砷化镓射频前端LNA设计

Design of GaAs RF front-end LNA

摘要: 基于砷化镓0.25 μm工艺的pHEMT器件，设计了一种具有高线性度、高增益、极低噪声性能的宽带低噪声放大器(LNA).电路为共源共栅结构，并采用级间匹配以达到提高高频增益延展带宽的效果.本设计分为0.7~1.0 GHz、1.6~2.2 GHz与2.3~2.7 GHz三个频段进行外部匹配，电源电压为5 V，测试结果显示，该低噪声放大器静态工作电流为75 mA，在三个频段分别获得27.2~25.8 dB、22~20 dB、19.2~18.7 dB的高增益，并且每个频段内都有较好的增益平坦度，具有0.45~0.75 dB极低的噪声系数和20~19.5 dBm的输出1 dB压缩点.

Abstract: A wideband low noise amplifier with high-linearity, high-gain and ultra-low noise is designed and fabricated in a 0.25 μm GaAs pHEMT process. A matching network is used between common-gate and common-source transistors in this circuit to obtain larger power gain in higher bands. The measurement results show that the quiescent current of the LNA was 75 mA in 5 V power supply. After external matching in three bands of 0.7~1.0 GHz, 1.6~2.2 GHz and 2.3~2.7 GHz, the LNA respectively provide a high and flat gain of 27.2~25.8 dB, 22~20 dB and 19.2~18.7 dB, a low noise figure of 0.45~0.75 dB and an OP1dB of 20~19.5 dBm.