Date of Award


Document Type


Degree Name

Master of Science


Department of Electrical and Computer Engineering

First Advisor

Andrew Terzuoli, PhD


This research involves the design, modeling, and testing of both tapered periodic surfaces (TPS) and transverse electromagnetic (TEM) horns. The goal is to reduce the off-boresight fields for a TEM horn and increase the peak-to-peak field levels on boresight. This is accomplished by applying a TPS to the free space end. Two tapers are designed - one that approximates an exponential impedance function and one that approximates a triangular impedance function. Both reduce the off-boresight fields of the TEM horn. In most cases the exponential taper reduces the field levels further than the triangular taper. This research shows that a TPS is an effective method of reducing diffraction. A procedure for designing a TPS to approximate a specific impedance function is presented. A two-dimensional finite difference time domain (FDTD) model predicts the tapers will reduce the diffraction. Experimental results verify the TPS's ability to reduce the peak off-boresight fields for a TEM horn antenna.

AFIT Designator


DTIC Accession Number



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The author's Vita page is omitted.