Beam forming metasurface structure and method based on amplitude and phase modulation

Abstract

The invention relates to a beam forming metasurface structure and method based on amplitude and phase modulation, the beam forming metasurface structure comprises a plurality of metasurface units, and the metasurface units with different structural parameters are uniformly arranged to form the metasurface structure; each metasurface unit comprises three metal layers and two dielectric layers; the first layer, the third layer and the fifth layer are metal layers from top to bottom, and the second layer and the fourth layer are dielectric layers. The metasurface capable of modulating the amplitude and the phase of the electromagnetic wave simultaneously is designed, the structure is simple, the profile is low, and the flexibility of electromagnetic wave regulation and control is improved; the excitation amplitude and phase distribution required by the target directional diagram are calculated based on the Taylor synthesis method and the superposition principle, the method is suitable for synthesis of various far-field directional diagrams, and the calculation method is simple and convenient.

Description

technical field [0001] The invention belongs to the field of metasurface electromagnetic control, in particular to a beam-forming metasurface structure and method based on amplitude and phase modulation. Background technique [0002] A new type of artificial electromagnetic surface, that is, a metasurface, is a two-dimensional planar structure composed of subwavelength microstructure units arranged in a periodic or quasi-periodic manner. Flexible regulation. At present, the research on phase-only modulation metasurfaces is very mature, which can realize functions such as high gain, beam deflection, polarization conversion, and helical phase wavefront. However, in order to achieve more precise control of electromagnetic waves, it is necessary to consider the regulation of the amplitude of electromagnetic waves. So far, there are few studies on metasurfaces with simultaneous modulation of amplitude and phase, and there are more new methods and functions to be explored. Base...

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Problems solved by technology

[0003] Southeast University published a fan-shaped beam (flat-top beam in the Cartesian coordinate system) generator in its patent document "An Arbitrary Waveform Generator and Setting Method Based on Metasurface", which is optimized by genetic algorithm The excitation amplitude and phase design a metasurface that can generate flat-top beams, but this invention only forms flat-top beams on the φ=0° plane, but in practical applications it is often necessary to Flat-top beams are formed on both surfaces at the same time, and when the method is extended to a two-dimensional planar array, the variables that need to be optimized increase in a quadratic relationship, and it takes a lot of time to optimize, which increases the difficulty and reduces the design efficiency

[0004] The University of Electronic Science and Technology of China announced a rectangular beamforming method based on a holographic artificial impedance surface in its patent document "A Rectangular Beamforming Holographic Artificial Impedance Surface", which consists of four monopoles and their feed network Exciting metasurfaces to achieve beamforming, but the design of this method produces a rectangular flat-top beam with large fluctuations in the main lobe and high sidelobe levels

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