Rat-race coupler

As ring coupler, also rat-race coupler or 180 ° hybrid, referred to an electrical component of the radio frequency technology, in which the sum or difference of two signals can be formed by interference.

Ring couplers are couplers, which are characterized by good characteristics and simplicity. Their function is based on λ/4-Leitungstransformation and a λ/2-Verzögerungsleitung. Application often find directional coupler as a power divider or in mixer circuits.

Scattering matrix of a directional coupler: