Analysis And Extended Research On The Six-port Radio Channel Of RFID Reader

The technology of radio frequency identification (RFID) is discussed. It utilizes microwave and transmitter/receiver antenna to realize identification of far distance object. Comparing with traditional IC cards and magnetic cards, RFID system has the advantages of reading father and using more conveniently for its communication with radio frequency, so it is increasing more and more extensive applications. This paper summarizes the radio channel technology of UHF RFID reader. Based on the above facts, this paper also summarizes the methods of studying radio channel of RFID reader, and then deeply analyses and extended researches the microstrip six-port net project. The lumped component six-port net project is developed. This paper also discusses the method of testing and measurement using network parameter, introduces the structure of the microstrip track and the layout of microstrip. Finally, multi-antennas configuration of the RFID reader is discussed based on the above two projects.The paper extended researches the microstrip six-port net project deeply, ADS(Advanced Design System) tools are adopted to model and simulate this project, and then the paper analyses the characteristic of radio channel both transmitter and receiver, analyses the extended transmission bands and simulates the adaptability, then designs lumped-distributed microstrip filter. At last, the difference can be elaborated comparing with the I/Q channel project.The paper also further analyses and designs the lumped component six-port net project that adopts multi-channel Zero-IF technique. Moreover, PCB board is made for validating and measurement. Experiments and practices prove the radio signal of tag which is demodulated from I and Q channel is perfectly quadrate, and the circuit board is extremely diminished in size. To a certain extent, this project equals with the microstrip six-port project.Moreover, the paper analyses the method of testing and measurement using network parameter for the radio channel of six-port net, and analyses the track structure,optimization and layout of microstrip from a practical standpoint, which also provides so much information for the integration of six-port net.Last chapter analyses the project of controlling the open and short of microstrip using PIN diodes and utilizing the RF SWITCH(IC) to accomplish the multi-antennas reader design. The chapter emphatically analyses the work characteristic and the selection of the PIN diodes devices, and simulates the controlling circuit, which demonstrates the realization of project.