Compact Dual-Band Hexagonal Ring Antenna with Shorting Pins for RFID Reader Applications

This paper reports a compact square-shaped microstrip patch antenna covering 0.9 GHz and 2.4 GHz bands for radio frequency identification (RFID) reader applications. The proposed antenna is a two-layered structure comprised of a hexagonal ring patch on the top and a slotted square patch on the bottom. The compactness is achieved by using four shorting pins at appropriate locations. The simulated results show that the antenna exhibits impedance bandwidth (S ₁₁ <; -10 dB) of 16.33 % and 6.25 % in the ultra-high frequency (0.9 GHz) and industrial, scientific and medical (2.4 GHz) bands, respectively. The shorting pins also enhance the resonating bandwidth and gain of the proposed RFID antenna. Regardless of very low-profile, the gain values at 0.9 GHz and 2.45 GHz are 5.55 dB and 8.38 dB, respectively.