A SRR-based near field RFID antenna

Abstract

In this paper, a compact near field reader antenna is proposed for ultra-high frequency (UHF) radio frequency identification (RFID) applications. The antenna structure is composed of two split-ring-resonators (SRRs) and miniaturized to a special small size of 21 * 21 * 1:6mm3 for mobile RFID application. The measured bandwidth of antenna prototype is 13MHz (914.5-927.5 MHz) with reflection coeffcient less than ¡10 dB, which covers the China RFID band II (920-925 MHz). Simulation shows that the proposed antenna achieves a strong and uniform magnetic field distribution in the near field region, and the reading range is up to 42mm with near field RFID tag. Through modifying the parameters of SRRs, the antenna can operate on different UHF RFID bands (Europe band, China band I&II etc.).