Female Body

Male Body


50 Ω

Maximum Operating Frequency

4.00 GHz

Coupling Mechanism

Interface Standards

The SMB "SubMiniature B" connector series was designed as a smaller snap-on coupling replacement for the SMA connector. Gender designation can be confusing, with the smaller 'jack' body containing the male pin and as such the smaller connector is male, and larger connector having the female receptacle. Built in accordance with MIL-C-39012, IEC 60169-10, and CECC 22130, SMB connectors can be mated with all connectors that meet these specification mating diameters regardless of manufacturer.

The SMB connector is not as robust as the SMA connector, and although they perform acceptably well under low-moderate levels of vibration, they are not suitable for harsh environmental conditions where the levels of vibration rise.


SMB can trace its origins back to the 1960s. In 1968, it was incorporated into MIL-C-39012 where it received its current designation of SMB.


SMB connectors are common due to their low cost, and can be found in a range of CPE devices such as cellular modems, SCADA radios, SDR, WiFi routers, and a range of other commercial wireless equipment. SMB connectors are also commonly used in older military hardware. Despite being a reasonably popular connector, the series offers no distinct advantage and is generally considered defunct.


Connector designs with differing coupling mechanisms (e.g., screw on and push-on) have their own unique series (such as SMC and SMP). A 75 Ω connector variation is available.

Male Dimensions Female Dimensions
SMB male plug RF connector CAD drawing
Courtesy of Rosenberger
SMB female socket RF connector CAD drawing
Courtesy of Rosenberger
Code Min (mm) Max (mm) Code Min (mm) Max (mm)
A     A    
B Ø 3.05 nom. B Ø 3.05 nom.
C Ø 2.08 - C - Ø 2.06
D - 2.97 D 0.18 0.94
E Ø 0.48 Ø 0.53 E    
F 3.33 3.58 F - 1.63
G 1.65 - G 3.58 -
H Ø 3.66 Ø 3.71 H    
K 0.00 0.18 K - -