A Current Variation-Based Monitoring Method for Microwave-Induced Damage Effects in Low-Noise Amplifiers

The low-noise amplifier (LNA), as a core component of receiver RF front-ends, finds extensive applications in satellite communications, radar systems, and other electronic systems. Under high-power microwave (HPM) pulse irradiation, its performance and reliability face significant challenges. Due to the high-power levels of HPM radiation, studying the damage effects on LNAs under HPM exposure has become an international research priority. This paper proposes an experimental methodology utilizing current variation monitoring to assess damage effects in LNAs under microwave injection conditions. During HPM injection testing on High Electron Mobility Transistor (HEMT)-based low-noise amplifiers, a real-time monitoring system was employed to observe key parameters including device gain variation. Simultaneously, a DC power analyzer was implemented to record dynamic current fluctuations within the device. A functional relationship was established through curve fitting between current variation and gain degradation. Comparative analysis between the conventional “reference signal method” and the proposed “current monitoring method” demonstrated that the final gain degradation values obtained through current monitoring align with noise analyzer measurements within an acceptable error margin. This approach provides a wide dynamic range monitoring solution for in-situ damage assessment of LNAs under microwave injection conditions, significantly enhancing the capability for real-time performance evaluation during HPM exposure experiments.