A high-gain circularly-polarized dual-band antenna array for RFID reader applications

In this paper, we propose a high-gain circularly-polarized (CP) dual-band antenna array for UHF (902-928 MHz) and microwave band (2.4-2.5 GHz) RFID applications. The proposed antenna consists of dual-ring radiators excited through apertures as the basic element. A 2-by-2 array formed by sequentially-rotated configuration exhibited 8 dBic gain at UHF band and 10 dBic gain at microwave band. Very good CP performance with axial ratio less than 1 dB was achieved at both bands.