Fully integrated passive uhf rfid transponder ic with 16.7-μ minimum rf input power

This paper presents a novel fully integrated passive transponder IC with 4.5- or 9.25-m reading distance at 500-mW ERP or 4-W EIRP base-station transmit power, respectively, operating in the 868/915-MHz ISM band with an antenna gain less than -0.5 dB. Apart from the printed antenna, there are no external components. The IC is implemented in a 0.5-μm digital two-poly two-metal digital CMOS technology with EEPROM and Schottky diodes. The IC's power supply is taken from the energy of the received RF electromagnetic field with help of a Schottky diode voltage multiplier. The IC includes dc power supply generation, phase shift keying backscatter modulator, pulse width modulation demodulator, EEPROM, and logic circuitry including some finite state machines handling the protocol used for wireless write and read access to the IC's EEPROM and for the anticollision procedure. The IC outperforms other reported radio-frequency identification ICs by a factor of three in terms of required receive power level for a given base-station transmit power and tag antenna gain.