Compact CPW Spoof Surface Plasmon Polariton Transmission Line With Interdigital Structure

By using interdigital structures, a new compact coplanar waveguide (CPW) SSPP transmission line (TL) is proposed. The equivalent circuit model is developed to analyze the effect of the interdigital structure. The analyses reveal that the proposed SSPP TL features reduced transversal width owing to the extra capacitors brought by the interdigital structures. On this basis, another improved SSPP is presented based on GCPW topology. This improved GCPW SSPP TL exhibits lower asymptotic frequency and more compact size. To validate the propagation performance, the proposed GCPW SSPP TL was fabricated and tested. The results show that the designed SSPP TL exhibits compact size, which is benefit to the miniaturization of the SSPP devices.