Investigation on Tolerances of Substrate Integrated Waveguide (SIW)

In this paper, the substrate integrated waveguide (SIW) is investigated into the effects of tolerances using the sensitivity approach. The changes in characteristics of transmission line due to the tolerances of its parameters have been analyzed to evaluate the worst case behavior. A set of sensitivity curves are given to help the design procedure and used to determine the tradeoff between performances and tolerances. The results from the present investigations have shed new light on design criteria. For instant, a low-impedance SIW is less sensitivity to tolerances in parameters and preferred to be chosen in consideration. The inverse problem is also studied to evaluate the required accuracies for the fabrications and substrates with a prescribed VSWR value. Computations for others conventional planar transmission lines are compared with the SIW, which have been demonstrated that an SIW transmission line is the less sensitive one.