超高频RFID芯片中高灵敏度ASK解调器的设计

Design of an ASK Demodulator with High Sensitivity for the Ultra-High Frequency RFID Chip

为了提高无源超高频(UHF)射频识别(RFID)标签的灵敏度和增大工作距离,设计了一种高灵敏度的ASK解调器。在该解调器的包络检波电路中,采用了开启电压补偿技术,以减小电荷传输管的导通压降;并设计了一种无二极管无电阻的参考电平产生电路。基于0.18μm标准CMOS工艺实现了该解调器,其芯片面积为0.010 mm2,满足第2代第1类UHF RFID通讯协议(EPC C1G2)的要求。测试结果表明,当载波频率为900 MHz、调制深度为80%~100%、数据率为26.7~128 kbit/s时,解调器能够解调信号的能量强度范围为-16^+20 dBm。在工作电压为0.8 V时,其功耗仅为0.56μW。

In order to improve the sensitivity of the passive ultra-high frequency （UHF） radio fre- quency identification （RFID） and increase the operation distance, an ASK demodulator with high sen- sitivity was designed. The threshold voltage compensation technology was used to reduce the drop voltage of the charge transfer transistor in the envelope detector circuit of the demodulator. In addition, a voltage reference circuit without the diode and resistance was designed. The demodulator was realized based on the 0. 18 txm standard CMOS process. The chip area is 0. 010 mm2, complying with the requirement of the EPC Class 1 Generation 2 standard protocol for the UHF RFID. The measured results indicate that the demodulator can correctly demodulate the input RF signal for the signal strength from -16 dBm to ＋20 dBm, with the carrier frequency of 900 MHz under the modulation depths of 80%-100%, with the data rates of 26.7-128 khit/s. The power consumption of the demodulator is only 0.56 μW at the supply voltage of 0.8 V.