Near-Field Antenna of RFID System

Abstract

Radio frequency identification (RFID) technology is a very important part of the Internet of Things. The antenna used in RFID system reader is one of its most important equipment, has become a research hotspot. Compared to far-field applications, RFID antennas typically use high-gain circularly polarized antennas or antenna arrays to increase their read distance. Near-field RFID reader antenna requires strong magnetic field, wide band and low gain characteristics, while the resulting magnetic field should be evenly distributed to avoid leakage read phenomenon. The main contents of this chapter are as follows. The RFID reader near field antenna based on the principle of magnetic field coupling has developed rapidly in recent years. In this paper, a double-layer open-circuit antenna are proposed. The near-field antennas have wideband and strong magnetic field characteristics, and are compact and simple to process. The open-loop antenna of the doublelayer terminal is located at the lower level and the upper layer is the radiation ring. The antenna size is smaller, and the feeder part and the radiation part of the isolation, a good deal to avoid interference between each other. Keywords: RFID, near field, antenna, electrically large Concept of near-field antennaRadio frequency identification (RFID) technologies, which were developed during the World War II, provide wireless identification and tracking capability [1,2]. The reader antenna is an important unit of RFID systems. Many new RFID antennas are developed for different applications [3][4][5][6][7]. Reader antennas can be classified into two types based on the working scope for different application purposes: near-field antenna and far-field antenna. Currently, ultra-high frequency (UHF) near-field RFID technology are fast developed in item-level identifications such as sensitive products tracking, biological products and medical products (blood, medicines, vaccines), biosensing applications and so on [8][9][10][11][12].