Moment Method Analysis of a Spherical FSS in Free Space

A program for analysing spherical patch antennas by means of the Moment Method in spectral domain is adapted to the analysis of frequency-selective surfaces (FSS). In the new model, a plane wave is impinging on a dipole array lying in free space. The plane wave is expanded into a series of spherical harmonics while the Green’s functions of the spherical structure are found with the aid of the G1DMULT algorithm. The developed code is verified against a commercial MoM simulator (FEKO™). Frequency selective behaviour of one dipole array is investigated in terms of varying radius of curvature and array size and compared to the results of a planar FSS built with the elements of the same dimensions. Results for the monostatic and bistatic radar cross section (RCS) of the array are presented.