Analysis of elliptical and circular microstrip antennas using moment method

A method of calculating the input impedance of either a circular or a slightly ellipitcal microstrip antenna excited by a coaxial probe is presented. Using the reaction integral equation and the exact dyadic Green's function, the finite substrate thickness is taken into account in the formulation. Good agreement with experimental results for an elliptical patch is obtained and a design procedure for a circularly polarized antenna is presented.