The SMA connector is a widely used semi-precision subminiature RF and microwave connector, especially for RF connections in electronic systems with frequencies up to 18 GHz and beyond. SMA connectors come in a variety of forms, male, female, straight, right angle, bulkhead fittings, and more, making them suitable for most requirements. Its ultra-small size also enables it to be used even in relatively small electronic devices.

SMA is commonly used to provide RF connections between circuit boards, and many microwave components include filters, attenuators, mixers, and oscillators. The connector has a threaded external connection interface with a hexagonal shape that allows for wrench tightening. They can be tightened to the correct tightness using a special torque wrench, allowing a good connection without over tightening.


The first SMA connector designed for 141 semi-rigid coaxial cable. The original SMA connector can be called the smallest connector because the center of the coaxial cable forms the center pin of the connection, eliminating the need for a transition between the coaxial center conductor and the center pin of a special connector.

The advantage is that the cable dielectric is directly connected to the interface without an air gap, and the disadvantage is that only a limited number of connect/disconnect cycles are possible. However, for applications using semi-rigid coaxial cable, this is unlikely to be a problem, as the installation is usually fixed after initial assembly.