Circularly Polarised Hexagonal Patch Antenna With Polygonal Slot for RFID Applications

A compact single feed circularly polarized microstrip patch antenna for RFID applications is proposed. Antenna geometry includes a regular hexagon shaped patch with a polygonal slot embedded at the centre. The slot accounts for circular polarization and an area reduction of 22.5 %. It is fabricated on FR4 substrate with dielectric constant 4.4 and size 50 mm x 50 mm x 1.6 mm. The measured results include 10dB impedance bandwidth of 5.5 % at the center frequency of 2.42 GHz, a return loss of 32 dB, minimum axial ratio of 1.82 dB, axial ratio bandwidth of 7.5%, gain of 4.9 dBi with a broadside radiation characteristic for the RHCP antenna. These results are well in tune with the simulated results and the proposed design is suitable for RFID reader antenna applications