RF connectors, also known as coaxial connectors, help transmit RF signals by connecting transmission lines to various applications. RF connectors are primarily used with coaxial cables. You'll find them used in TV receivers, two-way radios, Wi-Fi devices with antennas, and industrial and scientific measuring instruments. In this article, we'll cover some of the most common connectors, including: BNC, SMA, SMB, N-type, and TNC.
RF connectors are small, but can provide greater utility for coaxial cables. They need to match the specifications of the coaxial cable in order to reliably transmit the signals passing through it. Therefore, a general knowledge of coaxial cable connectors comes in handy when creating custom cable assemblies (or when requesting custom assemblies from a manufacturer). We've done the research and compiled the most relevant information for you in this blog post.
What is a coaxial cable?
In order to better understand how RF connectors function, we must first understand how coaxial cables work. To send radio frequencies from point A to point B, we must use a transmission line. Coaxial cable is the transmission line of choice because it keeps the transmitted signal between the inner and outer conductors. This means that coaxial cables have less signal loss and can be placed next to metal objects without any interference.
The diagram below shows that coaxial cable consists of: a center core (inner conductor), a dielectric insulator, a metal shield (outer conductor) and a jacket. The space between the inner and outer conductors is the impedance. This measurement is important for the function of the coaxial cable. The impedance must be the same over the entire length of the cable or signal reflection will result. When RF connectors are placed at the end of a coaxial cable, the impedances must match. Otherwise, the signal cannot be transmitted efficiently.
Common types of RF connectors
Well-designed RF connectors block external signals from the circuit and prevent any energy loss. These connectors have built-in fastening mechanisms such as threads, bayonets, brackets, or blind plugs. Important parameters to consider include: impedance, frequency range, power handling, size and cost.