FDTD analysis of patch antenna over a multi-layer substrate

In this paper, rectangular microstrip patch antenna over a multi-layer substrate configuration is presented. This patch antenna configuration improves the bandwidth and the radiation pattern of the patch. The finite-difference time-domain (FDTD) method with perfectly matched layer absorber (PML) as well as Mur's (1981) first order absorbing boundary conditions (Mur's FOC) is applied to determine the return loss, the effective dielectric constant, the input impedance and the radiation pattern of the proposed structure. In addition, the effect of changing the air gap layer thickness of that antenna is studied. The results obtained by the FDTD with PML are found to be in better agreement with the published measured data than those obtained by the FDTD with Mur's FOC.