Masters Theses

Abstract

Modern high-frequency electronic systems demand precise characterization and modeling techniques to ensure signal integrity and electromagnetic compatibility. This thesis presents three core studies focused on real-world challenges in high-speed and power electronics: EMI mitigation using 3D printed absorbers, wideband liquid dielectric characterization, and accurate transformer modeling.

The first study demonstrates a targeted approach to mitigating electromagnetic interference (EMI) in a commercial router. By using holography imaging to identify radiation hotspots, custom absorber structures were designed with commercially available materials, fabricated via 3D printing, and applied directly to emission sources. Radiated emission tests in a reverberation chamber showed up to 9 dB reduction in EMI, validating the method’s effectiveness for practical applications.

The second study proposes a wideband method (up to 30 GHz) to characterize liquid dielectrics using a differential microstrip line and the Djordjevic-Sarkar model. Dielectric constant (DK) and dissipation factor (Df) were extracted by comparing S-parameters of air and liquid-immersed conditions between measurement and simulation results. Experimental validation with PAO4 and DC-15 liquids showed strong agreement with traditional cavity resonance methods, with DK deviations under 1.5%.

The third study addresses transformer modeling across 100 kHz to 30 MHz by developing an equivalent circuit model that accurately captures winding effects, parasitic capacitance, and leakage inductance. The approach incorporates an optimized coupling coefficient based on physical parameters. Validation with air-core inductors demonstrated high model accuracy, with an average relative error of 2.2%.

Advisor(s)

Khilkevich, Victor

Committee Member(s)

Beetner, Daryl G.
Jiang, Lijun

Department(s)

Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2025

Journal article titles appearing in thesis/dissertation

Paper I: Pages 4-19; EMI Mitigation of Router with 3D Printed Absorber will be submitted to 2026 IEEE International Symposium on Electromagnetic Compatibility, Signal Power Integrity (EMC+SIPI).
Paper II: Pages 20-37; A Non-Destructive and Simple Setup Method for Dielectric Liquid Characterization in a Wide Frequency Range with Djordjevic-Sarkar Model has been accepted by 2025 IEEE International Symposium on Electromagnetic Compatibility, Signal Power Integrity (EMC+SIPI).
Paper III: Pages 38-50; High-Frequency Accurate Dual-Side Equivalent Circuit Model for Transformers has been accepted by Joint Asia-Pacific International Symposium on Electromagnetic Compatibility and International Conference on ElectroMagnetic Interference & Compatibility (APEMC/INCEMIC).

Pagination

xi, 57 pages

Note about bibliography

Includes_bibliographical_references_(pages 53-56)

Rights

© 2025 Reza Vahdani , All Rights Reserved

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 12526

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