Antenna Gain Enhancement Using a Holey Superstrate

Antenna gain enhancement using a holey dielectric superstrate on a microstrip patch antenna is presented. Antenna gain is increased by creating an in-phase electric-field area on the upper surface of the superstrate. In order to create the in-phase field, the effective permittivity of the superstrate is controlled by changing the radius of the holes in the superstrate. The proposed antenna is fabricated and measured. It achieves a 2.3-dB gain enhancement when the superstrate is added over the microstrip antenna at the design frequency of 5.8 GHz. The electric field is also simulated and it is observed to follow similar phase distributions on the superstrate.