High power resonant line system for corona and multipactor testing

Abstract

Space technology designers have nowadays to deal with an incessant demand of radiofrequency power, therefore the necessity to dispose of higher power test beds. Different strategies have been used that usually entail cost and design difficulties. In this paper a new focus on the issue is taken: a high power resonant line system, especially applicable for bidirectional devices multipactor and corona testing, is presented. The idea is to perform a full reflection of the carrier signal hence producing a stationary wave all along the line with peaks and nulls spread every λ/4. By means of a variable phase shifter every single point of the system will go through the complete range of incident and reflected power interference, in an ideal case from the total absence of power to a 6 dB gain with respect to the input signal power. Considering that high power breakdown effects are peak voltage dependent any gain obtained by the explained method would be of usefulness. The proposed system is made up of commercial components with no special characteristic provided they withstand the maximum power levels that are to be reached. Besides, tuning is not dependent on temperature or pressure and it also is able to work in a wide bandwidth. Detection methods must be reviewed for some are not applicable and others must be reconfigured. A bit more complex than usual calibration task is required and secondary effects in power measurements must be considered. A campaign of multipactor and corona tests, in continuous and pulsed power modes, has been carried on a system like the one described to demonstrate its functionality.