RF Switch Configuration Options

RF switches are broken down into several configurations, typologies, and technologies. The simplest distinction is the normally open-circuit or normally closed-circuit configurations. Generally, if unlabeled, a switch is normally open-circuit, though it is worth investigating to a high degree of confidence. If a switch remains in the switched state after power has been removed, the switch is known as a latching switch. Otherwise, after switching power is removed, the switch will revert to the default state. Though these configuration options aren’t complex from an outside perspective, they may have a significant impact on the power consumption, safety, system complexity, and cost in a larger system.

The main switch configurations are, routing, multiport, transfer, matrix, and bypass. The varieties of RF switches are often used in combination to form larger switch structures, sometimes utilizing signal paths with different frequency behaviors. The most common naming convention for switches is constructed of the number of inputs, or poles, and the number of output positions, or throws. For example, a single-pole single-throw (SPST) switch is a simple cut-off configuration, where a six-pole 10-throw (6P10T) is a complex matrix switch.

In addition to the simple configuration nomenclature, certain switch configurations have common names. A multiport switch is just a single-pole switch with three or more throws. Sometimes confusingly, a DPDT switch could also be designed as a 4-port transfer switch. The transfer configuration locks the switch into 2 modes, path 1 to 3 and 2 to 4 or path 1 to 2 and 3 to 4.