Broadband and multi-mode Fabry-Perot cavity antenna with gain enhancement

A broadband and multi-mode Fabry-Perot cavity antenna with gain enhancement is proposed in this paper. The Fabry-Perot cavity constitute of feeding slot radiator and one single-layer partially reflective surface based on metamaterial. Two uniform slot stubs are added symmetrically to the rectangle slot near the nulls of the electric field and extra one radiation mode is introduced. Merged with the full-wavelength provided by the initial slot, a wide bandwidth slot antenna with two resonances is obtained. And the operating bandwidth is broadened from 10.6% to 18.3%. Base on the feeding slot antenna, a 6 x 6 PRS array is added to obtain the Fabry-Perot cavity. The element of the PRS is composed of two circular rings printed on the two sides of the superstrate respectively. And the gain is increased by the positive reflection phase gradient produced by the PRS array. Measured results indicate the antenna demonstrates an impedance bandwidth of 14.8-18.5 GHz (22.2%) with a gain improved to 11.2 dB.