Date of Award

3-2023

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Electrical and Computer Engineering

First Advisor

Timothy S. Wolfe, PhD

Abstract

The quiet zone of a radar range is the region over which a transmitted EM field approximates a uniform plane wave to within some finite error tolerance. Any target to be measured must physically fit within this quiet zone to prevent excess measurement error. Compact radar ranges offer significant operational advantages for performing RCS measurements but their quiet zone sizes are constrained by space limitations. In this work, a scientific computing approach is used to investigate whether equivalent-current transmitters can be designed that generate larger quiet zones than a conventional version at short range. A time-domain near-field solver, JefimenkoModels, was developed based on a novel generalization of the Jefimenko equations. Quantitative methods were developed to efficiently evaluate the electric-field uniformity produced in a target-plane by an arbitrary aperture antenna. A collection of parameterized UHF antenna models were designed and then optimized using an adaptive PSO process. This resulted in the discovery of an unconventional range configuration with a target-plane located near the inner Fresnel near-field boundary. Several optimized transmitter designs were ultimately produced that achieve significant, wideband quiet zone expansion.

AFIT Designator

AFIT-ENG-MS-23-M-034

Comments

A 12-month embargo was observed.

Approved for public release: 88ABW-2023-0316

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