Research on microwave output characteristics of frequency-agile high power SiC photoconductive semiconductor switch

This study investigates a side-illuminated photoconductive semiconductor switch (PCSS) modulated by microwave-sinusoidal laser signals, demonstrating high voltage conversion efficiency, exceptional modulation depth (nearly 100% across 0.7-1.35 GHz) and low laser energy requirements (3.0-3.5 mJ). Through systematic characterization of microwave output dynamics, we reveal an inverse correlation between DC bias voltage (2-6 kV) and conversion efficiency. Concurrently, higher modulation frequencies (e.g., 1.35 GHz) fragment laser energy into denser pulse clusters (27 pulses vs. 14 at 0.7 GHz), reducing energy per pulse and degrading efficiency by nearly 50%. Critically, elevating laser energy to 3.5 mJ at 6 kV reverses this trend, boosting normalized efficiency to 87.68% by mitigating carrier starvation in high-field, non-saturated regimes. These findings underscore that synergistic optimization of vanadium/nitrogen co-doping ratios and pulse cluster design enables the efficiency recovery, while minimizing thermal loads. This work establishes a scalable framework for high-power PCSS design, advancing solid-state microwave sources for phased-array radar and directed-energy systems.