Orthomode transducer for mm-wave range

The orthogonal polarized signals are widely used in millimeter-wave applications such as in radar, communications, remote sensing and radiometry. The diplexing (i.e., combination or separation) of the orthogonal signals is imposed on the components, which are usually called as "orthomode transducers" (OMTs). In general, the OMT has three physical ports, though it exhibits properties of a four-port device, because the common port, usually with a square or circular cross section, provides two electrical ports that correspond to the independent orthogonal polarized signals. In modern systems, requirements to the OMT are a high cross-polarization discrimination between the orthogonal signals and a good match of all electrical ports. In the millimeter-wave range, it is a difficult problem to design and produce OMT meeting to the required specification, because of dimensions of the components are very small. Therefore, the development of a new OMTs design suitable for mm band is an important task. In the present report we consider a narrowband OMT design that suits most applications in radar and radio-relay link systems.