Conducting ring loaded annular slot array antennas

Low cost high gain antennas are required for wireless communications. Annular slot array antennas are good candidates for high gain applications. However their aperture efficiency is usually low. Previously, the authors proposed new methods for enhancing the antenna performance. The present paper describes an analytical method for the antenna loaded with an array of conducting rings. The solution is based on the boundary value method (BPM). The conducting rings can be considered as microstrip patches fed by the slots. The proposed method is fast and considers the effects of mutual coupling among the slots and conductor patches.