Surface Waves and Free-Space Waves Co-Modulated Metasurface With the Same Aperture

Application scenarios like wireless/satellite communications, cognitive radar, and integrated photonics systems demand more advanced interfaces that can manipulate both surface waves emitted by in-plane sources and free-space waves fed by horn antennas into the open air, as well as smoothly controlling the radiated beam patterns. Conventional metasurfaces can only control one of either surface waves or free-space waves, limiting their applications. This paper reveals the intrinsic connection between the holographic principle and the general Snell’s Law. Specifically, the phase gradient derived from the holographic principle can be interpreted as a modulated form of that in the generalized Snell’s Law. Based on that, this paper firstly proposes a surface waves and free-space waves co-modulated(SFC) metasurface with the ability to simultaneously control both surface waves and free-space waves at the same frequency. SFC metasurface antennas offer capabilities such as beam steering, beam shaping, and polarization adjustment, while they are simultaneously fed by surface waves and free-space waves. We conduct simulations and measurements on SFC metasurface antennas, which prove their capabilities of seamless beam scanning, polarization adjustment, and the concurrent domination of both surface waves and free-space waves.