SMB connector is one kind of coaxial RF connectors which have smaller size than SMA connector and were designed in 1960’s with snap-on coupling. The snap-on design permits rapid connection and disconnection in limited spaces.
SMB connectors are available either in 50ohm or 75ohm impedance. 50ohm SMB connectors usually was specified up to 4GHz, and 75ohm SMB connectors are specified for only 2GHz.
SMB connectors are designed originally with female contact in male body or male contact in female body. These connectors are popularly used in telecommunication and automotive.
Mechanical Feature:
SMB male
- Snap-on coupling
- Six slots radically spaced outer contact inside shell
- Shell is fixed and can’t be rotated.
- Female center contact
- Insulator surrounds female center contact wholly for 50ohm SMC male
- An air gap between female center contact and outer contact for 75ohm SMB male
SMB female
- Snap-on coupling
- A trough for mating captive after a smooth area of dia. 3.7mm, 3.0mm length from mating end
- Male center contact
- Insulator nestles up throughout against outer contact. An air gap between insulator and male center contact for 50ohm SMB female
- Reducing insulator amount. An air gap between male center contact and outer contact for 75ohm SMB connector
How to judge SMB connectors’ feature from outline:
SMB connector Male (Plug)
SMB connector Male (Plug)
SMB male’s diameter is around 6.5mm, and an outer contact with 6 slots radically spaced inside the shell.
SMB male connector, 50 ohm V.S. 75 ohm
SMB male connector, 50 ohm V.S. 75 ohm
SMB connector Female (Jack)
SMB connector Female (Jack)
A significant trough (groove) for mating purpose, and has around 3.70mm diameter.
SMB female connector, 50 ohm V.S. 75 ohm
SMB female connector, 50 ohm V.S. 75 ohm
SMB connector right angle type:
SMB connector right angle type
The cable entry way or PCB terminated way is at 90 degrees against coupling way.
SMB connector straight type:
SMB connector straight type
The cable entry way or PCB terminated way is at 180 degrees to coupling way.
SMB connector female/ jack bulkhead type:
Besides mating trough, there is an outer thread on body, then we can define this SMB connector is bulkhead type.
1) Rear mount type bulkhead
SMB connector Rear mount type bulkhead
SMB connector bulkhead type goes through the panel mounting hole toward the external of device from the internal, and mount it with washer and nut from outside.
2) Front mount type bulkhead
SMB connector Front mount type bulkhead
SMB connector bulkhead type goes through the panel hole toward the internal of device from the external, and mount it with washer and nut from inside.
SMB connector PCB connector:
SMB connector PCB connector
PCB type SMB connector normally has 2.9mm or 3.9mm leg lengths. Four legs and one conductor will go through PCB vertically, and be soldered in rear side of PC board.
SMB connector edge mount (end launch)
SMB connector edge mount (end launch)
SMB edge mount type connector will be mounted with the PCB from board’s edge side
SMB connector cable connector:
SMB connector cable connector
SMB connector will be terminated with RF coaxial cable by crimping, soldering or clamping to be SMB cable for RF signal transmission.
