Guided wave structure of spoof surface plasmon polaritons with ring cavities

The confined capability of the spoof surface plasmon polaritons (SSPPs) can be regulated by the periodic cell structure of the SSPP waveguide. In this paper, to further enhance the confinement to the SSPP interface fields and reduce the lateral dimension of the SSPP guided wave structure, the periodic unit loaded with rectangular ring cavities on both sides of the metal strip is proposed. The experimental results show that at a given periodic cell height, the proposed guided wave structure have a lower asymptotic frequency and steep sideband characteristics. That indicates it has good low-pass guided wave performance. Meanwhile, this structure is beneficial to device integration. (C) 2019 The Japan Society of Applied Physics