Engineering Commons^™

Geometry-Aware Methodology For Coupling Mechanism Analysis And Radiation Mechanism Analysis, Xu Wang

Doctoral Dissertations

"Due to the wide-band spectrum of digital signals, a variety of noise generators, including microprocessors, liquid crystal displays, digital microphones, high-speed traces, and double-data-rate memory modules, are found in consumer electronics products. Noise generated by digital circuits can couple to the antennas and degrade their sensitivity. Additionally, it also couples to metallic housings or heatsinks and produces a significant amount of emission. In this research, methodologies are presented to analyze the coupling and radiation mechanism in electronic devices.

To investigate the coupling between the distributive geometries in the radio frequency interference (RFI) problem, a mesh-dependent partition-based coupling mechanism analysis method …

Introduction Of A Variable Inductance Transformer For The Design Of Resonant Power Converters, Angshuman Sharma

Doctoral Dissertations

"Magnetic integration is a hot topic in power electronics that concerns the use of a transformer's leakage and magnetizing inductances purposefully in isolated power electronic converters, thereby giving the opportunity to save the cost and footprint of any additional inductor. This is of prime interest, especially in CLLLC resonant converters which require up to three inductors. For a complete integration of these inductances, the concept of a variable inductance transformer (VIT) is introduced in this thesis. A VIT is an adaptive magnetic structure that facilitates an easy adjustment of both magnetizing and leakage inductances to meet their desired values. However, …

Improved Decap Model And Placement Optimization Algorithm For Power Distribution Network Design, Jack Juang

Masters Theses

"Decoupling capacitors (decaps) are used in power distribution network (PDN) design to act as a low impedance return path for noise and act as a local source of charge when required by integrated circuits (IC). For placement of decaps, which can number even to the hundreds, many algorithms have been proposed including genetic algorithms (GA), iterative algorithm, and machine learning methods.

One limitation of iterative decap placement algorithms (adding one decap at a time) is how the construction of the algorithm affects the form of the final solution. For example, if the reward function (used in GA and machine learning …

A Real-Time Microwave Camera Using Zero-Bias Diode Detector, Liang Liu

Masters Theses

"This thesis presents the design of a microwave camera that utilizes a two-dimensional array of elliptical slot antennas and diode detectors to quickly and accurately locate radiation sources. Unlike traditional scanning techniques like ESM and holography, which rely on mechanical scanning, require a long measurement time, and are prone to mechanical errors, the microwave camera operates quickly and efficiently by using electronic switching to access the output of each detector. This results in a more precise and efficient means of locating radiation sources'--Abstract, p. iii

Static I-V Curve And Aging Test For Pim Characterization In Metallic Contacts, Kalkidan Anjajo

Masters Theses

"Spring clips and fabric-over-foams (FOFs) are widely used in mobile devices for electrical connection purposes. However, the imperfect metallic connections tend to induce passive intermodulation (PIM), resulting in a receiver sensitivity degradation, known as RF desensitization. Due to the complexity of the PIM characterization, there is not yet a way to evaluate PIM performance using a simple setup for environments like factories. In this study, a current-voltage (I-V) behavior-based PIM evaluation method is proposed and validated with various metallic contacts and contact forces. The test results demonstrated the feasibility of the PIM performance evaluation based on the measured static I-V …

Fiber Optic Sensors For Liquid Identifications, Wassana Naku

Doctoral Dissertations

"The fiber optic Fabry-Perot interferometer (FPI) is a widely utilized sensing configuration, offering numerous advantages over conventional electronic sensors, including high accuracy, distributed sensing capabilities, immunity to electromagnetic interference, and compact size. In this study, we propose a remarkably simple fiber optic-tip sensor system combined with machine learning techniques for the identification of pure and volatile organic liquids (VOLs).

A liquid droplet forms an extrinsic FPI (EFPI), with its effective reflectance being a function of the droplet's length. As the droplet evaporates, its length decreases. We conducted immersion tests using optical fiber tip sensors and monitored the time-transient responses of …

Design, Modeling And Analysis Of An Ac-Ac Dual Active Bridge Converter, Kartikeya Jayadurga Prasad Veeramraju

Doctoral Dissertations

"The Solid-State Transformer (SST) is gaining attention as an alternative to conventional iron-core transformers in the power electronic community. The power industry's increasing demands for smaller size, higher efficiency, and greater energy density have made the SST an attractive option. Among various power electronic converter topologies, the Dual Active Bridge (DAB) has become popular for its bidirectional power flow capability and galvanic isolation, primarily in the DC application space. Advancements in semiconductor technologies have introduced new bidirectional switches, opening avenues for novel SST topologies. This research investigates the application of the DAB as a single-stage SST and focuses on advancements …

Prediction And Root-Cause Analysis For Smart Speaker Intentional Electromagnetic Interference Attacks, Tanner Fokkens

Masters Theses

"Smart home and Internet of Things (IoT) devices have become ubiquitous in homes over the past decade. The smart speaker itself is often the device that interfaces all these devices together. Because of this, the smart speaker can become a point of attack for someone trying to exploit or hack into the smart home devices. In the past few years, it was discovered that smart speakers with microwave electromechanical system (MEMS) microphones are susceptible to intentional electromagnetic interference (I-EMI) attacks by modulating an audio command to a high-frequency carrier signal. This attack allows for command recognition for long-distances and smart …