Spoof surface plasmon (SSP) transmission line transition design using slow-wave coplanar waveguide (S-CPW)

In this paper, a new transition implementation design of spoof surface plasmon transmission line (SSP-TL) is proposed. The high-quality-factor slow wave coplanar waveguides (S-CPW) are used instead of the conventional transmission lines to achieve a high efficient transition in terms of momentum, impedance matching and mode conversion. The transition design can ensure a gradual transformation of quasi-TEM modes of S-CPW to the TM modes of SSP-TL. For demonstration purpose, an S-CPW-based SSP-TL is designed and characterized. The measured | S21 | and | S11 | of the proposed SSP-TL is less than -2 dB and better than -20 dB from 2.7 GHz to 4.0 GHz, respectively. It has been demonstrated that S-CPW lines can be an alternate candidate for transition design of SSP-TL for microwave frequency applications.