Dual band circularly polarized diamond-shaped antenna with directional capabilities for RFID application

A simple and novel diamond-shaped structure capable of producing dual band antenna with circular polarized enhancement is presented. The proposed antenna operates at both UHF and ISM bands which is suitable for RFID application. A pair of slots is introduced at the blended edge within the radiating element with optimum width and length, which can excite circular polarized antenna for both frequencies. The proposed antenna´s gain is improved by using a fixed air gap between substrate and ground plane. It is observed that there is good measure of agreement between the simulation and measurement return loss result, when compared.