Design And Implementation Of Optical Transceiver Module And Antennas Switching Controller For Distributed RFID Systems

RFID(Radio Frequency Identification)technology is a non-contact automatic identification technology.It is one of the key technologies in the Internet of things and has attracted a high level of research interest due to its large data storage capacity as well as remote reading.Now the RFID technology has widespread applications in our daily life.However,the explosive growth of information data is becoming a tough challenge to the RFID system.On the one hand,it requires plenty of RFID readers to cover large areas,such as workshop and warehouse,because of the limited reliable range of conventional RFID systems.On the other hand,there some "dead areas" in conventional RFID systems,in which the tags cannot be effectively detected.In this paper,we research a novel distributed RFID system.In this system,we apply the RoF(Radio over Fiber)distributed antenna system techniques to passive UHF RFID systems.By transmitting the RFID signal through optical fiber,the coverage of single RFID reader is expanded.In addition,RoF technology makes it easier to realize the management of multiple readers.Furthermore,we enhance the detection accuracy by switching the transmitting and the receiving antennas,since the dead area moves when the antennas matching state changes.In this paper,we design the optical transceiver module of the new RFID system.The optical transceiver module is specially devised for the UHF RFID systems,which offers many advantages over the broadband optical modules,such as simple structure and low production cost.The typical operation band is 902MHz?928MHz.To meet the demands of RFID systems,the downlink RF power is up to 30dBm and can be accordingly adjusted.The uplink gain is OdB,with the OIP3 being 20dBm and the SFDR being 105.8 dB·Hz2/3.In this paper,we design the antennas switching controller of the new RFID system.The antennas switching controller is used to control the switching of antennas,with the insertion loss of 1.6dB and the isolation no less than 54dB.The configuration of antennas switching,such as the switching time interval and the operating sequence of the antennas,can be configured flexibly by sending commands from the host.The demonstrator system with antennas switching shows that the tag detection accuracy can be improved by almost 15%.