Perfect Power Splitting in Waveguide Junctions Using a Metagrating-Inspired Methodology

We propose a semi-analytical, metagrating-inspired technique to eliminate reflection loss in a symmetrical three-channel H-plane waveguide junction, achieving seamless power splitting. As in metagratings, sparse periodic arrays of subwave-length scatterers (meta-atoms), the solution is devised by judicious engineering of the meta-atom distribution, relying on modal analysis and systematic formulation of constraints. Herein, we use a mode-matching-based technique to calculate the structure's power scattering coefficients and find an appropriate location at which a passive polarizable element may be placed to suppress spurious reflections. Subsequently, a proper geometry for this scatterer is found using a simple parametric sweep in a full-wave solver. The presented methodology is demonstrated and verified via full-wave simulations, using a metallic post to realize the meta-atom. This reliable scheme, yielding a simple solution based on a semi-analytical model, serves as an appealing alternative to current design procedures, which commonly require intricate formations or a specific split angle.