Circularly polarized equilateral triangle patch antenna for UHF RFID reader applications

A simple circularly polarized (CP) equilateral triangular patch antenna for UHF (902-928 MHz) radio identification (RFID) reader applications is proposed. In this design, good CP radiation is achieved by loading a near semi-circular notch is into the patch. Furthermore, the L-shaped probe-feed method is used for achieving good impedance matching that results in broad impedance and CP bandwidth. The experimental results show that the 3-dB AR (axial ratio) bandwidth is approximately 3% (902-929 MHz), while the 10-dB impedance bandwidth is approximately 25.4% (854-1102 MHz).