Design Of Novel Chipless RFID Tag

The Internet of things emphasizes the exchange of information,connects things to the network,and realizes the positioning,tracking and intelligent iden-tification of items.Radio frequency identification(RFID)technology is a means of information acquisition,and it is an effective way to realize the Internet of things.The RFID tag is an important information carrier,and the low cost of the chipless RFID tag is possible for the wide application of the RFID system.The contents and main innovations of this paper are as follows:In this paper,the frequency-based chipless RFID tag is designed from three factors:the dimension,coding density and coding capacity.Firstly,a chipless RFID tag based on bending structure is proposed which adopts single-side dis-tribution and double-side distribution to achieve miniaturization.An 8 bit chip-less RFID tag is achieved by the single-side distribution.Its spatial density is 73.5mm2/bit.And the 12bit chipless RFID tag based on double-side distribution is proposed.Its space density is increased by 25.7%.The average bandwidth of each bit is occupied 85.8MHz.Increasing the coding capacity can be achieved by increasing the number of bending arms.A 40 bit chipless RFID tag can be designed.The bandwidth of the 40 bit tag is 2.95GHz-5.65GHz,and the average bandwidth occupied by each encoding is 67.5MHz.Compared with the 12 bit chipless RFID tag,the average occupancy bandwidth is reduced by 21.33%.Then,a 16 bit chipless RFID tag implemented with a quasi-complementary structure is proposed.The chipless RFID tag is composed of 16 square rings with filter characteristic.The 16 square rings with different size are distributed on the upper and lower surfaces of the dielectric plate.The chipless RFID tag with the dimension of 24mm × 24mm operates at 1.95GHz-7.15GHz.The com-plementary structure increases the encoding capacity in the specific frequency bandwidth,but also increases the coupling between adjacent coding units.In order to reduce the coupling effect between the units,the structure is optimized by saw-tooth structure,and the size optimized 16 bit chipless RFID tag is 29.6mm × 29.6mm,and the frequency band occupied from 1.5GHz to 8.9GHz.In the high frequency region,the bandwidth occupied by each unit increases.Adding more coding units in the two adjacent coding units is an effective way to improve the coding capacity.Finally,a 24 bit chipless RFID tag implemented in the form of polycyclic heart distribution is proposed in this paper,which is with the dimension of 25mm × 41mm.The average bandwidth occupied of each cod-ing is 354MHz.