SMB Bulkhead Receptacle, 50 Ohm, DC–4 GHz
The 903-375J-53P: SMB is a snap-on coupling RF connector family, smaller than BNC, commonly used for DC to 4 GHz signal paths in telecom base stations, test equipment, and instrumentation where quick connect-disconnect is needed without the thread of an SMA.
The 4 GHz maximum frequency covers the full L-band and S-band, plus most IF and baseband signals used in cellular backhaul, GPS, and Wi-Fi front ends. It does not reach the 6 GHz of newer Wi-Fi 6E bands, so if your signal path runs above 4 GHz, this connector will introduce roll-off. For higher cycle life, look to an SMA with a threaded coupling.
This receptacle mounts through a panel hole (bulkhead) and is secured from the front side with the supplied nut and lockwasher — no separate hardware order needed. The center contact terminates via solder cup (solder termination), and the shield is also solder-terminated. The snap-on fastening means the mating SMB plug pushes on and pulls off without a coupling nut — confirm your cable assembly uses a standard SMB male plug.