Subwavelength and low-profile element using metallic hole for reflected antenna array

In this Letter, a novel subwavelength and low-profile element is proposed for the reflected antenna array applications. By using the metallic hole, the proposed element achieves a smaller dimension with the period of 0.1125 wavelength and the profile of 0.036 wavelength at the centre frequency of 13.5 GHz. The element obtains a wide reflected phase shifting range of 337.2 degrees in such a small dimension. The reflected magnitude and phase are less sensitive to the incidence angle over a large range from +60 degrees to -60 degrees. To verify the function of the proposed element with a metallic hole, a reflected antenna array with 2724 elements is designed, fabricated, and measured. The array achieves a maximum peak gain of 23.30 dBi at 13.25 GHz with a high aperture efficiency of 61.05%.