A UHF Passive RFID Tag Front-End Design With a Novel True Random Number Generator

Among various wireless communication methods, the ultra-high frequency (UHF) passive Radio Frequency Identification (RFID) electronic tags are widely used due to their ability to transfer information without internal power supply. In this study, a low-power UHF passive RFID tag front-end with a novel structure including a true random number generator is designed and fabricated in standard 180nm CMOS technology. The proposed front-end circuit includes an analog front-end, an RF front-end, and an impedance matching network. The received RF energy is impedance-matched to the analog front-end, generating a power supply voltage for the RF front-end. The RF front-end performs signal demodulation and generates a reference clock. A novel true random number generator (TRNG) is designed in the proposed RF front-end to achieve signal anti-collision functionality. The experimental results indicate that the total power consumption of the RFID tag front-end is $8.67\mu $ W, and the TRNG circuit can produce a series of random number with 85.5% of credibility, which effectively improves the randomness of the communication keys.