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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Разработка приемника-декодера сигналов стандарта ADS-B : магистерская диссертация / Development of the receiver-decoder for the ADS-B system

Чечеткин, В. А., Chechetkin, V. A. January 2014 (has links)
Разработан прототип приемника-декодера сигналов стандарта ADS-B. В ходе разработки предложена структурная схема выполнения устройства, а так же проведено комплексное исследование элементов устройства. Предложены принципиальные схемы и прототипы печатных плат для таких устройств как усилитель, инжектор питания, малошумящий усилитель, логарифмический детектор, а так же рассмотрена топология фильтра с двойной комплементарной спиралью. Приводятся результаты моделирования в различных пакетах программного обеспечения перечисленных выше устройств, а так же результаты их экспериментального исследования. Для обеспечения симуляции сигналов стандарта, а так же для обработки создано программное обеспечение. / A prototype of the receiver-decoder for the ADS-B system. During the development the block diagram of the device was proposed and a comprehensive study of elements of the device was done. Circuit schematics and layouts of printed circuit boards for devices such as amplifier, power injector, low noise amplifier, logarithmic detector and filter with a double complementary spiral were proposed. The results of the simulation of the listed above devices in a variety of software packages, as well as the results of an experimental study are presented. In order to simulate the signals, as well as for processing them special software was created.
82

Analysis & Design of Radio Frequency Wireless Communication Integrated Circuits with Nanoscale Double Gate MOSFETs

Laha, Soumyasanta 25 August 2015 (has links)
No description available.
83

Silicon-Based PALNA Transmit/Receive Circuits for Integrated Millimeter Wave Phased Arrays

Abdomerovic, Iskren 08 January 2020 (has links)
Phased array element RF front ends typically use single pole double throw (SPDT) switches or circulators with high isolation to prevent leakage of transmit energy into the receiver circuits. However, as phased-array designs scale to the millimeter-wave range, with high degrees of integration, the physical size and performance degradations associated with switches and circulators can present challenges in meeting system performance and size/weight/power (SWAP) requirements. This work demonstrates a loss-aware methodology for analysis and design of switchless transmit/receive (T/R) circuits. The methodology provides design insights and a practical, generally applicable approach for solving the multi-variable optimization problem of switchless power amplifier/low-noise amplifier (PALNA) matching networks, which present optimal matching impedances to both the power amplifier (PA) and the low noise amplifier (LNA) while maximizing power transfer efficiency and minimizing dissipative losses in each (transmit or receive) mode of operation. Three PALNA example designs at W-band are presented in this dissertation, each following a distinct design methodology. The first example design in 32SOI CMOS leverages PA and LNA circuits that already include 50 Ω matching networks at both input and output. The second example design in 8XP SiGe develops the PA and LNA circuits and integrates the PA output and LNA input matching networks into the PALNA matching network that connects the PA and the LNA. The third design in 32SOI CMOS leverages the loss-aware PALNA design methodology to develop a PALNA that achieves simulated maximum power added efficiency of 18 % in transmit and noise figure of 7.5 dB in receive at 94 GHz, which is beyond the published state-of-art for T/R circuits. In addition, for comparison purposes, this dissertation also presents an efficient, switch-based T/R circuit design in 32SOI CMOS technology, which achieves a simulated maximum power added efficiency of 15 % in transmit and noise figure of 6.5 dB in receive at 94 GHz, which is also beyond the published state-of-art for T/R circuits. / Doctor of Philosophy / In military and commercial applications, phased arrays are devices primarily used to achieve focusing and steering of transmitted or received electromagnetic energy. Phased arrays consist of many elements, each with an ability to both transmit and receive radio frequency (RF) signals. Each element incorporates a power amplifier (PA) for transmit and a low noise amplifier (LNA) for receive, which are typically connected using a single pole double throw (SPDT) switch or a circulator with high isolation to prevent leakage of transmit energy into the receiver circuits. However, as phased arrays exploit the latest technological advances in circuit integration and their frequencies of operation increase, physical size and performance degradations associated with switches and circulators can present challenges in meeting system performance and size/weight/power (SWAP) requirements. This dissertation provides a loss-aware methodology for analysis and design of switchless transmit/receive (T/R) circuits where the switches and circulators are replaced by carefully designed power amplifier/low-noise amplifier (PALNA) impedance matching networks. In the switchless T/R circuits, the design goals of maximum power efficiency and minimum noise in transmit and receive, respectively, are achieved through impedance matching that is optimal and low-loss in both modes of operation simultaneously. Three distinct PALNA example designs at W-band are presented in this dissertation, each following a distinct design methodology. With each new design, lessons learned are leveraged and design methodologies are enhanced. The first example design leverages already available PA and LNA circuits and connects them using 50 Ω transmission lines whose lengths are designed to guarantee optimum impedance match in receive and transmit mode of operation. The second example design develops new PA and LNA circuits and connects them using 50 Ω transmission lines whose lengths are designed to simultaneously achieve optimum impedance matching for maximum power efficiency in transmit mode of operation and lowest noise in receive mode of operation. The third design leverages a loss-aware PALNA design methodology, a multi-variable optimization procedure, to develop a PALNA that achieves simulated maximum power added efficiency of 18 % in transmit and noise figure of 7.5 dB in receive at 94 GHz, which is beyond the published state-of-art for T/R circuits. In addition, for comparison purposes with the third PALNA design, this dissertation also presents an efficient, switch-based T/R circuit design, which achieves a simulated maximum power added efficiency of 15 % in transmit and noise figure of 6.5 dB in receive at 94 GHz, which is also beyond the published state-of-art for T/R circuits.
84

Adaptive Suppression of Interfering Signals in Communication Systems

Pelteku, Altin E. 21 April 2013 (has links)
The growth in the number of wireless devices and applications underscores the need for characterizing and mitigating interference induced problems such as distortion and blocking. A typical interference scenario involves the detection of a small amplitude signal of interest (SOI) in the presence of a large amplitude interfering signal; it is desirable to attenuate the interfering signal while preserving the integrity of SOI and an appropriate dynamic range. If the frequency of the interfering signal varies or is unknown, an adaptive notch function must be applied in order to maintain adequate attenuation. This work explores the performance space of a phase cancellation technique used in implementing the desired notch function for communication systems in the 1-3 GHz frequency range. A system level model constructed with MATLAB and related simulation results assist in building the theoretical foundation for setting performance bounds on the implemented solution and deriving hardware specifications for the RF notch subsystem devices. Simulations and measurements are presented for a Low Noise Amplifer (LNA), voltage variable attenuators, bandpass filters and phase shifters. Ultimately, full system tests provide a measure of merit for this work as well as invaluable lessons learned. The emphasis of this project is the on-wafer LNA measurements, dependence of IC system performance on mismatches and overall system performance tests. Where possible, predictions are plotted alongside measured data. The reasonable match between the two validates system and component models and more than compensates for the painstaking modeling efforts. Most importantly, using the signal to interferer ratio (SIR) as a figure of merit, experimental results demonstrate up to 58 dB of SIR improvement. This number represents a remarkable advancement in interference rejection at RF or microwave frequencies.
85

Nonlinear devices characterization and micromachining techniques for RF integrated circuits

Parvais, Bertrand J. H. 10 December 2004 (has links)
The present work is dedicated to the development of high performance integrated circuits for wireless communications, by acting of three different levels: technologies, devices, and circuits. Silicon-on-Insulator (SOI) CMOS technology is used in the frame of this work. Micromachining technologies are also investigated for the fabrication of three-dimensional tunable capacitors. The reliability of micromachined thin-film devices is improved by the coating of silanes in both liquid- and vapor-phases. Since in telecommunication applications, distortion is responsible for the generation of spurious frequency bands, the linearity behavior of different SOI transistors is analyzed. The validity range of the existing low-frequency nonlinear characterization methods is discussed. New simple techniques valid at both low- and high-frequencies, are provided, based on the integral function method and on the Volterra series. Finally, the design of a crucial nonlinear circuit, the voltage-controlled oscillator, is introduced. The describing function formalism is used to evaluate the oscillation amplitude and is embedded in a design methodology. The frequency tuning by SOI varactors is analyzed in both small- and large-signal regimes.
86

Amplificadores de banda ancha y bajo ruido basados en tecnología de GaAs para aplicaciones de radiometría

Aja Abelán, Beatriz 19 January 2007 (has links)
En esta Tesis se ha realizado análisis, diseño y caracterización de los amplificadores de bajoruido y banda ancha en tecnología de GaAs PHEMT con aplicación a los módulos posteriores delradiómetro del instrumento de baja frecuencia del satélite Planck. La Tesis se compone de las siguientes partes:- Introducción y estudio del funcionamiento del radiómetro del instrumento de baja frecuencia de Planck.- Diseño y caracterización de amplificadores de bajo ruido utilizando tecnología de GaAs. Se presentan diseños MMIC en la banda Ka y en la banda Q, y un diseño MIC en la banda Q.- Diseño y construcción de los módulos posteriores en las bandas de 30 y 44 GHz. Se presentan varios prototipos fabricados en ambas bandas, así como medidas de cada uno de los subsistemas que los forman.- Desarrollo de técnicas de medida para receptores de banda ancha con detección directa y su aplicación a la caracterización de los módulos posteriores, mostrando el funcionamiento de los prototipos representativos para las dos bandas de frecuencia.- Integración de los módulos posteriores con los módulos frontales y presentación de algunos de los resultados de medida de los radiómetros completos. / This Thesis deals with the analysis, design and characterization of broadband low noise amplifiersin GaAs PHEMT technology with application to the radiometer Back-End Modules for the Planck Low Frequency Instrument (LFI). The Thesis is composed of the next parts:- Introduction and study about the radiometer of the Planck low frequency instrument.- Design and characterization of low noise amplifiers using GaAs technology. Ka-band MMIC designs and Q-band MMIC and a MIC design are presented.- Design and assembly of the 30 and 44 GHz back-end modules. Several prototypes have been manufactured in both frequency bands and the most representative test results of each subsystem are presented.- Development of measurement techniques for broadband direct detection receivers and their application to the characterization of the back-end modules. Performance of representative prototypes in both frequency bands is included.- Integration of the back end modules and front end modules and significant results of the tests for a radiometer in each frequency band.
87

Innovative transceiver approaches for low-power near-field and far-field applications

Inanlou, Farzad Michael-David 27 August 2014 (has links)
Wireless operation, near-field or far-field, is a core functionality of any mobile or autonomous system. These systems are battery operated or most often utilize energy scavenging as a means of power generation. Limited access to power, expected long and uninterrupted operation, and constrained physical parameters (e.g. weight and size), which limit overall power harvesting capabilities, are factors that outline the importance for innovative low-power approaches and designs in advanced low-power wireless applications. Low-power approaches become especially important for the wireless transceiver, the block in charge of wireless/remote functionality of the system, as this block is usually the most power hungry component in an integrated system-on-chip (SoC). Three such advanced applications with stringent power requirements are examined including space-based exploratory remote sensing probes and their associated radiation effects, millimeter-wave phased-array radar for high-altitude tactical and geological imaging, and implantable biomedical devices (IMDs), leading to the proposal and implementation of low-power wireless solutions for these applications in SiGe BiCMOS and CMOS and platforms.
88

Parametric Interaction in Josephson Junction Circuits and Transmission Lines

Mohebbi, Hamid Reza 06 November 2014 (has links)
This research investigates the realization of parametric amplification in superconducting circuits and structures where nonlinearity is provided by Josephson junction (JJ) elements. We aim to develop a systematic analysis over JJ-based devices toward design of novel traveling-wave Josephson parametric amplifiers (TW-JPA). Chapters of this thesis fall into three categories: lumped JPA, superconducting periodic structures and discrete Josephson transmission lines (DJTL). The unbiased Josephson junction (JJ) is a nonlinear element suitable for parametric amplification through a four-photon process. Two circuit topologies are introduced to capture the unique property of the JJ in order to efficiently mix signal, pump and idler signals for the purpose of signal amplification. Closed-form expressions are derived for gain characteristics, bandwidth determination, noise properties and impedance for this kind of parametric power amplifier. The concept of negative resistance in the gain formulation is observed. A design process is also introduced to find the regimes of operation for gain achievement. Two regimes of operation, oscillation and amplification, are highlighted and distinguished in the result section. Optimization of the circuits to enhance the bandwidth is also carried out. Moving toward TW-JPA, the second part is devoted to modelling the linear wave propagation in a periodic superconducting structure. We derive closed-form equations for dispersion and s-parameters of infinite and finite periodic structures, respectively. Band gap formation is highlighted and its potential applications in the design of passive filters and resonators are discussed. The superconducting structures are fabricated using YBCO and measured, illustrating a good correlation with the numerical results. A novel superconducting Transmission Line (TL), which is periodically loaded by Josephson junctions (JJ) and assisted by open stubs, is proposed as a platform to realize a traveling-wave parametric device. Using the TL model, this structure is modeled by a system of nonlinear partial differential equations (PDE) with a driving source and mixed-boundary conditions at the input and output terminals, respectively. This model successfully emulates parametric and nonlinear microwave propagation when long-wave approximation is applicable. The influence of dispersion to sustain three non-degenerate phased-locked waves through the TL is highlighted. A rigorous and robust Finite Difference Time Domain (FDTD) solver based on the explicit Lax-Wendroff and implicit Crank-Nicolson schemes has been developed to investigate the device responses under various excitations. Linearization of the wave equation, under small-amplitude assumption, dispersion and impedance analysis is performed to explore more aspects of the device for the purpose of efficient design of a traveling-wave parametric amplifier. Knowing all microwave characteristics and identifying different regimes of operation, which include impedance properties, cut-off propagation, dispersive behaviour and shock-wave formation, we exploit perturbation theory accompanied by the method of multiple scale to derive the three nonlinear coupled amplitude equations to describe the parametric interaction. A graphical technique is suggested to find three waves on the dispersion diagram satisfying the phase-matching conditions. Both cases of perfect phase-matching and slight mismatching are addressed in this work. The incorporation of two numerical techniques, spectral method in space and multistep Adams-Bashforth in time domain, is employed to monitor the unilateral gain, superior stability and bandwidth of this structure. Two types of functionality, mixing and amplification, with their requirements are described. These properties make this structure desirable for applications ranging from superconducting optoelectronics to dispersive readout of superconducting qubits where high sensitivity and ultra-low noise operation is required.
89

Power Scaling Mechanism for Low Power Wireless Receivers

Ghosal, Kaushik January 2015 (has links) (PDF)
LOW power operation for wireless radio receivers has been gaining importance lately on account of the recent spurt of growth in the usage of ubiquitous embedded mobile devices. These devices are becoming relevant in all domains of human influence. In most cases battery life for these devices continue to be an us-age bottleneck as energy storage techniques have not kept pace with the growing demand of such mobile computing devices. Many applications of these radios have limitations on recharge cycle, i.e. the radio needs to last out of a battery for long duration. This will specially be true for sensor network applications and for im-plantable medical devices. The search for low power wireless receivers has become quite advanced with a plethora of techniques, ranging from circuit to architecture to system level approaches being formulated as part of standard design procedures. However the next level of optimization towards “Smart” receiver systems has been gaining credence and may prove to be the next challenge in receiver design and de-velopment. We aim to proceed further on this journey by proposing Power Scalable Wireless Receivers (PSRX) which have the capability to respond to instantaneous performance requirements to lower power even further. Traditionally low power receivers were designed for worst-case input conditions, namely low signal and high interference, leading to large dynamic range of operation which directly im-pacts the power consumption. We propose to take into account the variation in performance required out of the receiver, under varying Signal and Interference conditions, to trade-off power. We have analyzed, designed and implemented a Power Scalable Receiver tar-geted towards low data-rate receivers which can work for Zigbee or Bluetooth Low Energy (BLE) type standards. Each block of such a receiver system was evaluated for performance-power trade-offs leading to identification of tuning/control knobs at the circuit architecture level of the receiver blocks. Then we developed an usage algorithm for finding power optimal operational settings for the tuning knobs, while guaranteeing receiver reception performance in terms of Bit-Error-Rate (BER). We have proposed and demonstrated a novel signal measurement system to gen-erate digitized estimates of signal and interference strength in the received signal, called Received Signal Quality Indicator (RSQI). We achieve a RSQI average energy consumption of 8.1nJ with a peak energy consumption of 9.4nJ which is quite low compared to the packet reception energy consumption for low power receivers, and will be substantially lower than the energy savings which will be achieved from a power scalable receiver employing a RSQI. The full PSRX system was fabricated in UMC 130nm RF-CMOS process to test out our concepts and to formally quantify the power savings achieved by following the design methodology. The test chip occupied an area of 2.7mm2 with a peak power consumption of 5.5mW for the receiver chain and 18mW for the complete PSRX. We were able to meet the receiver performance requirements for Zigbee standard and achieved about 5X power savings for the range of input condition variations.
90

Frequency Synthesis for Cognitive Radio Receivers and Other Wideband Applications

Zahir, Zaira January 2017 (has links) (PDF)
The radio frequency (RF) spectrum as a natural resource is severely under-utilized over time and space due to an inefficient licensing framework. As a result, in-creasing cellular and wireless network usage is placing significant demands on the licensed spectrum. This has led to the development of cognitive radios, software defined radios and mm-wave radios. Cognitive radios (CRs) enable more efficient spectrum usage over a wide range of frequencies and hence have emerged as an effective solution to handle huge network demands. They promise versatility, flex-ability and cognition which can revolutionize communications systems. However, they present greater challenges to the design of radio frequency (RF) front-ends. Instead of a narrow-band front-end optimized and tuned to the carrier frequency of interest, cognitive radios demand front-ends which are versatile, configurable, tun-able and capable of transmitting and receiving signals with different bandwidths and modulation schemes. The primary purpose of this thesis is to design a re-configurable, wide-band and low phase-noise fast settling frequency synthesizer for cognitive radio applications. Along with frequency generation, an area efficient multi-band low noise amplifier (LNA) with integrated built-in-self-test (BIST) and a strong immunity to interferers has also been proposed and implemented for these radios. This designed LNA relaxes the specification of harmonic content in the synthesizer output. Finally some preliminary work has also been done for mm-wave (V-band) frequency synthesis. The Key Contributions of this thesis are: A frequency synthesizer, based on a type-2, third-order Phase Locked Loop (PLL), covering a frequency range of 0.1-5.4 GHz, is implemented using a 0.13 µm CMOS technology. The PLL uses three voltage controlled oscillators (VCOs) to cover the whole range. It is capable of switching between any two frequencies in less than 3 µs and has phase noise values, compatible with most communication standards. The settling of the PLL in the desired state is achieved in dynamic multiple steps rather than traditional single step settling. This along with other circuit techniques like a DAC-based discriminator aided charge pump, fast acquisition pulse-clocked based PFD and timing synchro-negation is used to obtain a significantly reduced settling time A single voltage controlled LC-oscillator (LC-VCO) has been designed to cover a wide range of frequencies (2.0-4.1 GHz) using an area efficient and switch-able multi-tap inductor and a capacitor bank. The switching of the multi-tap inductor is done in the most optimal manner so as to get good phase-noise at the output. The multi-tap inductor provides a significant area advantage, and in spite of a degraded Q, provides an acceptable phase noise of -123 dBc/Hz and -113 dBc/Hz at an offset of 1 MHz at carrier frequencies of 2 and 4 GHz, respectively. Implemented in a 0.13 µm CMOS technology, the oscillator with ≈ 69 % tuning range, occupies an active area of only 0.095 mm2. An active inductor based noise-filter has been proposed to improve the phase-noise performance of the oscillator without much increase in the area. A variable gain multi-band low noise amplifier (LNA) is designed to operate over a wide range of frequencies (0.8 GHz to 2.4 GHz) using an area efficient switchable-π network. The LNA can be tuned to different gain and linearity combinations for different band settings. Depending upon the location of the interferers, a specific band can be selected to provide optimum gain and the best signal-to-intermodulation ratio. This is accomplished by the use of an on-chip Built-in-Self-Test (BIST) circuit. The maximum power gain of the amplifier is 19 dB with a return loss better than 10 dB for 7 mW of power consumption. The noise figure is 3.2 dB at 1 GHz and its third-order intercept point (I I P3) ranges from -15 dBm to 0 dBm. Implemented in a 0.13 µm CMOS technology, the LNA occupies an active area of about 0.29 mm2. Three different types of VCOs (stand-alone LC VCO, push-push VCO and a ring oscillator based VCO) for generating mm-wave frequencies have been implemented using 65-nm CMOS technology and their measured results have been analyzed

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