Spoof Localized Surface Plasmon Enhanced Isolation and Circulation

Abstract A miniaturized spoof plasmonic isolator comprising a deep‐subwavelength spoof localized surface plasmon (SLSP) resonator coupled with an ultrathin spoof surface plasmon polariton waveguide is proposed and experimentally demonstrated. The SLSP resonator coated with a magneto‐optical material can enhance the isolation property, allowing for multifrequency isolation, which can be dynamically controlled by changing the biased magnetic field intensity. This design scheme is extended to realize a four‐port circulator that allows one‐way transmission in opposite directions in two separate frequency bands. The proposed isolation and circulation devices have potential for nonreciprocal applications in microwave communication systems.