A Novel High-Gain Dual-Band Antenna for RFID Reader Applications

A novel high-gain dual-band antenna for radio frequency identification (RFID) reader applications covering free ISM bands of 2.45 and 5.8 GHz is presented in this letter. The antenna is composed of a U-shaped copper strip with unequal arm, a printed rectangular ring, and the ground plane. A good impedance bandwidth of 120 MHz has been achieved from 2.37 to 2.49 GHz for the lower band, while the upper band covers 420 MHz (from 5.55 to 5.97 GHz). The U-shaped feeding strip excites the rectangular ring effectively by providing a good impedance matching with over 85% of total antenna efficiency in both the frequency bands and also 9.56 and 10.17 dBi gain in the lower and higher frequency band, respectively.