Research And Design Of The Key Modules In Base Band Of UHF RFID Reader

RFID (Radio Frequency Identification) is an automatic identification technology, with which data can be duplex transported contactlessly between reader and tag. Because of its many advantages such as contactless, long working distance, suitable for bad environment, effcient recognizing ability, RFID is rapidly spreading in industry, commerce, and traffic transport management fields etc. In this paper ,UHF RFID reader ha been carefully researched.After carefull investigation, the following findings have been made in this paper: Firstly, severl popular wireless receiver have been analysised and image reject receiver has been introduced. Base on the advantages and disadvantages of severl receivers,the initial RFID reader on systematic framework was got. And the requirements of key modules in Base band of UHF RFID Reader were given.Secondly, for the requirement full differential modules, novel LPF and PGA have been desingned by the full banlanced different differential amplifier. Which programmable gain amplifier (PGA) reached 0-62 dB gain range, but the bandwidth keep Stabile under the situation changes, with the regulation of 2 dB accuracy and got A patent application: 200810034629.2Thirdly, In order to prevent the manufacture error and the change in temperature impact the cut-off frequency of LPF, a programmable low-pass filter articles designed in this paper, through the MOS switch on the low-pass filter cutoff frequency control to adapt to different circumstances demand.Fourthly, for the static DC offset and slowly varying dynamic DC offset, a DC offset cancellation have been designed.Finally, this dasign is implemented by TSMC RFCMOS 0.25μm process, and getting post simulation with parasitic parameters.