Dissertations / Theses on the topic 'Resonator transducer'

Information on the content and changes in the distribution of free and bound water in biological objects allows for the diagnosis of their condition. Microwave diagnostics of bioobjects using resonator transducers with coaxial probe structures provide an opportunity for non-destructive analysis with millimeter and submillimeter spatial resolution. Analytical methods were used to study the nature of the interaction of electromagnetic fields created by coaxial apertures of various configurations with samples. On the basis of the obtained results, directions for the implementation of microwave high-local diagnostics techniques are determined.

This thesis reports on the design and fabrication of micro-electro-mechanical (MEM) resonators on silicon that are piezoelectrically-transduced for operation in the very high frequency (VHF) range. These devices have a block-type or beam-type design, and are designed to resonate in their in-plane and out-of-plane bulk extensional modes. Two piezoelectric materials were taken into consideration, zinc-oxide (ZnO) and lead-zirconate-titanate (PZT). The resonators are fabricated on silicon-on-insulator (SOI) wafers and the metal/piezo/metal stack of layers forming the device is built and patterned on the device layer silicon via photolithography techniques, RF sputtering (for the piezo-layer) and electron-beam evaporation (for the metal layers). The designing aspect involved ANSYS simulations of the mode-shapes and estimation of frequencies, and these have correlated well with experimental results. Devices with RF sputtered ZnO were successfully fabricated and tested to give high quality factors at reasonably high frequencies. A gold ground plane was implemented to reduce the feed-through level and increase the signal-to-noise ratio. Extensive characterization of PZT was also done as a replacement for ZnO, as the former material has a much higher piezoelectric coefficient (~20X that of ZnO) and can therefore extend the operation of these MEM resonators into the UHF range. Although the basic design of the device remains the same, incorporation of PZT complicates the process flow considerably with respect to the chemistry now involved with the patterning of different layers. The frequency response for ZnO-based resonators as well as all the characterization data for PZT has been reported.

Thesis (M.S. in Engineering Acoustics and M.S. in Applied Science (Antisubmarine Warfare))--Naval Postgraduate School, September 1990.
Thesis Advisor(s): Baker, Steven R. Second Reader: Wilson, Oscar B. "September 1990." Description based on title screen as viewed on December 17, 2009. DTIC Identifier(s): Acoustic resonators, acoustic transducers, coupled network analysis, theses. Author(s) subject terms: Low frequency active, multiple scatter, sympathetic resonance, quasiresonance, coupled network analysis. Includes bibliographical references (p. 54). Also available in print.

This thesis presents the design, modeling, and experiment of a novel pressure sensor using a dual-mode AT-cut quartz crystal resonator with beat frequency analysis based temperature compensation technique. The proposed sensor can measure pressure and temperature simultaneously by a single AT-cut quartz resonator. Apart from AT-cut quartz crystal, a newly developed Langasite (LGS) crystal resonator is also considered in the proposed pressure sensor design, since LGS can operate in a higher temperature environment than AT-cut quartz crystal. The pressure sensor is designed using CAD (computer aided design) software and CAE software - COMSOL Multiphysics. Finite element analysis (FEA) of the pressure sensor is performed to analyze the stress- strain of the sensor's mechanical structure. A 3D printing prototype of the sensor is fabricated and the proposed sensing principle is verified using a force-frequency analysis apparatus. Next to the 3D printing model verification, the pressure sensor with stainless steel housing has been fabricated with inbuilt crystal oscillator circuit. The oscillator circuit is used to excite the piezo crystal resonator at its fundamental vibrational mode and give the frequency as an output signal. Based on the FEA and experimental results, it has been concluded that the maximum pressure that the sensor can measure is 45 (psi). The pressure test results performed on the stainless steel product shows a highly linear relationship between the input (pressure) and the output (frequency).

Le contexte de ce projet de doctorat celui des biocapteurs. Le but final est d’avoir un dispositif portable, composé par une partie jetable, capable de détecter des concentrations très faibles d’un analyte spécifique, à bon marché et compacte, que les médecins peuvent utiliser dans l’hôpital où chez les patients, sans avoir besoin d’un laboratoire entier. Les analytes peuvent être plusieurs (à partir de l’ADN pour la détection de maladies génétiques où des cellules cancéreuses pour la détection précoce du cancer). Cet objectif est possible seulement avec un transducteur qui arrive à convertir efficacement la présence biologique de l’analyte en information électrique. Le transducteur est dans le domaine de la photonique. On combine deux types de guides d’onde, un de type "ridge" diélectrique et un autre métallique, pour en créer un hybride qu’associe les faibles pertes d’une à la sensibilité de l’autre. L’élément innovant est la géométrie de ce guide hybride (Hybrid Plasmonic WaveGuide). Ce memoire explore l'étude theorique, les simulaiton, la fabbrication en salle blanche et la characterization des dispositifs hybride plasmoniques
Lab-on-a-chip (or LOC) devices scale down the laboratory processes for detecting illnesses and monitoring sick patients without the need of medical laboratories. These criteria are made possible with a transducer that can convert the biological presence of the target molecule into electrical information. Since the early 2000s, integrated photonics have offered a possible solution for a transducer compatible with LOC needs. In particular, silicon micro-ring resonators represent a compact and sensitive choice to use as a transducer in LOC devices. In agreement with the requirements of LOC devices, the objective of this project is to design and assess the performance of a compact photonic biosensor. The system will be based on integrated photonic transduction. The requirements are that it is compatible with an industrial fabrication platform and fluidic systems, with a sensitivity equal to or higher than the state-of-the-art and simple to functionalize in order to localize the target molecules in the sensitive regions of the sensor. This project details the design, fabrication, and characterization of such a biosensor. In particular, the photonic biosensor is a ring resonators with a Hybrid Plasmonic Waveguide (HPWG) cross-section that fulfills the LOC requirements

Due to the recent rapid growth in personal mobile communication devices (smartphones, PDA's, tablets, etc.), the wireless market is always looking for new ways to further miniaturize the RF front-ends while reducing the cost and power consumption. For many years, wireless transceivers and subsystems have been relying on high quality factor (Q) passives (e.g., quartz crystal, ceramics) to implement oscillators, filters, and other key RF front-end circuitry elements. However, these off-chip discrete components occupy large chip area and require power-demanding interfacing circuits. As a result, a great deal of research effort has been devoted to the development of micromechanical resonators that are much more amenable to direct integration with integrated circuit (IC). Over the past few years, vibrating RF MEMS (Micro-Electrical-Mechanical-System) resonator technology has emerged as a viable solution, most notably, the film bulk acoustic resonator (FBAR) and surface acoustic wave (SAW) resonator, which have already been successfully implemented into commercial products. Undoubtedly, micromechanical resonators such as FBAR's can perform as well as if not better than its bulky conventional counterparts and facilitate the miniaturization and power reduction of conventional RF systems. However, in some cases when multi-frequency functionality on a single-chip is needed, FBAR simply won't deliver. To address this dilemma, contour-mode MEMS resonators have been developed and regarded as the most viable on-chip high-Q alternative. Unlike FBAR, contour-mode resonators use lateral dimensions to define its resonating frequencies, thus allowing for single-chip multi-frequency functionality. However, there is still room for improvement with respect to lowering the motional resistance of these devices to allow matching to 50 Ω electronics, while retaining low power consumption, small size, and simpler manufacturing process. This dissertation presents the design, fabrication, characterization and experimental analysis of two types of micro-mechanical resonators. Piezoelectrically- and electrostatically-transduced micromechanical resonators will both be shown. Both types of resonator will be fabricated in the same micro-fabrication run, which makes the comparison between the two much more impartial. The impacts of substrate's resistivity over the device performances will also be studied. Among the most significant results, this dissertation also presents several ideas that are enabled by the use of silicon-on-insulator (SOI) wafer. A novel single-mask fabrication process that can produce capacitive resonator with nano-meter gap is demonstrated. The concept of dual-transduced micro-mechanical resonator is introduced by combining both piezoelectric and capacitive based resonators. Finally, frequency tuning of MEMS resonator are explored and detailed in this work as well.

For the past decade, a great deal of research has been focused towards developing a viable on-chip solution to replace the current state-of-the-art VHF and UHF filters based on SAW and FBAR technologies. Although filters based on SAW and FBAR devices are capable of fulfilling the basic requirements needed for IF and RF bandpass filtering and reference signal generation, an alternative solution that can enable the next generation of multi-frequency and multi-mode transceivers while enabling size and price reduction by allowing the manufacturing of single-chip monolithic RF transceivers is highly desired. In response to these new needs, piezoelectrically-transduced micromechanical filters have emerged as a plausible alternative to outperform current dominant technologies in size, cost, and IC manufacturing compatibility without compromising device performance in terms of insertion loss, rejection, power handling and linearity. This dissertation presents the design, fabrication, characterization and experimental analysis of low-loss VHF and UHF filters for wireless communication applications, based on piezoelectrically-transduced micromechanical resonators. The resonators employed in this work for the implementation of microwave filters, resonate in contour-mode shapes, which differ from commercially available thickness-mode FBAR resonators, for which the thickness sets the resonance frequency. The employment of contour-mode designs facilitate simultaneous synthesis of multiple frequencies on the same substrate through CAD layout-defined lateral dimensions, thus avoiding the complexity demanded by FBAR devices for the precise control of the piezoelectric layer thickness. Moreover, filters composed of acoustically-coupled piezoelectrically-transduced resonators operating at higher order modes with sizes up to 10 times smaller than their SAW counterparts operating at the same UHF range have been successfully implemented, without jeopardizing the key filter specifications. Throughout this dissertation, piezoelectrically-transduced MEMS filters based on mechanically, electrically and acoustically coupled contour-mode resonator(s) or resonator arrays were designed and fabricated. Filters with insertion loss as low as 2.6 dB at IF frequencies and 4.0 dB at RF frequencies have been demonstrated. Moreover, synthesized filters with extremely narrow bandwidth of 0.1 % and 0.2 % at frequencies between 160 MHz and 215 MHz have been developed, which comply the specifications for IF filters for GSM handsets. This particular type of filters each consist of just one single high-Q resonator, which leverages single crystalline silicon as the major part of their structure to obtain the sufficient quality factor required for the implementation of such small bandwidth. Among the most significant results, this dissertation presents two thin film piezoelectrically-transduced monolithic filters operating at 482 MHz and 536 MHz, which can be interfaced directly to a 377  antenna without the need of external matching components. This dissertation also has conducted a systematic comparison between commercial available SAW filters and the MEMS filters synthesized using piezoelectrically-transduced resonators. Parameters such as group delay and third intermodulation (IP3) have been measured and carefully compared. Evidentially, most of the fabricated piezoelectrically-transduced filters developed by this work have exhibited a similar or superior performance as compared to their commercial SAW counterparts

A novel micromachining technology on SOI substrates is presented that is capable of producing on-chip high-Q resonators and resonator arrays equipped with high aspect-ratio (30:1) microstructures and nano-gap capacitive transducers filled with high-k dielectrics. The newly developed IC-compatible MEMS microfabrication process consists of merely three standard photolithography steps, which is much simpler than the other SOI-based resonator device technologies. In order to achieve the optimum performance and yield of the resonators and resonator arrays, this SOI-based fabrication process has been carefully designed and investigated step by step. For capacitively-transduced extensional mode (e.g., radial-contour and wine-glass mode) resonators, formation of nano-scale capacitive gaps and large resonator-to-electrode overlap area is essential for reducing the motional resistance Rx and DC bias voltage by strengthening the capacitive transduction. Atomic Layer Deposition (ALD) technology with superb conformability and uniformity as well as outstanding thickness controllability is used to deposit the ultra-thin layer (~10 nm) of high-k dielectric material that acts as the solid capacitive gaps, which allows the mass production of on-chip capacitively-transduced resonators and resonator arrays with greatly enhanced electromechancial coupling coefficient, and thus lower motional resistance and DC bias voltage. Using this technique, high-Q micromechanical resonators and resonator arrays on SOI substrates operating at ultra-high frequencies (UHF) have been developed. The ultimate goal of this project is to implement on-chip narrow-band micromechanical filters with unprecedented frequency selectivity and ultra-low insertion loss. By fine-tuning the nonlinear characteristics of the capacitive transducers enabled by the new SOI technology, novel on-chip mechanical signal processors for frequency manipulation, such as mixer and multiplier, will be investigated.

Microelectromechanical resonators have found widespread applications in timing, sensing and spectral processing. One of the important performance metrics of MEMS resonators is the temperature sensitivity of their frequency. The main objective of this dissertation is the compensation and control of the temperature sensitivity of silicon resonators through engineering of device geometry and structural composition. This has been accomplished through formation of composite platforms or novel geometries based on dispersion characteristics of guided acoustic waves in single crystalline silicon (SCS) microstructures. Furthermore, another objective of this dissertation is to develop efficient longitudinal piezoelectric transduction for in-plane resonance modes of SCS resonators that have lithographically-defined frequencies, to reduce their motional resistance (Rm). A uniformly distributed matrix of silicon dioxide pillars is embedded inside the silicon substrate to form a homogenous composite silicon-oxide platform (SilOx) with nearly perfect temperature-compensated stiffness moduli. Temperature-stable micro-resonators implemented in SilOx platform operating in any desired in- and out-of-plane resonance modes show full compensation of linear temperature coefficient of frequency (TCF). Overall frequency drifts as small as 80 ppm has been achieved over the industrial temperature range (-40°C to 80°C) showing a 40x improvement compared to uncompensated native silicon resonators. A 27 MHz temperature-compensated MEMS oscillator implemented using SilOx resonator demonstrated sub-ppm instability over the industrial temperature range. Besides this, a new formulation of different resonance modes of SCS resonators based on their constituent acoustic waves is presented in this dissertation. This enables engineering of the acoustic resonator to provide several resonance modes with mechanical energy trapped in central part of the resonator, thus obviating narrow tethers traditionally used for anchoring the cavity to the substrate. This facilitates simultaneous piezoelectric-transduction of multiple modes with different TCFs through independent electrical ports, which can realize highly accurate self-temperature sensing of the device using a beat frequency (fb) generated from linear combination of different modes. Piezoelectrically-transduced multi-port silicon resonators implemented using this technique provide highly temperature-sensitive fb with a large TCF of ~8500 ppm/°C showing 100x improvement compared to other Quartz/MEMS counterparts, suggesting these devices as highly sensitive temperature sensors for environmental sensing and temperature-compensated/oven-controlled crystal oscillator (TCXO/OCXO) applications. Another part of this dissertation introduces a novel longitudinal piezoelectric transduction technique developed for implementation of low Rm silicon resonators operating in lithographically defined in-plane modes. Aluminum nitride films deposited on the sidewalls of thick silicon microstructures provides efficient electromechanical transduction required to achieve low Rm. 100 MHz SCS bulk acoustic resonators implemented using this transduction technique demonstrates Rm of 33Ω showing a 100x improvement compared to electrostatically transduced counterparts. Low-loss narrow-band filters with tunable bandwidth and frequency have been implemented by electrical coupling of these devices, showing their potential for realization of truly reconfigurable and programmable filter arrays required for software-defined radios.

Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.11.13 "Прилади і методи контролю та визначення складу речовин" (15 – Автоматизація та приладобудування) – Національний технічний університет "Харківський політехнічний інститут". Мета роботи: удосконалення резонансного діелькометричного методу контролю та визначення вологості рідких неполярних діелектриків задля підвищення його чутливості до рівня 10⁻⁵ з одночасною мінімізацією впливу "сортової невизначеності". Запропоновані та досліджені: спрощена математична модель емульсії на основі моделі штучного діелектрика Кока; нові багаточастотні різновиди резонансного діелькометричного методу; новий тип розподіленого вимірювального перетворювача. Розроблено, теоретично та експериментально досліджено вологоміри середньочастотного та дуже високочастотного діапазонів. Експериментальним шляхом підтверджено досягнення мети роботи.
Thesis for a candidate degree (PhD) in specialty 05.11.13 "Instruments and methods of control and determination of substances" (15 – Automation and Instrumentation) − National Technical University "Kharkiv Polytechnic Institute". The thesis is devoted to the improvement of the resonant dielectric method of monitoring and determining the humidity of emulsions such as liquid non-polar dielectric - water in order to increase its sensitivity to level 10⁻⁵ while simultaneously minimizing the type and grade of non-polar dielectric ("varietal uncertainty") on the measurement results. An analytical review and analysis of the existing methods and means of implementation of the dielectric method in general and its resonant variety has been carried out. The main research areas have been identified: development of a simplified emulsion model; development of new varieties of the resonant dielectric method with minimization of the effect of "varietal uncertainty" for measuring humidity at a level of 10⁻⁵; development of a new type of distributed transducer. A simplified emulsion model was chosen based on the Kok artificial dielectric model, its applications were determined by frequency, humidity, and the values of its systematic errors were determined. New multifrequency varieties of the resonant dielectric method have been developed based on the proposed mathematical model of the emulsion, taking into account the parasitic capacitances of the measuring generator and the measuring converter. Metrological characteristics of the generalized four-frequency method and its simplified three-and two-frequency varieties are obtained. The areas of applicability of multifrequency methods are analyzed and their systematic errors are determined. The most sensitive method, the two-frequency method, was determined, the effect of dielectric losses in water was analyzed for it, and the generation frequency of the measuring generator, which corresponds to its maximum sensitivity, 100 MHz, was determined. A new type of distributed-type measuring transducer is proposed for the practical implementation of the two-frequency method — a stepwise heterogeneous coaxial resonator; its theoretical and experimental studies are carried out; its advantages in relation to the known transducers are determined. A hygrometer of the mid-frequency range based on a concentrated-type capacitive transducer and a hydrometer of a very high-frequency range based on a stepped heterogeneous coaxial resonator have been developed. The circuit solutions of the measuring transducer and the measuring generator of the hygrometer of the midfrequency range, which provided the minimum values of their parasitic capacitances, were developed and implemented. The circuit solutions of the measuring transducer and the measuring generator of a hygrometer of a very high frequency range have been developed and implemented, which provided almost zero effect of their parasitic capacitances. A methodology has been developed for conducting experimental research on the implementation of four- and three-frequency methods using a mid-range moisture meter and implementing a two-frequency method and a simplified version of it using a very high-frequency moisture meter. Experimental studies on manufactured test emulsions, as well as analysis and processing of their results, were carried out. For all developed multi-frequency methods and moisture values of test emulsions in the range of 10⁻⁴ – 10⁻², the value of the relative extended uncertainty of moisture measurement did not exceed 5.28 %. For the humidity of the test emulsion 10⁻⁵, the value of this uncertainty did not exceed 10.39 % (due to the lack of stability of the frequency of the reference generator frequency Ch 3 - 34, which was used in the research). The developed improved multi-frequency resonance dielectric methods for determining humidity have increased the sensitivity to a level of 10⁻⁵ while minimizing "varietal uncertainty".

Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.11.13 "Прилади і методи контролю та визначення складу речовин" (15 – Автоматизація та приладобудування) – Національний технічний університет "Харківський політехнічний інститут". Мета роботи: удосконалення резонансного діелькометричного методу контролю та визначення вологості рідких неполярних діелектриків задля підвищення його чутливості до рівня 10⁻⁵ з одночасною мінімізацією впливу "сортової невизначеності". Запропоновані та досліджені: спрощена математична модель емульсії на основі моделі штучного діелектрика Кока; нові багаточастотні різновиди резонансного діелькометричного методу; новий тип розподіленого вимірювального перетворювача. Розроблено, теоретично та експериментально досліджено вологоміри середньочастотного та дуже високочастотного діапазонів. Експериментальним шляхом підтверджено досягнення мети роботи.
Thesis for a candidate degree (PhD) in specialty 05.11.13 "Instruments and methods of control and determination of substances" (15 – Automation and Instrumentation) − National Technical University "Kharkiv Polytechnic Institute". The thesis is devoted to the improvement of the resonant dielectric method of monitoring and determining the humidity of emulsions such as liquid non-polar dielectric - water in order to increase its sensitivity to level 10⁻⁵ while simultaneously minimizing the type and grade of non-polar dielectric ("varietal uncertainty") on the measurement results. An analytical review and analysis of the existing methods and means of implementation of the dielectric method in general and its resonant variety has been carried out. The main research areas have been identified: development of a simplified emulsion model; development of new varieties of the resonant dielectric method with minimization of the effect of "varietal uncertainty" for measuring humidity at a level of 10⁻⁵; development of a new type of distributed transducer. A simplified emulsion model was chosen based on the Kok artificial dielectric model, its applications were determined by frequency, humidity, and the values of its systematic errors were determined. New multifrequency varieties of the resonant dielectric method have been developed based on the proposed mathematical model of the emulsion, taking into account the parasitic capacitances of the measuring generator and the measuring converter. Metrological characteristics of the generalized four-frequency method and its simplified three-and two-frequency varieties are obtained. The areas of applicability of multifrequency methods are analyzed and their systematic errors are determined. The most sensitive method, the two-frequency method, was determined, the effect of dielectric losses in water was analyzed for it, and the generation frequency of the measuring generator, which corresponds to its maximum sensitivity, 100 MHz, was determined. A new type of distributed-type measuring transducer is proposed for the practical implementation of the two-frequency method — a stepwise heterogeneous coaxial resonator; its theoretical and experimental studies are carried out; its advantages in relation to the known transducers are determined. A hygrometer of the mid-frequency range based on a concentrated-type capacitive transducer and a hydrometer of a very high-frequency range based on a stepped heterogeneous coaxial resonator have been developed. The circuit solutions of the measuring transducer and the measuring generator of the hygrometer of the midfrequency range, which provided the minimum values of their parasitic capacitances, were developed and implemented. The circuit solutions of the measuring transducer and the measuring generator of a hygrometer of a very high frequency range have been developed and implemented, which provided almost zero effect of their parasitic capacitances. A methodology has been developed for conducting experimental research on the implementation of four- and three-frequency methods using a mid-range moisture meter and implementing a two-frequency method and a simplified version of it using a very high-frequency moisture meter. Experimental studies on manufactured test emulsions, as well as analysis and processing of their results, were carried out. For all developed multi-frequency methods and moisture values of test emulsions in the range of 10⁻⁴ – 10⁻², the value of the relative extended uncertainty of moisture measurement did not exceed 5.28 %. For the humidity of the test emulsion 10⁻⁵, the value of this uncertainty did not exceed 10.39 % (due to the lack of stability of the frequency of the reference generator frequency Ch 3 - 34, which was used in the research). The developed improved multi-frequency resonance dielectric methods for determining humidity have increased the sensitivity to a level of 10⁻⁵ while minimizing "varietal uncertainty".

The recent development of the commercially viable thin film electro-acoustic technology has triggered a growing interest in the research of plate guided wave or Lamb wave components owing to their unique characteristics. In the present thesis i) an experimental study of the thin film plate resonators (FPAR) performance operating on the lowest symmetrical Lamb wave (S0) propagating in highly textured AlN membranes versus a variety of design parameters has been performed. The S0 mode is excited through an Interdigital Transducer and confined within the structure by means of reflection from metal strip gratings. Devices operating in the vicinity of the stop-band center exhibiting a Q-value of up to 3000 at a frequency around 900MHz have been demonstrated. Temperature compensation of this type of devices has been studied theoretically and successfully realized experimentally for the first time. Further, integrated circuit-compatible S0 Lamb based two-port FPAR stabilized oscillators exhibiting phase noise of -92 dBc/Hz at 1 kHz frequency offset with feasible thermal noise floor below -180 dBc/Hz have been tested under high power for a couple of weeks. More specifically, the FPARs under test have been running without any performance degradation at up to 27 dBm loop power. Further, the S0 mode was experimentally demonstrated to be highly mass and pressure sensitive as well as suitable for in-liquid operation, which together with low phase noise and high Q makes it very suitable for sensor applications; ii) research in view of FPARs operating on other types of Lamb waves as well as novel operation principles has been initiated. In this work, first results on the design, fabrication and characterization of two novel type resonators: The Zero Group Velocity Resonators (ZGVR) and The Intermode-Coupled Thin Film Plate Acoustic Resonators (IC-FPAR), exploiting new principles of operation have been successfully demonstrated. The former exploits the intrinsic zero group velocity feature of the S1 Lamb mode for certain combination of design parameters while the latter takes advantage of the intermode interaction (involving scattering) between S0 and A1 Lamb modes through specially designed metal strip gratings (couplers). Thus both type of resonators operate on principles of confining energy under IDT other than reflection.

The first objective of this Dissertation is to present a methodology to calculate analytically the mode shapes and corresponding natural frequencies and determine critical buckling loads of mechanically coupled microbeam resonators with a focus on micromechanical filters. The second objective is to adopt a nonlinear approach to build a reduced-order model and obtain closed-form expressions for the response of the filter to a primary resonance. The third objective is to investigate the feasibility of employing subharmonic excitation to build bandpass filters consisting of either two sets of two beams coupled mechanically or two sets of clamped-clamped beams. Throughout this Dissertation, we treat filters as distributed-parameter systems. In the first part of the Dissertation, we demonstrate the methodology by considering a mechanical filter composed of two beams coupled by a weak beam. We solve a boundary-value problem (BVP) composed of five equations and twenty boundary conditions for the natural frequencies and mode shapes. We reduce the problem to a set of three linear homogeneous algebraic equations for three constants and the frequencies in order to obtain a deeper insight into the relation between the design parameters and the performance metrics. In an approach similar to the vibration problem, we solve the buckling problem to study the effect of the residual stress on the static stability of the structure. To achieve the second objective, we develop a reduced-order model for the filter by writing the Lagrangian and applying the Galerkin procedure using its analytically calculated linear global mode shapes as basis functions. The resulting model accounts for the geometric and electric nonlinearities and the coupling between them. Using the method of multiple scales, we obtain closed-form expressions for the deflection and the electric current in the case of one-to-one internal and primary resonances. The closed-form solution shows that there are three possible operating ranges, depending on the DC voltage. For low DC voltages, the effective nonlinearity is positive and the filter behavior is hardening, whereas for large DC voltages, the effective nonlinearity is negative and the filter behavior is softening. We found that, when mismatched DC voltages are applied to the primary resonators, the first mode is localized in the softer resonator and the second mode is localized in the stiffer resonator. We note that the excitation amplitude can be increased without worrying about the appearance of multivaluedness when operating the filter in the near-linear range. The upper bound in this case is the occurrence of the dynamic pull-in instability. In the softening and hardening operating ranges, the adverse effects of the multi-valued response, such as hysteresis and jumps, limit the range of the input signal. To achieve the third objective, we propose a filtration technique based on subharmonic resonance excitation to attain bandpass filters with ideal stopband rejection and sharp rolloff. The filtration mechanism depends on tuning two oscillators such that one operates in the softening range and the other operates in the hardening range. Hardware and logic schemes are necessary to realize the proposed filter. We derive a reduced-order model using a methodology similar to that used in the primary excitation case, but with all necessary changes to account for the subharmonic resonance of order one-half. We observe that some manipulations are essential for a structure of two beams coupled by a weak spring to be suitable for filtration. To avoid these complications, we use a pair of single clamped-clamped beams to achieve our goal. Using a model derived by attacking directly the distributed-parameters problem, we suggest design guidelines to select beams that are potential candidates for building a bandpass filter. We demonstrate the proposed mechanism using an example.
Ph. D.

Prior research focused on CMOS-MEMS integrated oscillator has been done using various foundry compatible integration techniques. In order to compensate the integration compatibility, MEMS resonators built on standard CMOS foundry process could not take full advantage of highest achievable quality factor on chip. System-in-package (SiP) and system-on-chip (SoC) is becoming the next generation of electronic packaging due to the need of multi-functional devices and multi-sensor systems, thus wafer level hybrid integration becomes the key to enable the full assembly of dissimilar devices. In this way, every active circuit and passive component can be individually optimized, so do the MEMS resonators and sustaining amplifier circuits. In this dissertation, GaAs-MEMS integrated oscillator in a hybrid packaging has been fully explored as an important functional block in the RF transceiver systems. This dissertation first presents design, micro-fabrication, simulation, testing and modeling of ZnO piezoelectrically-transduced MEMS resonators. A newly designed rectangular plate with curved resonator body fabricated in-house exhibits a very high Q of more 6,000 in the air for its width-extensional mode resonance at 166 MHz. In addition, a rectangular plate resonator with multiple Phononic Crystal (PC) strip tethers shows low insertion loss of -11.5 dB at 473.9 MHz with a Q of 2722.5 in the air. An oscillator technology with high-Q MEMS resonator as its tank circuit is presented to validate its key functionality as a stable frequency reference across a wide spectrum of frequencies. Particularly, a piezoelectrically-transduced width-extensional mode MEMS resonator is strategically designed to operate at two distinct layout-defined mechanical modal frequencies (259.5MHz and 436.7MHz). These devices were characterized and modeled by an extracted equivalent LCR circuit to facilitate the design of the oscillator using a standard circuit simulator. MEMS resonators have been integrated with the sustaining amplifier circuit at PCB level using wire-bonding technique and coaxial connectors. As shown by the time-domain measurements and frequency-domain measurements, these oscillators are capable of selectively locking into the resonance frequency of the tank circuit and generating a stable sinusoidal waveform. Meanwhile, the phase noise performance is rigorously investigated within a few oscillator designs. At last, 3-D printed hybrid packaging using additive manufacturing and laser machining technique has been developed for integrating a MEMS resonator on a silicon-on-insulator (SOI) substrate and a GaAs sustaining amplifier. Fabrication process and fundamental characterization of this hybrid packaging has been demonstrated. On-wafer probe measurements of a 50 Ω microstrip line on ABS substrate exhibit its insertion loss of 0.028 dB/mm at 5 GHz, 0.187 dB/mm at 20 GHz and 0.512 dB/mm at 30 GHz, and show satisfactory input and output return loss with the 3-D printed package. Parylene N is also experimentally coated on the package for improving water resistance as a form of hermetic packaging.

Les travaux visant au développement de capteurs passifs interrogeables sans fil pour sonder des températures supérieures à 600 °C s’inscrivent dans le projet européens SAWHOT. Des capteurs à ondes élastiques de surface sont modélisés, réalisés et caractérisés par une liaison radiofréquence. Le paramètre physique mesuré par ce capteur est la température, avec une mesure au-delà de 900°Cpour les applications de maintenance préventive des turbines à combustion ou pour le contrôle de procédés dans les fours de synthèse de nano-tubes de carbone. Les substrats piezoélectriques standards tels que le quartz ou le niobate de lithium ne sont pas envisageables : l’ensemble de ces travaux s’articule autour de la langasite, substrat piezoélectrique opérant jusqu’à 1470°C et ne présentant aucune température de transition (température de Curie) jusqu’à sa température de fusion située à 1470°C. Compte tenu de la vitesse des ondes élastiques de surface des coupes considérés et également des limitations imposées par les moyens de réalisations technologiques, ces résonateurs sont mesurés sans fil à une fréquence proche de la bande ISM centré en 434 MHz. Les dispositifs ainsi réalisés ont été encapsulés via une procédure innovante de mise en boîtier qui permet alors la mesure de capteurs à ondes élastiques de surface dans des environnements où la température dépasse 700°C. De nombreuses études expérimentales ont alors été menés dans le but d’évaluer les performances des capteurs à ondes élastiques de surface en terme de bilan de liaison radiofréquence, reproductible de la mesure, vieillissement au cours des cycles en températures
Development of wireless passive sensor for temperature measurement above 600°C has been performed in the frame of the European SAWHOT project. In this context, surface acoustic wave sensors have been designed, fabricated and characterized by radiofrequency measurement. Physical parameter measured by these sensors is the temperature, reaching values up to 900°C for monitoring in combustion engines andIn ovens used for carbon nano-tubes growth. In order to measure temperature in harsh environments, classical piezoelectric substrates are not usuable: langasite substrate has been considered as a favorable option since it exhibits no transition temperature and is able to operate until its exhibits no transition temperature and is able to operate until its melting temperature, at 1470 °C. regarding the parameters of the surface acoustic waves and the limitation of the fabrication process and devices, the resonators are measured wirelessly in the ISM band centered at 434 MHz (3μm of interdigital transducer period and a transducers with of 1μm). Two main manufacturing technologies are considered, stepper and nano-imprint technologies. The fabricated devices have been packaged by using an innovative process protecting the devices and allowing fir wireless measurements until 700°C. Multiple experiments have been performed in order to characterize the radiofrequency link between the reader and the sensor, the reproducibility of the measurement, the aging effect on the response of the device after high temperature cycles

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Brand, Oliver; Committee Member: Adibi, Ali; Committee Member: Allen, Mark G.; Committee Member: Bottomley, Lawrence A.; Committee Member: Degertekin, F. Levent.