WO2023279384A1 - Film antireflet, structure de transmission d'ondes électromagnétiques et procédé de préparation pour film antireflet - Google Patents

Film antireflet, structure de transmission d'ondes électromagnétiques et procédé de préparation pour film antireflet Download PDF

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Publication number
WO2023279384A1
WO2023279384A1 PCT/CN2021/105542 CN2021105542W WO2023279384A1 WO 2023279384 A1 WO2023279384 A1 WO 2023279384A1 CN 2021105542 W CN2021105542 W CN 2021105542W WO 2023279384 A1 WO2023279384 A1 WO 2023279384A1
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electromagnetic wave
medium
interface
incident
phase
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PCT/CN2021/105542
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English (en)
Chinese (zh)
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赖耘
褚宏晨
牟文日
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南京大学
南京星隐科技发展有限公司
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Priority to PCT/CN2021/105542 priority Critical patent/WO2023279384A1/fr
Publication of WO2023279384A1 publication Critical patent/WO2023279384A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11—Anti-reflection coatings
    • 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
    • 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
    • H01Q15/02—Refracting or diffracting devices, e.g. lens, prism
    • H01Q15/08—Refracting or diffracting devices, e.g. lens, prism formed of solid dielectric material
    • 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
    • H01Q15/14—Reflecting surfaces; Equivalent structures

Definitions

  • the invention relates to the technical field of metamaterials, in particular to an antireflection film, an electromagnetic wave transmission structure and a preparation method of the antireflection film.
  • an anti-reflection film is provided.
  • the antireflection film is arranged on the interface between a first medium and a second medium, the first medium is an electromagnetic wave incident medium, the second medium is an electromagnetic wave exit medium, and the first medium is incident on the first medium.
  • the electromagnetic wave is an incident electromagnetic wave, and the electromagnetic wave emitted by the second medium is a transmitted electromagnetic wave, and the dielectric constants of the first medium and the second medium are different, and it is characterized in that,
  • the anti-reflection film includes:
  • a plurality of control units arranged on the interface each of the control units has a corresponding control parameter, so that the plurality of control units can reduce the reflection of the incident electromagnetic wave on the interface through resonance, and The phase of the transmitted electromagnetic wave is changed on the interface, so that the transmitted electromagnetic wave has a preset phase distribution on the interface.
  • an electromagnetic wave transmitting structure including:
  • the first medium, the first medium is an electromagnetic wave incident medium, and the electromagnetic wave incident on the first medium is an incident electromagnetic wave;
  • the second medium is an electromagnetic wave exit medium
  • the electromagnetic wave emitted by the second medium is a transmitted electromagnetic wave
  • the dielectric constants of the first medium and the second medium are different
  • the anti-reflection film is arranged on the interface between the first medium and the second medium, and includes a plurality of control units arranged on the interface, and each of the control units has a corresponding control parameter, so that all The multiple control units reduce the reflection of the incident electromagnetic wave on the interface through resonance, and make the phase change of the transmitted electromagnetic wave on the interface, so that the transmitted electromagnetic wave has a predetermined effect on the interface.
  • the set phase distribution is arranged on the interface between the first medium and the second medium, and includes a plurality of control units arranged on the interface, and each of the control units has a corresponding control parameter, so that all The multiple control units reduce the reflection of the incident electromagnetic wave on the interface through resonance, and make the phase change of the transmitted electromagnetic wave on the interface, so that the transmitted electromagnetic wave has a predetermined effect on the interface.
  • a method for preparing an antireflection film comprising:
  • the first medium is the electromagnetic wave incident medium
  • the second medium is the electromagnetic wave exit medium
  • the electromagnetic wave incident on the first medium is the incident Electromagnetic waves
  • the electromagnetic waves emitted by the second medium are transmitted electromagnetic waves
  • the dielectric constants of the first medium and the second medium are different
  • the expected transmittance and the expected phase change adjust the electromagnetic parameters and/or structural parameters of each of the regulating units, so that the plurality of regulating units can reduce the incidence of the incident electromagnetic wave on the interface through resonance.
  • the reflection on the surface further has the desired transmittance, and the transmitted electromagnetic wave has the desired phase change on the interface so that the transmitted electromagnetic wave has the desired phase distribution on the interface.
  • Fig. 1 is the schematic diagram when electromagnetic wave is incident on the interface of two kinds of different permittivity media
  • Fig. 2 is a schematic diagram when electromagnetic waves are incident on the interface between two different dielectric constant media provided with the anti-reflection coating of the present application;
  • FIG. 3 is a schematic structural diagram of multiple control units in an embodiment of the present application.
  • Fig. 4 is a schematic diagram of structural parameters of a plurality of control units of the embodiment shown in Fig. 3;
  • Fig. 5 is a schematic diagram of the change of transmittance and phase change with frequency when a plurality of control units of the embodiment shown in Fig. 4 are arranged on the interface;
  • FIG. 6 is a schematic diagram of the principle of implementing interface stealth in this application.
  • Figure (a) in Figure 7 is a schematic diagram of the arrangement of a plurality of control units in the embodiment shown in Figure 4 to realize the stealth of the dielectric;
  • FIG. 7 figure among Fig. 7 is the field schematic diagram that this embodiment realizes dielectric stealth
  • FIG. 7 is a schematic diagram of the field when the electromagnetic wave is incident on the exposed surface of the dielectric
  • FIG. 8 is a schematic diagram of the arrangement of multiple control units in another embodiment of the present application to realize stealth on surfaces of arbitrary shapes;
  • FIG. 8 figure among Fig. 8 is the field schematic diagram that this embodiment realizes dielectric stealth
  • Figure 8 (c) is a schematic diagram of the field when the electromagnetic wave is incident on the exposed surface of the dielectric
  • Fig. 9 is a schematic diagram of the structural parameters of multiple control units on the 0° surface and the 10° slope of the embodiment shown in Fig. 8;
  • Fig. 10 is a schematic diagram of the structural parameters of multiple control units on the 20° slope and the 30° slope of the embodiment shown in Fig. 8;
  • Figure (a) in Figure 11 is a schematic diagram of the arrangement of multiple control units to achieve negative refraction in the embodiment shown in Figure 4;
  • FIG. 11 figure among Fig. 11 is the field schematic diagram that this embodiment realizes negative refraction
  • FIG. 12 is a schematic diagram of the arrangement of multiple control units to achieve the convergence of transmitted electromagnetic waves in another embodiment of the present application;
  • FIG. 12 figure among Fig. 12 is the field schematic diagram when the TE wave of this embodiment is incident;
  • FIG. 12 figure among Fig. 12 is the field schematic diagram when the TM wave of this embodiment is incident;
  • FIG. 13 is a schematic diagram of the structural parameters of multiple control units in the embodiment shown in FIG. 12 .
  • first and second are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features.
  • the features defined as “first” and “second” may explicitly or implicitly include at least one of these features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise specifically defined.
  • the incident electromagnetic wave will be partially reflected to form a reflected electromagnetic wave, while part of it will be transmitted to form a transmitted electromagnetic wave.
  • the intensity and exit angle of the transflective electromagnetic wave can be obtained by the Fresnel formula.
  • the propagation direction of the transmitted electromagnetic wave will be deflected compared with the incident electromagnetic wave. According to Fresnel's law, the refraction angle can be determined by the incident direction and the materials on both sides of the interface. The electromagnetic parameters are completely determined.
  • the incident angle is usually positive, so when the calculated refraction angle is positive, it means that the refraction angle and the incident angle are on the opposite side of the normal line of the interface, that is, the transmitted electromagnetic wave forms refraction in the traditional sense; and when When the calculated refraction angle is negative, it means that the refraction angle and the incident angle are on the same side of the normal line of the interface. At this time, the transmitted electromagnetic wave forms negative refraction.
  • anti-reflection coatings are usually used to effectively suppress reflected electromagnetic waves and increase transmittance.
  • the existing anti-reflection coatings mainly include multi-layer coating anti-reflection coatings and anti-reflection coatings whose refractive index changes along the vertical direction. Cancellation, the anti-reflection coating whose refractive index gradually changes along the vertical direction can use the gradient of refractive index to achieve layer-by-layer impedance matching, and then achieve the effect of weakening the reflection of incident electromagnetic waves and enhancing transmission.
  • the effect of regulating the wavefront of electromagnetic waves; relatively new anti-reflection coatings also include metamaterial anti-reflection coatings.
  • the current metamaterial anti-reflection coatings are usually composed of metal-dielectric-metal sub-wavelength structural units in the form of periodic arrangements. Material anti-reflection coating. Although this type of anti-reflection coating can eliminate reflection and achieve high transmission, it still cannot control the wavefront of transmitted electromagnetic waves.
  • Electromagnetic metasurfaces are composed of a series of subwavelength resonant units that can interact with incident electromagnetic waves arranged on a certain surface.
  • the use of electromagnetic metasurfaces can achieve flexible control of the amplitude, phase, and polarization of incident electromagnetic waves.
  • the transmissive electromagnetic metasurface can achieve efficient transmission wave modulation in a uniform background material (for example, air on both sides of the interface).
  • a uniform background material for example, air on both sides of the interface.
  • an inhomogeneous background material such as air on one side of the interface and dielectric on the other side
  • the transmission efficiency of the transmissive electromagnetic metasurface is often affected by the impedance mismatch of the interface, and some energy reflections will still occur.
  • high transmission efficiency cannot be achieved.
  • technicians use this type of electromagnetic metasurface they usually choose glass as the substrate to achieve higher transmittance, but at this time, its transmittance can only reach about 50% at most and cannot achieve higher breakthrough.
  • the present application provides a new type of antireflection coating that can not only reduce reflection and antireflection on the interface, but also regulate the wavefront of the transmitted electromagnetic wave.
  • the anti-reflection film 100 of the present application is arranged on the interface between the first medium and the second medium, wherein the first medium is the electromagnetic wave incident medium, and the second medium is the electromagnetic wave exit medium, and the electromagnetic wave incident on the first medium It is an incident electromagnetic wave, and the electromagnetic wave emitted from the second medium is a transmitted electromagnetic wave, and the dielectric constants of the first medium and the second medium are different.
  • incident electromagnetic waves will be reflected and refracted when incident on the interface, but after the anti-reflection film 100 is applied on the interface, the reflected electromagnetic wave can be effectively suppressed, and the wavefront of the transmitted electromagnetic wave can be adjusted at the same time.
  • the anti-reflection film 100 includes a plurality of control units 10, the plurality of control units 10 can be arranged on the interface, and configured to reduce the reflection of incident electromagnetic waves on the interface through resonance At the same time, the phase of the transmitted electromagnetic wave on the interface is changed, so that the transmitted electromagnetic wave has a preset phase distribution on the interface based on the arrangement sequence of the plurality of control units on the interface.
  • each control unit 10 has multiple control degrees of freedom, and then by debugging the multiple control degrees of freedom, the control unit 10 can be equipped with a set of control parameters to complete the configuration of the control unit 10 .
  • the group of control parameters includes electromagnetic parameters and/or structural parameters of the control unit 10, wherein the electromagnetic parameters may include the dielectric constant and magnetic permeability of the control unit 10, and the structural parameters may include the length, width, The height and/or the spacing between different internal material structures of the regulating unit 10 and/or the corresponding length, width, height, bending angle, etc. of each internal material structure.
  • the way of debugging multiple degrees of freedom may be to perform parameter traversal on preset formulas (such as the transmittance formula and the phase change formula at the same time), so as to select the best parameters.
  • the dielectric constant and permeability of the regulation unit 10 refer to the effective permittivity and effective permeability of the regulation unit 10 respectively, further, the effective dielectric
  • the constant and effective permeability can be obtained by the corresponding effective medium theory.
  • the permittivity and permeability referred to in this application are relative permittivity and relative permeability, and the corresponding effective permittivity and effective permeability are effective relative permittivity and effective relative permeability rate, so that technicians can calculate the control parameters corresponding to each control unit 10 conveniently.
  • the materials provided in each embodiment of the present application are all non-magnetic materials, that is, materials with a relative magnetic permeability of 1.
  • reducing the reflection of the incident electromagnetic wave on the interface in the working frequency band through resonance can be expressed as that the plurality of control units 10 make the reflected electromagnetic waves on the interface in the working frequency band interfere and cancel, and the transmitted electromagnetic waves interfere and expand, so as to achieve reduction.
  • the anti-anti-reflection effect; in addition, the preset phase distribution represents the expected phase distribution of the transmitted electromagnetic wave on the interface in order to achieve a certain transmission effect.
  • the transmitted electromagnetic wave needs to have the first phase distribution on the interface; in order to realize the negative refraction of the transmitted electromagnetic wave, it is necessary for the transmitted electromagnetic wave to have The second phase distribution; and in order to realize the convergence of the transmitted electromagnetic waves, the transmitted electromagnetic waves need to have a third phase distribution on the interface. Since the phase of the incident electromagnetic wave on the interface is fixed when the incident electromagnetic wave is incident on the interface, in order to make the transmitted electromagnetic wave have the desired phase distribution on the interface, each position on the interface needs to be introduced by the corresponding control unit corresponding phase change. It can be understood that the phase changes required to be introduced corresponding to each position on the interface may be partly the same, partly different, all the same, or all different, depending on the desired phase distribution.
  • the thickness of the anti-reflection film 100 is less than one-tenth of the wavelength of the incident electromagnetic wave in vacuum.
  • the traditional multi-layer anti-reflection film needs to meet the thickness of the anti-reflection film to be an odd multiple of a quarter of the wavelength of the electromagnetic wave in the anti-reflection film, and then it can be known that the minimum thickness of the anti-reflection film is A quarter of the wavelength of electromagnetic waves in antireflective coatings.
  • the electromagnetic parameters and/or structural parameters of the regulating unit 10 in the anti-reflection film can be configured so that the thickness of the anti-reflection film 100 is less than one-tenth of the wavelength of the incident electromagnetic wave in vacuum, so that some
  • the thickness of the anti-reflection film 100 in the embodiment can be less than a quarter of the wavelength of the electromagnetic wave in the anti-reflection film 100, so as to break through the thickness limit of the traditional multi-layer coating anti-reflection film, and provide a new thinner, capable
  • the anti-reflection film 100 realizes anti-reflection and phase regulation simultaneously.
  • the control unit 10 includes a plurality of metal pattern layers 11, arranged at intervals along the normal direction of the interface; and a spacer layer 12, arranged between adjacent metal pattern layers 11 so as to Adjacent metal pattern layers 11 are spaced apart; wherein, the control parameters of the control unit 10 include electromagnetic parameters of the metal pattern layer 11 and the spacer layer 12 , and/or structural parameters of the metal pattern layer 11 and the spacer layer 12 .
  • the control unit 10 can be configured.
  • the definitions of the electromagnetic parameters and structural parameters can refer to The foregoing expression is not repeated here.
  • the number of metal pattern layers 11 is greater than or equal to 3, which is beneficial to provide a sufficient number of degrees of freedom to complete the configuration of the control unit 10, so as to more effectively achieve the effects of anti-reflection, anti-reflection, and transmission phase control. It can be understood that, in order to avoid the adjustment unit 10 from being too thick and save adjustment time, the number of metal pattern layers 11 should not be too many, preferably less than or equal to 5, and more preferably, the number of metal pattern layers 11 is 3.
  • the metal pattern layer includes a metal wire forming a first pattern or a metal sheet forming a hollow second pattern.
  • the metal wire forming the first pattern includes a metal wire forming a Jerusalem-shaped cross pattern
  • the metal sheet formed with a hollowed-out second pattern includes a metal sheet formed with a hollowed-out Jerusalem-shaped cross pattern.
  • the use of the Jerusalem-type cross-structure metasurface is beneficial to realize the electromagnetic metasurface with phase gradient change, and also facilitates the regulation and control of the structural parameters of the control unit 10 .
  • the material of the metal wire includes at least one of copper, aluminum, silver, gold, and zinc; the material of the metal sheet includes at least one of copper, aluminum, silver, gold, and zinc. Therefore, the preparation materials of the metal wire and the metal sheet are various, which is beneficial to the preparation of the anti-reflection film 100 of the present application.
  • the material of the spacer layer 12 can be the same as that of the second medium, so that the preparation of the anti-reflection film 100 can also be facilitated.
  • the material of the metal wire and the metal sheet can also be a conductive material such as ITO (indium tin oxide), which can be selected by technicians according to the actual situation, which is not limited in this application.
  • Fig. 4 shows a group of optional structural size parameters for the plurality of control units shown in Fig. 3, and Fig. 5 correspondingly shows a plurality of control units shown in Fig. 4 when they are arranged on the interface.
  • the relative permittivity of the first medium on one side of the interface is 1, and the relative permittivity of the second medium on the other side of the interface is 4.4.
  • the thickness of the metal pattern layer 11 is 0.018mm, and there are two spacer layers 12 corresponding to a square.
  • a square The side length p is 7.73mm, and the thickness of the spacer layer is 1mm, thus the thickness of the anti-reflection film 100 of the embodiment shown in Figure 4 is 2.054mm, thus it can be seen that the thickness of the anti-reflection film 100 of the present embodiment is smaller than the incident electromagnetic wave in vacuum One-tenth of the wavelength (3mm).
  • the metal pattern layer 11 is made of copper, and the relative permittivity of the spacer layer 12 is the same as that of the second medium (relative permittivity is 4.4), so that it can operate at 9.8GHz ⁇ 10.2GHz as shown in FIG.
  • each Jerusalem-type cross pattern in the metal pattern layer 11 corresponds to three parameters of ⁇ , t , rx, wherein, ⁇ represents the line width of the Jerusalem-type cross pattern, and t represents the adjacent end of the Jerusalem-type cross pattern The width of the gap between r x represents the length of the Jerusalem-type cross pattern in the direction of the spacer layer 12x.
  • each metal pattern layer 11 shown in FIG. 4 is 1 mm, and the t is 0.8 mm.
  • the value of r x is different, and the unit of the value of r x in FIG. 4 is also mm.
  • Layer represents the metal pattern layer 11
  • Meta-atom represents the control unit 10
  • Layer1 represents the first metal pattern layer 11
  • Meta-atom1 represents the first control unit 10, and so on. It can be seen that in FIG. 5 , in the frequency range of 9.8 GHz to 10.2 GHz, each control unit 10 has a transmittance greater than 50%, and in the range of 9.92 GHz to 10.07 GHz, it has a transmittance of greater than 90% and close to 100%.
  • each control unit 10 can make corresponding phase changes occur on the interface of the transmitted electromagnetic wave respectively in the above-mentioned operating frequency band, as shown in Figure 5, the phase changes corresponding to each control unit 10 are almost equally spaced and cover 360°, thereby It is beneficial to realize the transmission effect that the propagating directions of incident electromagnetic waves and transmitted electromagnetic waves do not change.
  • the above-mentioned anti-reflection film 100 can be arranged on the interface with different dielectric constant media, and can reduce the reflection of incident electromagnetic waves on the interface in the working frequency band through the resonance of reflection, interference, destructive transmission, interference and expansion, and increase the transmission of transmitted electromagnetic waves. At the same time, it can also make the phase of the transmitted electromagnetic wave mutate on the interface, so that the transmitted electromagnetic wave has a preset phase distribution on the interface, so as to effectively regulate the wave front of the transmitted electromagnetic wave and achieve different transmission effects of the transmitted electromagnetic wave .
  • the surface of the anti-reflection film 100 includes a plane and/or a curved surface. Specifically, when the interface is a plane, at least part of the surface on the anti-reflection film 100 is a plane, so that the part of the plane fits the interface; when the interface is a curved surface, at least part of the surface on the anti-reflection film 100 is a corresponding curved surface, so that this part of the curved surface fits the interface; when the interface is an irregular surface, such as both a curved surface and a plane, then at least part of the surface on the anti-reflection film 100 is also a corresponding irregular surface, so that this part does not The ruled surface fits the interface. In this way, the anti-reflection and anti-reflection effects of the anti-reflection film 100 of the present application and the phase adjustment effect of the transmitted electromagnetic wave can be better guaranteed.
  • each regulating unit 10 has a corresponding first regulating parameter, and the plurality of regulating units 10 are configured to cause the transmitted electromagnetic wave to undergo a first phase change at the interface, so that the transmitted electromagnetic wave has a first phase change on the interface.
  • a phase distribution, the first phase distribution is configured such that the angle of refraction of the transmitted electromagnetic wave is close to or equal to the angle of incidence of the incident electromagnetic wave.
  • the angle of refraction of the transmitted electromagnetic wave is close to or equal to the angle of incidence of the incident electromagnetic wave, and the difference between the angle of refraction of the transmitted electromagnetic wave and the angle of incidence of the incident electromagnetic wave is within the range of ⁇ 10°, ⁇ 5°, or ⁇ 2°.
  • the plurality of control units 10 can deflect the propagation direction of the transmitted electromagnetic wave to the original propagation direction of the incident electromagnetic wave, and at the same time, the reflected electromagnetic wave is also suppressed, thereby It seems that the incident electromagnetic wave directly passes through this interface, which can be called "invisible interface".
  • the incident electromagnetic wave has a first equi-phase plane
  • the transmitted electromagnetic wave corresponding to the incident electromagnetic wave has a second equi-phase plane. From Huygens' principle, it can be seen that the equiphase planes represent the wavefronts of electromagnetic waves on which the phases of the electromagnetic waves are the same.
  • the first phase change satisfies the following relationship:
  • C 1 indicates the phase on the first isophase surface
  • C 2 indicates the phase on the second isophase surface
  • (C 2 -C 1 ) represents the cumulative phase difference between the first equi-phase plane and the second equi-phase plane
  • (C 2 -C 1 ) is a constant
  • ⁇ (x,y,z) represents the first phase distribution
  • x,y, z represent the three-dimensional Cartesian coordinates of any position on the interface, respectively.
  • this embodiment uses a plurality of control units 10 of the embodiment shown in Figure 4 to achieve the stealth effect of the dielectric, so that in this embodiment
  • the structural parameters (p, ⁇ , t, r x ) among the first control parameters of each control unit 10 are shown in FIG. 4 . Specifically, as shown in FIG.
  • a diamond-shaped dielectric with a flat surface is arranged in the first medium, the relative permittivity of the first medium is 1, and the relative permittivity of the rhombic dielectric (ie, the second medium) is 4.4,
  • the plane electromagnetic wave is incident on the surface of the rhombic dielectric at an angle of 45°; in addition, the serial number 1 in the figure (a) indicates Meta-atom1 (ie, the first control unit 10), and the serial number 2 indicates Meta-atom2 (ie, the second control unit 10), and so on, when each control unit 10 is arranged on the surface of the rhombic dielectric in the order shown in (a), a plurality of control units 10 can be formed on the surface of the rhombic dielectric
  • the uniform phase change of the anti-reflection coating 100 satisfies that the accumulated phase difference of the electromagnetic wave between the first equi-phase plane and the second equi-phase plane is a constant for different positions of the anti-reflection film 100, thereby realizing the
  • n t is the refractive index of the second medium
  • n i is the refractive index of the first medium
  • ⁇ i is the incident angle
  • ⁇ t is the outgoing angle
  • FIG. 7 (b) shows the numerical simulation diagram of this embodiment, it can be seen that after the plane electromagnetic wave is incident on the rhombic dielectric surface, no obvious reflection is formed on the dielectric surface, and the transmitted electromagnetic wave also maintains the flat wave of the plane electromagnetic wave front and direction of propagation.
  • Figure 7 (c) shows the schematic diagram of the field when the plane electromagnetic wave is incident on the exposed surface of the rhombic dielectric. It can be seen that the plane electromagnetic wave in the figure has obvious reflection on the dielectric surface, and the formed reflected electromagnetic wave is the same as the incident The electromagnetic wave has obvious interference, which makes the wave front of the transmitted electromagnetic wave obviously disturbed.
  • (a) to (b) of FIG. 8 simulate the dielectric cloaking effect of a curved surface.
  • a dielectric curved surface is formed by cutting a plurality of tiny planes (respectively slopes with inclination angles of 10°, 20°, and 30°).
  • the dielectric curved surface is arranged in the first medium, and the relative permittivity of the first medium is 1, the relative permittivity of the dielectric medium with a curved surface (that is, the second medium) is 12, and the plane electromagnetic wave is incident vertically downward on the curved surface.
  • Figure 8 (b) shows the numerical simulation diagram of this embodiment.
  • FIG. 8 (c) shows a schematic diagram of the field when a plane electromagnetic wave is incident on a bare dielectric surface. It can be seen that the plane electromagnetic wave in the figure has obvious reflection on the dielectric surface, and the formed reflected electromagnetic wave is the same as the incident The electromagnetic wave has obvious interference, so that the wave front of the transmitted electromagnetic wave is obviously disturbed and turned into an arc.
  • Fig. 9 and Fig. 10 have respectively shown the structural parameter schematic diagram of a plurality of regulating units on the 0° face, 10° bevel and 20° bevel, 30° bevel of the dielectric curved surface, namely Fig. 9 and Fig. 10 have shown this embodiment respectively
  • the control unit 10 has three metal pattern layers 11, the spacer layer 12 is a square and the side length p is 4.87mm, and the material of the metal pattern layer 11 is copper.
  • the relative permittivity of the spacer layer 12 is the same as that of the second medium (relative permittivity is 12) (not to be described in detail below), and each Jerusalem-type cross pattern corresponds to three parameters of ⁇ , t , rx, and the 0° plane
  • the ⁇ of each metal pattern layer above is 0.5mm, and the t is 0.5mm.
  • the values of r and x are different, and the unit of the value of r in the figure is also mm.
  • each type of control unit 10 has three metal pattern layers 11, the spacer layer 12 is rectangular and the side length p x is 7mm, p y is 4.87mm, each Jerusalem-shaped cross pattern
  • the ⁇ of each metal pattern layer on the 10° surface is 0.5mm
  • t is 0.5mm
  • the values of r x are different.
  • the value of r in the figure The units are also mm.
  • each type of control unit 10 has three metal pattern layers 11, the spacer layer 12 is rectangular and the side length p x is 5.93mm, p y is 4.87mm, each Jerusalem-shaped cross
  • the pattern corresponds to three parameters of ⁇ , t, and r x .
  • the ⁇ of each metal pattern layer on the 20° surface is 0.5mm
  • t is 0.5mm
  • the values of r x are different.
  • the r x in the figure The units of values are also mm.
  • each type of control unit 10 has three metal pattern layers 11, the spacer layer 12 is a square and the side length p is 4.87mm, and each Jerusalem-shaped cross pattern has ⁇ ,t, r x three parameters, the ⁇ of each metal pattern layer on the 30° surface is 0.5mm, t is 0.5mm, the value of r x is different, and the unit of the value of r x in the figure is also mm.
  • each regulating unit 10 has a corresponding second regulating parameter, and the plurality of regulating units 10 are configured to cause the transmitted electromagnetic wave to undergo a second phase change at the interface, so that the transmitted electromagnetic wave has a second phase change on the interface.
  • Two phase distributions, the second phase distribution is configured to cause the transmitted electromagnetic waves to form negative refraction.
  • the negative refraction means that the refraction angle of the transmitted electromagnetic wave and the incident angle of the incident electromagnetic wave are located on the same side of the normal line of the interface.
  • FIG. 11 multiple regulation units 10 of the embodiment shown in FIG. 4
  • the structural parameters (p, ⁇ , t, r x ) of the second control parameter of the control unit 10 can likewise be shown in FIG. 4 .
  • a dielectric with a flat surface is arranged in the first medium, the relative permittivity of the first medium is 1, and the relative permittivity of the dielectric (i.e.
  • the second medium is 4.4, and the plane electromagnetic wave Normal incidence to the surface of the dielectric; when each control unit 10 is arranged on the surface of the dielectric in the order shown in (a), a plurality of control units 10 can be formed on a straight dielectric surface
  • the reverse uniform phase change realizes the negative refraction effect of the transmitted electromagnetic wave.
  • ⁇ t -1.89°, that is, the refraction angle of the transmitted electromagnetic wave is negative, and it can be seen that the incident angle of the incident electromagnetic wave is located on the same side as the normal line of the interface, which quantitatively proves the wavefront control effect of the application on the transmitted electromagnetic wave .
  • Fig. 11 (b) shows the numerical simulation diagram of this embodiment. It can be seen that after the plane electromagnetic wave is incident on the flat dielectric surface, no obvious reflection is formed on the dielectric surface, and the transmitted electromagnetic wave has obvious negative refraction.
  • Figure 11(c) shows a schematic diagram of the field when the plane electromagnetic wave is incident on the bare surface of the flat dielectric. It can be seen that the plane electromagnetic wave in the figure has obvious reflection on the dielectric surface, and the formed reflected electromagnetic wave is the same as The incident electromagnetic wave has obvious interference, and the transmitted electromagnetic wave has the traditional refraction effect.
  • each regulating unit 10 has a corresponding third regulating parameter, and the plurality of regulating units 10 are configured to cause the transmitted electromagnetic wave to undergo a third phase change at the interface, so that the transmitted electromagnetic wave has a third phase change on the interface.
  • the third phase distribution is configured to converge the transmitted electromagnetic waves.
  • the third phase change satisfies the following relationship: in, Represents the third phase change, ⁇ (x,y) represents the third phase distribution, Indicates the phase distribution of the incident electromagnetic wave on the interface, ⁇ indicates the wavelength of the incident electromagnetic wave, x and y respectively indicate the horizontal and vertical coordinates of any position on the interface, and f indicates the focal length when the transmitted electromagnetic wave forms a convergence; or, in, Represents the third phase change, ⁇ (x) represents the third phase distribution, Indicates the phase distribution of the incident electromagnetic wave on the interface, ⁇ indicates the wavelength of the incident electromagnetic wave, x indicates the abscissa of any position on the interface, x 0 indicates the abscissa of the third phase distribution boundary point, and q indicates that the transmitted electromagnetic wave occurs on the interface The slope of the phase change.
  • Figure 12 to Figure 13 are designed for The antireflection film 100 with such a phase distribution.
  • a dielectric with a flat surface is disposed in the first medium, the relative permittivity of the first medium is 1, and the relative dielectric constant of the dielectric (ie, the second medium)
  • the dielectric constant is 4.4, and the electromagnetic wave is incident on the surface of the dielectric; when each control unit 10 is arranged on the surface of the dielectric in the order shown in (a), a plurality of control units 10 can form an axicon equivalent to an axicon on the flat dielectric surface.
  • the phase distribution of the phase so that the transmitted electromagnetic wave passing through the interface can be converged on the transmission side, and a Bessel-like distribution can be formed in the converging area.
  • Figures (b) and (c) of Figure 12 respectively show the numerical simulation diagrams of this embodiment, it can be seen that after the electromagnetic waves of TE polarization and TM polarization are incident on the flat dielectric surface, the dielectric surface is uniform There is no obvious reflection, but the transmitted electromagnetic wave has obvious convergence effect.
  • the black solid line in the figure indicates the intensity distribution of the lowermost area in the figure. It can be seen that this intensity distribution is similar to the Bessel distribution.
  • FIG. 13 shows a schematic diagram of structural parameters of a plurality of control units 10 on a flat dielectric surface in this embodiment, so that the structural parameters (p, ⁇ , t) of the third control parameters of each control unit 10 in this embodiment are , r x ) is shown in Fig. 13 .
  • control unit 10 there are 5 types of control units 10 on the surface, the control unit 10 has three metal pattern layers 11, the spacer layer 12 is a square and the side length p is 7.7mm, the material of the metal pattern layer 11 is copper, and the spacer layer
  • the relative permittivity of 12 is the same as that of the second medium (relative permittivity is 4.4), and each Jerusalem-type cross pattern corresponds to three parameters of ⁇ , t, r x , and the ⁇ of each metal pattern layer on the surface is uniform. is 0.8mm, t is 0.8mm, and the value of r x is different, and the unit of the value of r x in the figure is also mm.
  • the present application also provides an electromagnetic wave transmission structure, including: a first medium, the first medium is the electromagnetic wave incident medium, and the electromagnetic wave incident on the first medium is the incident electromagnetic wave; the second medium, the second medium is the electromagnetic wave exit medium, The electromagnetic waves emitted by the medium are transmitted electromagnetic waves, and the dielectric constants of the first medium and the second medium are different;
  • Each control unit has corresponding control parameters, so that multiple control units can reduce the reflection of the incident electromagnetic wave on the interface through resonance, and make the phase change of the transmitted electromagnetic wave on the interface, so that the transmitted electromagnetic wave has a Preset phase distribution.
  • the above-mentioned electromagnetic wave transmission structure is provided with the above-mentioned anti-reflection film at the interface of two different media, so that in the electromagnetic wave transmission structure, the reflection of the incident electromagnetic wave on the interface in the working frequency band is reduced, and the phase of the transmitted electromagnetic wave is also reduced. A sudden change will occur on the interface, so that the transmitted electromagnetic wave has a preset phase distribution on the interface, thereby effectively regulating the wavefront of the transmitted electromagnetic wave in the electromagnetic wave transmission structure.
  • the ratio m of the dielectric constant of the second medium to that of the first medium satisfies
  • m can be 1/12, 1/5, 1/4, 1/2, 2, 4, 5, 12.
  • the ratio m of the dielectric constant of the second medium to the dielectric constant of the first medium is 4.4 /1, and when the electromagnetic wave is incident from the second medium back to the first medium, the ratio of m is 1/4.4; similarly, in Figure 8, when the electromagnetic wave first enters the second medium from the first medium, the medium of the second medium
  • the ratio m of the electrical constant to the dielectric constant of the first medium is 12/1, and when the electromagnetic wave is incident from the second medium back to the first medium, the ratio m is 1/12.
  • the present application also provides a method for preparing an anti-reflection film, wherein the preparation method includes:
  • the ratio m of the dielectric constant of the second medium to the dielectric constant of the first medium can satisfy
  • the expected transmittance and the expected phase change adjust the electromagnetic parameters and/or structural parameters of the materials in each control unit, so that multiple control units can reduce the reflection of incident electromagnetic waves on the interface through resonance and have the desired transmission. rate, and the desired phase change of the transmitted electromagnetic wave at the interface, so that the transmitted electromagnetic wave has a desired phase distribution on the interface.
  • the magnetic parameters may include the dielectric constant and permeability of the control unit
  • the structural parameters may include the length, width, height of the control unit, or the distance between different internal structures of the control unit and the shape of a certain internal structure , length, width, height, etc.
  • the above preparation method can adjust the electromagnetic parameters and/or structural parameters of each material in the control unit according to the expected transmittance of the incident electromagnetic wave and the expected phase distribution of the transmitted electromagnetic wave on the interface, and apply the plurality of control units 10 to The interface forms an anti-reflection film with a phase control function.
  • the desired transmittance is greater than or equal to 50%. In another embodiment, the desired transmission is greater than or equal to 90%. In this way, the incident electromagnetic wave can be transmitted efficiently, thereby further optimizing the transmission effect of the transmitted electromagnetic wave.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)

Abstract

La présente demande concerne un film antireflet, une structure de transmission d'ondes électromagnétiques et un procédé de préparation d'un film antireflet. Le film antireflet est disposé sur une surface limite d'un premier diélectrique et d'un second diélectrique, le premier diélectrique étant un milieu incident d'onde électromagnétique, le second diélectrique est un milieu émetteur d'ondes électromagnétiques, une onde électromagnétique incidente sur le premier diélectrique étant une onde électromagnétique incidente, une onde électromagnétique émise par le second diélectrique étant une onde électromagnétique transmise, et le premier diélectrique et le second diélectrique présentant des constantes diélectriques différentes. Le film antireflet comprend : une pluralité d'unités de régulation et de commande agencées sur la surface limite, chaque unité de régulation et de commande présentant un paramètre de régulation et de commande correspondant, de sorte que la pluralité d'unités de régulation et de commande réduit la réflexion de l'onde électromagnétique incidente sur la surface limite par résonance, un changement de phase se produit sur l'onde électromagnétique transmise sur la surface limite, et ainsi l'onde électromagnétique transmise présente une distribution de phase prédéfinie sur la surface limite. Le film antireflet peut réguler et commander un front d'onde de l'onde électromagnétique transmise tout en mettant en œuvre un antireflet, ce qui permet d'obtenir différents effets de transmission.
PCT/CN2021/105542 2021-07-09 2021-07-09 Film antireflet, structure de transmission d'ondes électromagnétiques et procédé de préparation pour film antireflet WO2023279384A1 (fr)

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CN103268985A (zh) * 2013-04-24 2013-08-28 同济大学 一种电磁波波束调控装置
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CN103268985A (zh) * 2013-04-24 2013-08-28 同济大学 一种电磁波波束调控装置
CN211507911U (zh) * 2020-04-09 2020-09-15 上海府大科技有限公司 Ku波段超周期元胞及全相位覆盖波束偏折器

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