RF and Microwave SMA terminations are a type of high frequency passive electronic component. With most RF and microwave systems operating in 50 Ohm characteristic impedance, the need to insure maximum power transfer and minimize signal reflections is evident. This can be accomplished with an SMA termination. Just like an SMA connector, they screw into place and are thus also referred to as a connectorized or coaxial termination.
They are similar to all terminations, in that their purpose is to terminate a signal in any given circuit. In essence, they are absorbing the incident power. If unused ports, such as a test instrument, are not “terminated” they can cause interference by having the signal reflected back from the end.
The physical part consists of the connector type, SMA body, as well as a rod resistor, but disk resistors are also sometimes used as a substitute. The rod resistor is a cylindrical thin film type resistor that usually operates up to 26.5 GHz in frequency range, depending on the size of the rod.
The metal work or connector body can come in a variety of metals, but brass and copper are very popular. The SMA termination can also be plated in silver or gold and sometimes tin, depending upon the application and the customers’ preferences. Since it is a connector with threads, it is easy to install. It screws on just as a nut would on a bolt.