Silicon-Micromachined Low-Profile D-Band Orthomode Transducer With Co-Design for Planar System Integration

This article proposes a D-band orthomode transducer (OMT) with co-design using silicon-micromachined technology. This turnstile-junction OMT features overall dimensions of10× 10× 0.75mm3, exhibiting the lowest profile (0.35~λ ₀at 140 GHz) among all previously published counterparts, to the best of our knowledge. Three types of fine structures are used to address the OMT’s matching issue in such low profile, achieving a matching bandwidth approaching 30 GHz, with insertion loss below 0.45 dB and isolation greater than 84.3 dB. More importantly, to facilitate planar interconnection with active chips, a transversal transition is co-designed with the OMT, providing an integrated G-S–G interface. This design, with a total profile of 1 mm, enables the planar system integration for dual-polarized application. In addition, a two-step horn is further co-designed, offering the direct dual-polarized radiation. To validate the proposed concept, a prototype is fabricated and tested, demonstrating good port and radiation performance. By fully leveraging silicon-micromachined technology, this work offers an all-in-one solution for wireless system, featuring low profile, one-time processing, and easy integration with active chips, which will be a strong candidate for the emerging subterahertz and terahertz application.