Multicarrier Multipactor Analysis for High-power Passive Microwave Devices

The “long-term” multicarrier multipactor that is supposed to be stimulated by lower-power electric fields potentially threatens the safety of spaceborne microwave devices. In this paper, the instantaneous fluctuations of space electrons between the successive envelope periods of multicarrier signals with different carrier configurations are investigated based on particle-in-cell (PIC) simulations. The “long-term” multipactor discharge (LMD) is observed in a coaxial waveguide device for all the four chosen carriers with a 10-MHz frequency gap. Based on the LMD threshold power for each carrier, the equivalent P20 power is obtained using the ESA's Multipactor Calculator (MC) for the in-phase circumstance. Using a well know test case with known single carrier breakdown threshold, multicarrier multipactor design based on the P20 only for in-phase distribution would be dangerous for five and six carrier sets, while over conservative for three and four carrier sets.