Design of a semi-passive UHF RFID tag IC with freight security monitoring function

Abstract

A semi-passive ultra-high-frequency-band radio frequency identification tag IC with freight security monitoring function is proposed. The tag can record the number of times a container has been opened during transport and is compatible with Electronic Product Code Class-1 Generation-2 protocol. A switch-state monitoring unit is presented with power control logic that makes the tag return to sleep mode after each recording operation. An optimized differential rectifier is designed after the analysis and comparison of the different rectifier architectures. The rectifier is designed along with a voltage regulator and a wake-up circuit to comprise a power management unit for generating two output voltages of 1 and 1.8 V at 915 MHz. A baseband processor with a jitter suppression module is employed to improve system reliability. The tag chip is designed in TSMC 0.18 μm CMOS process and simulated with Spectre. According to the simulation results, the power consumption of the tag is 9.56 μW under activation mode, and the sleep current is only 645 pA under the typical condition.