Design of Filtering Orthomode Transducer Based on Cavity Resonators

A novel design for orthomode transducer (OMT) with an embedded bandpass filter function is proposed in this letter. The OMT consists of a common cavity resonator and four independent cavity resonators, which are coupled with each other via vertical and horizontal slots. By utilizing the two orthogonal resonant modes in a cavity resonator, a filtering OMT with different center frequency is achieved. To substantiate the efficacy and precision of the proposed design method, a filtering OMT was fabricated and subsequently subjected to measurement. The experimental results indicate that the proposed structure can achieve good filter function and high isolation over 40 dB between the output ports.