Enhancement of Inset Feed Microstrip Semicircular Patch Antenna Directivity using Dielectric Superstrate

The subject of enhancing microstrip patch antennas directivity, using either a frequency selective surface (FSS) or a double-negative (DNG) metamaterial slab, has been investigated by a number of researchers in recent years. The purpose of this paper is to show that we can also achieve the same goal by using a much simpler design for the superstrate, namely a dielectric slab, whose performance can be comparable to those of the other two typical choices for the superstrate. In this paper, we study the influence of dielectric superstrate on the performances of inset feed semicircular patch antenna. This dielectric layer is disposed above the patch and both are separated by the air. The return loss, radiation pattern, and directivity are studied using HFSS software. The simulation results show that the gain, directivity and S11 parameter of the antenna with dielectric superstrate are increased significantly at X band (8-12GHz). Compared with the conventional patch antenna with the same size but without superstrate, the performance of the proposed antenna is improved obviously. Keywords—patch antenna; HFSS; dielectric slab; return Loss; gain; directivity.