UHF band RFID tag antenna mounted on glass objects

A novel design of planar tag antenna with broadband operation for RFID system is proposed. With the use of two parasitic strips inset along the closed loop of the input IC chip in this proposed tag antenna, a new resonant mode close to the first operating mode of the regular dipole antenna is excited to enhance the operating bandwidth. And, the obtained impedance bandwidth across the operating band can reach about 77 MHz for UHF band. With omni-directional reading pattern, the measured reading distance is about 4 m as the tag antenna mounted on the glass object of the car.