Wide-coverage array antenna using a dual-beam switching for UHF RFID applications

Based on a dual-beam switching, the wide-coverage array antenna with a 4 × 4 proposed matrix which generates three dual-beams is presented for the ultra high frequency (UHF) radio frequency identification (RFID) applications. The 4 × 4 proposed matrix generates the three dual-beams which can find the approximate location of a tag by covering the wide spatial coverage of 180°. The main beam directions can be controlled by selecting the appropriate input port of the proposed matrix. Due to the compact structure and very low reflection coefficient, the circular polarized square quadrifilar spiral antenna (QSA) array incorporated with the 4×4 proposed matrix has been configured. The fabricated array antenna operates at the 902-928 MHz band and produces three dual-beams at ±12°, ±39°, and ±68°.