Directivity enhancement of aperture coupled microstrip patch antenna using two layers dielectric superstrate

Electromagnetic Band-Gap (EBG) structures are popular and efficient techniques for microwave applications; they are periodic metallic or dielectric materials. EBG may be combined with microstrip patch antenna to increase the directivity, the radiation efficiency and/or to suppress surface waves, to reduce the side lobes of the radiation pattern and to increase the bandwidth. In this paper, we study the influence of Unidimensionnel Electromagnetic Band Gap structure (1D-EBG) on the performances of an aperture coupled rectangular patch antenna. This 1D-EBG is chosen as two similar dielectric layers disposed above the patch. 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 layers are increased at X band (8-12GHz). Compared with the patch feed with the same aperture size but without dielectric layers, the performance of the proposed antenna is improved obviously.