Right-Angled V-Shaped Conformal Dual-Patch Antenna Array for RAIN RFID Doorway Portals

This paper presents a conformal ultra-high-frequency (UHF) radio frequency identification (RFID) reader antenna array for doorway portal applications. The dual-patch antenna is only 100 mm wide and right-angled (V-shaped) to fit the corners of a regular portal. Patches are arranged orthogonally to create horizontal and vertical-linearly polarized fields at near-zones and at far-field distances they provide slant-polarized fields. Beam steering is enabled by phase delaying the array elements to enhance the field coverage within the doorway portal. The antenna operates in the European UHF RFID band (865-868 MHz) with a 38 MHz, 10 dB impedance bandwidth. The antenna’s azimuth and elevation half-power beamwidth is 90° and 130°. The azimuth beam is tilted to 35° from the boresight where the gain is peaked at 5.5 dBi. This antenna is low-profile, low-cost and flame retardant and paintable. Inherited properties of the antenna’s substrate make the antenna non-toxic, self-extinguishing, lightweight and highly chemical resistant. The reader antenna is compatible with both RAIN and non-RAIN alliance UHF RFID readers.