Improvement of UHF RFID Detection Rate in Multipath Environment Using Beam-switching Antenna Array

Blind spots is one of the main problems in applying the Radio Frequency Identification (RFID) system in complex multipath environments. This paper presents a low-cost beam-switching antenna array for Ultra High Frequency (UHF) RFID, which significantly lowers the number of blind spots. The array makes use of orientation diversity and spatial diversity to overcome the fading. A unique low-cost and low-lost feeding network is designed to avoid any usage of phase shifters or power dividers, making the design economically efficient. Numerical optimizations and experimental demonstrations are performed to investigate the performances of the proposed antenna array and good agreements are obtained. The tag detection rate is compared with and without beam switching, and a significant improvement in detection rate is observed.