1 mm connector
Many microwave connectors were developed by Hewlett Packard, including the 1-mm connector, which has a transmission range up to 10 GHz, but is said to be usable up to 110 GHz.
The 1 mm plug has air as the dielectric, the diameter of the internal thread is 1 mm, and the external diameter is 4.55 mm, as with other miniature microwave plugs.
The 1-mm connector is used in development and microwave metrology for microwave analysis. In addition, the 1-mm connector is found in monolithic microwave semiconductor( MMIC) technology. The advantage of this small connector with an inner diameter of only 1 mm is that microwaves in this range would otherwise have to be transmitted using waveguides. It is also known as a W connector.
1-mm plugs are available with a characteristic impedance of 50 ohms and 75 ohms. The return loss of the 50-ohm connector is still above 16 dB at 10 GHz, and the insertion loss results from a factor of 0.1 dB multiplied by the square root of the frequency in gigahertz.