Design and Operation of a High Rep-Rate, Solid-State Switched, Bipolar Spiral Generator

Spiral generators are pulsed-power devices than can produce high-voltage pulses in an ultra-compact form factor. The spiral generator is charged at a lower DC voltage and a single switch shorts one end of the spiral stripline. The result is a highvoltage pulse on the order of hundreds of nanoseconds in width. Historically, spark gaps were used as the shorting switches. While beneficial for voltage holdoff capability, this prohibits reaching high pulse repetition frequencies (PRF) or the use in jitter sensitive applications. Previous work has demonstrated high repetition rate operation of a single-ended spiral generator using Silicon-Carbide (SiC) transistors as the spiral generator closing switch, which resulted in demonstrated PRF of 100 kHz at output voltage near 10 kV. This work will describe the advancement of solid-state spiral generator architecture to a bipolar system which converts a 1.2 kV input charge to 44 kV peak-to-peak pulses with sub- 10 ns risetime at 100 kHz PRF with pulse-to-pulse jitter of 160 ps. Commentary on the solid-state switching architecture, bipolar spiral generators, and resulting operation is presented.