A Miniaturized Circularly Polarized Antenna with Short Circuit Strip for RFID Reader

Abstract

A miniaturized circularly polarized microstrip antenna with a short circuit strip for Radio-Frequency identification (RFID) reader is proposed in this paper. The size of the miniaturized antenna is realized by the capacitive load provided by the connection between short-circuit strip and ground. The overall size of the antenna is 80mm×80mm×1.6mm(0.24λ×0.24λ×0.0048λ). Simulated results prove that the impedance bandwidth of this antenna (where return loss below -10 dB) is 19 MHZ (894-913 MHZ), and its axial ratio below -3 dB is 11 MHZ (897-908 MHZ), and the peak gain is -5.6 dBi across the bandwidth.