A Compact Quad-Ridge Orthogonal Mode Transducer With Wide Operational Bandwidth

We present the design and the measured performance of a compact quad-ridge orthomode transducer (OMT) operating in C-band with more than 100% fractional bandwidth. The OMT comprises two sets of identical orthogonal ridges mounted in a circular waveguide. The profile of these ridges was optimized to reduce significantly the transition length, while retaining the wide operational bandwidth of the quad-ridge OMT. In this letter, we show that the optimized compact OMT has better than -15 dB return loss with the cross polarization well below -40 dB in the designated 4.0-8.5 GHz band.