High-gain Low Side Lobe Level Fabry Perot Cavity Antenna with Feed Patch Array

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 0.5λ0 height. Constant high gain is obtained by resonating parasitic patches at near close frequencies in 5.725–5.875GHz ISM band. The structure with 9× 9 square parasitic patches with 1.125λ0 spacing between feed elements is fabricated on 5λ0 × 5λ0 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.