Meta-ports: Wideband Matching in Subwavelength Volumes

This paper proposes a new technique for improving impedance matching in waveguide ports and irises using the high index mode of locally resonant metamaterials below the bandgap. Using this subwavelength focusing method, named metamaterial port (meta-port), we can improve the matching in a step discontinuity, such as coupling the wave from propagative waveguides to evanescent filters. As examples, we utilize resonant pins inside a rectangular waveguide above the cut-off (9-18GHz) to realize a wideband matching solution in miniaturized microwave filters. Our solution improves the transmission from an iris, and reduces reflections at the waveguide ports, which may find applications in a wide variety of miniaturized meta-devices.