Дисертації: "Oscillators, Electric; Oscillators, Microwave"

1

Kratzenstein, L. "Electronically tuned 23 GHz Gunn oscillators for a microwave datalink." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/8327.

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Includes bibliographical references.
A market has been identified for 23 GHz, short-haul, low-capacity, digital radio. The dissertation presents the development of the varactor controlled Gunn oscillators that constitute the crystal locked microwave sources of the radio. An accurate description of a design procedure for Gunn oscillators at 23 GHz is presented. With reference to advanced modulation methods which require constant modulation indices, a method of linearising the voltage/frequency characteristic of the varactor controlled Gunn oscillator is described, which allows direct modulation of the source at 23 GHz. Due to the wide operating temperature of the radio a technique to temperature compensate the oscillator is presented. The dissertation ends with an investigation how the semiconductor device's spread affects the oscillator characteristics and an evaluation of the noise performance of the Gunn oscillator.

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2

Vermaak, Elrien. "Development of a low phase noise microwave voltage controlled oscillator." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1940.

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3

Li, Duo Ph D. Massachusetts Institute of Technology. "Attosecond timing jitter modelocked lasers and ultralow phase noise photonic microwave oscillators." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87930.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 111-119).
Photonic microwave oscillator based on optical frequency comb and ultrastable optical reference cavity represents the state-of-the-art solution to generate X-band microwaves of ultralow phase noise. Such high-quality microwave source enables a range of applications in which frequency stability and timing accuracy are essential to performance. Wide use of this technology, however, requires compact system architecture, low-term stability and low energy consumption, which drive the needs to develop high repetition-rate femtosecond lasers alternative to Ti:sapphire technology, and to explore a feasible means to achieve integrated photonic microwave oscillators. Ultrafast Cr:LiSAF lasers can be directly pumped with low-cost red laser diodes, and the electrical-to-optical conversion efficiency is as high as 10%. High repetition-rate femtosecond Cr:LiSAF lasers are developed with the help of semiconductor saturable absorber technology, efficient dispersion compensation mirror design algorithms, and heat management of the saturable absorber. The I-GHz Cr:LiSAF oscillator generates 55-fs pulses with 110 pJ pulse energy, which represents almost two orders of magnitude improvement in the output peak power over previous results. Timing jitter of 1 00-MHz Cr:LiSAF lasers is measured with a single-crystal balanced optical cross-correlator to be -30 as from 10 kHz to 50 MHz. Pump intensity noise coupled into phase noise through the self-steepening effect proves to be the major noise source. The most recent advance in silicon photonics and wafer-scale three-dimensional integration technology illuminates a pathway toward on-chip photonic microwave oscillators. Phase noise model of the proposed Erbium Silicon Photonics Integrated OscillatoR (ESPIOR) suggests that it is possible to achieve comparable noise performance with the Ti:sapphire-based system, without the need of carrier-envelope-offset frequency detection. A demonstration using fiber-optic components further indicates that it is practicable to realize optical frequency division and microwave readout in the proposed architecture. With the advancement of heterogeneous electronic-photonic integration, it would pave the way for an ultralow-noise microwave source fully integrated in a hybrid photonic-electronic chip on a silicon substrate.
by Duo Li.
Ph. D.

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4

Eklund, Anders. "Microwave Frequency Stability and Spin Wave Mode Structure in Nano-Contact Spin Torque Oscillators." Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188546.

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The nano-contact spin torque oscillator (NC-STO) is an emerging device for highly tunable microwave frequency generation in the range from 0.1 GHz to above 65 GHz with an on-chip footprint on the scale of a few μm. The frequency is inherent to the magnetic material of the NC-STO and is excited by an electrical DC current by means of the spin torque transfer effect. Although the general operation is well understood, more detailed aspects such as a generally nonlinear frequency versus current relationship, mode-jumping and high device-to-device variability represent open questions. Further application-oriented questions are related to increasing the electrical output power through synchronization of multiple NC-STOs and integration with CMOS integrated circuits. This thesis consists of an experimental part and a simulation part. Experimentally, for the frequency stability it is found that the slow but strong 1/f-type frequency fluctuations are related to the degree of nonlinearity and the presence of perturbing, unexcited modes. It is also found that the NC-STO can exhibit up to three propagating spin wave oscillation modes with different frequencies and can randomly jump between them. These findings were made possible through the development of a specialized microwave time-domain measurement circuit. Another instrumental achievement was made with synchrotron X-rays, where we image dynamically the magnetic internals of an operating NC-STO device and reveal a spin wave mode structure with a complexity significantly higher than the one predicted by the present theory. In the simulations, we are able to reproduce the nonlinear current dependence by including spin wave-reflecting barriers in the nm-thick metallic, magnetic free layer. A physical model for the barriers is introduced in the form of metal grain boundaries with reduced magnetic exchange coupling. Using the experimentally measured average grain size of 30 nm, the spin wave mode structure resulting from the grain model is able to reproduce the experimentally found device nonlinearity and high device-to-device variability. In conclusion, the results point out microscopic material grains in the metallic free layer as the reason behind the nonlinear frequency versus current behavior and multiple propagating spin wave modes and thereby as a source of device-to-device variability and frequency instability.
Dagens snabba utveckling inom informationsteknik drivs på av ständigt växande informationsmängder och deras samhällsanvändning inom allt från resursoptimering till underhållning. Utvecklingen möjliggörs till stor del hårdvarumässigt av miniatyrisering och integrering av elektroniska komponenter samt trådlös kommunikation med allt större bandbredd och högre överföringshastighet. Det senare uppnås främst genom utnyttjande av högre radiofrekvenser i teknologiskt tidigare oåtkomliga delar av spektrumet. Frekvensutnyttjandet har det senaste årtiondet ökat markant i mikrovågsområdet med typiska frekvenser runt 2.4 GHz och 5.2-5.8 GHz. I den spinntroniska oscillatorn (STO:n) möjliggörs frekvensgenerering i det breda området från 0.1 GHz upp till över 65 GHz av en komponent med mikrometerstorlek som kan integreras direkt i CMOS-mikrochip. Till skillnad från i konventionella radiokretsar med oscillatorer konstruerade av integrerade transistorer och spolar, genereras mikrovågsfrekvensen direkt i STO:ns magnetiska material och omvandlas därefter till en elektrisk signal genom komponentens magnetoresistans. Dessa materialegenskaper möjliggör ett tillgängligt frekvensband med extrem bredd i en och samma STO, som därtill kan frekvensmoduleras direkt genom sin styrström och på så sätt förenklar konstruktionen av sändarsystem. STO:ns icke-linjära egenskaper kan potentiellt också användas för att i en och samma komponent blanda ned mottagna mikrovågssignaler och på så sätt förenkla konstruktionen även av mikrovågsmottagare. STO:ns signalegenskaper bestäms av det magnetiska materialets fysik i form av magnetiseringsdynamik driven av elektriskt genererade spinnströmmar. I denna avhandling studeras denna dynamik experimentellt med särskilt fokus på frekvensstabiliteten i den hittills mest stabila STO-typen; nanokontakts-STO:n. Genom mätningar i tidsdomän av STO:ns elektriska signaler runt 25 GHz har frekvensstabiliteten funnits hänga samman med den typ av icke-linjärt beteende som också funnits vara utmärkande för tillverkningsvariationen i komponenterna. Mikroskopiska undersökningar av materialet visar att en trolig källa till denna variation är den magnetiska metallens uppbyggnad i form av korn i storleksordningen 30 nm, och datorsimuleringar av en sådan materialstruktur har visats kunna reproducera de experimentella resultaten. Därtill har en metod utvecklats för att med röntgenstrålning direkt mäta de små, magnetiska mikrovågsrörelserna i materialet. Denna röntgenteknik möjliggör detaljerade experimentella studier av magnetiseringsdynamiken och kan användas för att verifiera och vidareutveckla den existerande teorin för mikrovågsspinntronik. Sammantaget förs STO-teknologin genom denna studie ett steg närmare sina tänkbara samhällsbreda tillämpningar inom snabb, trådlös kommunikation för massproducerade produkter med integrerad sensor- och datorfunktionalitet.

QC 20160620

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5

Chipengo, Ushemadzoro. "Novel Concepts for Slow Wave Structures used in High Power Backward Wave Oscillators." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1499346841806681.

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6

Francis, Smita. "Optimisation of doping profiles for mm-wave GaAs and GaN gunn diodes." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2568.

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Thesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2017.
Gunn diodes play a prominent role in the development of low-cost and reliable solid-state oscillators for diverse applications, such as in the military, security, automotive and consumer electronics industries. The primary focus of the research presented here is the optimisation of GaAs and GaN Gunn diodes for mm-wave operations, through rigorous Monte Carlo particle simulations. A novel, empirical technique to determine the upper operational frequency limit of devices based on the transferred electron mechanism is presented. This method exploits the hysteresis of the dynamic velocity-field curves of semiconductors to establish the upper frequency limit of the transferred electron mechanism in bulk material that supports this mechanism. The method can be applied to any bulk material exhibiting negative differential resistance. The simulations show that the upper frequency limits of the fundamental mode of operation for GaAs Gunn diodes are between 80 GHz and 100 GHz, and for GaN Gunn diodes between 250 GHz and 300 GHz, depending on the operating conditions. These results, based on the simulated bulk material characteristics, are confirmed by the simulated mm-wave performance of the GaAs and GaN Gunn devices. GaAs diodes are shown to exhibit a fundamental frequency limit of 90 GHz, but with harmonic power available up to 186_GHz. Simulated GaN diodes are capable of generating appreciable output power at operational frequencies up to 250 GHz in the fundamental mode, with harmonic output power available up to 525 GHz. The research furthermore establishes optimised doping profiles for two-domain GaAs Gunn diodes and single- and two-domain GaN Gunn diodes. The relevant design parameters that have been optimised, are the dimensions and doping profile of the transit regions, the width of the doping notches and buffer region (for two-domain devices), and the bias voltage. In the case of GaAs diodes, hot electron injection has also been implemented to improve the efficiency and output power of the devices. Multi-domain operation has been explored for both GaAs and GaN devices and found to be an effective way of increasing the output power. However, it is the opinion of the author that a maximum number of two domains is feasible for both GaAs and GaN diodes due to the significant increase in thermal heating associated with an increase in the number of transit regions. It has also been found that increasing the doping concentration of the transit region exponentially over the last 25% towards the anode by a factor of 1.5 above the nominal doping level enhances the output power of the diodes.

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7

Alaslami, Nauwaf. "Design Procedures for Series and Parallel Feedback Microwave DROs." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/2235.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007.
Clear procedures for designing dielectric resonator oscillators (DROs) are presented in this thesis, including built examples to validate these design procedures. Both series and parallel feedback DROs are discussed and the procedures for building them are presented. Two examples at different frequencies for each type of DRO are constructed and tested with the results shown. The first is at a frequency of approximately 6.22 GHz and the second for the higher frequency of 11.2 GHz. The DROs for the desired frequencies are designed using the Microwave Office (MWO) software by AWR with the design based on the small-signal model (scattering parameters). Oscillators are produced using the negative resistance method. The circuit achieves low noise by using a dielectric resonator with a high Q factor. Both the series and parallel feedback DRO circuits can be mechanically tuned around the resonant frequency to maximize performance.

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8

SANTOS, BRUNO PALHARES DOS. "PHASE NOISE OPTIMIZATION OF MICROWAVE OSCILLATORS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7590@1.

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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Nesta dissertação foram projetados e desenvolvidos osciladores apresentando ruído de fase otimizado. Em virtude das limitações dos equipamentos analisadores de espectro na precisa medição do ruído de fase dos osciladores desenvolvidos nos laboratórios do CETUC, foi implementada a técnica de medição Método do Detector de Fase. Esta técnica consiste no desenvolvimento de um segundo oscilador com as mesmas características do existente, e com auxílio de misturadores, realizar o batimento dos mesmos para freqüências próximas a DC, onde nesta região a medição do ruído de fase torna-se viável. Entretanto, em aplicações dedicadas, verificou-se que o batimento entre dois osciladores operando em torno de 10 GHz produz uma freqüência intermediária instável, variando de 10 kHz à 50 kHz. Para evitar a realização de uma medição extremamente instável, utilizou-se o método de sincronização de freqüências (Injection Locking) entre os osciladores. Foi também destacada a influência do ruído de cintilação (Flicker Noise) na medida final do ruído de fase. A melhor medida aferida foi em torno de -100 dBc/Hz @ 3,25 kHz. Foi verificado através de diversas simulações que a freqüência de cintilação int c f , situada em 10 MHz, apresenta grande influência sobre as medições do ruído de fase realizadas à 3,25 kHz da portadora, degradando-o em cerca de 30dB.
In this dissertation, oscillators presenting optimized phase noise had been projected and develloped. Because of the limitation of the specter analyzer devices in the accurate measurements of the oscillators phase noise developed in the CETUC laboratories, it was implemented the measurement technique called Phase Detector Method. This technique consists on the development of a second oscillator with the same characteristics of the already existent one and, with aid of mixers, multiplies these signals together and provides the difference of the two signals next to DC, where, in this region, the measurement of the phase noise becomes viable. However, in dedicated applications, it was verified that the beating between two oscillators operating around 10GHz produces instable intermediate frequency, varying between 10kHz to 50kHz. To prevent the accomplishment of an extremely unstable measurement, the method of synchronization of frequency (Injection Locking) between the oscillators was used. Also the influence of the Flicker Noise in the final measure of the phase noise was detached. The best measure was around -100dBc/Hz@3,25kHz. It was verified through lots of simulations that the flicker corner frequency int c f , situated in 10MHz, presents great influence on the measures of the phase noise carried through to the 3,25kHz of the carrier, degrading it in about 30dB.

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9

Siripon, Nipapon. "Microwave balanced oscillators and frequency doublers." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/771938/.

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The research presented in this thesis is on the application of the injection-locked oscillator technique to microwave balanced oscillators. The balanced oscillator design is primarily analysed using the extended resonance technique. A transmission line is connected between the two active devices, so that the active device resonate each other. The electrical length of the transmission line is also analysed for the balanced oscillation condition. The balanced oscillator can be viewed with the negative resistance model and the feedback model. The former model is characterised at a circuit plane where the feedback network is cut. By using both the negative-resistance oscillator model and the feedback model, the locking range of the oscillator is analysed by extending Kurokawa's theory. This analysis demonstrates the locking range of the injection phenomenon, where the injection frequency is either close to the free-running frequency, close to (lin) x freerunning frequency or close to n x the free-running frequency. It also reveals the effect of different injection power levels on the locking range. Injection-locked balanced oscillators for subharmonic and fundamental modes are constructed. When the balanced oscillator is in the locking state, it is clearly shown that the output signal is better stabilised and the phase noise is attenuated. The experimental results agree with the analysis. Furthermore, the spurious signal suppression in a cascaded oscillator is investigated. The other focus of this research is on the design of frequency doublers. A balanced douber is designed and integrated with a balanced injection-locked oscillator. The experimental result shows that the output signal is clean and stabilised. The other important frequency doubler design technique studied is the use of the feedforward technique to significantly eliminate the fundamental frequency component. The design and the experiment show that the fundamental component can be suppressed to better than 50 dBc.

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10

Victor, Alan M. "Microwave Power Oscillator utilizing Thin-Film Varactor." NCSU, 2010. http://www.lib.ncsu.edu/theses/available/etd-03232010-100654/.

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Synthesis of Microwave Power Oscillators utilizing Thin-film Varactors. The application of the power oscillator is in high efficiency microwave sources for the direct carrier launch of microwave signals. The resulting work directing towards the efficient implementation for microwave transmitters.

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11

Badiere, Daniel N. "A study of high Q spiral inductor fabrication methods using a production silicon process with application to a current tuned microwave oscillator /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61016.pdf.

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12

Alberti, Mathias V. "Thermodynamics of the Henon-Heiles oscillators." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13056.

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13

Ma, Chi-chiu, and 馬志超. "Tribological study of carbon nanotube oscillators." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B44570120.

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14

Middleditch, Steven. "Microwave non linear adaptive filters and delay line oscillators." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444040.

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15

Sayyah, Ali Afkari. "The design of power combined oscillators suitable for millimetre-wave development." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phs275.pdf.

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16

Agrawal, Deepak Kumar. "Nonlinear effects and synchronization in MEMs oscillators." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648280.

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17

McKearney, James F. "Analysis of nonlinearities in a voltage-controlled oscillator." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01122010-020048/.

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18

Wang, Shenshen. "Theoretical approach to circular-polarization-independence of microwave-induced resistance oscillations and zero resistance state /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202007%20WANG.

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19

李華淸 and Wah-ching Lee. "Low sensitivities and roundoff noise digital oscillators and filters design." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31208290.

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20

Lee, Wah-ching. "Low sensitivities and roundoff noise digital oscillators and filters design /." [Hong Kong : University of Hong Kong], 1987. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12354429.

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21

Bunting, Jeremy. "The modelling and measurement of noise in microwave FET oscillators." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254670.

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22

Mochizuki, Koki. "Vortex motion studies of superconductors using mechanical oscillators /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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23

Dallas, Paul-Athos. "Determining the sources of flicker noise in GaAs MESFETs." Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283338.

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24

Moussounda, Renaud. "Analysis and Design of Coupled-Oscillator Arrays for Microwave Systems." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388354578.

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25

Toomey, Emily. "Microwave response of nonlinear oscillations in resistively shunted superconducting nanowires." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113924.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science , 2017.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 83-86).
Many superconducting technologies such as rapid single flux quantum computing (RSFQ) and superconducting quantum interference devices (SQUIDs) rely on the modulation of nonlinear dynamics in Josephson junctions for functionality. More recently, however, superconducting devices have been developed based on the switching and thermal heating of nanowires for use in fields such as single photon detection and digital logic. In this Master's thesis, I will use resistive shunting to control the nonlinear heating of a superconducting nanowire and compare the resulting dynamics to those observed in Josephson junctions. In particular, I will use a microwave drive to modulate the nonlinear behavior of the shunted nanowire, and will relate the observed results to the AC Josephson effect. New nanowire devices based on these conclusions may have promising applications in fields such as parametric amplification and frequency multiplexing.
by Emily Toomey.
S.M.

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26

Douglas, Dale Scott. "Flicker noise in cmos lc oscillators." Thesis, Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26550.

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Sources of flicker noise generation in the cross-coupled negative resistance oscillator (NMOS, PMOS, and CMOS) are explored. Also, prior and current work in the area of phase noise modeling is reviewed, including the work of Leeson, Hajimiri, Hegazi, and others, seeking the mechanisms by which flicker noise is upconverted. A Figure of Merit (FOM) methodology suitable to the 1/f3 phase noise region is also developed, which allows a new quantity, FOM1, to be defined. FOM1 is proportional to flicker noise upconverted, thus allowing the effectiveness of flicker noise upconversion suppression techniques to be evaluated, despite possibly changing bias points or tank Q, which would change phase noise and FOM in the 1/f2 region. The work of Hajimiri is extended with a simple Amplitude ISF DC component estimator for the special case of LC CMOS oscillators. A method of adaptive control of an oscillator core is presented, as well, comprised of a CMOS oscillator with a digitally adjustable N and P width, and a circuit (which is essentially a tracking ADC) which repeatedly adjusts the relative N to P width dependent on the estimate to maintain the condition of minimum flicker noise upconversion. A fixed calibration constant is sufficient to allow convergence to within 0.7dB of optimal FOM1 for all cases of N width, for a varactorless oscillator test cell. Finally, a circuit is proposed which would allow the flicker noise reduction technique of cycling to accumulation to be applied to continuous time oscillators, but is not rigorously vetted.

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27

Lee, Chong Kyong 1973. "Continuation methods for steady state analysis of oscillators." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99777.

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Oscillator circuits are an integral component of wireless communications systems and are increasingly in demand. As such systems gain widespread use, price becomes a very important factor in the design process, and the design cycle must be optimized. This puts an increasing emphasis on the proficiency of oscillator design automation tools. At the same time, as the performance requirements of such systems are becoming more stringent, the required simulation complexity is also increasing. More specifically, high frequency selectivity and low phase noise require very high quality factor oscillators, which in turn negatively affect the convergence performance of current simulation techniques. This thesis proposes a new continuation method for improving the convergence of oscillator simulations and compares this method to some of the methods reported in the literature. The proposed approach does not require a very good initial guess in order to converge to a final solution.

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28

Fitzpatrick, Justin Jennings. "Analysis and Design of Low-Jitter Oscillators." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd369.pdf.

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29

Anstie, James D. "A 50 K dual-mode sapphire oscillator and whispering spherical mode oscillators." University of Western Australia. School of Physics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0070.

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[Truncated abstract] This thesis is split into two parts. In part one; A 50 K dual mode oscillator, the aim of the project was to build a 50 K precision oscillator with frequency stability on the order of 1014 from 1 to 100 seconds. A dual-mode temperature compensation technique was used that relied on a turning point in the frequency-temperature relationship of the difference frequency between two orthogonal whispering gallery modes in a single sapphire crystal. A cylindrical sapphire loaded copper cavity resonator was designed, modelled and built with a turning point in the difference frequency between an E-mode and H-mode pair at approximately 52.5 K . . . The frequencies and Q-factors of whispering spherical modes in the 3-12 GHz range in the fused silica resonator are measured at 6, 77 and 300 K and the Q-factor is used to determine the loss tangent at these temperatures. The frequency and Q-factor temperature dependence of the TM2,1,2 whispering gallery mode at 5.18 GHZ is used to characterise the loss tangent and relative permittivity of the fused silica from 4-300 K. Below 22 K the frequency-temperature dependence of the resonator was found to be consistent with the combined effects of the thermal properties of the dielectric and the influence of an unknown paramagnetic impurity, with a spin resonance frequency at about 138 ± 31 GHz. Below 8 K the loss tangent exhibited a 9th order power law temperature dependence, which may be explained by Raman scattering of Phonons from the paramagnetic impurity ions. A spherical Bragg reflector resonator made from multiple concentric dielectric layers loaded in a spherical cavity that enables confinement of field in the centre of the resonator is described. A set of simultaneous equations is derived that allow the calculation of the required dimensions and resonance frequency for such a resonator and the solution is confirmed using finite element analysis. A spherical Bragg reflector resonator is constructed using Teflon and free-space as the dielectric materials. A Q-factor of 22,000 at 13.87 GHz was measured and found to compare well with the design values.

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30

Ng, Wing Lun. "Low-voltage high-frequency CMOS transformer-feedback voltage-controlled oscillators /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?ECED%202006%20NG.

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31

Wang, Le. "The design of a low noise VCO with innovative harmonic filtering resistor." Embargo, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/l%5Fwang%5F080906.pdf.

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32

Maldonado, Gustavo Omar. "Stochastic response of single degree of freedom hysteretic oscillators." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45804.

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During strong ground shaking structures often become inelastic and respond hysteretically. Therefore, in this study some hysteretic models commonly used in seismic structural analysis are studied. In particular the characteristics of a popular endochronic model proposed by Bouc and Wen are examined in detail. In addition, analytical expressions have also been developed for most commonly used bilinear model as well as another model, herein called as the hyperbolic model.

Master of Science

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33

Smith, Graham Murray. "Transferred electron oscillators at mm wave frequencies and their characterisation using quasi-optical techniques." Thesis, University of St Andrews, 1990. http://hdl.handle.net/10023/11106.

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A study of high frequency millimetre wave oscillators is performed operating at W- band and above, using test bench equipment designed and constructed in St. Andrews. Octave tuneable oscillators have been designed, constructed, and used to characterise developmental Gunn devices, as well as to provide ideal oscillators for test bench measurement systems. These oscillators have been sold to many millimetre-wave laboratories throughout Britain. The operation, optimisation and characterisation of these oscillators is described in detail, and various non-linear effects are explained and modelled successfully. The wideband tuneability and matching has also allowed evaluation of new developmental Gunn devices to accurately determine the optimum operating frequency range of the devices. This was part of a developmental program by GEC Hirst and MEDL which has now produced state of the art GaAs Gunn oscillators at 94GHz. Much of the characterisation of the oscillators is performed using novel quasi-optical techniques, which has allowed low loss accurate performance at these very high frequencies. Several quasi-optical techniques are described and the design, manufacture and evaluation of many optical components are given. In particular, the frequency and harmonic content of the oscillators was determined using a Martin-Puplett Interferometer which utilised a frequency counting technique. This enabled easy wideband measurements to be performed with much greater accuracy than traditional cavity wavemeters. In addition, a state of the art noise bench has been designed and constructed for operation at W -band and above, that utilises a novel open resonator to effect a very high Q suppression filter. The system has been shown to make noise measurements at much lower power levels and with greater sensitivity than comparable systems.

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34

Chan, Tat Fu. "Low power low phase noise CMOS LC quadrature voltage-controlled oscillators /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20CHANT.

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35

Ramanayaka, Aruna N. "Magnetotransport in Two Dimensional Electron Systems Under Microwave Excitation and in Highly Oriented Pyrolytic Graphite." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/phy_astr_diss/54.

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This thesis consists of two parts. The first part considers the effect of microwave radiation on magnetotransport in high quality GaAs/AlGaAs heterostructure two dimensional electron systems. The effect of microwave (MW) radiation on electron temperature was studied by investigating the amplitude of the Shubnikov de Haas (SdH) oscillations in a regime where the cyclotron frequency $\omega_{c}$ and the MW angular frequency $\omega$ satisfy $2\omega \leq \omega_{c} \leq 3.5\omega$. The results indicate negligible electron heating under modest MW photoexcitation, in agreement with theoretical predictions. Next, the effect of the polarization direction of the linearly polarized MWs on the MW induced magnetoresistance oscillation amplitude was investigated. The results demonstrate the first indications of polarization dependence of MW induced magnetoresistance oscillations. In the second part, experiments on the magnetotransport of three dimensional highly oriented pyrolytic graphite (HOPG) reveal a non-zero Berry phase for HOPG. Furthermore, a novel phase relation between oscillatory magneto- and Hall- resistances was discovered from the studies of the HOPG specimen.

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36

Bavisi, Amit. "Integrated multi-mode oscillators and filters for multi-band radios using liquid crystalline polymer based packaging technoloy." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-04062006-131113/.

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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.
Swaminathan, Madhavan, Committee Chair ; Cressler, John D., Committee Co-Chair ; Kenney, Stevenson J., Committee Member ; Peterson, Andrew, Committee Member ; Durgin, Gregory, Committee Member ; Sitaraman, Suresh, Committee Member.

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37

Deshpande, Pratik. "Ultra low noise microwave dielectric oscillators at 3.8GHz and 10GHz and high Q tunable Bragg resonators." Thesis, University of York, 2015. http://etheses.whiterose.ac.uk/12990/.

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The thesis is divided into three parts. The first part of the thesis describes the design and development of two prototypes of an ultra-low phase noise 3.8GHz dielectric resonator oscillator. The first prototype included vibration measurements with a reasonable phase noise measurements developed for Selex-ES. The phase noise for the first 3.8GHz oscillator is -117 dBc/Hz at 1kHz offset and -150 dBc/Hz at 10kHz offset. The second prototype was the improved modular yet compact oscillator was then developed which demonstrated a significantly improved phase noise performance of -125.6 dBc/Hz at 1kHz offset and -153 dBc/Hz at 10kHz offset which is the lowest noise reported in the literature in this frequency band using a ceramic dielectric resonator. In the second part of the thesis, a design and measurement of a high Q broad tuning aperiodic Bragg resonator operating at 10GHz is described. The resonator utilises an aperiodic arrangement of non (λg/4) low loss alumina plates (ℰr=9.75, loss tangent of ~1 to 2 ×10-5) mounted in a cylindrical metal waveguide. The insertion loss, S21, varied from -3.9 dB to -6.4 dB while the unloaded Q varies from 81,650 to 61,020 over the tuning range of 100MHz (1%). In the third part of the thesis, simulation, design and measurement of a low noise Bragg resonator oscillator operating at 10GHz is presented. The oscillators demonstrated a phase noise of -153 dBc/Hz at 10kHz offset and -123 dBc/Hz at 1kHz offset for an unloaded Q of 190,000. To achieve these results extensive optimization of different transistors with different power level and noise figure has taken place.

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38

Hellström, Jonas. "Nanosecond optical parametric oscillators and amplifiers based on periodically poled KTiOPO4." Doctoral thesis, KTH, Physics, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3269.

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Optical parametric oscillators (OPOs) and optical parametricamplifiers (OPAs) constitute a class of optical frequencyconverting devices that have many possible applications, e.g.in range finding, molecular spectroscopy and medicine. They canconvert the frequency of the incident pump field with highefficiency, and generate two waves at new frequencies that willbe continuously tuneable over a wide spectral range. Virtuallyany wavelengths within the transparency region of the nonlinearmaterial can be generated if the material can bequasi-phasematched (QPM). In addition, QPM gives thepossibility to utilise the largest nonlinear tensor element ofthe material and allows walk-off free interaction between thewaves.

The aims of this thesis have been to investigate thepossibility to use QPM KTiOPO₄crystals as nonlinear material in nanosecond OPOsand OPAs operating at room-temperature, and to explore theadvantages and shortcomings of these devices. The technique ofelectric field poling has been employed to implement the QPMstructure in flux grown KTiOPO₄(KTP).

The main conclusion is that periodically poled KTP (PPKTP)is a suitable material to use in nanosecond OPOs and OPAs. Thematerial properties that foremost make KTP into an attractivenonlinear material are: The large value of the nonlinearcoefficient d₃₃, the high resistance to optically inducedbreakdown, the low susceptibility to grey-track formation, theinsensitivity to the photorefractive effect, the widetransparency and the low coercive field.

The thesis shows that it is possible to pole large volumesof KTP with a high quality of the QPM structure. Highlyefficient nanosecond OPOs have been constructed during thisproject. Maximum conversion efficiencies have reached 45 % inthe case of a singly resonant OPO (SRO) built around a 3 mmthick PPKTP crystal. Total pulse energies for both the signal(1.72 µm) and the idler (2.8 µm) of up to 18 mJ wasreached and an average output power of 2 W was obtained forthis sample. However, up to 24 W was produced in a doublyresonant OPO operating close to degeneracy. The efficiencyreached 48 % for that case. Truly continuous and very widespectral tuning has also been demonstrated, as well as a narrowbandwidth OPO operating on one single longitudinal mode.

Keywords:optical parametric oscillators, opticalparametric amplifiers, quasi-phasematching, KTiOPO₄, nonlinear optics, frequency conversion, periodicelectric field poling, ferroelectrics, high-order secondharmonic generation, electro-optic effect.

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39

Chan, Wing Chun. "Supply and temperature compensated oscillator for super twisted nematic (STN) application /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20CHAN.

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40

Stewart, Brian K. "Development of a thin-film evaporative cooling system for a high energy thulium holmium lutetium lithium fluoride solid-state laser oscillator crystal /." Available online, Georgia Institute of Technology, 2005, 2004. http://etd.gatech.edu/theses/available/etd-12032004-114711/unrestricted/stewart%5Fbrian%5Fk%5F200505%5Fmast.pdf.

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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005.
S. Mostafa Ghiaasiaan, Committee Chair ; Sheldon M. Jeter, Committee Member ; Said I. Abdel-Khalik, Committee Member. Includes bibliographical references.

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41

Bonetti, Stefano. "Magnetization Dynamics in Nano-Contact Spin Torque Oscillators : Solitonic bullets and propagating spin waves." Doctoral thesis, KTH, Materialfysik, MF, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-26955.

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Magnetization dynamics in nano-contact spin torque oscillators (STOs) is investigated from an experimental and theoretical point of view. The fundamentals of magnetization dynamics due to spin transfer torque are given. A custom-made high frequency (up to 46 GHz) in large magnetic fields (up to 2.2 T) microwave characterization setup has been built for the purpose and described in this thesis. A unique feature of this setup is the capability of applying magnetic fields at any direction θe out of the sample plane, and with high precision. This is particularly important, because the (average) out-of-plane angle of the STO free magnetic layer has fundamental impact on spin wave generation and STO operation. By observing the spin wave spectral emission as a function of θe, we find that at angles θe below a certain critical angle θcr, two distinct spin wave modes can be excited: a propagating mode, and a localized mode of solitonic character (so called spin wave bullet). The experimental frequency, current threshold and frequency tuneability with current of the two modes can be described qualitatively by analytical models and quantitatively by numerical simulations. We are also able to understand the importance, so far underestimated, of the Oersted field in the dynamics of nano-contact STOs. In particular, we show that the Oersted field strongly affects the current tuneability of the propagating mode at subcritical angles, and it is also the fundamental cause of the mode hopping observed in the time-domain. This mode hopping has been observed both experimentally using a state-of-the-art real-time oscilloscope and corroborated by micromagnetic simulations. Micromagnetic simulations also reveal details of the spatial distribution of the spin wave excitations. By investigating the emitted power as a function of θe, we observed two characteristic behaviors for the two spin wave modes: a monotonic increase of the power for increasing out-of-plane angles in the case of the propagating mode; an increase towards a maximum power followed by a drop of it at the critical angle for the localized mode. Both behaviors are reproduced by micromagnetic simulations. The agreement with the simulations offers also a way to better understand the precession dynamics, since the emitted power is strongly connected to the angular variation of the giant magnetoresistance signal. We also find that the injection locking of spin wave modes with a microwave source has a strong dependence on θe, and reaches a maximum locking strength at perpendicular angles. We are able to describe these results in the theoretical framework of non-linear spin wave dynamics.
QC 20101130

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42

Tholén, Erik. "Intermodulation in microresonators : for microwave amplification and nanoscale surface analysis." Doctoral thesis, KTH, Nanostrukturfysik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11593.

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This work explores the effects of weak nonlinearity on harmonic oscillators.Two particular systems are studied experimentally: A superconductingresonator formed from a coplanar waveguide that oscillates at microwave frequencies,and the cantilever of an atomic force microscope (AFM) vibratingat ultrasonic frequencies. Both of these systems are described in the introduction,followed by a theory chapter giving a general theoretical framework for nonlinear oscillators. Basic properties of nonlinear oscillators, such asbifurcation and intermodulation, are explained using simple models. Experimental methods, including cryogenic and microwave measurement techniques,are described in some detail. The nonlinear superconducting resonator is studied for use as a parametric amplifier. A strong drive tone, called the pump, drives the oscillator nearthe point of bifurcation. A second, much weaker drive signal that is slightlydetuned from the pump, will cause energy to move from the pump to the signal, giving signal amplification. We have measured a signal gain greaterthan 22 dB in a bandwidth of 30 kHz, for a resonator pumped at 7.6 GHz.This type of amplifier is phase-sensitive, meaning that signals in phase withthe pump will be amplified, but signals in quadrature phase of the pump will be deamplified. Phase-sensitivity has important implications on the amplifier’snoise properties. With a parametric amplifier, a signal can be amplified without any additional noise being added by the amplifier, something that is fundamentally impossible for a standard amplifier. The vibrating AFM cantilever becomes a nonlinear oscillator when it is interacting with a surface. When driven with two frequencies, the amplitudeand phase of the cantilever’s response will develop mixing products, or intermodulation products, that are very sensitive to the exact form of the nonlinearity. Very small changes in the surface properties will be detectable when measuring the intermodulation products. Simultaneously measuring many intermodulation products, or acquiring an intermodulation spectrum,allows one to reconstruct the tip-surface interaction. Intermodulation AFM increases the sensitivity of the measurement or the contrast of the acquiredimages, and provides a means of rapidly measuring the nonlinear tip-surface interaction. The method promises to enhance the functionality of the AFM beyond simple topography measurement, towards quantitative analysis of the chemical or material properties of the surface.

QC 20100812

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43

Broomfield, Carl. "Ultra low phase noise with low residual flicker noise microwave oscillators & novel high Q printed helical filters." Thesis, University of York, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428530.

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44

Sundaresan, Krishnakumar. "Temperature Compensated CMOS and MEMS-CMOS Oscillators for Clock Generators and Frequency References." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13977.

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Анотація:

Silicon alternatives to quartz crystal based oscillators to electronic system clocking are explored. A study of clocking requirements reveals widely different specifications for different applications. Traditional CMOS oscillator-based solutions are optimized for low-cost fully integrated micro-controller clock applications. The frequency variability of these clock generators is studied and techniques to compensate for this variability are proposed. The efficacy of these techniques in reducing variability is proven theoretically and experimentally. MEMS-resonator based oscillators, due to their exceptional quality factors, are identified as suitable integrated replacements to quartz based oscillators for higher accuracy applications such as data converter clocks. The frequency variation in these oscillators is identified and techniques to minimize the same are proposed and demonstrated. The sources of short-term variation (phase noise) in these oscillators are discussed and an inclusive theory of phase noise is developed. Techniques to improve phase noise are proposed. Findings from this research indicate that MEMS resonator based oscillators, may in future, outperform quartz based solutions in certain applications such as voltage controlled oscillators. The implications of these findings and potential directions for future research are identified.

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45

Barale, Francesco. "Frequency dividers design for multi-GHz PLL systems." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24610.

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46

Rohde, Ulrich L. [Verfasser], and Dirk [Akademischer Betreuer] Killat. "A novel approach for generating active inductors for microwave oscillators - mathematical treatment and experimental verification of active inductors for microwave application / Ulrich L. Rohde. Betreuer: Dirk Killat." Cottbus : Universitätsbibliothek der BTU Cottbus, 2012. http://d-nb.info/1018892605/34.

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47

Kim, Taeik. "A CMOS tunable transmission line phase shifter and voltage-controlled oscillator for wireless communications /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/6131.

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48

Miri, Lavasani Seyed Hossein. "Design and phase-noise modeling of temperature-compensated high frequency MEMS-CMOS reference oscillators." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/41096.

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Frequency reference oscillator is a critical component of modern radio transceivers. Currently, most reference oscillators are based on low-frequency quartz crystals that are inherently bulky and incompatible with standard micro-fabrication processes. Moreover, their frequency limitation (<200MHz) requires large up-conversion ratio in multigigahertz frequency synthesizers, which in turn, degrades the phase-noise. Recent advances in MEMS technology have made realization of high-frequency on-chip low phase-noise MEMS oscillators possible. Although significant research has been directed toward replacing quartz crystal oscillators with integrated micromechanical oscillators, their phase-noise performance is not well modeled. In addition, little attention has been paid to developing electronic frequency tuning techniques to compensate for temperature/process variation and improve the absolute frequency accuracy. The objective of this dissertation was to realize high-frequency temperature-compensated high-frequency (>100MHz) micromechanical oscillators and study their phase-noise performance. To this end, low-power low-noise CMOS transimpedance amplifiers (TIA) that employ novel gain and bandwidth enhancement techniques are interfaced with high frequency (>100MHz) micromechanical resonators. The oscillation frequency is varied by a tuning network that uses frequency tuning enhancement techniques to increase the tuning range with minimal effect on the phase-noise performance. Taking advantage of extended frequency tuning range, and on-chip temperature-compensation circuitry is embedded with the sustaining circuitry to electronically temperature-compensate the oscillator. Finally, detailed study of the phase-noise in micromechanical oscillators is performed and analytical phase-noise models are derived.

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49

Yoon, Sangwoong. "LC-tank CMOS Voltage-Controlled Oscillators using High Quality Inductor Embedded in Advanced Packaging Technologies." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4887.

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This dissertation focuses on high-performance LC-tank CMOS VCO design at 2 GHz. The high-Q inductors are realized using wiring metal lines in advanced packages. Those inductors are used in the resonator of the VCO to achieve low phase noise, low power consumption, and a wide frequency tuning range. In this dissertation, a fine-pitch ball-grid array (FBGA) package, a multichip module (MCM)-L package, and a wafer-level package (WLP) are incorporated to realize the high-Q inductor. The Q-factors of inductors embedded in packages are compared to those of inductors monolithically integrated on Si and GaAs substrates. All the inductors are modeled with a physical, simple, equivalent two-port model for the VCO design as well as for phase noise analysis. The losses in an LC-tank are analyzed from the phase noise perspective. For the implementation of VCOs, the effects of the interconnection between the embedded inductor and the VCO circuit are investigated. The VCO using the on-chip inductors is designed as a reference. The performance of VCOs using the embedded inductor in a FBGA and a WLP is compared with that of a VCO using the on-chip inductor. The VCO design is optimized from the high-Q perspective to enhance performance. Through this optimization, less phase noise, lower power consumption, and a wider frequency tuning range are obtained simultaneously.

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50

Mukhopadhyay, Rajarshi. "Broadband and Low-Power Signal Generation Techniques for Multi-Band Reconfigurable Radios in Silicon-based Technologies." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14097.

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Wireless communication is witnessing tremendous growth with the proliferation of various standards covering wide, local, and personal area networks, which operate at different frequency bands. Future wireless terminals will not only need to support multiple standards, but also need to be multi-functional to keep pace with the demands of the consumers. For such an implementation, the local oscillator (LO) turns out to be the bottleneck, which must exhibit frequency agility by generating a very wide range of carrier frequencies in order to access all the specified communication standards. This dissertation presents various design techniques to realize compact low-cost low-power and broadband oscillators in silicon-based technologies. The two most suitable techniques for broadband signal generation: (1) Use of widely tunable active inductor, and (2) Use of switched resonator have been thoroughly evaluated. A fully reconfigurable active inductor with a widely tunable feedback resistor has been proposed. Using the proposed tunable active inductor in a VCO generates frequency tuning ranges higher than 100%, and helps achieve the highest PFTN Figure-of-Merit among Si-based active inductor VCOs reported in literature till date. The large-signal non-linearity of the active inductor has been utilized to develop the first reported broadband harmonic active inductor-based VCO. The degradation of phase noise due to active inductors is partially solved by a noise optimization guideline for active inductors. Utilizing the low saturation voltage of HBT technologies and high-Q short line inductors seems to be very useful to reduce power consumption of cross-coupled VCOs while achieving low phase noise performance simultaneously.

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Дисертації з теми "Oscillators, Electric; Oscillators, Microwave"

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