volume | PIER Journals

Abstract

A compact wideband circularly polarized radio frequency identification (RFID) reader antenna with a coupling inner ring is proposed. The antenna consists of a radiating patch, a feeding network, and vertical fences along the sidewalls. The radiating patch incorporates both an outer ring and a coupling inner ring, which significantly broadens the gain bandwidth. Meanwhile, the sidewall-loaded vertical fences effectively extend the surface current path, enabling directional radiation. The overall antenna size is 100 mm × 100 mm × 24.6 mm. Measured results show a -10 dB impedance bandwidth of 663-1191 MHz, a 3 dB axial ratio bandwidth of 710-1085 MHz, a 4.5 dBic gain bandwidth of 885-1150 MHz and a maximum gain of 6.36 dBic. Featuring a compact structure, wide impedance bandwidth, broad axial ratio bandwidth, and enhanced gain performance, the proposed antenna is well suited for ultra high frequency (UHF) RFID applications, particularly in space-constrained environments or in scenarios where tag antennas are susceptible to frequency deviations.

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Dr. Qiaomei Zhang

Dr. Wenchao Zhang

Professor Jiade Yuan