UHF RFID Architecture Analysis And Beamforming Based On Smart Antenna

As the basic technology of "internet of things",RFID(Radio Frequency Identification)has become a research focus.RFID is a short-range communication technology which realizes data exchange through radio signals by non-contact way among the objects.RFID has enhanced the management efficiency in various fields such as intelligent transportation,asset management,logistics management.But currently,many technical problem in RFID system like poor resistance to multipath interference,high tag-collision rate,limited identification range,and high positioning error are still unsolved,which restrict its further development.As the key part of data communication in RFID system,antenna has play an important role in system performance,which becomes research focus.This paper introduces the smart antenna into RFID system for solve above problems.The research effort of this paper including analysis of passive UHF RFID system structure based on smart antenna and beamforming method of smart antenna.The main contributions are as follows:First,the enhancement of RFID system performance by using smart antenna is verified by simulation method and theoretical analysis.In anti-collision,according to the operation principle of smart antenna,the tag anti-collision algorithm based on beam-swtich and the tag anti-collision algorithm based on power-control are presented,simulation results show that improvement of performance in anti-collision.In anti-multipath,the communication model for passive UHF RFID system is established,and the suppressing effect on multipath interference by using smart antenna is proved.The enhancement of maximum identification range is verified through the formula of two-way communication as derived.In positioning,a fast location method is presented based on smart antenna,and the main parameters of the method are analyzed.Second,a beamforming algorithm based on improved particle swarm is proposed to improve anti-interference ability for smart antenna.The simulation results show that,compared with applying traditional particle swarm,the improved algorithm can obtain single beam pattern which has stronger anti-interference ability.The phase difference is changed to achieve single beam scanning for expand identification area.