| The RFID system which is developed from the radio and Internet technology is automatic identification technology, and now is widely used in transportation, finance and others. In the RFID system, tags are the key parts based on semiconductor and integrated circuits (ICs). In a tag, there are mixed-signal circuits combined by both digital and analog circuits, and the analog one plays a very important role in performances of the whole tag. Since the core technique of current RFID is exclusive to a few large foreign companies, the objective becomes so urgent that high performance and low cost electronic tags should be focused on in future researches.This paper described RFID technology and the theory of the electromagnetic field, and proposed the part of the analog circuit based on ISO/IEC18000-3 protocol. Besides, the extra blocks required by analog block were also designed. The power management module including a reference voltage source, analog modules and digital modules power supply circuit improved the efficiency of energy conversion and power of the accuracy of electronic tags to extend the working distance. The sensitivity of demodulation block was improved by 10% and 100% demodulation circuit which could help decrease bit errors. The reset and low-voltage detection block enhanced the performance of the power management block in order to support digital block.The blocks were simulated in Charterted 0.35um EEPROM process, and were placed and routed in layout design. The IC was taped out after redesign and optimization. After the completion of the work, I set up the test environment including FPGA and reader, and tested the analog IC. The results showed that the design complies with the relevant provisions of the agreement, and the performance was improved significantly. |
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