Novel omnidirectional polarized tag antenna for UHF RFID applications

An UHF RFID tag antenna which is comprised of a trapezoidal loop and a dual-dipole radiator with an L-slit for omnidirectional polarized reading patterns is designed, fabricated and measured. For a conjugate match to the Monza3 microchip impedance of 44 - j231 at 915 MHz, an orthogonal dual-dipole tag antenna (91 mm × 91 mm) with L-slit on each dipole arm was designed. The read range of the prototype attached on a different glass can reach more than 9 m, which has been tested for an RFID reader with 4.0 W of EIRP.