Platelet ortho-mode transducer (OMT) for millimeter-wave applications

This contribution presents a manufacturing-oriented Ortho-mode Transducer configuration for polarimeter clusters at millimeter-waves. It is based on a turnstile junction with a proper recombination network. All the discontinuities were properly conceived so that the overall geometry can be manufactured in a multi-layer (platelet) fashion, using commercially-available metal layers. All the metal layers can be machined using the spark-erosion technique, which provides high accuracy and high repeatability for a large number of devices. A W-band implementation with standard WR10 output waveguides has been designed in the operative bandwidth 80-108 GHz. The simulated return loss is better than 25 dB in the overall bandwidth for both polarizations. The predicted insertion loss is 0.35 dB at 94 GHz (metal resistivity 10 ??cm). The isolation between the two polarizations is better than 60 dB owing to the symmetry of the device.