SMA and 3.5mm and K Connectors mating and working frequency bands

March 31, 2018

The outer conductor size of these connectors prevents the mating of incompatible connectors. Connectors in each of the shaded areas below have the same size outer conductor and therefore can safely be mated together.

However, damage to connectors occurs from wear, lack of cleaning, improper connection techniques, and poor handling techniques. When mated, a damaged connector can cause another connector to also become damaged. Therefore, clean and inspectall connectors before mating.

Connector_Type   Outer_diamension  Frequenc_Range   Mates_with... Notes

1.0 mm

To 110 GHz

1.0 mm

Much smaller connector than any of those below.

1.85 mm

To 70 GHz

2.4 mm

The outer thread size of the 1.85 and 2.4 connectors is bigger than SMA, 3.5, and 2.92. This makes the area of the outer conductor mating surface look very large compared to the relatively small air dielectric.

2.4 mm

To 50 GHz

1.85 mm

The 1.85 mm connector that is manufactured at Keysight has a groove in the male nut and female shoulder to distinguish these two connector types.

2.92 mm

To 40 GHz

3.5mm and SMA

These two connectors use the same center pin.

3.5 mm

To 34 GHz

2.92 mm and SMA


To 24 GHz

2.92 mm and 3.5 mm

Uses a PTFE dielectric.

Note: SMA connectors are a common and inexpensive type, but their lack of precision affects their durability and performance, and can cause increased wear when mated with other (precision) connectors. SMA connectors are only rated for a very limited number of connection cycles and should be examined before each use.