11.8 GHz two stage low noise amplifier

Aim: To research the matching of the noise and power of microwave amplifiers simultaneously by the use of interstage mismatching. To achieve optimum noise performance and in/out matching-well microwave low noise amplifiers (LNA). Methods: The two single-stage LNA were connected and the first-stage output power matching net was replaced by interstage mismatch net. While the interstage mismatch net achieved the change of resistance the noise and power of microwave amplifier could match simultaneously, Results: The principle and designing steps of low input/output VSWR were provided. Two stage LNA of 11.8 GHz was obtained. (frequency: 11.3 ∼ 12.3 GHz, noise figure: 1.9 dB, gain: 21 dB). Conclusion: Low noise and power maching LNA can be achieved according to this method, whose feasibility was demonstrated by the LNA's final experiment results.