Multipactor RF Breakdown in Coaxial Transmission Lines With Digitally Modulated Signals

The aim of this paper is the study of the RF multipactor breakdown in coaxial transmission lines excited by a single carrier with a digitally modulated signal. Employing an in-house developed code, numerical simulations are performed to determine the RF multipactor voltage threshold for several digitally modulated signals under different modulations schemes: quadrature phase-shift keying, 16-quadrature amplitude modulation, 16-amplitude and phase-shift keying, and 32-amplitude and phase-shift keying. Moreover, a coarse method based on the envelope integration to determine the RF multipactor voltage threshold when involving arbitrary digital modulations is also presented. These results are also compared with the "20-gap-crossing" rule used in the space standard document ECSS-E20-1A. In order to validate the theoretical results, a test campaign was performed for realistic modulated signals, finding good agreement between theoretical predictions and experimental data.