Ultra-wideband antenna for recording radio emission in the initial phase of a high-voltage laboratory atmospheric discharge

A compact ultra-wideband antenna, designed for the employment in the experiments on studying radio emission generated in the initial phase of the spark discharge, is presented. A flat type of antennas based on an expanding slit (Vivaldi antenna) is considered. The simulation and calculation of the antenna parameters are carried out. The results of using the antenna in laboratory experiments are demonstrated. It is shown that the generation of the highest frequency part of the radio emission spectrum coincides with the pre-breakdown stage of the discharge, before a sharp increase in the current starts.