Gain and Bandwidth Enhancement of 2 × 2 Square Dense Dielectric Patch Antenna Array Using a Holey Superstrate

Gain enhancement and bandwidth improvement of a 2 × 2 square dense dielectric patch antenna using a holey superstrate are proposed. This aperture-coupled antenna is fed by a conventional power divider. A dielectric superstrate layer is utilized to enhance the antenna gain. Moreover, by drilling a set of identical circular holes in the superstrate layer, the antenna bandwidth is improved, and the sidelobe level is decreased. The proposed antenna is fabricated and tested. The prototype yields an impedance bandwidth of 15.35% from 26.5 to 30.8 GHz. The proposed antenna exhibits a flat measured gain of about 16 dBi over all the bandwidth with a high simulated radiation efficiency of 92%. Furthermore, the sidelobe levels of the antenna are -15.8 and -21 dB in the E-plane and H-plane, respectively.