UHF RFID Reader Antenna with Air Gap: article / Norazlin Mohamad Razali

A stacked patch reader antenna with air gap for radio frequency identification (RFID) applications is proposed in this paper. The objectives of this project are to design an air gap sequentially fed-stacked RFID reader antenna for ultra-high frequency (UHF) band, to design a circular polarized (CP) antenna with high gain at 9 MHz of ultra-high frequency band, and lastly, to achieve a minimum size of the antenna having optimum performance. The antenna is comprised of a single truncated main patch with a parasitic patch on top of it that fed by four sequential perfect electrical conductor (PEC) probes. The probes are directly connected to an airgapped microstrip line which suspended above its ground plane. The design is simulated with the aid of Computer Simulation Technology (CST) microwave studio software. The resulted simulation shows that the antenna achieves a return loss of below -16 dB, gain of 8.917 dB, directivity of 8.857 dBi, voltage standing wave ratio (VSWR) of 1.36, and 3-dB axial ratio (AR) beamwidth of 70.5⁰.