Influence of Side Effect of EBG Structures on the Far-Field Pattern of Patch Antennas

The electromagnetic band gap structure always used as a part of antenna structure in order to improve the performance of the antenna especially for improves the gain and radiation pattern. In this paper, microstrip antenna is used due to the advantages such as easy and cheap fabrication, light weight, low cost, easy to feed, and better isolations among array elements, by suppressing surface wave modes. The two dominating side effects are the parasitic loading effect and cavity effect. The first causes the multi resonances antenna resulting in large bandwidth, the second effect is due to reflecting energy from EBG toward antenna and so decreasing the bandwidth. The EBG structure parameters and number of EBG rows is related to these effects. In this paper, we propose a rectangular microstrip patch antenna with EBG substrate of different structure EBG parameters and number of EBG rows; we compare the performance of the proposed antenna with a conventional patch antenna, in a same parametric analysis with HFSS simulator.