用于UHF RFID接收机的双模低噪声放大器的设计

Design of a Double Mode Low Noise Amplifier for UHF RFID Receivers

采用标准0.18μm CMOS工艺,设计了一种应用于UHF RFID接收机的双模低噪声放大器,用以满足侦听模式和阅读模式对接收机的不同需求。该低噪声放大器通过一种开关可控双模偏置电路,使其在高增益与高线性度两种模式间进行自由切换;运用复制型偏置技术,抑制了PVT变化对电路的影响;采用共模反馈技术和交叉耦合电容技术,改善了电路的线性度和噪声性能。仿真结果表明,在PVT变化的情况下,高增益模式时,放大器的增益(S21)达到11dB,输入匹配(S11)为-16.1dB,噪声系数(NF)为2.75dB,P1dB为-11.2dBm;高线性度模式时,增益(S21)达到4.2dB,输入匹配(S11)为-16.9dB,噪声系数(NF)为3.52dB,P1dB为0.35dBm。

A double mode low noise amplifier （LNA） for UHF RFID receivers was proposed based on standard 0.18/lm CMOS technology, so as to meet the different requirements from listen and talk operation modes. The low noise amplifier was able to switch between high gain mode and high linearity mode freely by a switch controlled double mode biasing circuit. To avoid being affected by PVT variations, the replica biasing technique was utilized. To improve the linearity and noise figure, the common mode feedback technique and cross coupling capacitance technique was employed. Simulation results showed that, under different PVT conditions, with the high gain mode, the proposed circuit achieved a gain of 11 dB, S11 of --16. ldB, noise figure of 2.75 dB, and P1dB of -11. 2 dBm, and with the high llnearity mode, it obtained a gain of 4.2 dB, Sal of --16.9 dB, noise figure of 3.52 dB, and P1dB of 0.35 dBm.