Hybrid Modes Spoof Surface Plasmon Polaritons Excitation and Propagation under Linear Polarized Incidence

The excitation and propagation of spoof surface plasmon polaritons (SSPPs) have always been the hot topics. The emergence of phase gradient metasurface (PGM) makes the excitation efficiency of SSPPs higher. However, the polarization state of the incident waves determines the mode of the excited SSPPs. In general, single (TE or TM) mode SSPPs will be coupled for linear polarized (LP) illumination, and hybrid (TE and TM) modes SSPPs will be coupled for circular polarized (CP) illumination. In order to get rid of the restriction of incident waves' polarization, we propose the combined metasurfaces to obtain hybrid modes SSPPs under LP incidence. The double-layered V-shaped structure is designed to efficiently realize linear-to-circular (LTC) polarization conversion transmissions at 11 GHz, and a Pancharatnam-Berry (PB) phase manipulating metasurface (PMM) composed of N-shaped structure can couple transmitted CP waves into hybrid modes SSPPs. The metallic patch array (MPA) is designed to propagate hybrid modes SSPPs with same wave vector. As results, the simulations show that x-polarized waves can be converted into left-handed circular polarized (LCP) transmitted waves and coupled into hybrid modes SSPPs, and y-polarized incident waves can be converted into right-handed circular polarized (RCP) transmitted waves and also coupled into hybrid modes SSPPs. This work offers a fire-new method for getting hybrid modes SSPPs and makes the excitation of SSPPs free from the limitation of incident waves' polarization conditions. It also has potential in absorbers, waveguides, detectors and some other microwave devices.