Choosing or Specifying an RF Switch Matrix

This application note describes the different types of switch matrix products available for IF, RF and microwave switching. It also discusses many of the important trade-offs that should be considered when selecting a switch matrix to fit an application. Many installations and facilities use switch matrix products throughout the entire signal chain. This paper describes portions of the system in two typical cases, on the transmit side where signals have already been modulated, or the receive side where signals have not yet been demodulated.

Signals received from an antenna or down-converted by a LNB, for instance, are part of the discussion, as is multiple carrier multiplexes being prepared for transmission. For these discussions, the paper has excluded switches designed for baseband or digital signals such as RS-232, ECL, RGB video, audio and similar signals. Although some of these signal types can cover many MHz of bandwidth, they require switch matrix designs that are substantially different than those of an RF, IF or microwave switch. For the purposes of this paper, it is assumed that the application is a satellite communication ground station. The process of selecting a switch can be applied equally well to other application areas, but it is convenient to use one of the most common applications, because it provides a variety of possible switching configurations for the discussion.