High-gain low side lobe level Fabry Perot Cavity antenna with feed patch array

Abstract

In this paper, a high gain, low side lobe level Fabry Perot Cavity antenna with feed patch array is proposed. The antenna structure consists of a microstrip antenna array, which is parasitically coupled with an array of square parasitic patches fabricated on a FR4 superstrate. The patches are fabricated at the bottom of superstrate and suspended in air with the help of dielectric rods at 0:5 λ0 height. Constant high gain is obtained by resonating parasitic patches at near close frequencies in 5.725-5.875 GHz ISM band. The structure with 9£9 square parasitic patches with 1:125 λ0 spacing between feed elements is fabricated on 5 λ0 £ 5 λ0 square ground. The fabricated structure provides gain of 21.5 dBi associated with side lobe level less than -25 dB, cross polarization less than -26 dB and front to back lobe ratio of more than 26 dB. The measured gain variation is less than 1 dB and VSWR is less than 2 over 5.725-5.875 GHz ISM band. The proposed structures are good candidates for base station cellular systems, satellite systems, and point-to-point links.