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Novel Turnstile Junction-Based Wideband Ortho-Mode Transducer with Stepped Tuning Stub for Ka-Band SATCOM
Lingala Srinivas , Sunil Singarapu
Abstract:   (260 Views)
This paper presents the design, fabrication, and analysis of a novel turnstile junction-based wideband orthomode transducer (OMT) for Ka-band satellite communication (SATCOM) systems. The proposed OMT integrates a four-stepped cylindrical tuning stub along with optimized E-plane and H-plane bends and an advanced power combiner, significantly enhancing impedance bandwidth, minimizing return loss, and improving polarization isolation-crucial for dual-polarized communication. The incorporation of this stepped tuning strategy provides improved broadband impedance transformation, enabling wide bandwidth operation, low insertion loss, and strong polarization isolation within a manufacturable architecture. Experimental validation demonstrates excellent performance, achieving a return loss better than -30 dB over 17 GHz to 34.6 GHz, isolation exceeding -60 dB, and a low insertion loss of less than 0.18 dB, with a fractional bandwidth of 68.21%. The measured results closely align with simulations, with minor discrepancies attributed to fabrication tolerances. Compared to conventional OMTs, the proposed structure offers superior electrical characteristics, reduced insertion loss, and improved polarization purity, making it a highly efficient and scalable solution for next-generation Ka-band SATCOM applications.
Keywords: Ortho Mode Transducer (OMT), turnstile junction, Ka-band SATCOM, Isolation, Return loss, Insertion loss.
Full-Text [PDF 1860 kb]   (83 Downloads)    
Type of Study: Research Paper | Subject: Antenna
Received: 2025/06/12 | Revised: 2026/06/29 | Accepted: 2026/05/17
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Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Creative Commons License
© 2022 by the authors. Licensee IUST, Tehran, Iran. This is an open access journal distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.