What are SMB/SMC connectors?

By AJ Born | November 07, 2023

Meet the Connector: SMB/SMC Connectors

The SMB (Sub-Miniature type B) and SMC (Sub-Miniature type C) coaxial RF connectors were first developed in the 1960s as sub-miniature connectors for fitment on RF cable and equipment. The SMB offers quick connect/disconnect snap-on mating, while the SMC has a #10-32UNF-threaded screw-type coupling mechanism that is suitable for high-vibration, rugged applications.

The connectors are available in 50 Ω and 70 Ω versions. SMB was designed for use from DC (0 Hz) to 4GHz and SMC has a maximum operating frequency of 6 to 12.4 GHz.

COAX Connectors’ SMB 50 ohm Right Angle Rear Mounted bulkhead mount solder crimp jack

COAX Connectors’ SMB 50 ohm Right Angle Rear Mounted bulkhead mount solder crimp jack is IP68 hermetically sealed and tested to 50 m unmated, with a single flat on the body. The center contact and crimp sleeve are annealed for enhanced performance. Suitable for RG174 and similar cables in group AD. “COAX Connectors has for many years been at the forefront of the development of variants of the SMB and SMC connector series to meet the ever-changing requirements of the RF and microwave industry,” said Brian Tea, sales manager at COAX Connectors.

The choice of materials and type of surface plating is dictated by environmental demands for use. Harsh environments require IP68 versions of popular standard and customer-specific designs.

SMC may be considered reverse polarity as female jacks have a male/pin and the male plug connectors have a socket for the central contact.

SSMB and SSMC are smaller versions of SMB and SMC connectors.

Design Notes

Mounting configurations: Snap-on mating (SMB) and #10-32UNF-threaded screw-type coupling mechanism (SMC).

Characteristics: 50 Ω or 75 Ω impedance. DC to 4 GHz (SMB); 6 to 12.4 GHz (SMC)

Materials: Typically brass with a nickel or gold finish. Male center contacts are typically brass with gold plating. Female center contacts are beryllium copper with gold plating.

COAX Connectors has developed connector variants using brass

COAX Connectors has developed connector variants using brass for the body and center contact for lower frequency applications, and these are also available in both gold and nickel-plating finishes as well as non-reflective black.

Markets, Industries, Applications:

SMB and SMC connectors are used in radio equipment and electronic instruments in the telecommunications, medical, industrial, factory automation, and robotics markets.


SMB and SMC connectors are available from many suppliers, including Amphenol,   COAX Connectors Ltd., Cinch Connectivity Solutions, Hirose Electric, ITT Cannon, Radiall, Rosenberger, TE Connectivity, Delta Electronics Manufacturing, HUBER+SUHNER, Telegartner, and VidaRF

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Like this article? Check out our other Meet the Connector and Networking articles, our Military/Aerospace Market Page, and our 2023 Article Archive

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AJ Born
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