Design and verification of a broadband highly-efficient plasmonic circulator*

Circulators play a significant role in radar and microwave communication systems. This paper proposes a broadband and highly efficient plasmonic circulator, which consists of spoof surface plasmon polaritons (SSPPs) waveguides and ferrite disks to support non-reciprocal mode coupling. The simulated performance of symmetrically designed circulator shows that it has an insertion loss of roughly 0.5 dB while the isolation and return loss is more than 12 dB in the frequency range of 6.0 GHz–10.0 GHz (relative bandwidth of 50%). Equivalent circuit model has been proposed to explain the operating mechanism of the plasmonic circulator. The equivalent circuit model, numerical simulations, and experimental results are consistent with each other, which demonstrates the good performance of the proposed plasmonic circulator.