Microstrip patch arrays for satellite communications

Procedures for the calculation of self and mutual impedance, in microstrip antennas using a transmission line model or a cavity model are compared. Experimental and theoretical results of mutual coupling are given for E and H plane. Measurements and computations were done on a two-elements array of rectangular patches (1 to 2 GHz band), and 2 elements of an 8 element linear array (20 GHz band). For mutual coupling between rectangular patches both theories are efficient particularly when spacing is large; for smaller distances the initial assumptions are no longer fulfilled and it is necessary to take into account all the slots, and the perturbation of the field distribution. In an array with more than two elements the computation of the surface (S) parameters shows fairly good agreement for S12, but a discrepancy for S1, j j2.