一种3~5GHz超宽带单端输入差分输出LNA

Design of a 3~5 GHz LNA with the Function of Both a Single-end Input and Differential Output is Achieved

摘要: 采用0.18 μm CMOS 工艺设计了一种应用于UWB的低噪声放大器（low noise amplifier， LNA）.该LNA 工作频率为3~5 GHz，采用Matlab数学建模方法优化噪声系数，同时采用了单端输入差分输出的电路结构实现信号差分输出；采用了RC反馈技术和源级负反馈技术进行输入宽带匹配.设计使用Cadence 软件进行后仿真，仿真结果显示，平均输出增益（S21、S31）为16.1 dB，3~5GHz范围内S11<-10.9 dB，NF为2.04~2.68 dB，差分输出端口最大误差相位为4°.使用1.8 V电源供电，直流功耗为18.4 mW.

Abstract: In this paper, a fully integrated ultra-wideband (UWB) low noise amplifier (LNA) employing a cascode topology is designed with 0.18 μm RF CMOS technology. By using Matlab mathematical modeling of noise figure,the noise figure is optimized. By using a special architecture, the function of both a single-end input and differential output is achieved. The wideband input impedance matching is conducted by employing an RC feedback network, a degenerating inductor. The simulation results show that the average power gain (S21 or S31) is about 16.1 dB and the input return loss (S11) is less than -10.9 dB over the whole frequency range of 3 to 5 GHz. In addition, the noise figure (NF) is from 2.04 to 2.68 dB,the max phase error of output port is 4°, while consuming 18.4 mW under a 1.8 V single supply voltage.