5.8 GHz dual-polarized aperture-coupled microstrip antenna

The paper presents the design of a dual-polarized aperture-coupled microstrip patch antenna suitable for passive 5.8 GHz radio frequency identification (RFID) applications. The antenna provides two orthogonal ports with nearly 30 dB isolation and crosspolarization levels of nearly 20 dB for both ports. Using the orthogonal ports, both transmit and receive functions can be implemented on the same antenna. This type of antenna could be very useful for RFID transponders which have to receive energy from an RFID reader and send back identification information.