3.5 mm, 2.92 mm and SMA Connector Compatibility

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Are 3.5 mm, 2.92 mm and SMA Connectors Compatible?
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Raghav Kapur - everything RF

Jul 9, 2017

Yes. SMA, 3.5mm, and 2.92mm (K) connectors all have similar mechanical characteristics which allows them to be mated to each other. However, because the dimensions of each connector are slightly different the connection is not ideal and does result in degraded electrical performance.

The outer diameter of a SMA Connector is about 4.13 mm (0.163 in) and the outer diameter of the of the other two connectors are 3.5 mm and 2.92 mm (IEEE-std-287 defines the connector interface names based on their outer diameter).

Practically, the degraded electrical performance is not very significant and can be ignored in many cases/applications. However if you are working on a very sensitive system, then you should use matching connector interfaces for connections.

A point to note when mating an SMA connector with a 3.5 mm or 2.92 mm connector, the SMA's pin engages first and the threads are second - Due to which the connection must be made carefully to avoid damaging the connectors. When mating the 3.5 mm and 2.92 mm connectors with SMA connectors the threads mate first and then the pin providing a more stable connection which is less likely to damage the connectors.

Similarly, 2.4 mm and 1.85 mm connectors are also compatible with each other.