一款32~38 GHz毫米波宽带低噪声放大器的仿真设计

毫米波电子系统在雷达与卫星通信、电子对抗、遥测遥感、航天测控等通信接收系统领域有着广泛的应用。其中,低噪声放大器(Low Noise Amplifier,LNA)作为毫米波通信系统前端接收机的第一级关键电路,在工作带宽内将前端接收到的微弱信号进行放大,并在抑制信号噪声干扰、降低噪声系数,提高接收灵敏度起着至关重要的作用。文章研究设计了一款工作频率范围为32~38 GHz的低噪声放大器,该放大器采用赝同晶型高电子迁移率晶体管(Pseudomorphic High Electron Mobility Transistor,PHEMT)三级级联的电路结构,并采用自偏压供电。在级联的输入端通过匹配网络实现最佳噪声反射系数,在级联的输出端通过匹配电路保证高增益和最大功率传输。末级利用高通滤波器实现增益平坦性,利用电阻网络调节输出驻波比。通过仿真分析表明,该低噪声放大器在32~38 GHz工作频率范围内的噪声系数NF≤2 dB,带内增益G≥20.5 dB,输入与输出回波损耗RL≤9.5 dB。

The millimeter wave electronic system has a wide range of applications in the field of communication receiving systems such as radar and satellite communications,electronic countermeasures,telemetry and remote sensing,and aerospace measurement and control.Among them,the Low Noise Amplifier(LNA),as the first-stage key circuit of the front-end receiver of the millimeter wave communication system,amplifies the weak signal received by the front-end within the working bandwidth.And it plays a vital role in suppressing signal noise interference,reducing noise figure,and improving receiving sensitivity.This paper studies and designs a low-noise amplifier with a working frequency band of 32~38GHz.The amplifier adopts a three-stage cascade circuit structure of Pseudomorphic High Electron Mobility Transistor(PHEMT)tubes and uses self-bias to supply power.The best noise reflection coefficient is achieved through a matching network at the input end of the cascade,additionally,high gain and maximum power transmission are ensured through a matching circuit at the output end of the cascade.The final stage uses a high-pass filter to achieve gain flatness,and a resistor network is used to adjust the output standing wave ratio.Simulation analysis shows that the low-noise amplifier has a noise figure NF≤4.5 dB,in-band gain G≥20 dB,and input and output return loss RL≤-10 dB in the 32~38 GHz working frequency range.