different scenarios and array settings. Finally, computational modeling of electric tripole using the high frequency simulation software (HFSS) was performed, enabling the extraction of the L-shape and UPA spatial array gain. Then, the performance of the proposed tensor methods is evaluated in a more realistic scenario, and compared to idealized omnidirectional and unitary gain antenna array models
Elmegri, Fauzi O. M. "Model and design of small compact dielectric resonator and printed antennas for wireless communications applications : model and simulation of dialectric resonator (DR) and printed antennas for wireless applications : investigations of dual band and wideband responses including antenna radiation performance and antenna design optimization using parametric studies." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14742.
Повний текст джерелаElmegri, Fauzi. "Model and design of small compact dielectric resonator and printed antennas for wireless communications applications. Model and simulation of dialectric resonator (DR) and printed antennas for wireless applications; investigations of dual band and wideband responses including antenna radiation performance and antenna design optimization using parametric studies." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14742.
Повний текст джерелаGeneral Secretariat of Education and Scientific Research Libya
Nuckols, John Eric. "Implementation of Geometrically Based Single-Bounce Models for Simulation of Angle-of-Arrival of Multipath Delay Components in the Wireless Channel Simulation Tools, SMRCIM and SIRCIM." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35989.
Повний текст джерела
[Vita removed March 5, 2012. GMc]
Master of Science
Ulrich, Gary A. "Computer model for a towed submarine communication antenna." Thesis, Springfield, Va. : Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA372223.
Повний текст джерела"June 1999". Includes bibliographical references (leaves 97-98). Also available online.
Ulrich, Gary A. (Gary Alan) 1962. "Computer model for a towed submarine communication antenna." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9551.
Повний текст джерелаIncludes bibliographical references (leaves 97-98).
A finite difference computer model is developed to simulate the exposure statistics of a radio frequency buoyant antenna as it is towed in a random seaway. The model allows the user to prescribe antenna properties (length, diameter, density, etc.), sea conditions ( significant wave height, development of sea), and tow speed. The model then simulates the antenna-sea interaction for the desired duration to collect statistics relating to antenna performance. The model provides design engineers with a tool to predict antenna performance trends, and conduct design tradeoff studies. The antenna envisioned is a submarine floating antenna which would enable communications at speed and depth, greatly enhancing the stealth and survivability of the US Navy's submarine force.
by Gary A. Ulrich.
S.M.
Nav.E.
Patwari, Neal. "Measured and Modeled Time and Angle Dispersion Characteristics of the 1.8 GHz Peer-to-Peer Radio Channel." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/32201.
Повний текст джерелаMaster of Science
Diallo, Kadidiatou. "Antennes miniatures basses fréquences, reconfigurables pour le LTE." Thesis, Université Côte d'Azur, 2021. http://www.theses.fr/2021COAZ4010.
Повний текст джерелаThis thesis focuses on the study, design and optimization of miniature multiband and frequency reconfigurable antennas for IoT and mobile applications in LTE and 5G frequency bands. Ground planes of dimensions 120*60 mm² were used. First the design of a dual-band PIFA antenna operating in the ISM 868 MHz and 915 MHz bands is carried out. Then, we proposed the design and optimization of a two-port multi-antenna system, operating on the low frequency LTE band (from 700 MHz to 900 MHz) and covering at the same time the LTE 2600 band and part of the 5G middle band. This antenna system consists of two PIFAs antennas associated with parasitic elements that used to expand their bandwidths in certain frequency bands. One of the antennas operates on three frequency bands and it is frequency tunable on the low band. The other antenna operates only on two frequency bands, the LTE 2600 band (from 2500 MHz to 2700 MHZ) and 5G middle band (from 3.4 GHz to 3.8 GHz). The frequency agility of the reconfigurable antenna is achieved by using a varactor diode which is directly biased on antenna feeding port. Finally, thanks to the study of the characteristic modes of the ground plane, the positions of the MIMO system antennas are chosen so that they are naturally isolated without the use of conventional decoupling methods. The final system covers the LTE [700 - 900 MHz] band, reconfigurable in frequency, the LTE 2600 band and part of the 5G middle band. The measurements showed good port isolation (|S21| -20 dB) in the two bands where the system operates in MIMO mode. The efficiencies measured in the reconfigurable band are not very high, however, they remain correct for the intended application
Cardia, Daniel Vitor Faria. "Determinação de modelos simplificados de fontes equivalentes de campos elétricos e magnéticos aplicáveis à análise de compatibilidade eletromagnética de sistemas embarcados." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-12032018-083256/.
Повний текст джерелаIt will be shown in this work a method for simplified models determination of equivalent sources for electric and magnetic fields, applicable to embedded systems electromagnetic compatibility analysis. These models are obtained by laboratory tests with analytical calculation techniques associated to numerical and hybrid calculations. This work highlights the application of measurement method by Large Loop Antennas (LLAs) for the creation of radiated emission equivalent sources and the application of a corresponding method for obtaining radiated electromagnetic fields. The contribution of this work is the acquisition of these equivalent sources of radiated emission, which allows the evaluation of the magnetic and electric field contribution in electromagnetic environments. And it also contributes with the application of a methodology to obtain the electric fields from previously determined magnetic fields. In special, this work may be considered as an evolution of the Master\'s Thesis [1]
Potgieter, Brendon Ryan. "Experimental modal analysis and model validation of antenna structures." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5423.
Повний текст джерелаENGLISH ABSTRACT: Numerical design optimisation is a powerful tool that can be used by engi- neers during any stage of the design process. Structural design optimisation is a specialised usage of numerical design optimisation that has been adapted to cater speci cally for structural design problems. A speci c application of structural design optimisation that will be discussed in the following report is experimental data matching. Data obtained from tests on a physical structure will be matched with data from a numerical model of that same structure. The data of interest will be the dynamic characteristics of an antenna structure, focusing on the mode shapes and modal frequencies. The structure used was a scaled, simpli ed model of the Karoo Array Telescope-7 (KAT-7) antenna structure. Experimental data matching is traditionally a di cult and time-consuming task. This report illustrates how optimisation can assist an engineer in the process of correlating a nite element model with vibration test data.
AFRIKAANSE OPSOMMING: Numeriese ontwerp-optimisering is 'n kragtige ingenieurshulpmiddel wat ty- dens enige stadium in die ontwerpsproses ingespan kan word. Strukturele ontwerp-optimisering is 'n gespesialiseerde gebruik van numeriese ontwerp- optimisering wat aangepas is om spesi ek van diens te wees by die oplos van strukturele ontwerpsprobleme. 'n Spesi eke toepassing van strukturele ontwerp-optimisering wat in hierdie verslag bespreek sal word, is eksperi- mentele datakorrelasie. Data afkomstig van toetse op 'n siese struktuur sal gekorreleer word met data afkomstig van 'n numeriese model van die selfde struktuur. Die data van belang is die dinamiese eienskappe van 'n anten- nastruktuur, spesi ek die modusvorme en modale frekwensies. Die betrokke struktuur wat gebruik is, is 'n vereenvoudigde skaalmodel van die Karoo Array Telescope-7 (KAT-7) antennastruktuur. Eksperimentele datakorrelasie is, tradisioneel gesproke, 'n moeilike en tydro- wende taak. Hierdie verslag sal illustreer op watter wyse optimisering 'n inge- nieur van hulp kan wees in die proses om 'n eindige elementmodel met vibrasietoetsdata te korreleer.
Laird, Daniel T. "Logistics Regression Model on Antenna Control Unit Autotracking Mode." International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596414.
Повний текст джерелаOver the past several years DoD imposed constraints on test deliverables, requiring objective measures of test results, i.e., statistically defensible test and evaluation (SDT&E) methods and results. These constraints force testers to employ statistical hypotheses, analyses and modeling to assess test results objectively, i.e., based on statistical metrics, analytical methods, probability of confidence complemented by, rather than solely on expertise, which is too subjective. In this and companion papers we discuss methods of objectifying testing. We employ an earth coordinate model and statistical modeling of telemetry (TM) tracking antenna employing time-space position information (TSPI) and derived statistical measures for tracking-error and auto-tracking mode. Test data were statistically analyzed via analysis of covariance (ANCOVA) which revealed that the antenna control unit (ACU) under test (AUT) does not track statistically identically, nor as practically or efficiently in C-band while receiving data carriers in both S- and C-bands. The conclusions of this paper add support to that hypothesis. In this third of three papers we use data from a range test, but make no reference to the systems under test as the purpose of this paper is to present an example of tools useful for employing a SDT&E methodology.
Juyal, Prateek. "Directive microstrip disc radiators based on TM1m modes." IEEE TAP, 2016. http://hdl.handle.net/1993/32074.
Повний текст джерелаFebruary 2017
Strojny, Brandan Thomas. "EXCITATION AND ANALYSIS OF CHARACTERISTIC MODES ON COMPLEX ANTENNA STRUCTURES." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1301006813.
Повний текст джерелаHeyssler, Matthias. "Probing the standard model and beyond at high-energy colliders." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4873/.
Повний текст джерелаTheodossopoulos, Konstantinos. "Rectilinear slot model of an inclined slot radiator in rectangular waveguide." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/577.
Повний текст джерелаHo, Chung-Man Peter. "Antenna effects on indoor wireless channels and a deterministic wide-band propagation model for in-building personal communication systems." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-01102009-063157/.
Повний текст джерелаMurray, Kevin Paul. "The design of antenna systems on complex structures using characteristic modes." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385200.
Повний текст джерелаКостановський, Валерій Вікторович, та Valery V. Kostanovskyi. "Методологія підвищення ефективності технічного обслуговування активних фазованих антенних решіток радіолокаційних станцій". Thesis, Національний авіаційний університет, 2021. https://er.nau.edu.ua/handle/NAU/48988.
Повний текст джерелаThe work is devoted to the development of the methodology for improving the efficiency of maintenance of active phased array antennas (APAA) of radar stations. In this paper, mathematical models of reliability and efficiency of operation of active phased array antennas according to the criteria of technical use and economic efficiency are developed and improved. Mathematical models of reliability of electrical products describing sudden and gradual failures are improved in the work. Reliability models of maintenance – free APAA with k – level structural scheme of reliability at sudden and gradual failures of antenna array modules are developed and investigated. Accounting for gradual failures of antenna array modules can increase the reliability of APAA from 30 % to 80 %. Mathematical models of reliability of serviced APAA are developed. Improved methods for determining the required number of spare antenna array modules to provide APAA maintenance. Developed and researched models of optimal maintenance of radars with APAA, the use of which allows to reduce from 15 % to 35 % of the operating costs at the stage of warranty service. Strategies for maintenance and operation of APAA radar based on operating time and actual condition are determined, models and methods for implementation of these strategies at the stage of post-warranty service are developed.
Sung-hoon, Jang, Han Sung-hee, and Kim Heung-bum. "Auto-tracking antenna pattern effects on multipath channel model at test range." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607672.
Повний текст джерелаTelemetry propagation channel is modeled to predict PCM/FM telemetry receiving signal level at APG(Anheung Proving Ground), ADD(Agency for Defense Development). Channel model is composed of direct wave and reflected wave in sea surface, so-called 2-ray model. Our 2-ray model includes transmitting antenna radiation pattern, auto-tracking antenna radiation pattern, sea surface reflection coefficient and phase depending on incident angle. Vertical and horizontal polarized receiving signal strength is obtained from pre-calculated flight trajectory of transmitter. Calculated results are compared with measured data in real flight test. 2-ray channel model can predict almost identical receiving signal level and calculate starting point of multi-path fading effect. Using these results, receiving system can be moved to more proper position before flight test.
Kim, Kangwook. "Numerical and experimental investigation of impulse-radiating antennas for use in sensing applications." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/14944.
Повний текст джерелаAfacan, Gonenc. "The Electrical Characteristics Of Antennas In Their Operational Environment." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609119/index.pdf.
Повний текст джерела. In addition, important aspects of simulation tool were investigated. Then, an F-4 aircraft model was used to observe the electrical characteristics of antennas mounted on it. Using 3D model of F-4 aircraft, realistic antenna placement points were assigned and monopoles were attached to those points. Alternatively, a simplified F-4 model was also used and for two different models, identical simulations were done, followed by accuracy and performance analysis between the results obtained from simplified and exact models. As the outcome of these simulations, certain parameters like impedance, antenna-to-antenna coupling and radiation pattern values were examined. Additionally, change in antennas&rsquo
electrical characteristics due to their position over the airframe was investigated. In addition, a 1:10 down-scaled and copper-plated F-4 aircraft model was obtained and equipped with identical antennas. By using the measurements done on this scale model, antenna-to-antenna coupling results of MWS®
were verified by measurements. Finally, advantages and disadvantages of using electromagnetic simulation tools and scale model measurements for such antenna studies were discussed.
Padmosutoyo, Slamet Suharsa. "NEC, NECGS, and MININEC numerical models of LF top-hat monopole antennas." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26100.
Повний текст джерела