Dual-Stacked SiC Vertical Photoconductive Switch for Modulation Bandwidth Extension of Frequency-Agile Power Microwave

A dual-stacked vertical SiC photoconductive switch is proposed for wider bandwidth in frequency-agile photonic microwave application. In order to operate in higher working-voltage and smaller interstage capacitance for wider bandwidth response, the dual stacked switch is constructed with two coaxial single device in series. The single device is fabricated on 0.5 mm-thick commercial 4H-SiC substrate using double-sided transparent electrode. The dual stacked switch can be triggered almost simultaneously by coaxial light illumination. By simulation and test, the dual-stacked switch shows a wider modulation bandwidth from 0.5 GHz to 1.8 GHz, while the single device can only operate with a upper limit frequency up to 1 GHz. In high voltage tests, the dual-stacked switch has a device power capacity of 2.56 MW, which can hold off voltage of 20 kV and output peak current of 128 A @50 Ω load. The peak microwave-power is 102 kW @ 1.3 GHz.