What is an Orthomode Transducer (OMT)?

An Orthomode Transducer (OMT) is a 3 port waveguide component that is used to separate Horizontally and the Vertically polarized signals from a circular polarized signal or, vice versa, i.e., combine Horizontally and Vertically polarized signals in to a circularly or elliptically polarized signal.

An OMT has two rectangular/square ports from where the Horizontally/Vertically polarized waves are input/output and one port for the circularly polarized wave.

When a circular polarized signal is fed at the input of an OMT, it separates the linear orthogonal components from the signal to provide the horizontally polarized part of the wave at one port and the vertically polarized part of the signal at the other port. It provide high isolation between the two ports.

An OMT is a bi-directional device, so when operating in reverse, it combines a horizontally polarized wave at one port with a vertically polarized wave at the other port to output a single circularly polarized wave.

The OMT can support circular, elliptical and linear polarized waveforms depending on the relative phase and amplitude of the two orthogonal input signals. When used with a polarizer, this component can support both left-hand and right-hand circular polarized waveforms simultaneously.

The OMT is suitable for applications like satellite data transmission, satellite television broadcasting, military radar systems, telecommunications antennas, sensors, radiometers and instrumentation.