Frequency and radar cross section of a rectangular microstrip antenna containing anisotropic substrate

An accurate design of a rectangular patch on a thick substrate is applied by using the moment´s method, in which all components of electric and equivalent magnetic surface currents are considered. The electric field integral equation for a current element on a grounded dielectric slab is developed by entire domain sinusoidal basis functions without edge condition based on Galerkin´s technique; the resulting system of equations is solved for the unknown current modes on the patch. Effects of uniaxial anisotropy in the substrate on the complex resonant frequency of the microstrip patch antenna are also investigated. Numerical results indicate that both the resonant frequency and the radar cross section are slightly shifted due to the epsiv_x permittivity change and drastically change due to the epsiv_z permittivity change, the effect of the uniaxial substrate on the radar cross section versus the directivity of the rectangular microstrip structure are also presented. Accuracy of the computed techniques presented and verified with other calculated results.