A new,low-cost RFID tag analog front-end compatible with ISO 14443A and ISO 14443B is presented. By substituting conventional multi-circle antenna with single-circle antenna, the package cost of the tag is greatly reduced. Based on this exasperate antenna performance,a new rectifier with high power conversion efficiency and low turn-on voltage is presented. The circuit is implemented in an SMIC 0.18μm EEPROM process. Measurement results show that with a 120kΩ load,the power conversion efficiency reaches as high as 36%. For a sinusoidal wave with magnitude of 0. 5V, the output DC voltage reaches IV,which is high enough for RFID tags. The read distance is as far as 22cm.
A novel AC to DC charge pump with high performance is presented. Due to the pMOS structure and threshold voltage canceling technology, the efficiency and the output voltage are greatly improved. Test results show that the output voltage and power efficiency are improved by 125% and 104% respectively at 13.56MHz for a 1V sinusoidal input compared to the traditional MOS diodes structure.
