Microstrip antenna gain enhancement by metamaterial radome with more subwavelength holes

A high gain patch antenna using more subwavelength hole metamaterial as radome operating at 3.5 GHz band is proposed in this work. We use a metamaterial superstrate, which is constructed by stacking three layers of Jerusalem cross structure. The structure can be applied to modify the radiation pattern and increase antenna gain. The proposed structure is made by three layers FR4 and the Jerusalem cross structure is printed on the front slab at each layer. This radome´s refraction index approximately equals zero and increases the antenna gain at a frequency close to 3.5 GHz. In addition, we change the number of subwavelength holes in metamaterial radome to further enhance antenna gain. A patch antenna which is covered by the proposed metamaterial radome can achieve a maximum gain of 7.8 dBi.