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The Marx circuit structure based on fast high-power semiconductor devices is the classical way of generating picosecond pulses. However, most reported studies suggest that as the number of stages in the Marx circuit increases, the output pulse amplitude tends to saturate. This has of late made high-voltage picosecond-pulse generation a challenge. In this paper, as the number of stages increases, the internal resistance of the avalanche transistor tends to decrease with increasing current flowing through the avalanche transistor. A step-by-step wiring and debugging of the avalanche transistor-based Marx circuit demonstrates this experimentally. That is, for a certain range in the number of stages, saturation of the output pulse amplitude for the Marx circuit of avalanche transistors is not apparent. Introducing a parallel structure for the transistors not only increases the current level of the entire circuit but also further reduces the equivalent resistance of the avalanche transistors, thereby improving the output efficiency. Drawing on microstrip transmission theory, and combining the Marx circuit and avalanche transistor parallel structure, component parameters and circuit topology of the picosecond-pulse generator were redesigned, and a 30-level Marx circuit with a parallel structure of two avalanche transistors was developed. The picosecond-pulse generator outputs a pulse with adjustable voltage amplitude of 0.9–3.1 kV, a 350-ps full-width at half-maximum, a 150-ps rise time, and an adjustable high-stability repetition rate of up to 10 kHz. The number of pulses is precisely controlled. The generator is an all-solid-state compact device with high frequency suitable for research needs. [ABSTRACT FROM AUTHOR]

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 ?). The effectiveness (Output pulse voltage amplitude / Charge voltage ? Stages) of this Marx circuit reached to 41.7%, improving considerably on previous efforts. [ABSTRACT FROM AUTHOR]

Triggered vacuum switch (TVS) is significant in the field of pulse power technologies, especially in high power application. Particularly, the rise-time of trigger pulse is important for paralleled TVSs which are frequently used to increase peak current. Trigger source based on pulse transformer and solid state switch has good reliability and low jitter, thus, the design of a fast-rise-time trigger source based on solid-state switch and pulse transformer is crucial for the parallel connected TVS. The work presented here extends the state of the art in the area of high power pulse generator. This paper introduces the design procedure of a pulse transformer based on closed magnetic core and a discharging circuit based on solid-state switches in detail. The influence of leakage inductance and distributed capacitance of the pulse transformer on the output pulse waveform are analyzed. PSPICE simulations are studied to optimize the design of the pulse transformer. Based on the theoretical calculations and simulations, special winding structures, suitable material of magnetic core, and proper width of copper strip are carried out to obtain faster rise-time. Four parallel connected MOSFETs are used in the trigger source because of their anti-paralleled diodes and high switching-speed. The experimental results show that, the pulse transformer can generate a rectangular pulse with an adjustable amplitude of 0?5 kV, a pulse width of 0?5 ?s, and the rise-time is about 160 ns. Lastly, the pulse transformer has a compact structure and can be used to trigger the TVS reliably. [ABSTRACT FROM AUTHOR]