A Micromachined Dual-Band Orthomode Transducer

TitleA Micromachined Dual-Band Orthomode Transducer
Publication TypeJournal Article
Year of Publication2014
AuthorsLeal-Sevillano, C. A., T. YingaTao, M. J. Lancaster, J. A. Ruiz-Cruz, J. R. Montejo-Garai, and J. M. Rebollar
JournalIEEE Transactions on Microwave Theory and Techniques
Date PublishedJanuary
AbstractIn this paper, an orthomode transducer (OMT) for dual-band operation and optimized for stacked micromachined layers implementation is presented. The proposed design avoids the use of septums, irises, pins, or small features and minimizes the number of equal-thickness micromachined layers required. In this way, the micromachining fabrication is simplified, making the proposed design a very attractive candidate for high frequency applications and for low-cost batch production. A W-band dual-band design (one different polarization in each frequency band) with more than 10% fractional bandwidth for each band and 30% separation between bands is presented. In addition, proper routing and layered bends are designed for an optimum standard interfacing with the same orientation of the input/output ports. Two OMTs in a back-to-back configuration are fabricated using a thick SU-8 photo-resist micromachining process. A total of six stacked SU-8 layers, all of them with the same thickness of 635 micrometers, are used. The experimental results are coherent with the tolerance and misalignment of the process, validating the proposed novel OMT design.