Investigation of a compact pulse modulator

A high power pulse modulator is presented. It is made up of capacitors, a trigger switch, an air core transformer, a water dielectric pulse forming line（PFL）, a hydrogen switch, and a field-emission vacuum diode. The circuit simulation saftware Pspice was used to calculate the diode voltage, diode current and charging voltage of PFL. The static electric field of the PFL and switch is analyzed. When the hydrogen switch breakdown voltage was 520 kV, a 60 ns pulse width and 230 kV, 30 kA pulse was obtained on the field-emission diode. The rise times values of diode voltage with different gases such as H2, N2, SF6 in man swithch have been compared.It is concluded that hydrogen switch can reduce the rise time of diode voltage obviously. The results are in agreement with theory etical analyses