A Flexible Transmission Line of Spoof Surface Plasmon Polaritons at Microwave Frequencies

This paper presents a flexible transmission line based on spoof surface plasmon polaritons (SSPPs). The transmission line (TL) consists of a flexible dielectric substrate, ultrathin corrugated metallic strips and transition structures. The flexible ability of the TL is based on the ultrathin and foldable substrate, and also due to the excellent field confinement of the SSPPs to guarantee high transmission performance in the cases of bending and twisting. Prototype of the SSPP TL is fabricated and tested. The measured results show that in the working frequency from 12 to 18 GHz, the TL maintains a reflection coefficient below −10 dB and a transmission loss about 2 dB when it is bent or twisted. This TL applies the excellent characteristics of SSPPs to flexible microwave circuits, and may have good application prospects.