Research And Design Of Passive UHF RFID Transponder With Temperature Sensor Based On ISO18000-6B Protocol

Radio Frequency Identification (RFID) technology is a non-contact andautomatic identification technology. Tags are identified automatically throughradio-frequency signal in two-way transmission. RFID transponders have severaladvantages, such as waterproof, antimagnetic, thermo-stability, long life, wideidentification distance, big data capacity, reading and writing convenience and so on.Therefore, RFID transponder, as a substitute for the traditional bar code, has beenwidely used in commodity, entrance guard, medical, transport and many other fields.RFID with intelligent sensor is a very important part of Wireless SensorNetworks (WSN). The combination of RFID technology and WSN has become a hotdevelopment direction. And the development of cold-chain logistics creates muchspace to develop the RFID transponder with embedded temperature sensor.This thesis designs the circuits of the radio analog front-end and the temperaturesensor for UHF RFID temperature transponder based on ISO18000-6B protocol. Thecharge pump, protection circuit, regulator and demodulator are designed andsimulated with SMIC18ee2P4M process. The charge pump, protection circuit and theregulator provide1.5V supply voltage for subsequent circuits. The charge pump is6-class Dickson architecture cascaded with diode connected NMOS. The protectioncircuit uses an architecture which is similar with series regulator, and the outputvoltage is fixed by four MOS threshold voltage. The regulator uses series regulatorarchitecture, whose final output voltage is stabilized in1.5V. The demodulator usesthe non-coherent metrod, and contains envelope detector, low-pass filter andhysteresis comparator.The temperature sensor is achieved by time-domain digital quantification, and itcontains pulse generator, PTAT (Proportional to Absolute Temperature) oscillator andcounter. The pulse generator finally generates a wide pulse whose width is200μs. It isa digital circuit and achieved by handling the preamble order. The PTAT oscillator isachieved by transmitted the PTAT current which is generated by PTAT current sourceto oscillator which is based on hysteresis comparator. The periods of the oscillationsignals are related with temperature. The counter is a9-bits asynchronous one, whichconsists of9divide-by-2dividers. This circuit architecture is simple and uses fewcomponents.Compared with the previous UHF RFID temperature tag, the architecture saves atimes oscillator, so the power dissipation is reduced. What’s more, the timed oscillator comes from the reader, so the precision and then the resolution ratio are both largelyimproved.The whole temperature sensor is designed, simulated and taped-outseperately in UMC18CMOS process.