B. Simulation
A parameter study was conducted for the proposed antenna to investigate the impact of the cavity. The proximity of the cavity walls to the patch and also the depth of the cavity were analyzed in terms of their impact on the return loss and radiation performance of the antenna. Also shown in Figure 2 are cases when the cavity depth is varied. This trend is similar to increasing the substrate thickness of a conventional patch while maintaining the size of the patch; as the thickness increases the resonant frequency decreases.