The magnetic tunability of ferrites has been studied and applied on many electric components for working in various frequency bands. Filters or resonators loaded by ferrites can thus work for different frequency requirements by tunning external biasing field. However, filters or resonators built by traditional waveguides are large in size. And for tunning with biasing field below the ferroresonance point, dissipation in ferrites will increase rapidly if the working frequency is near the ferroresonance zone. It leads to the drop of Q values of resonators and the tuning range is limited to stay away from ferroresonance. For the filter, remaining high Q values in wide frequency tuning range is the base of good performance and tunability. In industry, demands of cost reduction and integration encourage the miniaturization of electric components. It is always challenging but attractive to find solutions compromising size, performance, and implement ability. In this project, investigation for possible solutions of magnetic bias tunable filter is made and their comparisons are presented. Analysis and simulation are made to a specific ferrites-loaded substrate integrated waveguide resonator. With homogeneous below-resonance biased field, results in the reference are reached again and analyzed. With biasing filed above the ferroresonance, higher Q values and smaller size can be achieved and the drop of Q is avoided. A magnet structure is designed to study how the resonator works in inhomogeneous biasing filed. Biasing of below-resonance field is achieved with the magnets structure, though the performance is not good as homogeneous biasing case. A 3-order filter is then built based on the resonator working in the below-resonance bias. It’s a band-pass filter and tunable. A magnet structure is also built and simulated for the filter to verify its feasibility. / Magnetisk avstämning av ferriter har studerats och applicerats på många elektriska komponenter för arbete i olika frekvensband. Filter eller resonatorer lastade av ferriter kan därmed fungera för olika frekvenskrav genom att tuna externt biasing fält. Filtren eller resonatorerna byggda av traditionella vågledare är dock stora i storlek. Och för tunning med biasing field under ferroresonanspunkten, kommer avledning i ferriter att öka snabbt om arbetsfrekvensen är nära ferroresonanszonen. Det leder till sänkning av Q-värden för resonatorer och inställningsområdet är begränsat för att hålla sig borta från ferroresonans. För filtret är kvarvarande höga Q-värden i brett frekvensinställningsområde grunden för god prestanda och avstämning. Inom industrin uppmuntrar krav på kostnadsminskning och integration till miniatyrisering av elektriska komponenter. Det är alltid utmanande men attraktivt att hitta lösningar som kompromissar med storlek, prestanda och implementerbarhet. I detta projekt undersöks möjliga lösningar av magnetiskt bias tunable filter och deras jämförelser presenteras. Analys och simulering görs till en specifik ferritbelastad substratintegrerad vågledarresonator. Med homogent vinkelfält under resonans nås resultaten i referensen igen och analyseras. Med biasing arkiverad över ferroresonansen, högre Q-värden och mindre storlek kan uppnås och fallet av Q undviks. En magnetstruktur är utformad för att studera hur resonatorn fungerar i inhomogen biasing fil. Biasing av nedanstående resonansfält uppnås med magnetens struktur, men prestandan är inte bra som homogen biasing fall. Ett 3-ordningsfilter byggs sedan baserat på resonatorn som arbetar i nedanstående resonans bias. Det är ett bandpassfilter och kan justeras. En magnetstruktur byggs och simuleras också för filtret för att verifiera dess genomförbarhet.

<p dir="ltr">In this research, a novel acoustic sensor with a waveguide is made to induce the local volumetric resonance of concrete material. The sensor is embedded in fresh concrete and monitors the in-place elastic modulus and strength development of the concrete. The resonant peak of the EMI spectrum of the sensor is governed by the concrete material in the proximate area of the sensor. The sensor itself does not affect the position of the resonant peak.</p><p dir="ltr">This research covers theoretical demonstration, sensor design and prototyping, remote testing systems, experimental study, and machine learning. Current work demonstrated the sensor successfully produced the resonant peaks that are related to the concrete curing process (R-square=0.86 for lab testing and R-square=0.64 for field testing); however, the sensitivity (S=1.00 Hz/psi) of the resonant frequency is not sufficient for practical application.</p><p dir="ltr">Machine learning algorithms were employed to map the EMI spectra to concrete strength profile. Several existing architectures were explored and evaluated. A novel machine learning scheme was proposed and successfully improved the accuracy of prediction. The algorithm is also able to handle real-time data with decent generalization among diverse concrete mixtures.</p><p dir="ltr">The integration test for the sensing system, including the sensor, the data collection device, the data pipeline, and the trained machine learning models, was performed in field testing of eight States. The averaged MAPE of the field prediction results is 23.43% for field structures and 16.13% for companion beam samples.</p><p dir="ltr">The knowledge produced during this study further advanced the application of EMI sensors in the NDE of concrete material. The EMI resonator tailored for local structural resonance is reported in this study for the first time. The EMI data processing algorithm using machine learning that is generalizable among various concrete mixtures is employed in this study for the first time. This study would be helpful for the real-world application of the EMI technique in the NDE of concrete and other phase-changing materials.</p>

<p dir="ltr">Cell polarity as defined by biologists is the cell ability to sense, determine its direction and orient itself in specific direction (e.g., front and back, top and bottom, and inside and outside). Recent studies have shown that loss of cell polarity at the tissue-level is a signature of a tumor. Detecting tumor cells based on their polarization, i.e., their electrical permittivity at the single-cell level could open the door for potential new diagnosing tools. Developing sensitive tools that are affordable and can perform fast reading is an after-sought goal. Currently, biochemical techniques are the adapted methods for research and analysis. These techniques include fluorescence-based, affinity-based, electrochemistry-based, and optical-based methods. The main disadvantages of these methods are their bulky size, and high cost due to the use of the complex pre-labeling and cannot handle small numbers of cells. On the other hand, biophysical sensing techniques for single cell focus on the whole cell intrinsic properties such as molecular compositions, volume, mass, electrical properties (i.e., conductivity and permittivity), mechanical properties. Biophysical sensing based on electrical methods would be non-invasive, fast, safe for the cells, and affordable. </p><p dir="ltr">In this thesis, novel sensors for single-cell detection are presented. Design, simulation, fabrication, and in some cases, experimental characterization of these proposed microfluidic sensors are discussed in details. The use of low and high frequency readouts for cell detection as well as the long-term goal of integration as a CMOS sensing platform are demonstrated. Detection and counting of air-bubbles on mm-sized RF ring resonator are demonstrated as a first proof of concept. Miniaturized RF ring resonator and co-planar-waveguide (CPW) devices that are integrated with microfluidic channels to characterize single-cells are then discussed. Furthermore, a novel CMOS capacitor sensor for cell detection is proposed for the first time. The idea of the proposed sensor is based on a perforated MIM capacitor that allows the detection of cells by a change in the dielectric constant of the capacitor perforated with a micro-channel.</p>

<p>With the advent of increasingly complex radio systems at higher frequencies and the slowing of traditional CMOS process scaling with power concerns, there has been an increased focus on integration, architectural, and material innovations as a continued path forward in MEMS and logic. This work presents the first comprehensive experimental study of resonant body transistors in a commercial 14nm FinFET process, demonstrating differential radio frequency transduction as a function of transistor biasing through electrostatic, piezoresistive, and threshold voltage modulation. The impact of device design changes on unreleased resonator performance are further explored, highlighting the importance of phononic confinement in achieving an f*Q product of 8.2*10¹¹ at 11.73 GHz. Also shown are initial efforts towards the understanding of coupled oscillator architectures and a perovskite nickelate material system. Finally, development of resonators based on two-dimensional materials, whose scale is particularly attractive for high-frequency nano-mechanical resonators and acoustic devices, is discussed. Experiments towards dry transfer of tellurene flakes using geometries printed via two photon polymerization are presented along with optimization of a fabrication process for gated RF devices, presenting new opportunities for high-frequency electro-mechanical interactions in this topological material. </p>

Metamaterials are humanly engineered artificial electromagnetic materials which produce electromagnetic properties that are unusual, yet can be observed readily in nature. These unconventional properties are not a result of the material composition but rather of the structure formed. The objective of this thesis is to investigate and design smaller and wideband metamaterial-inspired antennas for personal communication applications, especially for WiMAX, lower band and higher band WLAN applications. These antennas have been simulated using HFSS Structure Simulator and CST Microwave Studio software. The first design to be analysed is a low-profile metamaterial-inspired CPW-Fed monopole antenna for WLAN applications. The antenna is based on a simple strip loaded with a rectangular patch incorporating a zigzag E-shape metamaterial-inspired unit cell to enable miniaturization effect. Secondly, a physically compact, CSRR loaded monopole antenna with DGS has been proposed for WiMAX/WLAN operations. The introduction of CSRR induces frequency at lower WLAN 2.45 GHz band while the DGS has provided bandwidth enhancement in WiMAX and upper WLAN frequency bands, keeping the radiation pattern stable. The next class of antenna is a compact cloud-shaped monopole antenna consisting of a staircase-shaped DGS has been proposed for UWB operation ranges from 3.1 GHz to 10.6 GHz. The novel shaped antenna along with carefully designed DGS has resulted in a positive gain throughout the operational bandwidth. Finally, a quad-band, CPW-Fed metamaterial-inspired antenna with CRLH-TL and EBG is designed for multi-band: Satellite, LTE, WiMAX and WLAN.

The objectives of this work are to review, investigate and model the microwave planar filters of the modern wireless communication system. The recent main stream of microwave filters are classified and discussed separately. Various microwave filters with detailed applications are investigated in terms of their geometrical structures and operational performances. A comprehensive theoretical study of microwave filters is presented. The main types of microwave filters including the basic low-pass filters such as Butterworth and Chebyshev filters are fully analysed and described in detail. The transformation from low-pass prototype filters to high-pass filters, band-pass filters and band-stop filters are illustrated and introduced. Research work on stepped impedance resonator (SIR) and asymmetric stepped impedance resonator (ASIR) structure is presented. The characteristics of λg/4, λg/2 and λg (λg is the guided wavelength of the fundamental frequency in the free space) type SIR resonators, and the characteristic of asymmetric SIR resonator are categorized and investigated. Based on the content mentioned above, novel multi-standard high performance asymmetric stepped impedance resonator single-wideband and dual-wideband filters with wide stopbands are proposed. The methodologies to realize wide passband and wide stop-band filters are detailed. In addition, multi-standard high performance triplewideband, quadruple-wideband and quint-wideband filters are suggested and studied. The measurement results for all prototype filters agree well with the theoretical predictions and simulated results from Ansoft HFSS software. The featured broad bandwidths over single/multiple applicable frequency bands and the high performances of the proposed filters make them very promising for applications in future multistandard wireless communication.

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<p>Developing a hybrid platform that combines nanophotonic circuits and atomic physic may provide new chip-scale devices for quantum application or versatile tools for exploring photon-mediated long-range quantum systems. However, this challenging project demands the excellent integration of cold atom trapping and manipulation technology with cutting-edge nanophotonics circuit design and fabrication. In this thesis project, we aim to develop a novel suspended membrane platform that serves as a quantum interface between laser-cooled, trapped atoms in an ultrahigh vacuum and the photons guided in the nanophotonic circuits based on high-quality silicon nitride microring resonators fabricated on a transparent membrane substrate. </p> <p><br></p> <p>The proposed platform meets the stringent performance requirements imposed by nanofabrication and optical physics in an ultra-high vacuum. These include a high yield rate for mm-scale suspended dielectric photonic devices, minimization of the surface roughness to achieve ultrahigh-optical quality, complete control of optical loss/in-coupling rate to achieve critical photon coupling to a microring resonator, and high-efficiency waveguide optical input/output coupler in an ultrahigh vacuum environment. This platform is compatible with laser-cooled and trapped cold atoms. The experimental demonstration of trapping and imaging single atoms on a photonic resonator circuit using optical tweezers has been demonstrated. Our circuit design can potentially reach a record-high cooperativity parameter C$>$500 for single atom-photon coupling, which is of high importance in realizing a coherent quantum nonlinear optical platform and holds great promise as an on-chip atom-cavity QED platform.</p>