Bandwidth enhancement for thin substrate UHF RFID patch antenna

This paper presents an unconventional bandwidth enhancement technique for thin substrate UHF RFID linearly polarized patch antennas. The patch antenna is made from polyethylene dielectric substrate and aluminum adhesive strip conductive layers. A microstrip fed rectangular patch antenna is designed to operate between 902 and 928 MHz UHF RFID frequencies. Impedance bandwidth is enhanced by intentional impedance mismatch at the edge of the patch. An 88.98 MHz impedance bandwidth was achieved through a –32% intentional impedance mismatch. Antenna’s gain and other parameters were not majorly affected by this technique. This technique is also suitable for other applications operating in 433 MHz or 2.4 GHz. Transceivers that can handle reflected power is recommended to use with this type of bandwidth enhancement.