A Simple Orthomode Transducer for Centimeter to Submillimeter Wavelengths

We describe a simple orthomode transducer suitable for operation from centimeter to submillimeter wavelengths with appropriate scaling. It is fabricated as a split-block assembly with all waveguides in the same plane, and requires no septum or polarizing wires. The OMT operates over a 1.3:1 frequency band, narrower than a full waveguide band (typically 1.5:1). For a WR-10 version of the OMT, covering 78-102 GHz, the polarization isolation is > 37 dB and the return loss at the rectangular waveguide ports > 24 dB. The practical upper frequency for this design is probably limited by the precision of alignment that can be achieved between the block halves, which affects the polarization isolation.