There are five main factors for selecting SMA RF connector:
1. Type of interface mechanism
The connecting mechanism of the connector not only provides convenient and fast connection or separation of coaxial transmission lines, but also provides stable electrical performance and environmental protection devices. When there is not enough space to rotate the connecting nut in the application, the non torsional connecting mechanism should be selected. In addition, the non torsion connection mechanism is also very useful for frame connectors,
2. Electrical performance
a. Characteristic impedance: the connector shall match the impedance of the transmission system and cable, otherwise the system performance will be degraded;
b. Withstand voltage: the maximum withstand voltage value of the connector shall meet the withstand voltage requirements of the system;
Generally speaking, in broadband applications, some favorable broadband impedance matching characteristics should be sacrificed to obtain the required high voltage rating.
c. Maximum efficiency.
3. Cable installation method and cable type
a. Cable connection: there are two methods of connector cable installation: one is to weld the central conductor, and the standard tightness method of combing and braiding conductor is still common. It is especially suitable for occasions without special installation tools and is convenient for on-site maintenance. II. Clamping method for welding central conductor and crimping braid. Due to the high efficiency of crimping method. With reliable termination performance and good consistency, it has become a general method today.
b. Cable type: appropriate connectors shall be selected according to the characteristics of various cables (such as flexible cable, semi-rigid cable, corrugated conductor insulated cable and foam insulated cable). Generally, cables with small outer diameter shall be matched with small connectors.
4. Termination Form
The connector can be used for RF coaxial cable, printed circuit board, frame drawer functional components and their connection interfaces.
5. Material and coating
The shell and inner conductor are mainly brass, beryllium copper, tin bronze, and the insulating material is mainly tetrafluoroethylene.
The central conductor is generally plated with silver or gold, and the shell is plated with nickel or silver. SMA, SMB, SSMB and SMC outer conductors are all gold plated.
RF coaxial connector is used to transmit RF energy, and its frequency range can reach 18GHz or higher. The basic structure includes:
The male and female neutral contacts are made of external interface materials. The outermost part is the contact. The outer part plays the same function as the outer shielding layer of the cable: transmitting signals and shielding grounding.