Design of the Planar Cross Dipole Reader Antenna for UHF RFID Systems

Abstract

The planar dipole reader antenna using a dual polarization, which consists of two dipole radiating patches and Wilkinson power divider, is presented. The electric cross dipole is added to generate a symmetric radiation pattern and to compensate the high back radiation due to the shortened patches. From experimental results, the measured impedance bandwidth of the antenna (defined by −10 dB return loss) is 30 MHz (907 MHz–954 MHz, Korea standard = 917 MHz–923.5 MHz). Simulated isolation between the two input ports is over 35 dB. The measured gain of the proposed antenna is stable with frequency. The average gain is about 6.3 dBi.