Numerical analysis of finite frequency selective surfaces with rectangular patches of various aspect ratios

The finite frequency selective surface studied consists of a two-dimensional array, finite in one dimension and infinite in the other, of perfectly electrically conducting plates in free space. The analysis uses a Green´s function formulation in the spectral domain, and the resulting equation is solved using the method of moments. Techniques are demonstrated for increasing the speed of the numerical computation so that the problem can be solved on a VAX 11-780 in a reasonable amount of time. Two types of basis functions, one subsectional and the other complete domain, are used to represent the currents on the patches. Both yield similar results and both are suitable for use in this problem. Techniques are demonstrated for approximating the tails of the infinite integrations which allow a more accurate solution than truncation. Results for scattered power density and patch currents illustrate the edge effect and incident angle dependencies. Results showing 3 dB bandwidth, resonance peak versus frequency, and scattered power versus frequency are plotted for patches with aspect ratios varying from 0.1 to 1