Fully Embedded Microstrip Filtering Crossover Using 2D MTM-EBGs

The metamaterial-based electromagnetic bandgap (MTM-EBG) structure is a fully planar, periodically loaded multiconductor transmission line (MTL) structure. The periodic loading allows a forward propagating microstrip-like mode and a backward propagating coplanar waveguide-like mode to couple power contradirectionally. This contradirectional coupling gives rise to the structure's bandgap (S. Barth et al., “A Miniaturized Uniplanar Metamaterial-Based EBG for Parallel-Plate Mode Suppression,” IEEE Transactions on Microwave Theory and Techniques, Vol. 64, No.4, 1176–1185, April 2016). The size and location of the bandgap can be controlled by varying the reactive loading and/ or host-MTL properties of the MTM-EBG unit cells. The MTM-EBG has been extended to two dimensions in order to model the uniplanar compact EBG (UC-EBG) (S. Barth et al., “The MTM-EBG as a Rigorous Multiconductor Model of the UC-EBG and Approaches for Miniaturization,” IEEE Transactions on Antennas and Propagation, Vol. 70, No.4, 2822–2831, April 2022). Similar to the 1D MTM-EBG, the 2D MTM-EBG exhibits a bandgap at certain frequencies but unlike the 1D MTM-EBG, it can possess different bandgaps for different directions of propagation, as determined by the reactive loading and/ or host MTL properties of the unit cells.