Why Different Connectors?

Why different connectors?

Many coaxial connector types are available in the audio, video, digital, RF and microwave industries, each designed for a specific purpose and application. Much of the development of the smaller connectors that perform well into the GHz and millimeter wave range has been conducted by test equipment measurement companies. One of their considerations is the number of connect-disconnect cycles that a connector pair can withstand while still performing as expected.

Why different sizes and frequencies?

The frequency range of any connector is limited by the excitation of the first circular waveguide propagation mode in the coaxial structure. Decreasing the diameter of the outer conductor increases the highest usable frequency. Filling the airspace with dielectric lowers the highest frequency and increases losses. The mating process typically changes the geometry of the mating surfaces and resistance loss at those interfaces as well as geometric changes result in variation of impedance and loss.

Some RF connectors are sexless. Most connectors have female structures with slotted fingers that introduce a small inductance. The fingers accommodate tolerance variations, but reduce repeatability and may ultimately break after 1000 connections. There are slotless versions of connectors available, but they are, for the most part, relegated to instrument interfaces. Slotless female connectors are very difficult to clean and require very careful connection and disconnection.