Design and analysis of broadband circularly polarized compact planar antennas for 2.45 GHz RFID handheld reader applications

Abstract

AbstractIn this article, an innovative design of a broadband circularly polarized compact planar antenna for RFID (radio frequency identification) receivers is presented. The suggested structure used the concept of slots loaded parasitic element printed underneath a coplanar waveguide-fed radiator to achieve the circularly polarized (CP) radiation and size reduction. A parasitic element loaded with F-slot and L-slot, and a window-type slotted ground plane was used to achieve resonance at 2.45 GHz with right-handed circularly polarized radiation for RFID handheld reader application. Experimental results confirmed that the designed antenna of size 16.5 × 14.8 × 1.6 mm3 attained a −10 dB impedance bandwidth of 15.8% (from 2.330 to 2.716 GHz) and 3 dB AR bandwidth of 3.43% (from 2.410 to 2.494 GHz). An axial ratio of 0.43 dB was achieved in the boresight of the antenna at the 2.45 GHz RFID band. The concept of electric field distribution on the antenna was used to elaborate the excitation of CP radiation in the antenna.