An universal method for full wave analysis of arbitrarily shaped microstrip antenna on finite ground substrate

A coupled surface-volume integral equation approach is presented for analysis of arbitrarily shaped microstrip antennas on finite ground substrate. The method is more universal than traditional MoM. The basis functions defined in pairs of tetrahedral volume elements (SWG) and on pairs of triangular patches (RWG) are used to represent the unknown currents in dielectric cells and on conductive patches respectively. Formulas for calculating the Z-matrix in MoM are provided in detail. In particular, the boundary condition of conductor-dielectric interface is satisfied by adding a Δ Z-matrix to Z-matrix. Numerical results of three typical microstrip antennas show the validity of the method in this paper.