High Gain Microstrip Patch Array Antenna for Long Range Microwave RFID Applications

As the radio frequency identification (RFID) technology is gradually moving towards higher frequency bands, the reading range of RFID has increased substantially. High gain antennas are needed to facilitate the long range reading process. Highly selective reader antennas with narrowband characteristics are preferable to avoid interference between neighboring RFID tags. This paper presents a high gain and narrowband circularly polarized microstrip patch array antenna operating at the microwave RFID band. The antenna consists of 16 patch elements excited through aperture coupling and powered with an efficient corporate feeding network. The simulated gain of the antenna is 17.3 dBi over a bandwidth of 4.95 to 5.06 GHz. The fabricated prototype antenna exhibits high degree of conformity with the simulated characteristics. The proposed antenna is lightweight, planar and the panel size is measured 140 mm × 120 mm × 0.3 mm. It is also suitable for communication in a wireless local area network (WLAN).