为抑制干扰和提高电路的线性，采用0. 13 μm ＲF CMOS 工艺设计了一款无需声表滤波器的射频前端电路系统． 该设计采用一种新的带干扰消除环路可变增益低噪声跨
导放大器、25%占空比本振信号的无源混频器和互阻放大器架构来实现抗干扰、低噪声、高线性的射频前端． 流片和测试结果表明: 该电路抑制带外强干扰达20 dB 以上，在2. 4 GHz可实现44. 98 dB 增益和2. 03 dB 噪声系数，同时获得－ 7 dBm 的输入三阶互调截点和+ 72 dBm 的输入二阶互调截点，实现了无需声表滤波器和抗干扰特性; 整个射频前端供电电压为1. 2 V，功耗为36mA．

In order to suppress interferences and improve the linearity of circuits,a SAW-less RF front-end system is designed by using a 0.13 μm RF CMOS process.This design adopts a novel variable-gain low-noise transconductance amplifier with a loop eliminating interferences,a 25% duty-cycle current-commutating passive mixer and a transimpedance amplifier,so as to achieve an RF front-end system of anti-interference,low noise and high linearity.Tapeout and test results show that the designed front-end system accomplishes the goals of 20 dB out-band interference rejection,44.98 dB gain and 2.03 dB noise figure at 2.4GHz with a － 7 dBm 3rd input intermodulation point ( IIP3) and a + 72 dBm 2nd input intermodulation point ( IIP2) being obtained,which means that the designed system needs no surface acoustic wave filter and is of anti-interference characteristic.In addition,the designed system has a power supply voltage of 1.2 V and a power consumption of 36mA.