Filtering line waves at the impedance-interface using metamaterials in the millimeter-wave band

Edge waves have been one of the hot spots of research in electromagnetic fields in recent years. They exist between different interfaces such as impedance interfaces which are capacitive and inductive. Different kinds of edge wave components have been invented, including transmission lines, antennas and splitters. In this work, we design an impedance interface waveguide using metamaterial unit cells. The dispersion properties of the unit cells and the impedance interface are investigated. A Vivaldi antenna is used as the transition section between the traditional microstrip line and the impedance interface waveguide to convert the transverse electromagnetic mode to edge waves. We use split ring resonators to design different filters with narrow and broad stopbands. The filters are fabricated and measured, and are consistent with simulation results. The filters have good transmission and filtering properties at high frequency. The proposed mode-matching technique and component integration method will be helpful for the development of diverse microwave components.