Effect of fretting wear damage in RF connectors subjected to vibration: DC contact resistance and phase-noise response

In many applications, RF connectors are subjected to severe environmental vibration. Vibration induces micro-displacements, leading to fretting wear damage in the contact. The purpose of this study is to investigate the effect of fretting wear on the microwave signal and more precisely on the additive phase noise [1, 2]. A dedicated vibration test was developed, combining DC and microwave measurement. It consisted of a shaker, a vector network analyzer, a phase-noise analyzer using a cross-correlation technique, and a system for measuring electrical contact resistance. Degradation of phase noise by fretting wear was demonstrated. Two contributions were identified: relative fretting displacement amplitude, by fluctuating the total transmission distance, induced phase noise at the specific fretting frequency proportional to the fretting displacement; also, by inducing oxide debris in the interface, gross slip fretting wear damage decayed DC electrical contact resistance and microwave signal transmission. The study established quantitative correlations between the evolution of DC, transmission loss and phase-noise parameters.