Design of compact RFID reader antenna with high transmit/receive isolation

A radio frequency identification (RFID) reader antenna with high transmit/receive isolation, which consists of two circularly-polarized radiating patches, is presented. The high isolation is achieved by the symmetric design of the antenna geometry and proper arrangement of four feed points on the patches, which are fed by branch-line hybrid couplers. The experimental results show the transmit/receive isolation of more than 36 dB in the 860–960 MHz RFID frequency band. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2478–2481, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22017