An UHF RFID transponder for ISO 18000-6B

An UHF radio frequency identification (RFID) transponder complying with Chinese UHF RFID band setting is presented in this paper. The RFID transponder is composed of analog-RF front-end and digital signal processing unit. The analog-RF front-end is mainly made up of voltage multiplier, limiter, power-on-reset (POR), clock generator, demodulator and modulator. This work proposes a novel clock generating scheme with features of area effective and high precision which uses ring oscillator and counter, accompanying preamble sent by reader before data communication. Clock generator drives transponder with clock variation less than ±1.76% which is below ±15% requested by standard. Besides, a new demodulator is presented in this paper. Silicon area of demodulator is only 21% of traditional structure and it could demodulate input signal with data rate ranging from 10 Kbps to 870 Kbps. Full chip area without test pads is 0.7 mm2@0.18 ¿m CMOS process and consumes 15 ¿W without Memory.