The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Gabor expansion of an equivalent dipole antenna
Author:	Manzhura, Oksana
View Online:	njit-etd1996-067 (xi, 65 pages ~ 2.0 MB pdf)
Department:	Department of Electrical and Computer Engineering
Degree:	Master of Science
Program:	Electrical Engineering
Document Type:	Thesis
Advisory Committee:	Niver, Edip (Committee chair) Whitman, Gerald Martin (Committee member) Akansu, Ali N. (Committee member)
Date:	1996-01
Keywords:	Antennas, Dipole.
Availability:	Unrestricted
Abstract:	The Gabor representation in the context of an aperture problem is an expansion of a radiated field in terms of a discrete set of linearly shifted and spatially rotated elementary Gaussian beams. The parameters that can be varied in this summation are the number of beams and corresponding beam widths. As the difficulty associated with the unique determination of the expansion coefficients was alleviated, the method has been successfully applied to one and two dimensional apertures. Although, the asymptotic evaluation of expansion functions has reduced the computational burden drasticallym it was at the expense of some loss in accuracy. The numerical experiments have established that the narrow beam algorithm with almost a priori predictability can be used in a variety of problems. Here, the Gabor representation has been applied to a narrow rectangular aperture illuminated with a sinusoidal field. The narrow aperture (height >> width) excited by sinusoidal field distribution approximates an equivalent dipole with a similar current distribution with only exception that aperture radiates into a half-space whereas 'the dipole covers the entire space. Utilizing the narrow beam algorithm, once the expansion coefficients were determined, the radiated electric field potential in near, mid and far zones were evaluated. The criteria in determining the number of expansion coefficients was based on re-generation of the aperture field distribution with sufficient accuracy. It was observed that even though wide beam algorithm was applied, less number of terms resulted in erroneous side lobes and higher number of terms caused Gibbs phenomena in the region close to the aperture plane. The numerical evaluations are carried out for the half-wavelength high narrow aperture. Far zone numerical results of radiated potential utilizing Gabor expansion are compared to analytical expressions determined via Fourier transform. The unique application developed in this work in expressing the radiated field of an equivalent dipole antenna revealed that Gabor expansion can be a valuable tool in studying practical radiation and propagation problems.