Dissertations / Theses on the topic 'Amplifiers, Radio frequency'
To see the other types of publications on this topic, follow the link: Amplifiers, Radio frequency.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Amplifiers, Radio frequency.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Kunselman, Gary L. "Radio frequency power amplifiers for portable communication systems." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/41493.
Abstract:
Portable communication systems require, in part, high-efficiency radio frequency power amplifiers (RF PA) if battery lifetime is to be conserved. Conventional amplifier classifications and definitions are presented in a unified and concise format. The Bipolar Junction Transistor (BJT) and Metal-Semiconductor Field Effect Transistor (MESFET) are evaluated as active devices in high-efficiency RF PA designs. Two amplifier classes (class CE and class F) meet the system requirements of an 850 MHz operating frequency, a power output of 3 W, a battery supply voltage of 9 Vdc, and a sinusoidal-type signal to be amplified. Both classes are evaluated through recent research literature and simulated using the PSpice® computer simulation program. Class CE and class F are found to provide efficiencies exceeding 80 percent under the given system constraints.Master of Science
2
Cui, Xian. "Efficient radio frequency power amplifiers for wireless communications." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195652135.
3
Fedorenko, Pavlo. "Phase distortion in envelope elimination and restoration radio frequency power amplifiers." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/34822.
Abstract:
The objective of this research is to analyze and improve linearity of envelope elimination and restoration (EER) radio frequency (RF) power amplifiers. Envelope elimination and restoration was compared to other efficiency enhancement techniques and determined to likely be the most suitable solution for implementation of multimode, multiband portable RF transmitters. Distortion, stemming from dynamic power-supply modulation of RF transistors in EER RF power amplifiers was identified as one of the key challenges to the development of commercially viable EER transmitters. This dissertation presents a study of phase distortion in RF power amplifiers (PAs) with emphasis on identification of the origins of phase distortion in EER RF power amplifiers. Circuit-level techniques for distortion mitigation are also presented.
Memory effects in conventional power amplifiers are investigated through the accurate measurement and analysis of phase asymmetry of out-of-band distortion components. Novel physically-based power amplifier model is developed for attributing measured memory effects to their physical origin. The amount of linearity correction, obtained through pre-distortion for a particular RF power amplifier, is then correlated to the behavior of the memory effects in the corresponding PA.
Heterojunction field-effect transistor and heterojunction bipolar transistor amplifiers are used for investigation of voltage-dependent phase distortion in handset EER RF PAs. The distortion is found to stem from vector addition of signals, generated in nonlinear circuit elements of the PA. Specifically, nonlinear base-collector capacitance and downconversion of distortion components from second harmonic frequency are found to be the dominant sources of phase distortion.
Shorting of second harmonic is proposed as a way to reduce the distortion contribution of the downconverted signal. Phase distortion is reduced by 50%, however a slight degradation in the amplitude distortion is observed. Push-pull architecture is proposed for EER RF power amplifiers to cancel distortion components, generated in the nonlinear base-collector capacitance. Push-pull implementation enables a 67% reduction in phase distortion, accompanied by a 1-2 dB reduction in amplitude distortion in EER RF power amplifiers.
This work, combined with other studies in the field, will help advance the development of multimode, multiband portable RF transmitters, based on the envelope elimination and restoration architecture.
4
Kim, Hyungwook. "CMOS radio-frequency power amplifiers for multi-standard wireless communications." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44786.
Abstract:
The development of multi-standard wireless communication systems with low cost and high integration is continuously requested and accompanied by the explosive growth of the wireless communication market. Although CMOS technology can provide most building blocks in RF transceivers, the implementation of CMOS RF power amplifiers is still a challenging task. The objective of this research is to develop design techniques to implement fully-integrated multi-mode power amplifiers using CMOS technology.
In this dissertation, a load modulation technique with tunable matching networks and a pre-distortion technique in a multi-stage PA are proposed to support multi-communication standards with a single PA. A fully-integrated dual-mode GSM/EDGE PA was designed and implemented in a 0.18 um CMOS technology to achieve high output power for the GSM application and high linearity for the EDGE application. With the suggested power amplifier design techniques, fully-integrated PAs have been successfully demonstrated in GSM and EDGE applications.
In Addition to the proposed techniques, a body-switched cascode PA core is also proposed to utilize a single PA in multi-mode applications without hurting the performance. With the proposed techniques, a fully-integrated multi-mode PA has been implemented in a 0.18 um CMOS technology, and the power amplifier has been demonstrated successfully for GSM/EDGE/WCDMA applications.
In conclusion, the research in this dissertation provides CMOS RF power amplifier solutions for multiple standards in mobile wireless communications with low cost and high integration.
5
Myoung, Suk Keun. "Low frequency feedforward and predistortion linearization of RF power amplifiers." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1150416616.
6
Landin, Per. "Digital Baseband Modeling and Correction of Radio Frequency Power Amplifiers." Doctoral thesis, KTH, Signalbehandling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-94762.
Abstract:
Aspects related to behavioral modeling and correction of distortions for radio frequency (RF) power amplifiers (PAs) are treated in the thesis. When evaluating the performance of a behavioral model it is important to, first of all, use an evaluation criterion, and second, make sure that the criterion actually tells something about the behavior one wishes to describe. This is used in the weighted error spectral power ratio (WESPR) criterion by means of a frequency dependent weighting function. When the parameters of the models are estimated a suitable error criterion should likewise be used. The frequency weighting function in the WESPR is used in the extraction of the parameters. It is shown on two types of PAs that the model performance measured as WESPR can be improved while the model complexity is reduced compared to the standard frequency neutral criterion. When building a model of a system it is advantageous to take account of the physical structure and incorporate this knowledge into the model. It can improve model performance and possibly reduce the number of parameters. By starting from a physically motivated nonlinear model of a RF PA, the commonly used memory polynomial (MP) models are derived. Additionally, three novel MP model structures are derived. Using data measured on a PA it is found that two of these model structures have lower model errors while using fewer parameters than models previously published in the literature. Methods to increase the power efficiency and the linearity of RF PAs have been investigated. One of these methods is digital predistortion (DPD) which improves the linearity, thus facilitating operation at higher power levels which improves power efficiency. The other method is a signal shaping method that makes the signal more favorable to the PA by reducing the highest peaks to lower values. It is experimentally shown that the combination of DPD and signal shaping results in an increase of power efficiency in the order of 2-4 times. An instability in the feedback loop that updates the parameters of the DPD was also identified and two solutions were proposed. One solution changes the parameters of the DPD in such a way that the instability is avoided and the other changes the signal to avoid high amplitudes. The nonlinear effects of class-D outphasing amplifiers are considered. Four model structures are proposed and evaluated on data measured from two amplifiers. In order to reduce the distortions in the output signal from the amplifiers an algorithm using constant envelope amplitude (purely phase-modulated) signals is proposed. The DPD is evaluated and found to reduce the distortions in a state-of-the-art 32 dBm class-D outphasing PA to make it fulfill the linearity requirements for downlink signals used in the universal mobile telecommunications system (UMTS).Denna avhandling behandlar ett antal aspekter av digital beteendemodellering och korrektion av effektförstärkare för radiofrekvensapplikationer. När prestandan hos en beteendemodell skall bedömas är det för det första viktigt att ha ett utvärderingskriterium och för det andra är det viktigt att detta kriterium fokuserar på de relevanta delarna av beteendet man är intresserad av. Detta används i kriteriet weighted error spectral power ratio (WESPR) genom att en viktning införs. Denna viktning används för att fokusera på de aspekter av beteendet som är viktiga att beskriva. På samma sätt är det viktigt att fokusera på att minimera de relevanta delarna av modellfelet. Genom att använda viktningen från WESPR när parametrarna i beteendemodellen skall estimeras visas det på två olika typer av PA att modellprestandan kan förbättras och modellkomplexiteten reduceras när ett relevant felkriterium används. När en modell av ett system byggs är det fördelaktigt att använda den kunskap man har om det fysikaliska systemet. Det kan förbättra modellprestandan samtidigt som antalet parametrar kan reduceras. Genom att börja med en fysikaliskt motiverad modell av en effektförstärkare och införa antaganden härleds de populära minnespolynomen. Dessa har tidigare inte haft någon fysikalisk förklaring. Dessutom härleds tre nya minnespolynom. Av dessa visar två av strukturerna lägre modellfel samtidigt som färre parametrar används än i de tidigare publicerade minnespolynomen. Metoder för att förbättra energieffektiviteten och linjariteten i effektförstärkare har undersökts. En av dessa metoder är digital predistorsion (DPD) vilken förbättrar linjariteten och möjliggör på så vis högre uteffekter, vilket i sin tur förbättrar energieffektiviteten. Den andra testade metoden går ut på att förändra signalen genom att reducera effekttopparna så att signalen blir lämpligare för förstärkaren. Det visas experimentellt att kombinationen av dessa metoder kan resultera i förbättringar av energieffektiviteten på 2-4 gånger. En instabilitet i återkopplingsslingan för parameteruppdateringen av DPD identifieras och två förslag på lösningar ges. Det första förslaget modifierar parametrarna så att instabiliteten undviks. Det andra förslaget förändrar signalen så att de höga amplituderna undviks och systemet stabiliseras på detta sätt. Slutligen studeras de ickelinjära effekterna i klass-D utfasningsförstärkare. Tre modellstrukturer föreslås och utvärderas på uppmätta data från två olika förstärkare. För att reducera störningarna i utsignalen från förstärkarna föreslås en DPD-algoritm som använder signaler med konstant amplitud (rent fasmodulerade signaler). Denna DPD utvärderas och det visas att den kan reducera störningar i utsignalen hos en modern 32 dBm klass-D utfasande förstärkare så att den uppfyller linjaritetskraven för signaler som används i nedlänken (från basstation till mobil enhet) i telekommunikationssystemet universal mobile telecommunications system (UMTS).
QC 20120514
7
Hella, Mona Mostafa. "CMOS radio frequency power amplifiers for short-range wireless standards /." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486399160107527.
8
Warr, Paul. "Octave-band feedforward linearisation for software defined radio receiver amplifiers." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340270.
9
Mugisho, Moise Safari. "Design of a high efficiency S-band power amplifier for a Cubesat." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2454.
Abstract:
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016.In all radio frequency (RF) electronic communication systems, power amplifiers (PAs) are used to generate the final transmitted signal. Specifically, these PAs are used to increase the output power of the transmitted signal. The PA accomplishes this by converting the applied direct current (DC) power to the PA into RF power, while being driven by a RF input signal. The portion of DC power that is not converted into RF power is dissipated as heat. The power conversion mechanism that takes place in a PA is described by the power conversion efficiency (PE) and the power added efficiency (PAE). A CubeSat is a small satellite in the shape of a 10 × 10 × 10 cm cube, weighing less than 1 kg and contains a RF electronic communication system which allows communication with the satellite. A CubeSat requires a PA with high PE in order to increase the lifetime of the on-board battery, facilitate thermal management on-board the satellite, increase system reliability, and reduce the size and manufacturing cost of the satellite. To maximize the theoretical PE of a RF PA, several design techniques and classes of operation were investigated, the basis of which lies in the fulfilment of the necessary and sufficient conditions for a maximum PE. A PA, which uses the Class-F-1 (inverse Class-F) mode of operation, fulfils the necessary and sufficient conditions for a maximum theoretical PE, and therefore presents itself as a good option for a high efficiency PA. This thesis presents the design of a Class-F-1 PA, using the Cree CGH40010F GaN power active device. An optimum output matching network is used to terminate the drain of the GaN power active device with the required load impedances at the fundamental, 2nd and 3rd harmonic frequencies of operation. The designed PA delivers a maximum PE of 95 % at an operating frequency of 2.2 GHz, a maximum PAE of 82 % at an operating frequency of 2.2 GHz and a maximum output power of 40.6 dBm at an operating frequency of 2.2 GHz.
10
Isaksson, Magnus. "Radio Frequency Power Amplifiers : Behavioral Modeling, Parameter Reduction, and Digital Predistortion." Doctoral thesis, KTH, Signalbehandling, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24198.
Abstract:
This work considers behavioral modeling, parameter-reduction, and digital predistortion of radio frequency power amplifiers. Due to the use of modern digital modulation methods, contemporary power amplifiers are frequently subjected to signals characterized by considerable bandwidths and fast changing envelopes. As a result, traditional quasi-memoryless amplitudeto-amplitude (AM/AM) and amplitude-to-phase (AM/PM) characteristics are no longer sufficient to describe and model the behavior of power amplifiers; neither can they be successfully used for linearization. In this thesis, sampled input and output data are used for identification and validation of several block structure models with memory. The time-discrete Volterra model, the Wiener model, the Hammerstein model, and the radial-basis function neural network are all identified and compared with respect to in-band and out-of-band errors. Two different signal types (multitones and noise), with different powers, peak-to-average ratios, and bandwidths have been used as inputs to the amplifier. Furthermore, two different power amplifiers were investigated, one designed for third generation mobile telecommunication systems and one for second generation systems. A stepped three-tone measurement technique based on digitally modulated baseband signals is also presented. The third-order Volterra kernel parameters were determined from identified intermodulation products. The symmetry properties of the Volterra kernel along various portions of the three dimensional frequency space were analyzed and compared with the symmetry of the Wiener and Hammerstein systems.QC 20100824
11
Boloorian, Majid. "Linearisation of radio frequency power amplifiers using the Cartesian feedback technique." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261369.
12
Franco, Marcelo Jorge Herczfeld Peter R. "Wideband digital predistortion linearization of radio frequency power amplifiers with memory /." Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/485.
13
Brand, Konrad Frederik. "The experimental design and characterisation of Doherty power amplifiers." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019.1/2594.
14
Chan, kwong Fu. "Large-signal characterization/modeling and linearization techniques for RF power amplifiers /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20CHANK.
15
Abbasian, Sadegh. "Radio frequency switch mode power amplifiers and synchronous rectifiers for wireless applications." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55218.
Abstract:
This thesis focuses on identifying and evaluating device, circuit, and system level issues that affect the power efficiency of class-D and class-F switch-mode amplifiers, and class-F synchronous rectifiers. The amplifier and rectifier circuits are used to implement pulse encoded switch-mode power amplifier systems. A detailed power efficiency analysis of current mode class-D amplifiers is presented for variable duty cycle pulse trains. A device model with current saturation in the switch is introduced and gives insight into how to select an appropriate load line for variable duty cycle switching conditions. Other new results include the effect of capacitive switching losses which are usually neglected in current mode amplifiers. The analytical results are compared with simulation results and confirm that the model can provide good predictions of power efficiency for a more general class of pulse encoded signals. Class-F amplifiers are also investigated in this work. The work investigates how input harmonic matching impedances at the gate affect amplifier power efficiency. Second harmonic matching is very important and desensitizes the circuit to nonlinear capacitances in the device. Third harmonic input terminations are much less significant. A comparison of voltage and current mode circuits is also made and the current mode is better in terms of maximizing power efficiency. The work is supported by experimental results. Class-F amplifier circuits are reconfigured into synchronous rectifiers using the theory of time-reversal duality. Time-reversal duality is usually applied in the context of lossless circuits and a discussion of how loss impacts the circuit duals is presented. The rectifier dual always has slightly higher power efficiency and insights into why this occurs are described. Experimental results are shown for voltage and current mode class-F rectifiers as well as a wideband current mode class-F rectifier. The thesis concludes with the analysis and experimental results for an energy recycling switch-mode power amplifier. A signal splitting network is implemented at the output of the amplifier and out-of-band power is rectified to enhance the power efficiency of the amplifier. Experimental results confirm that energy recycling can increase power efficiency. Concluding remarks based on this research are summarized in the context of how best to use these circuits for implementing high efficiency amplifiers and rectifiers for wireless applications.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
16
Rafla, Ramez. "Integrated inductor modeling and CMOS low noise amplifiers for radio-frequency applications." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32971.
Abstract:
A large demand for bandwidth, both for voice and data communication, has increased the need for high-speed systems. Specifically, a wireless revolution is establishing renewed standards and design requirements, such as higher operation frequencies and higher levels of integration.The improved performance of traditional technologies, such as CMOS, which used to be geared towards digital circuits running at lower frequencies, makes them now suitable for Radio-Frequency applications. The challenge is not only to design RF systems, but also to establish design methodologies for their building-blocks.
This thesis is concerned with one of those building blocks, namely the low noise amplifier, when implemented using modern submicron CMOS technologies. The design of this circuit, as well as that of many of the RF building blocks, requires accurate integrated inductor modeling tools. The challenge of modeling inductors implemented in silicon technologies lies in the complex electro-magnetic behavior of these devices. A powerful modeling engine, McGill Inductor Modeler (MIND), was implemented for this purpose, and proven to be accurate and precise.
The contribution of this work is twofold: First, proving that performant high-frequency CMOS RF LNA's could be achieved. Second, creating a powerful and versatile inductor modeling tool.
17
Jurkov, Alexander S. "Lossless multi-way power combining and outphasing for radio frequency power amplifiers." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79230.
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 102-106).
For applications requiring the use of power amplifiers (PAs) operating at high frequencies and power levels, it is often preferable to construct multiple low power PAs and combine their output powers to form a high-power PA. Moreover, such PAs must often be able to provide dynamic control of their output power over a wide range, and maintain high efficiency across their operating range. This research work describes a new power combining and outphasing system that provides both high efficiency and dynamic output power control. The introduced system combines power from four or more PAs, and overcomes the loss and reactive loading problems of previous outphasing systems. It provides ideally lossless power combining, along with nearly-resistive loading of the individual power amplifiers over a very wide output power range. The theoretical fundamentals underlying the behavior and operation of this new combining system are thoroughly developed. Additionally, a straight-forward combiner design methodology is provided. The prototype design of a 27.12 MHz, four-way power combining and outphasing system is presented, implemented, and its performance is experimentally validated over a 1OW-1OOW (10:1) output power range.
by Alexander S. Jurkov.
S.M.
18
Chen, Yi-Jan Emery. "Development of integrated RF CMOS power amplifiers for wireless communications." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14821.
19
Lotter, Paul. "Development of feedforward RF power amplifier." Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/2206.
Abstract:
Thesis (MTech(Electrical Engineering))--Cape Peninsula University of Technology, 2006.Electronic communication systems have become an integral part of our everyday lives. RF (Radio Frequency) power amplifiers form part of the fundamental building blocks of an electronic communication system. RF power amplifiers can also be one of the major causes of distortion in an electronic communication system. This thesis describes the linearity requirement for a RF power amplifier that is used in a transmitter section of an electronic communication system. Furthermore, five different linearisation techniques are presented and their characteristics compared. Since a power amplifier employing the Feedforward linearisation technique was designed, built and tested, this thesis focuses on the Feedforward technique. The design methods for the various Feedforward components are presented. The measured parameters of the Feedforward linearised amplifier are compared with the measured parameters of a non-linearised amplifier.
20
Mbeutcha, France Gaspari. "A High-Side Wideband Current and Voltage Sensor for Radio-Frequency Power Amplifiers." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17464/.
Abstract:
The radio-frequency power amplifier (RF PA) is one of the critical elements within the wireless, as it is expected to provide a suitable output power with high efficiency and linearity. Improving the power efficiency of the RF power amplifier is a key challenge of the modern wireless communications, especially in the presence of wideband modulations signals. In fact, to achieve this goal, various techniques are investigated, including supply voltage modulation (e.g., envelope- tracking). In the supply-modulated Pas employed in modern telecom base stations, it is important to measure the dynamic current drained by the power amplifier and the dynamic voltage at the supply terminal.
This thesis project is focused on the design and realization of a high-side wideband (frequency response from dc up to > 100 MHz) voltage and current sensor suitable for supply-modulated power amplifiers. In order to be used with Gallium Nitride (GaN) PAs, the sensor must be able to withstand dynamic supply voltages up to 80 V and dynamic drain currents up to 2 A. The proposed current sensor is based on a shunt resistor approach, where the voltage drops across the resistor is firstly attenuated, and then amplified by a balanced differential circuit consisting of two cascaded stages. The voltage sensor consists of an operational amplifier configured as a buffer.
The first part of the project, developed at the DEI EDM Lab (UNIBO), was dedicated to the analysis of the sensing architecture, the simulation of the resulting circuit. The design of the board its characterization and board test were realized in at the Warsaw University of Technology in Poland.
21
Ko, Yus. "Design and optimization of 5GHz CMOS power amplifiers with the differential load-pull techniques." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013036.
22
Gibiino, Gian Piero <1986>. "Nonlinear Characterization and Modeling of Radio-Frequency Devices and Power Amplifiers with Memory Effects." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7383/.
Abstract:
Despite the fast development of telecommunications systems experienced during the last two decades, much progress is expected in the coming years with the introduction of new solutions capable of delivering fast data-rates and ubiquitous connectivity. However, this development can only happen through the evolution of radio-frequency systems, which should be capable of working at high-power and high-speed. At the same time, the power dissipation of these systems should be minimized. In this dissertation, methods for the characterization and modeling of transistors and power amplifiers are presented, along with the necessary nonlinear measurements techniques. In particular, dynamic electrical effects, originated by the properties of the semiconductor materials and by the system configurations, are investigated. Consequently, these phenomena, which cannot be ignored to obtain the wanted performance, are empirically identified and included in models for Gallium Nitride (GaN) transistors and power amplifiers driven by a dynamic voltage supply.
23
Fioravanti, Paolo. "Large signal design of silicon field effect transistors for linear radio frequency power amplifiers." Thesis, De Montfort University, 2006. http://hdl.handle.net/2086/13294.
24
Jha, Nand Kishore. "Design of a complementary silicon-germanium variable gain amplifier." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24614.
25
Silva, Clara Maria Apolinário Lucas da. "Low noise amplifiers' design for radioastronomy." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14549.
Abstract:
Mestrado em Engenharia Electrónica e TelecomunicaçõesSpace exploration has always been an ambition to human kind. Nowadays the new technologies that could be used in radioastronomy field have made this goal even more attainable. The big manufacturers that produce the equipment and the necessary components have made a big reinforcement that boosted the creation of new colossal projects, such as the SKA. Within this bold project stands this thesis with the intention of establishing a new approach to the implementation of the recent technologies on the design of low noise amplifiers. This work has the objective of filling the need of decreasing the cost of the numerous components that incorporate the reception's systems. The low noise amplifier is inserted on the radiometer which follows the antenna and is the first electronic device reached by the electromagnetic radiation coming from space. The construction's importance of an amplifier that introduces a low level of noise at reduced cost is due to the massive amount of this type of elements that exists on a project of this magnitude. It is also due to the high quality that this device must have to assure the consequent decoding that follows.
A exploração do espaço sempre foi uma ambição do ser humano. Hoje em dia as novas tecnologias aplicadas na área de radioastronomia tornaram possível que esta última meta ficasse cada vez mais atingível. O reforço fornecido pelas grandes empresas que produzem o equipamento e os componentes necessários, impulsionou o avanço de novos projectos grandiosos tais como o SKA. No âmbito deste projecto arrojado apresenta-se esta dissertação com o intuito de estabelecer uma nova aproximação à implementação de recentes tecnologias no desenho de amplificadores de baixo ruído. O enquadramento deste trabalho bem colmatar a necessidade de diminuir o custo dos vários componentes que integram os sistemas de recepção. O amplificador de baixo ruído está inserido no radiómetro, que, após a antena, é o primeiro dispositivo a ser alcançado pela radiação electromagnética proveniente do espaço. A importância da construção de um amplificador que introduza um nível de ruído baixo com um custo reduzido deve-se principalmente à quantidade massiva destes elementos num projecto desta envergadura e à necessidade da sua qualidade ter de ser elevada para garantir a consequente descodificação do sinal recebido.
26
Chen, Chih-Hung. "CMOS RF front-end design of a very narrowband transceiver with 0.18[micrometers]." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
27
Gray, Blake Raymond. "Design of RF and microwave parametric amplifiers and power upconverters." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43613.
Abstract:
The objective of this research is to develop, characterize, and demonstrate novel parametric architectures capable of wideband operation while maintaining high gain and stability. To begin the study, phase-incoherent upconverting parametric amplifiers will be explored by first developing a set of analytical models describing their achievable gain and efficiency. These models will provide a set of design tools to optimize and evaluate prototype circuit boards. The prototype boards will then be used to demonstrate their achievable gain, bandwidth, efficiency, and stability. Further investigation of the analytical models and data collected from the prototype boards will conclude bandwidth and gain limitations and end the investigation into phase-incoherent upconverting parametric amplifiers in lieu of negative-resistance parametric amplifiers.
Traditionally, there were two versions of negative-resistance parametric amplifiers available: degenerate and non-degenerate. Both modes of operation are considered single-frequency amplifiers because both the input and output frequencies occur at the source frequency. Degenerate parametric amplifiers offer more power gain than their non-degenerate counterpart and do not require additional circuitry for idler currents. As a result, a phase-coherent degenerate parametric amplifier printed circuit board prototype will be built to investigate achievable gain, bandwidth, and stability. Analytical models will be developed to describe the gain and efficiency of phase-coherent degenerate parametric amplifiers. The presence of a negative resistance suggests the possibility of instability under certain operating conditions, therefore, an in-depth stability study of phase-coherent degenerate parametric amplifiers will be performed.
The observation of upconversion gain in phase-coherent degenerate parametric amplifiers will spark investigation into a previously unknown parametric architecture: phase-coherent upconverting parametric amplifiers. Using the phase-coherent degenerate parametric amplifier prototype board, stable phase-coherent upconversion with gain will be demonstrated from the source input frequency to its third harmonic. An analytical model describing the large-signal transducer gain of phase-coherent upconverting parametric amplifiers from the first to the third harmonic of the source input will be derived and validated using the prototype board and simulations.
28
Huang, Wenxiang. "A broadband RF CMOS frond-end for multi-standard wireless communication." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1170882877.
29
Nel, Christoffel Antonie. "The creation of nonlinear behavioral-level models for system level receiver simulation." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50128.
Abstract:
Thesis (MScEng)--Stellenbosch University, 2004.ENGLISH ABSTRACT: The aim of this thesis was to investigate the use of behavioral level models in receiver simulations using the capabilities of Agilent's Advanced Design System. Behavioral level modeling has become increasingly attractive because it offers faster and easier results for system level simulations. The work in this thesis focused strongly on nonlinear measurements to characterize the various nonlinear phenomena that are present in amplifiers and mixers. Measurement automation software was developed to automate the process. An error correction technique was also developed to increase the accuracy of spectrum analyzer measurements. The measured data was used to implement the behavioral level amplifier and mixer models in ADS. The accuracy of the models was compared to measured data and the different available models were compared. Finally the models were combined to realize different receivers and were used to do typical receiver tests. These test include gain and gain compression, two-tone intermodulation and spurious responses. The results are compared to measured data to test the accuracy and usefulness of the models and simulation techniques.
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis was om stelsel-vlak gedrags-modelle te ondersoek soos hulle in Agilent se Advanced Design System (ADS) aangebied word. Die modellering van die stelselvlak-gedrag van komponente en stelsels is aantreklik aangesien dit 'n hoë vlak beskrywing van komplekse kommunikasie stelsels moontlik maak. Akkurate stelsel-vlak simulasies sal lei tot vinnige ontwikkeling en evaluasie van nuwe sisteme. Die resultate wat verkry word is egter afhanklik van die beskikbaarheid van akkurate stelsel-vlak gedragsmodelle Die tesis het baie sterk op metings staat gemaak om die nie-liniêre gedrag van versterkers en mengers te karakteriseer. Meet sagteware is ontwikkel om die verskillende metings te automatiseer. Fout korreksie vir spetrum-analiseerder-metings is ook ontwikkel. Die gemete data is gebruik om die nie-liniêre gedrags-modelle in ADS te implementer. Die modelle is in simulasies gebruik en die akuraatheid van die simulasies is teen gemete data getoets. Die finale deel van die tesis gebruik die modelle om tipiese ontvanger karakteristieke te voorspel. Die volgende toetse is gedoen: aanwins en kompressie, twee-toon intermodulasie en hoer orde meng produkte. Die resultate van die toetse is met gemete data vergelyk om die akuraatehied en bruikbaarheid van die verskillende modelle te vergelyk.
30
Fourie, Paul. "Pulse power device characterization for amplifier design." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16323.
Abstract:
Thesis (MSCIng)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: Bi-polar Si transistors optimized for pulse conditions is still the most popular choice as amplification element in the final stages of solid-state radar amplifiers in L and S band. With the radar market being small, the design data for these devices is normally fairly limited and it is up to the designers to thoroughly characterize them for their designs. This is normally done through loadpull experiments. Professional automated load-pull equipment is very expensive especially at the higher power levels. In spite of being automated and under computer control, load-pull exercises still is very time consuming and as such expensive. For small companies that only occasionally need to design such amplifiers it is not economically viable to acquire such equipment and different strategies have to be found to stay competitive. This report investigates such a strategy and its implementation. A procedure to quickly and accurately characterize such devices was developed and two amplifiers were designed and build with this procedure and compared to their traditional counterparts for verification. The results were very promising and with a bit more work, the technique can likely be used to characterize these devices for design work outside of the parameters designated by the manufacturers.
AFRIKAANSE OPSOMMING: Bipolere Silikon transistors wat vir werking onder gepulsde toestande geoptimiseer is, is nog steeds die mees gewilde keuse as versterkingselement in die finale stadiums van vastetoestand radar versterkers in die L en S bande. Met die radar mark wat geredelik klein is, is die ontwerp inligting vir hierdie elemente gewoonlik redelik karig en is dit die taak van die ontwerpers om die elemente te karakteriseer vir hulle ontwerp doeleindes. Dit word normaalweg gedoen deur lastrek eksperimente. Geoutomatiseerde lastrek toerusting is baie duur, veral as dit onder hoë drywingstoestande moet werk. Al is die toerusting geoutomatiseer en onder rekenaar beheer, is lastrek oefeninge nog steeds baie tydrowend en daarom dan ook baie duur. Vir klein maatskappye wat net nou en dan nodig het om sulke versterkers te ontwerp is dit gewoon nie ekonomies regverdigbaar om sulke toerusting aan te skaf nie, en ander strategië moet gevind word om ekonomies kompeterend te bly. Hierdie verslag ondersoek so 'n strategie en die implimentering daarvan. n Prosedure om gepulsde bipolere transistore vinnig en akkuraat te karakteriseer is ontwikkel en twee versterkers is met die prosedure ontwerp en gebou. Die versterkers is geverifieer deur hulle met hulle tradisionele eweknië te vergelyk. Die resultate lyk baie belowend en met n bietjie meer werk kan die metode waarskynlik ook gebruik word om die transistors buite die toepassings gebied, soos deur die vervaardigers aangedui, te gebruik.
31
Jansen, Roelof. "Evaluation of Doherty Amplifier Implementations." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/20445.
Abstract:
Thesis (MScIng)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Modern communication systems demand efficient, linear power amplifiers. The amplifiers are often operated in the backed-off power levels at which linear amplifiers such as class B amplifier are particularly inefficient. The Doherty amplifier provides an improvement as it increases efficiency at backed of power levels. Doherty amplifiers consists of two amplifiers, a carrier amplifier and a peaking amplifier, of which the output is combined in a novel way. Implementation of the Doherty amplifier with transistors is not ideal. One of the main problems is the insufficient current production of the peaking amplifier at peak envelope power (PEP) if it is implemented as a class C amplifier. A suggested solution to this problem is a bias adaption system that controls the peaking amplifier gate voltage dynamically depending on the input power levels. The design and evaluation of such a adaptive Doherty amplifier is the main goal of this thesis. A classical Doherty amplifier with and an uneven Doherty amplifier with unequal power division between the carrier and peaking amplifiers are also evaluated and compared with the adaptive Doherty amplifier. The amplifiers are designed using a 10 W LDMOS FET device, the MRF282. The adaptive Doherty amplifier and the uneven Doherty amplifier show significant improvements in efficiency and output power over the even Doherty amplifier. At PEP the adaptive Doherty delivers 42.4 dBm at 39.75 % power added efficiency (PAE), the uneven Doherty amplifier 41.9 dBm at 40.75 % PAE and the even Doherty amplifier 40.8 dBm at 38.6 % PAE. At 3dB backed-off input power the adaptive Doherty amplifier has an efficiency of 34.3%, compared to 34.9 5% for the uneven Doherty amplifier and 29.75 % for the even Doherty amplifier.
AFRIKAANSE OPSOMMING: Moderne kommunikasie stelsels vereis effektiewe, linieêre drywing versterkers. Die versterkers word dikwels in laer drywings vlakke bedryf waar linieêre versterkers soos ’n klas B versterker besondere lae effektiwiteit het. Die Doherty versterker bied ’n uitweg omdat dit verbeterde effektiwiteit by lae drywings vlakke bied. ’n Doherty versterker bestaan uit twee versterkers, die hoof versterker en die aanvullende versterker, waarvan die uittrees met ’n spesiale kombinasie netwerk bymekaar gevoeg word. Die implementasie van Doherty versterkers met transistors is nie ideaal nie. Een van die hoof probleme is die onvoldoende stroom wat deur die aanvullings versterker gebied word by piek omhulsel drywing (POD). ’n Oplossing vir die probleem is om ’n aanpassings sisteem te gebruik wat die aanvullende versterker se hekspanning dinamies beheer afhangende van die intree drywings vlakke. Die ontwerp en evaluasie van so ’n aanpassings Doherty versterker is die hoof doel van hierdie tesis. ’n Klassieke Doherty versterke met gelyke drywings verdeling en ’n ongelyke Doherty versterker wat gebruik maak van ongelyke drywings verdeling tussen die hoof-en aanvullende versterkers is ook gevalueer en vergelyk met die aanpassings Doherty versterker. Die versterkers was ontwerp met ’n 10 W LDMOS FET, die MRF282. Die aanpassings Doherty versterker en die ongelyke Doherty versterker het aanmerklike verbeteringe in effektiwiteit en uittree drywing gebring in vergelyking met die ewe Doherty versterker. By POD het die aanpassings versterker 42.4 dBm teen 39.75 % drywing toegevoegde effektiwiteit (DTE) gelewer, die ongelyke Doherty versterker 41.9 dBm teen 40.75 % DTE, en die ewe Doherty versterker 40.8 dBm teen 38.6 DTE. By ’n intree drywingsvlak 3 dB laer as POD het die aanpassings Doherty versterker ’n effektiwiteit van 34.3 % getoon, in vergelyking met die onewe Doherty versterker se 34.9 % en die ewe Doherty versterker se 29.75 % DTE.
32
Mahdavi, Sareh. "RF power amplifiers and MEMS varactors." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112576.
Abstract:
This thesis is concerned with the design and implementation of radio frequency (RF) power amplifiers and micro-electromechanical systems---namely MEMS varactors. This is driven by the many wireless communication systems which are constantly moving towards increased integration, better signal quality, and longer battery life.The power amplifier consumes most of the power in a receiver/transmitter system (transceiver), and its output signal is directly transmitted by the antenna without further modification. Thus, optimizing the PA for low power consumption, increased linearity, and compact integration is highly desirable.
Micro-electromechanical systems enable new levels of performance in radio-frequency integrated circuits, which are not readily available via conventional IC technologies. They are good candidates to replace lossy, low Q-factor off-chip components, which have traditionally been used to implement matching networks or output resonator tanks in class AB, class F, or class E power amplifiers. The MEMS technologies also make possible the use of new architectures, with the possibility of flexible re-configurability and tunability for multi-band and/or multi-standard applications.
The major effort of this thesis is focused on the design and fabrication of an RF frequency class AB power amplifier in the SiGe BiCMOS 5HP technology, with the capability of being tuned with external MEMS varactors. The latter necessitated the exploration of wide-tuning range MEMS variable capacitors, with prototypes designed and fabricated in the Metal-MUMPS process.
An attempt is made to integrate the power amplifier chip and the MEMS die in the same package to provide active tuning of the power amplifier matching network, in order to keep the efficiency of the PA constant for different input power levels and load conditions.
Detailed simulation and measurement results for all circuits and MEMS devices are reported and discussed.
33
Lou, Shuzuo. "Design of CMOS RF low-noise amplifiers and mixer for wireless applications /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20LOU.
34
Kim, Hyun-Woong. "CMOS RF transmitter front-end module for high-power mobile applications." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47592.
Abstract:
With the explosive growth of the wireless market, the demand for low-cost and highly-integrated radio frequency (RF) transceiver has been increased. Keeping up with this trend, complimentary metal-oxide-semiconductor (CMOS) has been spotlighted by virtue of its superior characteristics. However, there are challenges in achieving this goal, especially designing the transmitter portion. The objective of this research is to demonstrate the feasibility of fully integrated CMOS transmitter module which includes power amplifier (PA) and transmit/receive (T/R) switch by compensating for the intrinsic drawbacks of CMOS technology.
As an effort to overcome the challenges, the high-power handling T/R switches are introduced as the first part of this dissertation. The proposed differential switch topology and feed-forward capacitor helps reducing the voltage stress over the switch devices, enabling a linear power transmission. With the high-power T/R switches, a new transmitter front-end topology - differential PA and T/R switch topology with the multi-section PA output matching network - is also proposed. The multi-stage PA output matching network assists to relieve the voltage stress over the switch device even more, by providing a low switch operating impedance. By analyzing the power performance and efficiency of entire transmitter module, design methodology for the high-power handling and efficient transmitter module is established. Finally, the research in this dissertation provides low-cost, high-power handling, and efficient CMOS RF transmitter module for wireless applications.
35
Yu, Xin [Verfasser], and Georg [Akademischer Betreuer] Fischer. "Contributions to Digital Predistortion of Radio-Frequency Power Amplifiers for Wireless Applications / Xin Yu. Betreuer: Georg Fischer." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2012. http://d-nb.info/1026365481/34.
36
Pinarello, Sandro [Verfasser]. "Adaptive strategies for enhancing the efficiency of radio frequency power amplifiers in back-off operation / Sandro Pinarello." München : Verlag Dr. Hut, 2017. http://d-nb.info/1126297739/34.
37
Hershberger, Kyle M. "In-situ S-Parameter Analysis and Applications." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51839.
Abstract:
This thesis will begin with an investigation on the limitations associated with the predominate two-port stability analysis techniques with respect to multi-stage RF amplifier design. The primary focus will be to investigate and develop network analysis techniques that allow internal ports to be created within a RF circuit. This technique will facilitate the application of existing stability analysis techniques in ways that are not commonly known. Examples of situations where traditional network and stability analysis is insufficient will be presented, and the application of the newly developed techniques will be examined.
38
Narasimha, Raju Divya. "Study of ESD effects on RF power amplifiers." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4993.
Abstract:
Today, ESD is a major consideration in the design and manufacture of ICs. ESD problems are increasing in the electronics industry because of the increasing trend toward higher speed and smaller device sizes. There is growing interest in knowing the effects of ESD protection circuit on the performance of semiconductor integrated circuits (ICs) because of the impact it has on core RF circuit performance. This study investigated the impact of ESD protection circuit on RF Power amplifiers. Even though ESD protection for digital circuits has been known for a while, RF-ESD is a challenge. From a thorough literature search on prior art ESD protection circuits, Silicon controlled rectifier was found to be most effective and reliable ESD protection for power amplifier circuit. A SCR based ESD protection was used to protect the power amplifier and a model was developed to gain better understanding of ESD protected power amplifiers. Simulated results were compared and contrasted against theoretically derived equations. A 5.2GHz fully ESD protected Class AB power amplifier was designed and simulated using TSMC 0.18 micrometer] technology. Further, the ESD protection circuit was added to a cascoded Class-E power amplifier operating at 5.2 GHz. ADS simulation results were used to analyze the PA's RF performance degradation. Various optimization techniques were used to improve the RF circuit performance.ID: 029809372; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references.
M.S.
Masters
Electrical Engineering and Computer Science
Engineering and Computer Science
39
Yoon, Youngchang. "Reconfigurable CMOS RF power amplifiers for advanced mobile terminals." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/48987.
Abstract:
In recent years, tremendous growth of the wireless market can be defined through the following words: smartphone and high-data rate wireless communication. This situation gives new challenges to RF power amplifier design, which includes high-efficiency, multi-band operation, and robustness to antenna mismatch conditions. In addition to these issues, the industry and consumers demand a low-cost small-sized wireless device. A fully integrated single-chip CMOS transceiver is the best solution in terms of cost and level of integration with other functional blocks. Therefore, the effective approaches in a CMOS process for the abovementioned hurdles are highly desirable. In this dissertation, the new challenges are overcome by introducing adaptability to a CMOS power amplifier. Meaningful achievements are summarized as follows. First, a new CMOS switched capacitor structure for high power applications is proposed. Second, a dual-mode CMOS PA with an integrated tunable matching network is proposed to extend battery lifetime. Third, a switchless dual-band matching structure is proposed, and the effectiveness of dual-band matching is demonstrated with a fully-integrated CMOS PA. Lastly, a reconfigurable CMOS PA with an automatic antenna mismatch recovery system is presented, which can maintain its original designed performance even under various antenna mismatch conditions. Conclusively, the research in this dissertation provides various solutions for new challenges of advanced mobile terminals.
40
Overstreet, William Patton. "VHF bipolar transistor power amplifiers: measurement, modeling, and design." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71166.
Abstract:
Widely used design techniques for radio frequency power amplifiers yield results which are approximate; the initial design is usually refined by applying trial-and-error procedures in the laboratory. More accurate design techniques are complicated in their application and have not gained acceptance by practicing engineers. A new design technique for VHF linear power amplifiers using bipolar junction transistors is presented in this report. This design technique is simple in its application but yields accurate results.
The design technique is based upon a transistor model which is simple enough to be useful for design, but which is sufficiently accurate to predict performance at high frequencies. Additionally, the model yields insight into many of the processes which take place within the typical RF power transistor. The fundamental aspect of the model is the inclusion of charge storage within the transistor base. This charge storage effect gives rise to a nearly sinusoidal collector current waveform, even in a transistor which ostensibly is biased for class B or nonsaturating class C operation.
Methods of predicting transistor input and output impedances are presented. A number of other topics related to power amplifier measurement and design are also included. A unique measurement approach which is ideally suited for use with power amplifiers is discussed. This measurement approach is a hybrid of the common S-parameter measurement technique and the "load-pull" procedure. Practical considerations such as amplifier stability, bias network design, and matching network topology are also included in the report.Ph. D.
41
Li, Jia, and 李佳. "Photonic microwave processor based on fiber optical parametric amplifier." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43085374.
42
Li, Jia. "Photonic microwave processor based on fiber optical parametric amplifier." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43085374.
43
Choi, Kiyong. "Parasitic-aware design and optimization of CMOS RF power amplifier /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/6078.
44
Glock, Stefan [Verfasser]. "Semi-Physical Behavioral Modeling of Radio Frequency Power Amplifiers for the Optimization of the Linearity-Efficiency Tradeoff / Stefan Glock." München : Verlag Dr. Hut, 2014. http://d-nb.info/1058284975/34.
45
Sahu, Biranchinath. "Integrated, Dynamically Adaptive Supplies for Linear RF Power Amplifiers in Portable Applications." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7607.
Abstract:
Energy-efficient radio frequency (RF) power amplifiers (PAs) are critical and paramount to achieve longer battery life in state-of-the-art portable systems because they typically determine and dominate the power consumption of such devices. In this dissertation, a high-efficiency, linear RF PA with a dynamically adaptive supply and bias current control for code division multiple access (CDMA) and wideband CDMA (WCDMA) is conceived, simulated, and experimentally demonstrated with a discrete PCB-level design and in integrated circuit (IC) form. The PA efficiency is improved by dynamically adjusting both its supply voltage and bias current, there by minimizing its quiescent power dissipation. The PA supply voltage is derived from the battery by a noninverting, synchronous buck-boost switching regulator because of its flexible functionality and high efficiency. Adjusting the PA supply voltage and bias current by tracking the output power, instead of following the complete envelope in large baseband bandwidth wireless applications, is achieved by a converter with a lower switching frequency and consequently higher light-load efficiency, which translates to prolonged battery life.
A discrete PCB-level prototype of the proposed system with 915 MHz center frequency, CDMA IS-95 signal having 27-dBm peak-output power resulted in more than four times improvement in the average efficiency compared to a fixed-supply class-AB PA while meeting the required performance specifications. In the IC solution fabricated in AMIs 0.5-micron CMOS process through MOSIS, a dual-mode, buck-boost converter with pulse-width modulation (PWM) control for high power and pulse-frequency modulation (PFM) for low power is designed and implemented to improve the PA efficiency during active and standby operation, respectively. The performance of the dynamically adaptive supply and bias control IC was validated by realizing a 25-dBm, 1.96 GHz center frequency, WCDMA PA over an input supply range of 1.4 4.2 V. The PA with dual-mode power supply and bias control IC showed an average-efficiency improvement of seven times compared to a fixed-supply class-AB PA, which translates to five times improvement in battery life assuming the PA is active for 2 % of the total time and in standby mode otherwise.
46
Mays, Kenneth W. "A 40 GHz Power Amplifier Using a Low Cost High Volume 0.15 um Optical Lithography pHEMT Process." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/552.
Abstract:
The demand for higher frequency applications is largely driven by bandwidth. The evolution of circuits in the microwave and millimeter frequency ranges always demands higher performance and lower cost as the technology and specification requirements evolve. Thus the development of new processes addressing higher frequencies and bandwidth requirements is essential to the growth of any semiconductor company participating in these markets. There exist processes which can perform in the higher frequency design space from a technical perspective. However, a cost effective solution must complement the technical merits for deployment. Thus a new 0.15 um optical lithography pHEMT process was developed at TriQuint Semiconductor to address this market segment. A 40 GHz power amplifier has been designed to quantify and showcase the capabilities of this new process by leveraging the existing processing knowledge and the implementation of high frequency scalable models. The three stage power amplifier was designed using the TOM4 scalable depletion mode FET model. The TriQuint TQP15 Design Kit also implements microstrip transmission line models that can be used for evaluating the interconnect lines and matching networks. The process also features substrate vias and the thin film resistor and MIM capacitor models which utilize the capabilities of the BCB process flow. During the design stage we extensively used Agilent ADS program for circuit and EM simulation in order to optimize the final design. Special attention was paid to proper sizing of devices, developing matching circuits, optimizing transmission lines and power combining. The final design exhibits good performance in the 40 GHz range using the new TQP15 process. The measured results show a gain of greater than 13 dB under 3 volt drain voltage and a linear output power of greater than 28 dBm at 40 GHz. The 40 GHz power amplifier demonstrates that the new process has successfully leveraged an existing manufacturing infrastructure and has achieved repeatability, high volume manufacturing, and low cost in the millimeter frequency range.
47
Hietakangas, S. (Simo). "Design methods and considerations of supply modulated switched RF power amplifiers." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514298363.
Abstract:
Abstract This thesis studies the design methods and properties of supply-modulated switch-mode radio frequency power amplifiers. Besides simulation based studies and theory review, two amplifiers were designed: a discrete MESFET class E amplifier (0.5 W at 1 GHz), and an integrated pHEMT class E-1 amplifier (2.0 W at 1.6 GHz) with an on-chip resonator. The existing design methods of the resonant output network of switching amplifiers were reviewed and some extensions on the handling of nonlinear capacitances were proposed. The effects of varying supply voltage were studied and suggestions were given to minimize Vdd / AM and Vdd / PM distortion in supply modulated amplifiers. The implementation of the bias feed was also discussed resulting in proposing a combination of a short transmission line and a small inductor, which provides both fast supply modulation and little effect on harmonic impedances. The main contributions are related to the study of the input impedance of a class E power amplifier, where the effects of supply dependent input impedance and timing skew generated by injected harmonic distortion were analyzed. The stabilization of the amplifier was also discussed. Based on the findings, a push-pull class E amplifier with extra cross-coupled feedback capacitors and second harmonic traps at the gates appears to be a very good starting point for a further studyTiivistelmä Tämä väitöstyö käsittelee radiotaajuuksilla toimivien käyttöjännitemoduloitujen kytkintehovahvistimien ominaisuuksia ja suunnittelumenetelmiä. Suunnittelumenetelmiin liittyvän katsauksen ja simulaatioihin perustuvan tutkimusten lisäksi kaksi vahvistinta toteutettiin väitöstutkimuksen aikana: diskreettikomponentein toteutettu E-luokan vahvistin (MESFET, 0.5 W ja 1 GHz) ja integroituna piirinä toteutettu käänteinen E-luokan vahvistin (pHEMT, 2.0 W ja 1.6 GHz), jonka lähdön resonaattoripiiri sisällytettiin integroituun piiriin. Kytkinvahvistimien suunnittelumenetelmiä verrattiin ja kehitettiin edelleen siten, että suunnitteluvaiheessa voidaan ottaa huomioon esim. transistoripiirin takaisinkytkennässä olevan kapasitanssin epälineaarisuus. Työssä tutkittiin myös käyttöjännitemodulaation vaikutusta kytkinvahvistimien toimintaan, ja tutkimuksen tuloksena annettiin muutamia ehdotuksia käyttöjänniteriippuvan amplitudi- (Vdd / AM) ja vaihemodulaation (Vdd / PM) vähentämiseksi. Lähdön biasointipiirin toteutukseen suositeltiin pienen kelan ja siirtolinjan yhdistelmää. Yhdistelmän avulla pyritään maksimoimaan modulaationopeus ja minimoimaan vaikutukset harmonisiin impedansseihin. Pääkohtina väitöksessä ovat E-luokan kytkinvahvistimesta saadut tutkimus- ja mittaushavainnot käyttöjännitteen funktiona muuttuvasta transistorin tuloimpedanssista sekä suurikokoisen transistorin tuloissa tapahtuvan, säröytymisen aiheuttaman tulosignaalien ajoitusvirheen analyysi. Näiden lisäksi vahvistimen stabiilisuuteen kiinnitettiin huomiota. Saatujen havaintojen perusteella voimme todeta, että push-pull -tyyppinen E-luokan vahvistin olisi mielenkiintoinen valinta jatkotutkimuksille
48
Kim, Jihwan. "High performance radio-frequency and millimeter-wave front-end integrated circuits design in silicon-based technologies." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44704.
Abstract:
Design techniques and procedures to improve performances of radio-frequency and millimeter-wave front-end integrated circuits were developed. Power amplifiers for high data-rate wireless communication applications were designed using CMOS technology employing a novel device resizing and concurrent power-combining technique to implement a multi-mode operation. Comprehensive analysis on the efficiency degradation effect of multi-input-single-output combining transformers with idle input terminals was performed. The proposed discrete resizing and power-combining technique effectively enhanced the efficiency of a linear CMOS power amplifier at back-off power levels. In addition, a novel power-combining transformer that is suitable to generate multi-watt-level output power was proposed and implemented. Employing the proposed power-combining transformer, a high-power linear CMOS power amplifier was designed. Furthermore, receiver building blocks such as a low-noise amplifier, a down-conversion mixer, and a passive balun were implemented using SiGe technology for W-band applications.
49
Thrivikraman, Tushar. "Analysis and Design of Low-Noise Amplifiers in Silicon-Germanium Hetrojunction Bipolar Technology for Radar and Communication Systems." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19755.
Abstract:
This thesis presents an overview of the simulation, design, and measurement of state-of-the-art Silicon-Germanium Hetro-Junction Bipolar Transistor (SiGe HBT) low-noise amplifiers (LNAs). The LNA design trade-off space is presented and methods for achieving an optimized design are discussed.
In Chapter 1, we review the importance of LNAs and the benefits of SiGe HBT technology in high frequency amplifier design. Chapter 2 introduces LNA design and basic noise theory. A graphical LNA design approach is presented to aid in understanding of the high-frequency LNA design process. Chapter 3 presents an LNA design optimization method for power constrained applications. Measured results using this design technique are highlighted and shown to have record performance. Lastly, in Chapter 4, we highlight cryogenic noise performance and present measured results from cryogenic operation of SiGe HBT LNAs.
We demonstrate in this thesis that SiGe HBT LNAs have the capability to meet the demanding needs for next generation wireless systems. The aim of the analysis presented herein is to provide designers with the fundamentals of designing SiGe HBT LNAs through relevant design examples and measured results.
50
Zhu, Changwen. "Nonlinear Analysis and Digital Pre-Distortion of the SC-FDMA Signals in LTE Uplink System." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2105.
Abstract:
Single-carrier frequency division multiple access (SC-FDMA) has become a popular alternative to orthogonal frequency division multiple access (OFDM) in multi-user communication on LTE uplink systems. This is primarily due to the low peak-to-average power ratio (PAPR) of SC-FDMA compared to that of OFDM. Long-term evolution (LTE) uses SC-FDMA on the uplink to exploit this PAPR advantage to reduce transmit power amplifier (PA) back-off in mobile user terminals. However, the latest generation of communication systems requires high power efficiency and a large quantity of capacity in transmitting mobile data, bringing out some other critical problems: 1) the nonlinearity of Radio Frequency (RF) power amplifiers inevitably affects the power efficiency. Working beyond the saturation point is the main reason for power amplifiers having nonlinear properties; 2) In order to obtain adequate capacity, wide bandwidth is applied to the latest communication systems. Since in previous systems the pre-distorter would focus on memory-less distortion with relatively narrow bandwidth, this change makes memory distortion become a serious issue, degrading the transmission quality in the wireless communication systems.
The intent of this thesis is to present nonlinear analysis of the SC-FDMA Spectrum with the RF power amplifier. Relevant mathematical models were considered and applied to the RF power amplifier in terms of intermodulation products and the third-order intercept point. The equivalent mathematical model is applied for the first time to SC-FDMA signals and with the previous formulation of the PA model, the derivation of the expressions for spectrum regrowth of amplified SC-FDMA signals was first established and finally simulated with Matlab software. The digital pre-distortion (DPD) technology was also applied to SC-FDMA signals for the first time in this thesis. An inverse intermodulation and Autoregressive Moving-Average (IM-ARMA) model was introduced to linearize the PA distortion with memory in the LTE uplink system. The DPD was finally implemented by Matlab R2010b.
Conclusions are drawn that amplified power emission levels can be expressed by the form of third-order intercept point (IP_3). The expressions for spectrum regrowth of amplified SC-FDMA signals have been verified for the first time with the comparison of simulation, measurement and calculation results. The effects of third order intermodulation have a greater impact than higher order components with respect to out-of-band emission power levels. Furthermore, the DPD algorithm reduced the spectrum regrowth of SC-FDMA signals by 12 dB. The proposed pre-distorter can effectively solve the distortion problem caused by the memory effect in RF power amplifier.