The effect of the loss tangent on the bandwidth of the microstrip antennas in stacked configuration

We treat in this paper the effects of the uniaxial anisotropy and the loss tangent on resonant frequencies of microstrip patches consist of two perfectly conducting rectangular plates stacked, embedded in a bilayer medium containing isotropic or anisotropic materials. The Green's functions are discussed in detail and numerical results are validated by comparing the computed results with previously published data. The numerical results show that the loss tangent of dielectric substrate has almost no effect on resonant frequencies, but it strongly affects the imaginary parts of the resonant frequencies of the antenna. Once the imaginary parts are modified so the bandwith affected.