Design of low distortion high voltage coaxial-type transmission line for quasi-square wave nano-pulse with several hundred kilovolts in vacuum

A high voltage quasi-square wave pulse with an amplitude of above 500 kV is successfully transmitted using a coaxial-type matched transmission line in vacuum. To enhance the surface flashover voltage and reduce the distortion of pulse shape, the matched symmetric coaxial solid dielectric configuration with the positive angle of 45° and the socket-type field shaper are proposed and applied to the coaxial transmission line. This type of transmission line provides not only the high capability of hold off voltage but also good pulse shape corresponding to the input pulse. The transmission of quasi-square wave short pulse with an amplitude of above 500 kV, a pulse duration of above 20 ns, and a rise time of 20-30 ns without the surface flashover and the pulse distortion phenomena is experimentally and numerically presented.