Full‐Polarization Frequency Controlled Multimode Spoof Surface Plasmon Polaritons Excitation via Anisotropic Metastructure

Surface plasmon polaritons (SPPs) have great applications in imaging, sensing, waveguide, and communication. Especially in the trending of electromagnetic (EM) metastructure field, researchers used the phase gradient design to achieve the efficient surface wave propagating performance ranging from GHz to THz. However, due to the intrinsic coupling interference from the current structure design, the phase and amplitude of different polarization are hard to freely manipulate simultaneously, making the design of multifunctional channels SPPs still a challenging project. Here, an anisotropic structure is proposed to realize independent control of both polarization and amplitude along different component of the wavefront. By analyzing the polarization dependent mechanism, the hexagon and half-hexagon meta-atom are introduced to the coupler structure to tailor the desired phase gradient along different directions under different polarized EM waves. Then the dispersion of coupler is further coupled with the propagating patch metasurface by optimization algorithm. As a result, the multifunctional SPP is achieved, and the multimode excitation can be generated under both linear and circular polarized incidence. Both simulation and experiment validate the effectiveness and wideband of spoof SPPs excitation performance, verifying that this method reduces the excitation condition of surface wave and improves the multiplexing effect of propagation channel.