Study of the Multipactor Effect in Ridge Gap Waveguide Technology
Sarah Bonte; Manuel Sancho; Angela Coves; Eva Rajo; José J. Vague.
Mulcopim 2025  (Valencia, octubre 2025.)

Abstract:

Multipactor is an undesired high-power effect that frequently occurs under high-vacuum conditions in microwave and millimeter-wave components. These components are used in a wide range of different scenarios, such as satellite communication payloads, traveling-wave tubes, as well as particle accelerators. When in a high-vacuum environment, the free electrons, that are inside the device, are accelerated by the electromagnetic fields operating at radio frequency (RF), and they impact against the metallic walls. Then, more secondary electrons are released, giving rise to an avalanche of electrons, and producing a resonant discharge inside the affected component with many adverse consequences. Among them, we find detuning of resonant cavities, power dissipation, a significant increase of noise in communication systems, and even physical damage in the component involved. While multipactor susceptibility has been extensively studied in conventional waveguides, its impact on other guided technologies, such as Ridge Gap Waveguides (RGWs), remains largely unexplored.

The ridge gap waveguide technology has emerged as a promising one for high-frequency applications and components (i.e. filters), due to their low-loss characteristics and compatibility with standard fabrication processes. In this article, the power threshold level (related to the multipactor effect) within ridge gap waveguides is studied, focusing on understanding the distribution and propagation of electromagnetic energy along this waveguide structure. Through simulations, the dependence of multipactor threshold levels on various parameters, such as the ridge dimensions and its proximity to the bed of pins is studied. The insights provided in this research, will help with the future design and implementation of efficient and reliable high-frequency communication and sensing systems for space applications utilizing ridge gap waveguide technology.