Multipactor and Mitigation in X-band Waveguide

This work focuses on multipactor effect mitigation techniques in X-band waveguide geometries. The primary focus areas are surface modifications, surface conditioning, and the exploration of additive manufacturing. In this context, ”surface modifications” encompasses coatings using materials like titanium nitride and geometric alterations, such as incorporating dimpled surfaces. The domain of additive manufacturing, commonly referred to as 3D printing, is also critically examined, particularly assessing the performance of 3D-printed copper compared to its traditionally machined counterpart. Surface conditioning, as delineated in this study, refers to a rapid succession of shots. This technique is examined for its potential mitigating effects on the multipactor phenomenon. The X-band setup utilizes a plug-and-play design, allowing for quick interchanging of parts. Multipactor is observed through global detection methods such as power readings and the use of a double-balanced mixer sensitive to microwave phase changes due to multipactor onset. Stepped impedance transformers were used as the base geometry for all tests. Single-shot multipactor thresholds were compared across various mitigation techniques. Among the mitigation techniques evaluated, the dimpled geometric configuration exhibited the most substantial multipactor hold-off compared to nonmodified components. It was established that 3D-printed test pieces performed on par with their traditionally machined counterparts. Furthermore, conditioning of the test pieces exhibited a significant increase in the single-shot threshold, achieved through both cost-effective and straightforward means.