Compact solid-state Marx-bank sub-nanosecond pulse generator based on gradient transmission line theory

Abstract

For non-invasive treatments in the biomedical field, sub-nanosecond pulse electric field matching ultra-wideband antennas have aroused great interest for their excellent directivity and targeted treatment. Sub-nanosecond pulse generators have proved difficult to control in pulsed power technologies despite many studies of pulse generators based on avalanche transistor theory and the Marx circuit. However, no solution exists to the problems of non-ideal waveform of the output sub-nanosecond pulse and the relatively low effectiveness of the Marx circuit. To resolve these problems, the paper describes a sub-nanosecond pulse generator simulation model based on gradient transmission line theory in PSPICE simulation software and the development of a compact solid-state sub-nanosecond pulse generator (18 cm×18 cm×4 cm). From experimental tests, trigger signals of 5-V amplitude, 5-ns rise and fall times (pulse-width 10 ns-50 ns) were generated by Field-Programmable Gate Array (FPGA). A pulse with 1600-V voltage amplitude, 300-ps full width at half maximum, 150-ps rise time, and 10-kHz high-stability repetition rate was generated in an attenuator load with high-bandwidth (8 GHz, 50 Ω). The effectiveness (Output pulse voltage amplitude / Charge voltage × Stages) of this Marx circuit reached to 41.7%, improving considerably on previous efforts.