Effects of the resistive patch and the uniaxial anisotropic substrate on the resonant frequency and the scattering radar cross section of a rectangular microstrip antenna

The moment method technique is developed to examine the scattering properties of a rectangular microstrip patch antenna with non zero surface impedance. The boundary condition for the electric field is used to derive an integral equation for the electric current. The necessary terms for representing the surface resistance on the patch are derived and included in the integral equation in the form of a resistance matrix. The scattering radar cross section (RCS) of a microstrip antenna, including the effect of the surface resistance and the effect of a uniaxial substrate, is analysed. Effects of uniaxial anisotropy in the substrate on the complex resonant frequency of the microstrip patch antenna are also investigated. Numerical results show that the surface resistance significantly affects the RCS and radiation of the rectangular microstrip patches. Moreover, it is shown that the permittivity εz has a stronger effect on the resonant frequency, the radiation and the scattering radar cross section than the permittivity εx. It is worth noting that our calculated frequencies do not depend on the surface resistance.