Space fed ring microstrip antenna array with stacked rectangular microstrip antenna feed

Broadband Space fed design of compact square ring microstrip antennas fed by proximity fed rectangular microstrip antenna or by 3 × 3 gap-coupled array configurations of rectangular microstrip antennas, is proposed. Various space fed configurations of ring patch namely, single patch, 1 × 3 and 3 × 1 ring microstrip antennas, plus shaped and 3 × 3 spaced fed patch array configurations are studied. An optimum peak gain of nearly 16 dBi with BW of more than 2.7 GHz in 4 GHz frequency band is obtained in Spaced fed configuration of 3 × 3 ring microstrip patches.