The Research On Phase Noise Of The UHF RFID System

RFID is a new technology of non-contact automatic identification which booms up in recent several years and is one of the most important and revolutionary technology in 21th century.At the present time both in theory and application aspects it comes to the front more and more in that UHF RFID technology is the most advanced in the world.This paper in allusion to the phase noise of the UHF RFID system.In this paper, starting with the background of RFID system, the communication principle of the backscatter modulation RFID system and the main international standards of RFID with their application bands were introduced and analyzed,the RF front-end circuits architecture of RFID reader was chosen.Secondly, the paper presents the phase noise conception and characterization methods, then deep research and analysis for its characteristic. Phase noise is one of most important performance parameters which influence on oscillator of UHF RFID reader. The paper introduced three models of phase noise .It included two linear time-invariant system models: Leeson empirical model and Razavi model, one time-varying phase noise model: Hajimiri&Lee model.Then, according to spectrum characteristics of transmitter and link parameters of receiver in UHF RFID system, the specification of the Transmitter and receiver has been analyzed systemically in reader, and it has been proven correct by the system simulation model.Final, This paper introduces a new analysis method of phase noise requirements on a local oscillator for a UHF RFID system.In general case, phase noise requirements are derived considering a reciprocal mixing with an interference signal. In UHF RFID systems using the same oscillator for the transmitted signal and the LO, range correlation phenomenon effects the phase noise requirements. This paper has derived new phase noise equation considering the range correlation effect on the RFID system and a simulation has been done. The results for UHF RFID system show that range correlation effect is the important factor in RFID system design.