A 600kV resonant pulse transformer combined to a helical antenna

Abstract

A complete pulsed power source, named MOUNA, is composed of a set of batteries, a DC/DC converter to charge four capacitors, four synchronized spark gap switches, a resonant transformer generating 600kV/265ns pulses, an oil peaking switch and a dipole antenna. This device must transmit waveforms with a wide frequency band and a high figure-of-merit. However, to radiate very high electric fields, the low gain of the dipole antenna is detrimental. The use of a directional antenna may improve performance really significantly focusing the radiation in a preferred direction. The main characteristics of the axial helical antenna (compactness, high gain on the axis, wideband spectrum and high impedance) make it an excellent candidate. In this paper, the first results concerning the design of the antenna (number of turns, size...), of a switch oscillator directly implemented at the output of the transformer are presented. The design of the novel radiating source composed of the MOUNA pulsed power source, the switch oscillator and the helical antenna is also described. The pulsed source and the oscillator contains in a volume of only 25 litres. Finally a CST-based simulation is proposed to predict the performances of this wideband source.