Are all the components of various interfaces in RF circuits 50 ohms (Ω)?

Let's first understand the relevant knowledge of transmission lines. Transmission lines are used to propagate signal energy and come in many types, such as coaxial cables, micro-strip lines, strip lines, and so on. A common RF cable is a coaxial cable, which is generally composed of an inner conductor, a dielectric, an outer conductor, and a sheath. However, some cables may also have multiple layers of shielding and protective layers.

The maximum power transmission and minimum signal reflection of a signal are determined by the impedance of the transmission line and the impedance matching in the system. The impedance of the transmission line is called the characteristic impedance

In order to balance the minimum loss and maximum power capacity, a 50 ohm characteristic impedance was chosen as a compromise between 77 ohms and 30 ohms. Therefore, it is customary for everyone to uniformly choose 50 ohms as the characteristic impedance.

This is also the reason why the impedance of the input or output ports in general RF devices or equipment is basically 50 ohms. Therefore, RF circuits are also designed based on impedance matching of 50 ohms.

Jiangsu Elesun Cable can produce 50 ohms and 75 ohms coaxial cable eg. RG6,RG59,RG58,and RG179, the impedance to tolerance is ±2 ohms.