What is the insertion loss stability of a coaxial relay over millions of switching cycles?

The insertion loss stability of a coaxial relay over millions of switching cycles degrades gradually as the relay's contacts wear. The degradation mechanism: each switching cycle causes: micro-arcing at the contacts during make and break (even at low RF power levels without hot-switching, there is a brief moment of contact bounce), mechanical wear of the contact surfaces (the gold plating gradually wears through to the base metal), and contamination accumulation (microscopic particles from the contact surfaces accumulate in the relay housing). The typical insertion loss progression: for a high-quality relay (Teledyne, Dow-Key) rated for 5 million cycles: cycles 0-1M: insertion loss stable within ±0.02 dB of initial value. Cycles 1M-3M: gradual increase of 0.02-0.05 dB. Cycles 3M-5M: more rapid increase of 0.05-0.15 dB above initial value. Beyond rated life: unpredictable degradation, eventual contact failure (open circuit or high-resistance connection). The end-of-life criterion: when the insertion loss exceeds the specified maximum (typically 0.3-0.5 dB at the rated frequency), the relay should be replaced. Similarly: if the return loss degrades below specification, or if the insertion loss becomes inconsistent (varying with each switching cycle), the relay has reached the end of its useful life.