Engineering Commons^™

Design Of High Efficiency Doherty Power Amplifier, Kobi G. Kelly, Severin Pindell

Electrical Engineering

The project includes design and fabrication of a high efficiency power amplifier for a student design competition held at International Microwave Symposium (IMS) 2023. Efficient power amplifiers are critical for base station communication requiring efficient use of available power. The final design optimizes power added efficiency (PAE) and linearity. The amplifier will operate at 2.45 GHz. Competitive PAE above 50%, and C/I above 30 dB is achieved by leveraging a Doherty class amplifier using accurate discrete CGH4006P transistor models to simulate an efficient and linear design. Unique design features include optimal transistor bias point selection and power split ratios between …

Design And Operation Of A Microwave Flow Cytometer For Single Cell Detection And Identification, Jeffrey A. Osterberg

All Dissertations

Microwave dielectric sensing has become a popular technique in biological cell sensing for its potential in online, label-free, and real-time sensing. At microwave frequencies probing signals are sensitive to intracellular properties since they are able to penetrate cell membranes, making microwave flow cytometry a promising technology for label-free biosensing. In this dissertation a microwave flow cytometer is designed and used to measure single biological cells and micro particles. A radio frequency (RF)/microwave interferometer serves as the measurement system for its high sensitivity and tunability and we show that a two-stage interferometer can achieve up to 20 times higher sensitivity than …

Multi-Physics-Based Approach To Active Microwave Thermography, Seyed Ali Mirala

Doctoral Dissertations

“The goal of this work is to advance a novel nondestructive testing (NDT) method for controlled, rapid, and effective inspection of a structure through the integration of microwave NDT and thermography, referred to as Active Microwave Thermography (AMT). In AMT, the structure under test is exposed to microwave radiation and the thermal profile of the structure is monitored via a thermal camera in order to obtain desired information regarding the structure. This new technique is applicable across a wide range of NDT needs including detection of voids, delamination, water ingress, debonding, and cracks in numerous structures such as carbon fiber …

Electro-Magnetic Responsive Ni0.5zn0.5fe2o4 Nano-Particle Composite, Jaiprakash Kanagaraj

Electronic Theses and Dissertations

The purpose of this study is to simulate and synthesize a Radar (or Radiation) Absorbent Material (RAM) by using polymers and nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) magnetic nanoparticles. There is an ardent desire in military, space and electronics for lighter, faster, cheaper and widespread bandwidth providing RAM materials. Electromagnetic property such as magnetic permeability and electric permittivity play a major in controlling the radiation. The appropriate combination of permeability and permittivity properties is acquired for the synthesis of RAM providing wide-ranging bandwidth. The apt property is achieved by rule of mixture, mixing of particular composition of epoxy polymer having low permeability …

Free-Space Measurements Of Dielectrics And Three-Dimensional Periodic Metamaterials, Clifford E. Kintner

Graduate Theses and Dissertations

This thesis presents the free-space measurements of a periodic metamaterial structure. The metamaterial unit cell consists of two dielectric sheets intersecting at 90 degrees. The dielectric is a polyetherimide-based material 0.001” thick. Each sheet has a copper capacitively-loaded loop (CLL) structure on the front and a cut-wire structure on the back. Foam material is used to support the unit cells. The unit cell repeats 40 times in the x-direction, 58 times in the y-direction and 5 times in the z-direction. The sample measures 12” × 12” × 1” in total. We use a free-space broadband system comprised of a pair …

Development Of Active Microwave Thermography For Structural Health Monitoring, Ali Foudazi

Doctoral Dissertations

"Active Microwave Thermography (AMT) is an integrated nondestructive testing and evaluation (NDT&E) method that incorporates aspects of microwave NDT and thermography techniques. AMT uses a microwave excitation to generate heat and the surface thermal profile of the material or structure under test is subsequently measured using a thermal camera (or IR camera). Utilizing a microwave heat excitation provides advantages over traditional thermal excitations (heat lamps, etc.) including the potential for non-contact, selective and focused heating. During an AMT inspection, two heating mechanisms are possible, referred to as dielectric and induction heating. Dielectric heating occurs as a result of the interaction …

Filter Synthesis And Design Techniques For Highly Adaptable Systems, Eric James Naglich

Open Access Dissertations

Software defined radio and cognitive radio (SDR/CR) are promising concepts toward more optimally using the electromagnetic spectrum for communications and data transfer. These systems are highly agile in terms of modulation technique and frequency of operation due to early digitization and software processing of received radio frequency signals. However, the front ends of SDR/CR systems often use static antennas and switched banks of static, wide bandwidth filters before the digitization process. These components limit the ability of SDR/CR systems to operate in environments with high levels of interference and are therefore a bottleneck in the path to achieving optimal adaptation …

3d Electromagnetic Simulation Tool Exposure For Undergraduate Electrical Engineers: Incorporation Into An Analog Filters Course, Bobby B. Pheng

Master's Theses

With the growth of wireless communications, comes the need for engineers knowledgeable in 3D electromagnetic (EM) simulation of high-frequency circuits. To give electrical engineering students a better understanding of the behavior of electromagnetic fields, experiments including the use of 3D EM simulation software were proposed. Most students get lost in differential equations, curls, and divergences; this thesis aims to remedy that by exposing them to 3D EM simulation, which may motivate them toward further study in electromagnetics. Also, experience using EMPro is very beneficial for future RF/microwave/antenna engineers, as use of 3D EM simulation is becoming a requirement for this …

Addressing Computational Complexity Of Electromagnetic Systems Using Parameterized Model Order Reduction, Majid Ahmadloo

Electronic Thesis and Dissertation Repository

As operating frequencies increase, full wave numerical techniques such as the finite element method (FEM) become necessary for the analysis of high-frequency and microwave circuit structures. However, the FEM formulation of microwave circuits often results in very large systems of equations which are computationally expensive to solve. The objective of this thesis is to develop new parameterized model order eduction (MOR) techniques to minimize the computational complexity of microwave circuits. MOR techniques provide a mechanism to generate reduced order models from the detailed description of the original FEM formulation. The following contributions are made in this thesis:

1. The first …