Quasi-Octave Bandwidth In-Phase Three-Layer Platelet Orthomode Transducer Using Improved Power Combiners

A 64% instantaneous bandwidth turnstile-junction-based orthomode transducer (OMT) made up of only three layers in a platelet configuration is presented. Such frequency coverage, while maintaining a very much reduced number of layers, is accomplished mainly by incorporating an improved power combiner based on noncontacting matching steps machined in one layer. This solution makes a real impact on the compactness concept of these OMTs while maintaining an excellent electrical performance. An OMT in the 10-20-GHz band was designed and measured by obtaining a return loss of 25 dB, an isolation between rectangular ports of 50 dB, a cross-coupling of 45 dB, and an insertion loss below 0.2 dB.