The Analysis of Multi-Carrier UHF Passive RFID Systems

• Main Authors: Che-Jung Kuo, 郭哲榮
• Other Authors: Hsin-Chin Liu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/78695012310534459598

碩士 === 國立臺灣科技大學 === 電機工程系 === 96 === In recent years, the applications of passive RFID systems have gained more attentions. Because a tag must obtain its operating power from a continuous wave transmitted from a reader In a passive RFID system, the readable range is hence limited. Consequently many researches on readable range extension have been proposed. In this thesis, we use a multi-carrier method to supply the operating power of a passive tag. In an interrogation region, continuous wave emitters, which provide additional operating power to passive tags, are deployed following the similar manner of base station deployment in a cellular phone system. Because the transmission powers of continuous wave emitters must jointly consider the tag minimum modulation depth constraint and the tag minimum operating power requirement, the transmission powers of continuous wave emitters must be carefully chosen. In this thesis, an analytical analysis of continuous wave emitter transmission powers is derived. Assuming all tags are uniformly distributed in an interrogation region, the optimum continuous wave emitter transmission power that leads to the largest reader readable range can be obtained according to the analysis. Simulation results show that the optimization of continuous wave emitter transmission powers can achieve better read range extension. In addition, using modified waveform command can loosen the tag modulation depth constraint and hence further extend the reader coverage.