Low-cost single-fed circularly polarized stacked patch antenna for UHF RFID reader applications

摘要

A single-fed circularly polarized (CP) Radio Frequency Identification (RFID) reader antenna with a simple structure has been proposed for worldwide Ultra-High Frequency (UHF) band applications. The purpose of the antenna was to provide a low-cost and easy-fabricated solution with wide bandwidth and high performance. The proposed antenna is composed of a corner-truncated square driven patch with a stacked square parasitic patch and a microstrip match stub suspended above the ground plane. Good impedance matching and good CP radiation characteristics have been obtained. Experimental results of a fabricated prototype with the center operating frequency at 900MHz showed that the antenna has the desirable performance with a gain level of about 9 dBi, VSWR of lower than 1.5 and axial ratio of less than 3 dB within the frequency range of 840 ~ 960 MHz.