Accuracy and Modeling Improvements for an Integral Equation Framework Applied to Thin Layer Microstrip and Substrate Integrated Waveguide (Siw) Structures

For the analysis and design of printed circuit boards or structures and antennas embedded in general layered media, many commercial design tools based on integral equation methods (IE) or finite elements (FEM) are available. But in practice we make often the experience, that the efficiency is often very low leading to long meshing and solution runtimes. Furthermore sometimes doubtful solutions occur and it is often difficult to verify the accuracy of the results and we are missing typical modeling capabilities such as the direct integration of lumped elements within (microstrip) circuit or antenna structures. In this contribution, an improved Legendre Filon quadrature is introduced well suited for the computation of coupling integrals of our IE approach leading to a higher efficiency and accuracy for the analysis of arbitrary structures but especially for circuits on thin layers which often lead to not reliable results with commercial solvers [5]. In this context we show the additional integration of lumped L and C elements in such circuits not possible with HFSS together with an interface for a co-simulation with HFSS. Another application comprises the improved modeling of substrate integrated waveguides (SIW) and antennas based on a very accurate size dimensioning of equivalent quadratic vias for the improved design process of e.g. leaky-wave antennas.