Multi-Beam Forming and Controls by Metasurface With Phase and Amplitude Modulations

Independent Control of Copolarized Amplitude and Phase Responses via Anisotropic Metasurfaces

“…This work introduced a key idea to design A–P controllable metasurfaces within the terahertz and microwave bands, by considering the cross‐polarized response in view of its broader operational bandwidth, relatively simple design procedure, and weaker interactions between the amplitude and phase responses, thereby paving the way to a series of interesting applications. [ 33–36 ] However, this working mechanism does not enable an anisotropic response, i.e., independent control of the responses to two linear, orthogonal polarizations. Subsequent studies have demonstrated the possibility to control copolarized amplitude and phase responses by relying on indium tin oxide‐based [ 37 ] and Huygens [ 38 ] metasurfaces, but with inherent restrictions in the attainable amplitude range, or the operability limited to a single polarization.…”

“…From the application viewpoint, a typical scenario of interest for the above‐mentioned A–P controllable metasurfaces is a shared‐aperture antenna with multibeam radiation patterns. Although in most cases the attention is focused on pencil beams, [ 36,41,42 ] vortex beams are eliciting a growing attention. However, available studies on this subject [ 15,39,43,44 ] rely on the tailoring of the phase‐response only, with separation mechanisms based on the working polarization or space, which do not really yield a true superposition of multimode vortex beams.…”

Transmission‐Reflection Controls and Polarization Controls of Electromagnetic Holograms by a Reconfigurable Anisotropic Digital Coding Metasurface

“…[1,2] Based on metamaterials, many exceptional phenomena and fantastic devices have been reported, such as negative refraction, [3,4] invisible cloaks, [5][6][7] and transformation optics lens. [8,9] Different from 3D metamaterials, metasurfaces are kinds of 2D planar metamaterials, having advantages of small size, easy fabrication, and low loss, which also have powerful capabilities in the manipulation of EM waves, [10][11][12] such as phase manipulations, [13][14][15] amplitude modulations, [16][17][18][19] polarization controls, [20][21][22] and surface wave manipulations. [23,24] of focusing holographic imaging is designed, fabricated, and measured.…”

Direct routing of intensity-editable multi-beams by dual geometric phase interference in metasurface

“…Recently, by applying complex-amplitude addition theorem and introducing meta-atoms with independent amplitude and phase modulations, the propagation of EM wave can be completely tailored by amplitude-phase metasurface. Compared with phase-only metasurfaces, the major advantage of such metasurface is that better wavefront-shaping performances, e. g., ultra-low side-lobes or reduced speckle in hologram [21][22][23][24][25], can be directly achieved through theoretical formulas, without resorting to the complex and time-consuming optimizations. Due to these merits, the amplitude-phase modulation metasurfaces insure a wide range of applications such as high quality holography, synthesis of complex wave fields, and so on [21,22].…”

“…Due to these merits, the amplitude-phase modulation metasurfaces insure a wide range of applications such as high quality holography, synthesis of complex wave fields, and so on [21,22]. The metasurface composing of C-shaped meta-atoms can arbitrarily control the power of each diffraction order or realize high-resolution holograms for linearly-polarized excitations [23][24][25]. By introducing lossy components, e. g., chip resistors or resistive film [26], to dissipate the unwanted energy, the metasurface with varying geometrical parameters can support both reflection amplitude and phase control [26], but this method could not be easily scaled to other frequencies, because the precise control of lossy values still remains challenging especially in much higher frequencies, e. g., in terahertz band.…”