Study Of Oscillator Circuit In RFID

Radio Frequency Identification (RFID) is one kind of non-contactautomatic identification technologies. In this thesis, starting with the background ofRFID system, the communication principle of the backscatter modulation RFID systemand the main international standards of RFID with their application bands wereintroduced and analyzed, the RF front-end circuits architecture and work flow of RFIDreader was chosen.The characteristics of passive elements applied to VCOs were investigated in thispaper. First, the equivalent models of on-chip inductor and the parasitic parameters andcomputation methods were proposed. To improve the Q factor of the inductor withinoperation band, the general design rules of on-chip inductor, the on-chip capacitor andprinciple of variable capacitor were introduced and presented, the computation methodof parasitic capacitance of interconnect in IC was obtained.Second, the fundamental theory of voltage-controlled oscillators (VCOs) andoscillator's classes were introduced briefly in this thesis, and it also summarized theimplementation method of LC VCOs systematically. Phase noise is one of mostimportant performance parameters which influence on VCOs. The three phase noisemodels for phase noise analysis were studied respectively.In the end, the general process of LC-VCOs' design and optimization issummarized. A LC VCO for UHF RFID was designed in SMIC 0.18urn RF/MixedCMOS process. This LC VCO has a tuning range from 860MHz to 960MHz; phasenoises were -63.01dBc@10kHz , -93.25dBc@100kHz and -124dBc@1MHzrespectively.