Multimode Orbital Angular Momentum Generation Based on Spoof Surface Plasmon Polaritons With Multiple Mode Regulation Mechanisms

Vortex waves carrying orbital angular momentum (OAM) can realize super-resolution radar imaging and improve channel capacity in communication systems, arousing great interest of researchers; however, the majority of OAM-generating designs have drawbacks such a large size, difficult integration, and a small amount of OAM mode. Taking advantage of the miniaturization and integration compatibility of spoof surface plasmon polaritons (SSPPs), we present a compact multi-OAM-mode generation with multiple mode regulation mechanisms. In this design, a leaky-wave antenna (LWA) based on a periodically modulated looped SSPP waveguide is used to convert the SSPP wave into vortex beams carrying OAM. According to the phase regulation of the SSPP waveguide and the LWA principle, adjusting the frequency or the polarization of the modulation element of the proposed LWA can change the generated OAM mode. To validate the proposed method, two SSPP LWAs with different polarized radiating elements are designed and fabricated. The measured results agree well with the simulated results.