Branch Line Bridge Using Double-Layered Spoof Surface Plasmon Polaritons As Main Transmission Line

In this paper, a branch line bridge using double-layered fishbone and comb spoof surface plasmon polaritons (SSPPs) as main transmission is proposed. gradient double-layered fishbone SSPPs and sector-structure is used to impedance transition section with four ports. realize mode conversion between quasi - transverse electromagnetic wave (TEM) in coplanar waveguide and transverse electromagnetic wave (TM) in SSPPS. four comb SSPPs was formed bridge arm of the branch line bridge, realizing the 3dB output of the straight and coupling port. The new branch bridge has the advantages of strong coupling and high bandwidth utilizatil.