Generation of Millimeter-Wave Vortex Beams Based on Spoof Localized Surface Plasmons

In this letter, an efficient design based on spoof localized surface plasmons (spoof LSPs) is proposed to generate millimeter-wave (MMW) vortex beams. A textured ring resonator with annularly distributed strips is adopted to excite and enhance the LSP modes. By loading a hybrid coupler into the two-port network, two orthogonal modes with the required ±90° phase delays are achieved to generate OAM waves. Both simulations and experiments demonstrate that MMW vortex beams can be efficiently radiated by the OAM antennas. The approach discussed here provides a way for OAM generation, which has great application potential in the material sensors.