Design Of UHF Band RFID Reader Antenna And Tagantenna

RFID(Radio frequency identification)technology has been used in field of military,logistics,retailing,transportation,security and assets management be-cause of its automatic reading,wide working environment,moving objects iden-tify and other features.This paper mainly expounds the design of UHF band near field reader antenna,UHF band tag antenna and chip-less tag antenna which use ink-jet printing process.Firstly,an UHF band reader antenna is introduced.UHF band RFID system has drew a lot of attention of researcher due to its far reading distance and small size etc.But as for near field antenna,it's hard to meet the requirements of small size,strong near magnetic fields and low gain contemporary.Based on this situa-tion,this paper proposed an UHF band near-field reader antennas.A novel antenna using dual S-shaped micro-strip lines are proposed to generate a strong and even magnetic field for broadband UHF near-field RFID applications.The antenna achieves good impedance matching and uniform magnetic field distribution over the entire UHF RFID band of 819MHz-993MHz;a reading distance of 70mm using the Impinj UHF near-field button and a simulated far-field gain of lower than-7dBi.Secondly,the UHF band tag antenna with ink-jet printing process in intro-duced.With nano metallic ink printed directly on various substrates,the ink-jet printing method is more simple,cost sa-vings and environmental friendly than the traditional processing methods such as etching and plating.In this paper,UHF band tag antennas are designed to meet the reaquirements of ink-jet printing pro-cess.One UHF band tag antenna with small size of 24mm×8mm is proposed,which is manufactured by nano-printing process.It's theory reading distance is 80cm.Another design is an UHF band tag antenna which size is 31mm × 24mm.The maximum gain is-3.2dBi and the theory reading distance is 160cm.The op-erating band of both tag antennas are about 200MHz,which cover the entire UHF RFID band.Finally,the design of chip-less tag antenna is introduced and analyzed.Due to the data chip,General tag antenna has high price cost and the manufacturing process is more complicated.In order to reduce costs and manufacturing com-plexity,a LC resonant structure based chip-less tag antenna is proposed,which achieves a 12bit data carrying capacity in the bandwidth of 3-4.5GHz.The chip-less tag antenna is printed on PET film by using ink-jet printing process.The test results and simulation results are roughly coincide.After that the chip-less tag antenna is optimized to increase the isolation between the antenna elements,thereby to increasing the antenna's coding resolution and enhance the reading per-formance of the chip-less tag antenna.