Analysis and Design of a Novel Structure of Tag for RFID
Date Issued
2007
Date
2007
Author(s)
Lin, Hsin-Hsu
DOI
zh-TW
Abstract
In this thesis, we propose a novel structure of tag for RFID system. The way of antennas configuration and loading impedance design are different from conventional tags. The conventional tag has only one antenna, which is used for both receiving and scattering. The antenna is designed to match tag IC for receiving and switched between match state and mismatch state for backscattering. With this design, the maximum backscattering level difference cannot be obtained and also no power is supplied to the tag during the mismatch state. To simultaneously solve the above two problems, we propose a novel tag structure. The novel structure contains two independent antennas. One antenna is for receiving that is designed to match the tag IC for maximum power transfer. The other is for scattering. The scattering antenna is alternatively connected to two optimized impedance states for maximum backscattering level difference. With this new structure it is expected that the reading range can be much increased.
We construct a system for measuring the backscattering field. We measure the backscattered signal and compare the detection performance. Experimental results show that performance obtained by the novel structure is 6dB better than that of the conventional tag.
In addition, mutual coupling is an important problem for tag antennas. This type of interaction may reduce energy received and result in the failure of tag detection. Therefore, we investigated the effect of mutual coupling on RFID performance. By measurements and simulations, we can analyze the impact of electrical and geometrical variables on readability of the tag and try to provide a feasible solution.
Subjects
射頻辨識
負載阻抗
後向散射
散射場
互耦合
Radio Frequency Identification (RFID)
Impedance loading
Backscattering
Scattering field
Mutual coupling.
Type
thesis