Compare the exact parts, not only the family names
Use the rated performance of the selected connector and complete assembly to decide between SMA and 2.92mm.
When to consider SMA
SMA is widely used for compact RF modules and cable assemblies. The catalog reference on this site is DC–18 GHz; other designs can differ, so confirm the exact part specification.
When to consider 2.92mm
The catalog series reference is DC–40 GHz. For microwave measurements, request performance data for the complete signal path at your operating frequency.
Mechanical compatibility has limits
Some SMA and 2.92mm designs can mate, but a mixed connection does not inherit the higher frequency rating. Check contact dimensions, connector condition and specified tightening torque before use.