Compact and High-Gain RFID Reader Antennas for Future Internet of Things Applications

This research presents a novel low-profile slot antenna for S-band RFID applications that is activated by a coplanar waveguide feed line. The suggested CPW-fed slot antenna (CPW-SA) has a very broad impedance bandwidth (−10 dB BW) of 1660–3880 MHz (2220 MHz) and good impedance matching at an operational frequency of 2450 MHz. Its size is also appropriate. Additionally, the impacts of a backed-reflector on antenna performances are proposed and thoroughly examined in this research. We demonstrate the use of a tiny metallic reflector to reduce the consequent back lobes formed by the CPW-SA, thereby optimizing antenna gain in the boresight direction at 2450 MHz. In order to boost electromagnetic power in the primary direction, the field distribution is redirected. By altering the little air gap between the metallic reflector and the rear face of the suggested CPW-SA, these effects are produced. The designed reader antenna has a unidirectional radiation pattern, a high gain of around 9.0 dBi, and is lightweight at 2450 MHz. The overall performance is good for RFID sensors operating at microwave frequencies.