Multipacting, which is the resonant build-up of secondary electrons, is often a concern in RF devices, as accelerated resonant electrons bombard cavity walls. As multipacting continues, an exponential build-up of secondary electrons occurs, which leads to strong thermal effects that affect the integrity of the cavity and results in significant power losses. Accurate predictions of multipacting effects are crucial for optimizing RF cavity designs.


VSim’s multipactor solver can be used with imported external fields. Particle emission surfaces are customizable, and pre-built or custom secondary emission yield models can be imported for multipacting simulations. Electron trajectories can also be tracked with VSim.

In VSim, each particle has a scaling parameter that multiplies the electromagnetic field, allowing multiple power or voltage levels to exist simultaneously. Using these “field scaled” particles allows the scanning of multiple power levels in one run.


With VSim, multipacting at multiple power levels can be computed in one simulation with the variable coupling electrons, allowing for quick finding of the cut-off resonance in the stripline.

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