Limiter Performance Improvement Through Thermal Management of GaN SBD Combined Microjet Cooling With Optimized Substrate

In this article, we report enhancing RF performance by improving the thermal management of gallium nitride (GaN) Schottky barrier diodes (SBDs), demonstrated through the application of a limiter. Benefiting from the rapid heat dissipation of microjet cooling, the impact of heat accumulation on the performance of GaN SBDs is analyzed, demonstrating the dependence of GaN lateral heterojunction devices on high thermal conductivity substrate. A GaN-SBD using high thermal conductivity SiC substrate was developed, reducing on-resistance by 8% and improving saturation current by 12%. By combining microjet cooling with optimized substrates, the thermal management capability of GaN SBDs was significantly enhanced. RF performance was effectively evaluated using a passive limiter monolithic microwave integrated circuit (MMIC), showing the isolation was significantly improved by 3.5 dB at 80 W, and the reflected power was increased by 14%. The results highlight the improvements in RF performance achieved through enhanced thermal management of GaN SBDs and present a preliminary exploration of microjet cooling in high-power limiters.