"A",
"B",
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"

SMA: The 'Sub-Miniature A' connector is a 50 ohm threaded connector. The main application of SMA connectors is on components for microwave systems. The connector normally has a frequency range to 18 GHz, but high performance varieties can be used to 26.5 GHz. Frequency Range vs Connector Type
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The SMA connector is comprised of an outer conductor [normally ground] and an inner conductor which normally carries the signal. An SMA connector is used with a Coax Cable 'Manufacturers' The BNC Connector is a similar style connector, but larger.
Refer here for Coax Connector Manufacturers








