Influence of Gate Dimensions on High Power Microwave Injection Effects for AlGaAs/GaAs pHEMT

High-power microwaves (HPM) coupled into the RF front-ends through antennas pose a significant threat to the low-noise amplifier (LNA). As the core component of the LNA, the reliability of pHEMT devices faces major challenges. This paper presents a comprehensive study on the performance variations of pHEMT devices with different gate lengths during HPM injection, using TCAD simulation. The study compares the temperature variation, electric field distribution, and current density across devices with varying gate lengths under HPM injection conditions. The findings reveal that, regardless of the gate length, hotspots consistently form in the gate-source access region during HPM injection, with this region being the first to experience thermal failure. Notably, as the gate length increases, the peak temperature in the device under HPM injection exhibits a distinct decreasing trend, highlighting the significant impact of gate length on device performance under high-power microwave conditions. This analysis provides new insights into the thermal management and reliability of HEMT devices in high-power applications, emphasizing the crucial role of gate length in mitigating thermal failure.