Date of Award

Summer 2009

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering

First Advisor

Richie, James E.

Second Advisor

Yaz, Edwin E.

Third Advisor

Wolski, Mark R.

Abstract

Cylindrical geometries are prevalent everywhere in the world today. These geometries are used in many different engineering applications, including but not limited to, missiles for the military and MR bores in the medical industry. This is why it is important to investigate the effects that these objects have on electromagnetic (EM) scattering. A numerical technique known as the Method of Moments (MoM) is one of many techniques used to solve these types of EM scattering problems. The MoM converts an integral equation into a linear system of equations and casts this system as a matrix equation with an unknown vector to be determined. This unknown vector is numerically solved using a computer program. In this work, scattering from a perfect electric conducting (PEC) cylinder, infinite and uniform in the z-direction, is used to investigate the dependence of the MoM solution with respect to variations of the incident field. In this problem, the PEC cylinder is excited by an incident field. This incident field induces currents along the cylinder surface. These surface currents then radiate to produce a scattered field. The criterion used here to measure accuracy of the MoM solution is the root mean squared error (RMSE) between the far field pattern found using the analytic (exact) solution and the far field pattern found using the MoM. By comparing the required number of unknowns needed to maintain a specific RMSE for various incident fields, the dependence of the incident field on the MoM solution will be determined. Experimental results show that the MoM solution accuracy is directly dependent on the incident field. The MoM solution is essentially a function of the number of unknowns, the source type and location, and the cylender size. If any of these parameters are varied, the accuracy of the MoM solution is altered.

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