Moment-method analysis of large, axially symmetric reflector antennas using entire-domain functions

Abstract

The moment-method technique utilizing entire domain basis functions is applied to the analysis of large, axially symmetric reflector antennas. The electric surface current is modeled as a finite series of sinusoids whose domain consists of the entire generating curve. This expansion results in a matrix size of less than 5% of that produced with subdomain basis functions. Only a slight increase in the CPU requirements occurs from this analysis. The results from this technique show good agreement when compared to both physical optics and a subdomain-based moment-method formulation on small, axially fed paraboloidal and hyperboloidal reflector antennas. Extension to a large 100- lambda paraboloidal reflector with f/D=0.4 produces results comparable to that obtained using physical optics. Convergence is obtained with as few as two expansion terms per wavelength. Discretization of the generating curve with four points per wavelength leads to results which agree within 0.5 dB over data from a more densely defined curve. >