Analysis And Design Of Key Module Of Receive Link For 2.45GHz Semi-passive Tag

In recent years, the rising of the Internet of things and Intelligent wear industry continue to promote the radio frequency identification(RFID) technology development. This technology has been widely used in areas such as commodity supply chain, military, medical treatment, crisis management and so on. With the increasing application demands, people's requirements for radio frequency identification systems have gradually improved. Semi-active tags are compromise product of long read distance of active tags and low power consumption of passive tags, recent years it has received widely attention. This paper mainly studies the key module circuit of RF receiver based on ISO18000-4 protocol, which mainly includes mixer, GFSK analog demodulator module and the circuit of frequency divider.This paper analyzes the research progress of RFID system, then shows the advantages and disadvantages of various RF receiver structure. The low IF image rejection receiver in 2.45 GHz is analyzed in detail, the receiver includes LNA, Mixer, complex filter, RSSI and demodulator module. This paper introduce a Mixer whose linearity and noise figure are improved.The main index of conversion gain is 15 dB,noise figure is 14.8dB,IIP3 is 2dBm,the overall current is 2.25 mA and the power supply is 1.8V.The demodulator of GFSK is mainly composed of a zero crossing detection circuit and waveform keep circuit.In order to make the whole chip more integrated,this paper also introduces the design process of divider circuit,which uses the phase switching structure to complete the prescaler.The circuit design applies the process of UMC 0.18?m,the area of the Mixer is 1.024mm*1.096 mm,including buffer and bandgap.The area of GFSK demodulator is 0.250mm*0.274 mm. The Mixer has been tapeout and the performance is meeting the demands of the receiver. The whole receiver was tapeout and is ready for testing.