为检测微弱的射电信号,要求望远镜接收机噪声性能良好.低噪声放大器（Low Noise Amplifier, LNA）作为接收机前端关键电路,其噪声系数和增益决定了整机的噪声性能.设计了一款1.2–2.2 GHz的低噪声放大器,电路采用两级级联结构,第2级通过引入负反馈,在改善增益平坦度和拓宽带宽的同时减小噪声,级间经过后级输入阻抗优化后仅需一个隔直电容.并引入有损输出匹配网络,实现高增益、低噪声、良好回波损耗和较为平坦的宽带LNA设计.测试结果表明,在1.2–2.2 GHz频段增益30–33 dB,噪声温度平均值为47 K,输出1 d B压缩点大于11.3 dBm.测试性能良好,可用于该频段接收机系统中.

A new transformer matching method for ultra-wideband (UWB) low noise amplifier is presented, which effectively extends the bandwidth and has little effect on the circuit noise. Low-frequency gain compression are realized by combining Frlan-style transformer and RC feedback loop topology in the interstage. The output matching network is composed of the Rabjohn-style transformer and LC network after Norton transformation. The power gain is enhanced by using two-stage cascode topology. The proposed UWB LNA is based on a 0.25um GaAs PHEMT process, and the post-layout simulation results show the maximum power gain of 21 dB, minimum NF of 1.6 dB in the frequency range of 4-15 GHz. The input reflection coefficient is less than -7dB. The output reflection coefficient is less than 10dB. The average output 1-dB compression point is 14dBm. The chip size is 0.82 mm(2).

采用0.25 μm GaAs赝配高电子迁移率晶体管(pHEMT)工艺,设计并实现了一种应用于5G通信2.2～4 GHz频段的高增益共源共栅低噪声放大器(LNA).通过将并联RC负反馈与共栅接地电容结合,不使用源极电感,实现了宽带高增益的LNA设计.测试结果表明,2.2～4 GHz频段增益大于24 dB,输出3阶互调(OIP3)为28 dBm,噪声系数(NF)小于0.78 dB,功耗为190 mW,芯片面积为(810×710)μm2.综合指标(FOM)为14.4 dB,与同类LNA相比具有一定的优势.