CN118610774B - Full-space integrated terahertz super-surface unit based on liquid crystal - Google Patents
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- 229910052751 metal Inorganic materials 0.000 claims abstract description 36
- 239000002184 metal Substances 0.000 claims abstract description 36
- 239000000463 material Substances 0.000 claims abstract description 7
- 239000004642 Polyimide Substances 0.000 claims description 20
- 229920001721 polyimide Polymers 0.000 claims description 20
- 239000010453 quartz Substances 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 13
- 239000000758 substrate Substances 0.000 claims description 13
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 6
- 239000010931 gold Substances 0.000 claims description 6
- 229910052737 gold Inorganic materials 0.000 claims description 6
- 238000002310 reflectometry Methods 0.000 claims description 3
- 238000002834 transmittance Methods 0.000 claims description 2
- 230000005540 biological transmission Effects 0.000 abstract description 15
- 238000003384 imaging method Methods 0.000 abstract description 10
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- 238000004364 calculation method Methods 0.000 description 6
- 108091026890 Coding region Proteins 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000013139 quantization Methods 0.000 description 4
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- 238000011161 development Methods 0.000 description 2
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- 238000005457 optimization Methods 0.000 description 2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910021542 Vanadium(IV) oxide Inorganic materials 0.000 description 1
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- 239000002887 superconductor Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- GRUMUEUJTSXQOI-UHFFFAOYSA-N vanadium dioxide Chemical compound O=[V]=O GRUMUEUJTSXQOI-UHFFFAOYSA-N 0.000 description 1
- 239000013598 vector Substances 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
- H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
- H01Q15/0026—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective said selective devices having a stacked geometry or having multiple layers
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- G—PHYSICS
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- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/133711—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by organic films, e.g. polymeric films
- G02F1/133723—Polyimide, polyamide-imide
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
- H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
- H01Q15/0046—Theoretical analysis and design methods of such selective devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/30—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array
- H01Q3/34—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array by electrical means
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Abstract
The invention discloses a full-space integrated terahertz super-surface unit based on liquid crystal, which is used for performing multifunctional dynamic control on full-space terahertz waves; realizing 3-bit state coding of the super-surface unit in a specific frequency band (0.4-0.44 THz, 0.7-0.72 THz), and realizing the maximum phase shift of approximately 315 degrees in a transmission mode and a reflection mode respectively, so that dynamic programmable manipulation of the full-space terahertz wave is realized; the invention adopts an electrically tunable liquid crystal material combined with a metal super-surface for phase shift, and when incident terahertz waves interact with the super-surface, three functions including beam steering, orbital angular momentum and holographic imaging are flexibly switched by actively regulating and controlling the coding mode of the super-surface through external bias voltage.
Description
Technical Field
The invention relates to the technical field of super-surface design, in particular to a full-space integrated terahertz super-surface unit based on liquid crystal
Background
Terahertz waves have the advantages of low energy, high broadband and rich biological resonance information, and have wide application prospects in the aspects of wireless communication, biomedicine, nondestructive detection and the like. The development of terahertz technology has led to an increase in demand for highly efficient functional devices, especially miniaturized and integrated devices, that accommodate this band. The multifunctional terahertz device capable of dynamically reconfiguring the function is important for further improving the integration of the system and expanding the application program scene. Super-surface, a kind of metamaterial with a two-dimensional structure composed of artificial structural elements with sub-wavelength, is widely applied to terahertz devices so as to strengthen interaction between the metamaterial and terahertz waves. They provide unprecedented freedom to manipulate terahertz amplitude, phase, polarization and Orbital Angular Momentum (OAM) characteristics.
However, for conventional super-surface designs, the unit structure is determined, and limited Electromagnetic (EM) characteristics cannot meet the urgent need for developing a multi-functional integrated terahertz device. In practical applications, multifunctional dynamic control of terahertz waves is expected. The advent of digitally encoded subsurface-based programmable subsurface in recent years provides a promising solution. By actively switching the coding sequence, the programmable subsurface may exhibit excellent programmable EM properties. In general, conventional programmable subsurface devices can be controlled by electrical, mechanical, optical, and thermal means. Among other things, electrical tuning is always efficient and cost effective, especially for miniaturized and integrated systems. In the microwave frequency range, programmable supersurfaces that use diodes to switch between the "0" and "1" elements have been widely used. However, diodes are not suitable for terahertz devices due to structural size and parasitics. Thus, various tunable materials such as graphene, vanadium dioxide, superconductors, and liquid crystals are integrated to the super surface for achieving active modulation of terahertz waves. Compared with other electrical control devices, the manufacture of the terahertz device based on liquid crystal is compatible with the standard liquid crystal display technology, so that the large-scale production is economical and easy and convenient. In particular, dynamic manipulation of terahertz waves can be achieved by changing the phase retardation by changing the orientation of liquid crystal molecules due to the birefringence effect of the liquid crystal. Furthermore, the encoded liquid crystal-based supersurface may be pixelated. Each pixel is electrically addressable, providing the possibility to design a multi-bit programmable subsurface.
The subsurface device can be classified into transmission and reflection according to the propagation direction of EM waves. The transmission and reflection multiplexing of EM waves gives the super-surface a rich dual channel steering capability. Therefore, the proposal of the full-space super surface provides a promising strategy for further improving the information capacity and maximally utilizing the space resources. However, the existing research mainly focuses on dynamic control of EM waves in either transmission or reflection modes, while the research on the other half space remains blank. This inevitably limits the application potential of the super-surface, especially in the implementation of multi-functional terahertz devices.
In conclusion, the existing super-surface device applied to the terahertz wave band mainly has the problems of single function, low information carrying capacity, low space resource utilization rate, lack of an efficient design method and the like.
Disclosure of Invention
The invention aims to provide a full-space integrated terahertz super-surface unit based on liquid crystal, which solves the problems in the background technology.
The full-space integrated terahertz super-surface unit based on the liquid crystal comprises a quartz substrate, a square annular cross structure metal patch, an alignment layer polyimide medium, a liquid crystal medium, polyimide, a metal grating, polyimide, a liquid crystal medium, polyimide, a strip-shaped metal patch and a quartz substrate in sequence from top to bottom.
Further, the quartz substrate is used for supporting the super surface structure, and gold is used as metal, so that the dielectric constant is 3.75, the loss tangent is 0.0004, and the conductivity is 4.561 X10: 10 7.
Further, the square ring-shaped cross structure metal patch is used as a resonator, so that the structure has high transmissivity or reflectivity.
Further, the metal grating is used as a filtering layer to transmit x polarized waves and reflect y polarized waves, so that terahertz waves can be ensured to be transmitted and reflected efficiently in different frequency bands;
Further, the strip-shaped metal patch, the metal patch and the metal grating are used together as electrodes for applying bias voltage, the medium is made of flexible polyimide material, the dielectric constant is 3.0-3.6, the loss tangent is 0.0001-0.05, and the surface of the flexible polyimide material is provided with grooves with consistent directions, and the grooves are used as alignment layers, so that liquid crystal molecules are arranged according to the directions of the grooves.
Further, the dielectric constant of the liquid crystal medium is 2.55-3.65, and the loss tangent is 0.01-0.03.
Further, the optimized ultra-surface unit period is 310-330 mu m, the thickness of gold is 0.8-1.2 mu m, the thickness of polyimide medium is 1-10 mu m, the thickness of liquid crystal medium is 210-230 mu m, the thickness of liquid crystal medium is 1150-1250 mu m, the thickness of quartz substrate is 280-320 mu m, the outer diameter of square ring patch in square ring cross structure metal patch is 310-330 mu m, the inner diameter is 280-300 mu m, the length of long arm of cross patch is 280-300 mu m, the width is 25-35 mu m, the length of short arm is 120-140 mu m, the width is 25-35 mu m, the length of metal grating is 310-330 mu m, the width is 31-33 mu m, the gap is 31-33 mu m, the length of strip metal patch is 310-330 mu m, the width is 50-100 mu m, and the dielectric constant of liquid crystal medium is adjusted by changing bias voltage to realize 315 DEG coverage of phase.
According to the full-space integrated terahertz super-surface unit optimization design method based on the liquid crystal, linear polarized wave incidence is adopted, and the amplitude and the phase of the optimized super-surface unit are calculated.
Further, the optimized phase is quantized to 8 steps, namely, the phase distribution only comprises phase distributions with equivalent phases of 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 ° to form a 3-bit coding unit, 2 units with phase differences of 180 ° are arbitrarily selected from the 3-bit coding unit to form a 1-bit coding unit, the units are arranged according to the quantized phase distribution, 40×40 units are arranged in total, and each column represents a subarray and comprises 2×40 units.
The full-space integrated terahertz super-surface unit holographic imaging method based on the liquid crystal is characterized in that the encoding state of a liquid crystal super-surface unit device is changed through external bias voltage to realize holographic imaging.
Compared with the prior art, the invention has the following remarkable advantages that (1) the super surface is designed from two dimensions by combining the phase control of transmission and reflection so as to realize the dynamic control of the terahertz wave in the whole space. (2) The invention is based on electrically tunable liquid crystal materials, and the proposed programmable subsurface features the realization of 3-bit state encoding in specific frequency bands (0.4-0.44 THz, 0.7-0.72 THz) and the realization of maximum phase shifts of approximately 315 ° in transmissive and reflective modes, respectively. (3) The invention provides a full-space integrated terahertz super-surface device based on liquid crystal, which integrates dual-beam steering, OAM light beam and holographic imaging technology, can realize flexible switching of three functions by actively regulating and controlling the arrangement of switching coding sequences, and has wide application prospect in the fields of miniaturized integrated communication systems and the like.
Drawings
FIG. 1 is a schematic diagram of a full-space subsurface unit designed in accordance with the present invention;
FIG. 2 is a graph of amplitude and phase results for a full-space subsurface unit of the present invention;
FIG. 3 is a graph of phase encoding and far field calculation results for implementing a dual beam steering function for a full-space subsurface of the present invention;
Fig. 4 is a diagram of the result of performing 8-order quantization and far-field calculation on the phase distribution of the OAM beam function implemented by the full-space super surface of the present invention;
FIG. 5 is a far field schematic of an object of the full space holographic imaging of the present invention;
fig. 6 is a graph of the result of 8-order quantization and far-field calculation of the phase distribution of the full-space super-surface implementing holographic imaging function of the present invention.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings.
Embodiment 1 is a full-space integrated terahertz super-surface device based on liquid crystal, and the full-space dual-beam steering function is realized by changing the coding state of a liquid crystal super-surface unit through externally connecting bias voltage.
The embodiment of the invention provides a full-space integrated terahertz super-surface device based on liquid crystal for realizing a double-beam steering function and a design method thereof, wherein the structure of a unit device is shown as figure 1, and the unit device specifically comprises a quartz substrate 1, a square annular cross-shaped metal patch 2, an orientation layer polyimide medium 3, a first liquid crystal medium 4, polyimide 5, a metal grating 6, polyimide 7, a second liquid crystal medium 8, polyimide 9, a strip-shaped metal patch 10 and a quartz substrate 11, in particular, the quartz substrate has a dielectric constant of 3.75, a loss tangent of 0.0004, the quartz substrate is used for supporting the super-surface structure, gold is adopted as metal, the conductivity is 4.561 multiplied by 107, the square annular cross-shaped metal patch 2 is used as a resonator for ensuring that the structure has high transmittance or reflectivity, the metal grating 6 is used as a filter layer for transmitting x polarized waves and reflecting y polarized waves for ensuring that terahertz waves are transmitted and reflected in different frequency bands, the strip-shaped metal patch 10 and the metal patches 2 and 6 are jointly used for applying electrodes of bias voltages, the dielectric material is adopted as a flexible polyimide material, the dielectric constant is 3.5, the loss tangent is 0.0027, the liquid crystal has a surface orientation layer and is arranged in a direction of the dielectric constant of 0.02, and the dielectric constant is arranged according to the dielectric constant of the dielectric constant is 0.55. The optimized super-surface unit period is 320 mu m, the gold thickness is 1 mu m, the polyimide medium thickness is 5 mu m, the first liquid crystal medium 4 thickness is 225 mu m, the second liquid crystal medium 8 thickness is 1200 mu m, the quartz substrate thickness is 300 mu m, the square ring patch outside diameter 320 mu m, inside diameter 290 mu m, the long arm length 290 mu m, the width 30 mu m, the short arm length 130 mu m, the width 30 mu m, the metal grating 6 length 320 mu m, the width 32 mu m, the gap 32 mu m, the strip-shaped metal patch 10 length 320 mu m, and the width 80 mu m. By varying the bias voltage, the dielectric constant of the liquid crystal medium is adjusted to achieve 315 ° coverage of the phase.
Further, by adopting linear polarized wave incidence, the amplitude and phase of the optimized super-surface unit are calculated, and as shown in fig. 2, it is proved that 315 DEG phase coverage can be realized by adjusting the dielectric constant of the liquid crystal by changing the bias voltage.
In order to reduce the computational complexity, the optimized phase is quantized to 8 steps, namely, quantized to only include phase distributions of equivalent phases of 0 ° (S0), 45 ° (S1), 90 ° (S2), 135 ° (S3), 180 ° (S4), 225 ° (S5), 270 ° (S6) and 315 ° (S7), so as to form a 3-bit encoding unit, and 2 units with 180 ° phase difference are arbitrarily selected from the 3-bit encoding units, so as to form a 1-bit encoding unit. Here, the design selects "S2" and "S6" and arranges them in accordance with the quantized phase distribution, whose phase encoding distribution is shown in fig. 3a, d, for a total of 40×40 cells, each column representing a sub-array comprising 2×40 cells. With linearly polarized wave incidence, as shown in figures 3b, c, e, f, dual beam steering effects are obtained in both transmitted and reflected far field spaces.
The periodic variation of the code sequence from fig. 3a to 3d occurs by applying a different bias voltage to each sub-array in the super-surface, the steering angle of the beam being actively modulated. The bias voltage was changed so that the code sequence "00001111000011110000" (fig. 3a, sequence one) became "00110011001100110011" (fig. 3b, sequence two), the transmitted beam was steered from θ= ±7.5° to θ= ±15° in the range of 0.4-0.44THz, and at the same time, the reflected beam was steered from θ= ±5° to θ= ±10° in the range of 0.7-0.72 THz. Therefore, the design example can dynamically regulate and control the steering angle of the full-space terahertz wave through externally connecting bias voltage under the condition of not changing the super-surface structure.
The transmitted or reflected power efficiency is defined as:
;
P main and P full represent the total power of the main beam and the total power transmitted or reflected into space, respectively, and the power efficiency represents the sidelobe suppression capability and the power ratio of the main beam. Simulation calculation shows that at the frequency of 0.4-0.44THz, the transmission power efficiency under the coding sequence is 68.17%, the maximum power difference between main beams is 0%, the transmission power efficiency under the coding sequence II is 68.38%, and the maximum power difference between main beams is 2.9%. At 0.7-0.72THz, the reflected power efficiency under the coding sequence is 74.51%, the maximum power difference between the main beams is 0%, the reflected power efficiency under the coding sequence II is 75.95%, the maximum power difference between the main beams is 0.91%, and the power efficiency and the uniformity are higher. The dual-beam steering implemented by the design can significantly improve the flexibility and efficiency of the communication system, and support dynamic beam forming and multiple-input multiple-output (MIMO) technology in a multi-user environment.
Example 2a full-space integrated terahertz super-surface device based on liquid crystal, the OAM beam function was realized by changing the encoding state of the liquid crystal super-surface cell device by externally connecting a bias voltage.
In the embodiment, on the basis of the ultra-surface device in the embodiment 1, only the external voltage of the unit device (shown in fig. 1 a) is changed, so that the active regulation and control of the phase position of the unit device are realized. For a subsurface composed of m×n cells, the phase of the cell (M, N) can be expressed as:
;
Where θ mn is the azimuth of the cell (m, n), φ 0 is the initial phase, and r mn and r f are the position vectors of the cell (m, n) and the source, respectively.
The ultra-surface units designed in example 1 are arranged according to the phase, through the 8-order quantization phase, as shown in fig. 4a and d, so as to simulate the application of different bias voltages to change the orientation of liquid crystal molecules, and the phase regulation and the coding of each unit are realized. The super-surface in this example may implement the code switching of fig. 4a and d. The supersurface consists of 40 x 40 units. The linear polarized wave incidence is adopted to simulate the super surface, and the phase distribution in the transmission and reflection modes of the super surface rotates along the clockwise direction for one circle to cover the spiral phase of 2 pi, so that the phase distribution is consistent with the preset phase distribution. The purity of the OAM beam satisfies the following conversion relation:
;
Where W l represents the spectral pattern weight for a topological charge number of l, ψ represents the angular distribution of the topological pattern, and azimuth angle φ is a periodic function. For the topological charge number l= +1, the mode purity for the vortex waves generated by the transmission and reflection modes was 83.5% and 78.4%, respectively. For the topological charge number l= +2, the mode purity of transmission and reflection is 85.2% and 76.9%, respectively. The result shows that the method can generate high-quality OAM light beams with different topological charges in both transmission and reflection modes. The OAM beam realized by the embodiment can carry a plurality of independent information channels, and the capacity and the data transmission rate of a communication system are greatly improved. In future optical fiber communication and free space optical communication, OAM technology is expected to become an important means for realizing ultra-high speed and large capacity communication.
Example 3 full-space integrated terahertz super-surface device based on liquid crystal, the encoding state of the liquid crystal super-surface unit device is changed through externally connecting bias voltage, and the holographic imaging function is realized.
In the embodiment, on the basis of the ultra-surface device in the embodiment 1, only the external voltage of the unit device (shown in fig. 1 a) is changed, so that the active regulation and control of the phase position of the unit device are realized. The far-field image of the target is shown in fig. 5 (a). And according to the target image, utilizing the optimization calculation of the GS algorithm to finally obtain the designed phase distribution of the target image. After the 8-order quantization phase, as shown in fig. 5 (b), the super-surface units designed in example 1 are arranged according to the phase, 40×40 units are all arranged, and the phase distribution of the super-surface can be switched arbitrarily by applying different bias voltages, so that the change of phase coding is realized. The far field results of transmission and reflection using linearly polarized wave incidence are shown in fig. 6, which is highly coincident with the target image. According to the power efficiency calculation method in example 1, the imaging efficiencies of the characters "N" and "J" were 69.6% and 71.3%, respectively, in the transmission mode in the range of 0.4 to 0.44THz, and 73.1% and 74.2%, respectively, in the reflection mode in the range of 0.7 to 0.72 THz. Therefore, the method provided by the invention can realize far-field images with any effect, and can be expanded to the field of high-resolution holographic imaging by increasing the number of units. By combining the embodiment 1 and the embodiment 2, the dual-beam steering technology realized by the invention improves the efficiency and the quality of multi-user communication and adapts to the dynamic network environment. The OAM beam technology provides a new approach for high-capacity, broadband transmission and quantum communication. Holographic imaging technology exhibits important application value in large data storage, immersive communication, and complex signal processing. The invention integrates the functions, and is expected to promote the development of a communication system to a more efficient, intelligent and safe direction.
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| CN113131218A (en) * | 2021-03-29 | 2021-07-16 | 四川大学 | THz broadband switchable super surface for polarization conversion and wavefront regulation |
| CN117424000A (en) * | 2023-11-24 | 2024-01-19 | 东南大学 | 1-bit transmission type polarization multiplexing multifunctional terahertz digital coding super-surface |
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| CN106410422A (en) * | 2016-10-28 | 2017-02-15 | 东南大学 | 3-bit transmission type electromagnetic code metamaterial applied in terahertz band |
| EP3570375A1 (en) * | 2018-05-14 | 2019-11-20 | Paris Sciences et Lettres - Quartier Latin | Reconfigurable antenna assembly having a metasurface of metasurfaces |
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| CN113131218A (en) * | 2021-03-29 | 2021-07-16 | 四川大学 | THz broadband switchable super surface for polarization conversion and wavefront regulation |
| CN117424000A (en) * | 2023-11-24 | 2024-01-19 | 东南大学 | 1-bit transmission type polarization multiplexing multifunctional terahertz digital coding super-surface |
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