This manuscript presented the programmable metasurface based on LC (liquid crystal) material to manipulate the THz (terahertz) wave. To manipulate the EM (electromagnetic wave), the programmable and digital coding met...
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ISBN:
(纸本)9781510670754;9781510670747
This manuscript presented the programmable metasurface based on LC (liquid crystal) material to manipulate the THz (terahertz) wave. To manipulate the EM (electromagnetic wave), the programmable and digital coding metasurfaces have been widely used in the microwave range using the semiconductor controlling elements (PIN diode and varactor diode). However, in the THz range, these semiconductor components have limited applications. Herein, a 1-bit digital programmable metasurface based on LC is proposed to achieve the THz wave manipulation with electrical control. The 1-bit digital coding metasurface is composed of two kinds of meta-atoms including "0" and "1" digital codes corresponding to the opposite reflection phase response "0" and "." respectively. The reflection phase of the metasurface element is nearly 1800 manipulating between biased (1) and unbiased (0) states of the coding sequence. When the different coding sequence is applied to the metasurface array, the phase profile between metasurface elements is changed dynamically and manipulate the incident THz beam. The proposed LC-based THz metasurface unit cell is applied with the different biasing voltages and in result the relative permittivity of the LC material is changed from 2.63 to 3.67 based on the orientation of the LC molecules. However, the resonant frequency is switching from 0.121 THz to 0.108 THz and achieved the 180 degree phase differences. Furthermore, 36x36 metasurface array is enabled to perform multi-functionalities including dual beam and multi-beam steering, beam splitting that could be implemented in the application of sensing, imaging, defence RCS (radar cross section) reduction and wireless communication such as RIS (Reconfigurable Intelligent Surfaces).
coding metasurface is a good candidate to achieve flexible electromagnetic wave beam manipulations, but with challenges of integration and alignment issues, especially at millimeter-wave band. To alleviate the above p...
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ISBN:
(纸本)9781728105635
coding metasurface is a good candidate to achieve flexible electromagnetic wave beam manipulations, but with challenges of integration and alignment issues, especially at millimeter-wave band. To alleviate the above problems, an integrated coding metasurface is designed, to inherently integrate a planar feeding with coding metasurface in a single-layered printed circuit board. In addition, by pre-designing the coding sequence, multiple beam functions can be achieved. As a validation, this paper demonstrates a single coding metasurface to generate boresight pencil beam in the far-field and tilted zero-order Bessel beam in the near-field simultaneously.
A new projecting pattern is designed based on the principle of Pseudo-Random coding in this paper, and its decoding method is also studied according to Mathematical Morphology. Here, we initiate a new way which makes ...
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ISBN:
(纸本)9780819480866
A new projecting pattern is designed based on the principle of Pseudo-Random coding in this paper, and its decoding method is also studied according to Mathematical Morphology. Here, we initiate a new way which makes the feature points of two adjacent windows to validate with each other. By this way, we not only assure the validity of the matching result, but also resolve the problems of shadowing when the coded structured light is projected into the surface of the complex 3D scene, and overlapping of some parts of coding picture because of the different shooting angles of the camera, which results in the matching error of the feature points. The results of the experiments prove that the method has the advantages of simplicity and high speed. Through this approach, we can realize the automatic extracting and matching of the feature points with high accuracy.
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