Gain and Bandwidth Enhancement of Slot Antenna Using Two Unprinted Dielectric Superstrate

This paper presents a high-gain and wideband antenna with a compact, simple and low-profile structure. the design strategy of high gain fabry-perot resonator antennas (fpra), which have a superstrate with increasing phase in the operating band, has been applied to design the antenna. a double-layered unprinted dielectric superstrate is used as a partially reflective surface (prs) to enhance the gain of the antenna and to produce a reflection phase curve versus frequency with a positive slope. the superstrate is composed of two dielectric slabs, and it is truncated so that its dimension to be about 1.5λ×1.5λ. by using such an unprinted double-layered dielectric, as a superstrate, the bandwidth of about 14.3% can be achieved. to further increase the size of the upper unprinted slab, the gain can be enhanced, without compromising the bandwidth. a prototype antenna has been designed and simulated at 9 ghz. the achieved peak gain is 17 db.