具有带外抑制的限幅低噪声放大器一体化设计

Integrated Design of Limiter Low Noise Amplifier with Out-of-Band Rejection

基于0.15μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺,研制了一款27.5~31 GHz具有带外抑制特性的限幅低噪声放大器(LNA)单片微波集成电路(MMIC)。限幅器采用两级并联结构,用微带线进行输入输出匹配,以减小限幅器的插入损耗和电压驻波比。未单独设计滤波器,而是在LNA的匹配网络中加入滤波支路,且分散置于各级匹配网络中,以减小噪声损耗。LNA为三级级联结构,采用单电源和电流复用结构,以实现较小的电流和功耗。测试结果表明,该MMIC在27.5~31 GHz内增益大于21 dB,噪声系数小于3.6 dB,1 dB压缩点输出功率大于5.5 dBm,在17.6~20.6 GHz内带外抑制比小于-50 dBc,可以承受20 W的脉冲输入功率。

Based on the 0.15μm GaAs pseudomorphic high electron mobility transistor(PHEMT)process,a 27.5-31 GHz limiter low noise amplifier(LNA)monolithic microwave integrated circuit(MMIC)with out-of-band rejection characteristics was successfully developed.The two-stage parallel structure was adopted by the limiter and microstrip lines were used for input and output matching to reduce the insertion loss and voltage standing wave ratio of the limiter.The filter was not designed separately,but the filter branches were added to the matching network of the LNA and distributed in all levels of the matching network to reduce the noise loss.The LNA was a three-stage cascade structure,which adopted a single power supply and current reuse structure to achieve low current and power consumption.The test results show that the MMIC has a gain of more than 21 dB at 27.5-31 GHz,a noise figure of less than 3.6 dB,an output power of more than 5.5 dBm at 1 dB compression point,and an out-of-band rejection ratio of less than-50 dBc at 17.6-20.6 GHz.It can withstand 20 W pulse input power.