Comparison of Fabrication Tolerance Sensitivity between Substrate Integrated Waveguide and Microstrip Circuits

This paper presents the use of equivalent parametric circuit models for the investigation of fabrication tolerance sensitivity in substrate integrated waveguide (SIW) components. As the adopted models are parametric, they permit to easily determine the effect of small variations in the geometry of the component, due to the manufacturing process. This feature allows an extremely fast sensitivity analysis and fabrication yield estimate in the case of a mass production. As an example, the sensitivity study of a cavity SIW filter is shown and discussed. Furthermore, the paper presents the comparison of the fabrication tolerance sensitivity between two filters with identical performance, fabricated in SIW and microstrip line technology, respectively. This comparison shows how the sensitivity of scattering parameters is significantly smaller in the SIW filter than in the microstrip counterpart.