The purpose of this paper is to illustrate three types of basis functions and their asymptotic forms defined over the patch to model the unknown currents.
A rigorous calculation of a microstrip structure that contains isotropic and anisotropic substrates via Galerkin's method is presented. The dyadic Green's functions of the problem are efficiently determined by the (TM, TE) representation.
The resonant frequency of a rectangular microstrip patch antenna using these different asymptotic basis functions is investigated. The effect of uniaxial anisotropy in the resonant frequency is presented for these asymptotic currents.
Comparisons are made, and show that the utilization of the asymptotic basis function provides a significant improvement in the computation time over the exact form in the evaluation of the resonant frequency of a microstrip patch antenna. Convergent solutions are in good agreement with the exact sinusoid basis function without edge condition and with those obtained from literature.
