Transition Structure from Substrate Integrated Fin-Line (SIFL) to Microstrip Line

This paper presents a multilayer structure based on substrate integrated fin-line (SIFL), featuring designs for both microstrip-to- unilateral fin-line transitions and microstrip-to-antipodal fin-line transitions. The substrate integrated configuration overcomes the limitations of conventional fin-line transition structures that require installation within waveguides. Compared to traditional fin-line transitions, this approach offers advantages such as lower cost, easier fabrication, and improved integration with other electronic components. Through simulation and experimental validation, it is demonstrated that the insertion loss is less than 1.5 dB within the 8 GHz to 10 GHz frequency range, with test results closely aligning with the design curves.