Efficient analysis of gap-waveguide structures through a rigorous mode-matching approach

Gap waveguide structures combine the ideas of parallel plate waveguides and electromagnetic bandgaps to form novel efficient high frequency waveguiding structures. Since the concept relies on the use of periodic structures with bandgap properties the analysis is very complex. Our proposed analysis approach is based on efficient use of Method of Moments/Mode-matching to rigorously determine the scattering of each element in the grid. To achieve this, the currents on the elements are first determined by using the Green's function of a single element in a parallel-plate waveguide. The solution is then expanded to all the elements from which dispersion properties can be determined. The results of our approach are verified using full-wave commercial software. They show excellent agreement, but it is important to point out that they are obtained in a fraction of the time compared to the full-wave software.