Abstract: The authors present a security-enhanced UHF RFID (radio-frequency identification) transponder with novel demodulator. The demodulator, which takes advantage of the rectifier’s first stage as the envelop detector, dosen’t need a separate envelop detector. A novel average detector is also designed, which generates an output voltage having large voltage difference with the envelop signal, making the design demand for the comparator less rigorous. Because the DC level of the envelop signals can vary significantly with the distance between transponder and reader, the comparator is designed to have rail-to-rail common mode input range. To ensure a security communication between transponder and reader, a 128-bit advanced encryption standard (AES) algorithm is employed in the baseband processor. The whole transponder chip is implemented in 0.18μm CMOS process with a die size of 880μm × 950μm. Measurement results show that the minimum input RF signal that can be demodulated is 100 mV and the maximum input data rate is 160 kb/s.

Key words: UHF RFID transponder, demodulator, AES

摘要： 设计一种具有新型解调电路和安全功能的超高频RFID标签芯片。该解调电路不需要单独的包络检测电路, 而是利用标签芯片已有的整流器的第一级作为包络检测电路。同时还设计了一种特殊的均值检测电路, 输出电压和包络信号之间有很大的电压差, 使得比较器的设计更加容易。受标签和读写器距离的变化影响, 包络信号的直流电压在很大范围内变化, 因此还设计了具有轨到轨共模输入范围的比较器。为了保证标签和读写器之间通信的安全, 在数字基带处理器中集成了128位的高级加密标准算法(AES)。整个标签芯片 采用0.18μm工艺实现, 芯片面积为880μm×950μm。测试结果表明, 标签芯片可以解调出的射频输入信号最小幅度为100 mV, 最大的数据率为160 kb/s。

关键词: 超高频RFID标签, 解调电路, 高级加密标准(AES)