Multifunctional holographic tunable metamaterial structure

Abstract

The application provides a multifunctional holographic adjustable metamaterial structure, and belongs to the technical field of metasurfaces, and comprises: a plurality of cavity units arranged in a honeycomb cavity structure in a periodic and close arrangement mode, the cavity units are made of polylactic acid material, the structural characteristic scale of the cavity units is in the same order of magnitude as that of sound waves and electromagnetic waves, each cavity unit comprises a regular hexagonal dielectric substrate and a side wall vertically arranged on each side of the regular hexagonal dielectric substrate, the side wall and the regular hexagonal dielectric substrate form a gradually changing impedance transition, all the side walls enclose a cavity, a partition unit extends from each side wall to the center of the cavity, all the partition units divide the cavity into six sub-cavities, and the six sub-cavities form a resonance mode; and the multifunctional holographic adjustable metamaterial structure has the characteristics of electromagnetic wave absorption, sound wave absorption and light weight and high strength.

Description

Technical Field

[0001] This invention relates to the field of metasurface technology, and more particularly to multifunctional holographic tunable metamaterial structures. Background Technology

[0002] Metasurfaces are two-dimensional metamaterials that replace the three-dimensional subwavelength units in metamaterials with two-dimensional subwavelength units. Their manipulation of electromagnetic waves does not rely on the accumulation of optical path during propagation, but rather on the precise modulation of the amplitude, phase, and polarization of electromagnetic waves through changes in parameters such as the size and shape of the two-dimensional units. Compared to metamaterials, metasurfaces are more compact, have lower losses, and are easier to fabricate, offering significant advantages in holographic imaging and thus attracting widespread attention from the academic community.

[0003] With the rapid development of modern electronic technology, electromagnetic pollution has become increasingly prominent, posing a serious threat to human health and the normal operation of precision electronic equipment. Traditional electromagnetic wave absorbing materials, such as ferrites, carbon-based materials, and ceramics, have significant drawbacks in application: their high density limits their use in aerospace, while their poor corrosion resistance affects their environmental adaptability. Current materials science research is rapidly developing from single-function to multi-functional integration. Taking aerospace as an example, aircraft skin materials need to simultaneously meet multiple requirements, including stealth (including infrared and radar stealth), structural support, sound insulation, and heat insulation. Traditional single-function material systems are insufficient to meet these complex application needs.

[0004] In the prior art, Chinese invention patent application CN120321935A, entitled "A Three-Dimensional Structure Wave-Absorbing Metamaterial," provides a three-dimensional structure wave-absorbing metamaterial that can achieve ultra-wideband absorption and large-angle stability at a relatively thin thickness. This three-dimensional structure wave-absorbing metamaterial only absorbs electromagnetic waves. Because this structure lacks an absorption modulation structure for acoustic vibrations, it does not have the function of absorbing sound waves, resulting in significant limitations in its functional implementation. Summary of the Invention

[0005] The purpose of this invention is to provide a metamaterial structure that combines electromagnetic wave absorption, sound wave absorption, and lightweight and high strength properties.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution: a multifunctional holographic tunable metamaterial structure, comprising: multiple periodically and closely arranged cavity units in a honeycomb cavity structure, the cavity units being made of polylactic acid material, the structural feature scale of the cavity units being on the same order of magnitude as the wavelength of sound waves and the wavelength of electromagnetic waves, each cavity unit including a regular hexagonal dielectric substrate and sidewalls perpendicularly disposed on each side of the regular hexagonal dielectric substrate, the sidewalls forming a gradually changing impedance transition with the regular hexagonal dielectric substrate, all sidewalls enclosing to form a cavity, and a partition unit extending from each sidewall to the center of the cavity, all partition units dividing the cavity into six sub-cavities, the six sub-cavities forming a resonant mode.

[0007] Beneficial Effects: The multifunctional holographic tunable metamaterial structure of this invention breaks through the limitations of traditional metamaterials with single functions through integrated material-structure-function design. In acoustics, when sound waves enter the structure, the cavity structure generates echo-like sound waves to cancel the incoming sound waves, thus achieving sound wave absorption. Since heat is generated during sound wave absorption, multiple cavity units can generate appropriate turbulence to improve heat transfer efficiency in the thermal field. The structure is made of polylactic acid, ensuring the overall structure remains ultra-lightweight. In electromagnetism, electromagnetic waves pass through the polylactic acid unit structure, where the dielectric constants of the internal air and the material differ, altering the propagation of the electromagnetic waves. Each side of the regular hexagonal dielectric substrate is vertically connected to a sidewall, enhancing the overall structural strength. The structural feature dimensions of the cavity units are on the same order of magnitude as the wavelengths of sound and electromagnetic waves, exhibiting good sound absorption coefficients in the 30kHz-300kHz frequency band and good electromagnetic wave absorption efficiency in the Ka band.

[0008] Preferably, the dielectric constant of the air inside the cavity is different from that of the cavity unit, so that the propagation direction of the electromagnetic wave will change when it passes through the cavity unit.

[0009] Preferably, the sound wave enters the cavity and generates an echo-like sound wave inside the cavity to cancel out the incoming sound wave, thus forming sound wave absorption.

[0010] Preferably, a circular hole is formed in the center of the regular hexagonal dielectric substrate, and the dividing unit includes dividing branches. Two dividing branches extend from each sidewall to the outer edge of the circular hole. The dividing branches include a first branch to a seventh branch connected vertically in sequence. The end of the first branch is vertically connected to the sidewall, and the end of the seventh branch is connected to an arc-shaped eighth branch.

[0011] Beneficial effects: After the overall structure of the present invention absorbs sound waves and electromagnetic waves, the absorbed waves will be converted into heat energy inside the structure, causing the temperature of the overall structure to rise. At this time, the temperature of the air medium in each sub-cavity rises, while the temperature inside the circular hole is relatively low. A convection circulation will be formed between the sub-cavities and the circular holes to achieve heat dissipation. The present invention can realize a double-layer air free convection heat exchange mechanism structure with a through ventilation channel in the middle.

[0012] Preferably, the temperature rises after the structure absorbs electromagnetic waves and sound waves, the temperature of the air medium in each sub-cavity rises, the temperature inside the circular hole is lower than the temperature inside the sub-cavity, and a convection circulation is formed between the sub-cavity and the circular hole.

[0013] Preferably, the honeycomb cavity structure is a multi-layer structure, which includes multiple honeycomb units, and each honeycomb unit includes multiple cavity units arranged in layers.

[0014] Preferably, the radius of the circular hole ranges from 0.5mm to 1.1mm; the length of the first branch ranges from 0.2mm to 0.4mm, the length of the second branch ranges from 0.8mm to 1.2mm, the length of the third branch ranges from 0.2mm to 0.4mm, the length of the fourth branch ranges from 0.5mm to 0.9mm, the length of the fifth branch ranges from 0.2mm to 0.4mm, the length of the sixth branch ranges from 0.5mm to 0.9mm, the length of the seventh branch ranges from 0.2mm to 0.6mm, and the arc angle of the eighth branch is 40 degrees.

[0015] Beneficial effects: To optimize heat dissipation efficiency, the lengths of the second, fourth, and sixth branches decrease sequentially, forming an inverted triangular structure. The main advantage of this design is that when airflow passes through the central opening, the inverted triangular structure allows for a smaller cross-sectional area at the opening, thereby enhancing the internal and external pressure difference effect of the gas flow. This mechanism not only improves the gas flow efficiency but also more effectively removes heat, significantly improving the system's heat dissipation performance.

[0016] Preferably, there is a gap between adjacent sidewalls; the partition unit includes a circular column and a first connecting arm located between the sidewall and the circular column, a second connecting arm located between the circular column and the central axis of the overall structure, and a regular hexagonal cover plate is provided above the cavity.

[0017] Beneficial effects: After the overall structure of the present invention absorbs sound waves and electromagnetic waves, the absorbed waves will be converted into heat energy inside the structure, causing the temperature of the overall structure to rise. At this time, the temperature of the air medium in each sub-cavity rises, and the heat can be dissipated through the gap between adjacent sidewalls.

[0018] Preferably, the outer radius of the annular column ranges from 1.2mm to 1.8mm, and the inner radius of the annular column ranges from 0.3mm to 0.7mm; the length of the first connecting arm ranges from 2.5mm to 3.5mm, the length of the second connecting arm ranges from 2.5mm to 3.5mm, the width of the first or second connecting arm ranges from 0.3mm to 0.7mm, and the length of the sidewall in the direction perpendicular to the length direction of the first connecting arm ranges from 8mm to 12mm.

[0019] Preferably, the distance from each vertex of the regular hexagonal dielectric substrate to its center ranges from 2.5 mm to 3.5 mm; the thickness of the sidewalls ranges from 0.1 mm to 0.3 mm.

[0020] Beneficial effects: The smaller extension thickness of the sidewalls enables a more gradual impedance transition between the trapezoidal sidewalls and the regular hexagonal dielectric substrate, thereby effectively suppressing field reflection at the edge of the regular hexagonal dielectric substrate and significantly reducing the transmission loss of the structure. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] Figure 1 This is a schematic diagram of the multifunctional holographic tunable metamaterial structure provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the hollow unit in the multifunctional holographic tunable metamaterial structure provided in Embodiment 1 of the present invention; Figure 3 This is a top view of the hollow unit in the multifunctional holographic adjustable metamaterial structure provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram showing the dimensions of the partition unit in the multifunctional holographic adjustable metamaterial structure provided in Embodiment 1 of the present invention; Figure 5 This is a perspective view of the two-layer cavity unit in the multifunctional holographic tunable metamaterial structure provided in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the multifunctional holographic tunable metamaterial structure provided in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the hollow unit in the multifunctional holographic tunable metamaterial structure provided in Embodiment 2 of the present invention; Figure 8 This is a perspective view of the hollow unit in the multifunctional holographic tunable metamaterial structure provided in Embodiment 2 of the present invention; Figure 9This is a top view of the hollow unit in the multifunctional holographic adjustable metamaterial structure provided in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram showing the dimensions of the partition unit in the multifunctional holographic tunable metamaterial structure provided in Embodiment 2 of the present invention; In the figure: 10 cavity unit, 11 regular hexagonal dielectric substrate, 110 circular hole, 12 sidewall, 13 cavity, 131 first sub-cavity, 132 second sub-cavity, 133 third sub-cavity, 20 partition unit, 21 partition branch, 211 first branch, 212 second branch, 213 third branch, 214 fourth branch, 215 fifth branch, 216 sixth branch, 217 seventh branch, 218 eighth branch, 22 first connecting arm, 23 circular column, 24 second connecting arm, 30 regular hexagonal cover plate.

[0023] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] Example 1 like Figure 1 As shown, this embodiment provides a multifunctional holographic tunable metamaterial structure, including: multiple periodically and tightly arranged cavity units 10 in a honeycomb-like cavity structure. The cavity units 10 are made of polylactic acid material. The structural feature scales of the cavity units 10 are on the same order of magnitude as the wavelengths of sound waves and electromagnetic waves, respectively. See [link to documentation]. Figures 2 to 5 Each cavity unit 10 includes a regular hexagonal dielectric substrate 11 and sidewalls 12 perpendicularly disposed on each side of the regular hexagonal dielectric substrate 11. The sidewalls 12 form a gradually changing impedance transition with the regular hexagonal dielectric substrate 11. All sidewalls 12 enclose a cavity 13. A partition unit 20 extends from each sidewall 12 toward the center of the cavity 13, and all partition units 20 divide the cavity 13 into six sub-cavities. The six sub-cavities form a resonant mode. In this embodiment, the cavity 13 includes three first sub-cavities 131 and three second sub-cavities 132, which are arranged sequentially at intervals.

[0026] The honeycomb cavity structure is a multi-layered structure, comprising multiple honeycomb units, each of which includes multiple cavity units arranged in a stacked manner. In this embodiment, the honeycomb cavity structure is a two-layered structure, comprising two honeycomb units, each of which includes two cavity units arranged in a stacked manner.

[0027] See Figure 4 A circular hole 110 is formed in the center of a regular hexagonal dielectric substrate 11. The partition unit 20 includes partition branches 21, with two partition branches 21 extending from each sidewall outwards from the edge of the circular hole. The partition branches 21 include a first branch 211, a second branch 212, a third branch 213, a fourth branch 214, a fifth branch 215, a sixth branch 216, a seventh branch 217, and an eighth branch 218. The first branch 211 to the seventh branch 217 are connected vertically in sequence. One end of the first branch 211 is vertically connected to the sidewall 12. The other end of 11 is vertically connected to one end of the second branch 212. The other end of the second branch 212 is vertically connected to one end of the third branch 213. The other end of the third branch 213 is vertically connected to one end of the fourth branch 214. The other end of the fourth branch 214 is vertically connected to one end of the fifth branch 215. The other end of the fifth branch 215 is vertically connected to one end of the sixth branch 216. The other end of the sixth branch 216 is vertically connected to one end of the seventh branch 217. The other end of the seventh branch 217 is connected to the arc-shaped eighth branch 218.

[0028] See also Figure 4 The radius of the circular hole 110 ranges from 0.5mm to 1.1mm. After rigorous optimization calculations and electromagnetic simulation verification, the length L1 of the first branch 211 extending along the positive Y-axis ranges from 0.2mm to 0.4mm, with the optimal parameter selected as 0.3mm. The length L2 of the second branch 212 extending along the negative X-axis ranges from 0.8mm to 1.2mm, with the optimal parameter selected as 1mm. The length L3 of the third branch 213 extending along the positive Y-axis ranges from 0.2mm to 0.4mm, with the optimal parameter selected as 0.3mm. The fourth branch 214 extending along the positive X-axis... The length L4 extending in the first direction ranges from 0.5mm to 0.9mm, and the optimal parameter is selected as 0.7mm after optimization; the length L5 extending along the positive Y-axis of the fifth branch 215 ranges from 0.2mm to 0.4mm, and the optimal parameter is selected as 0.3mm after optimization; the length L6 extending along the negative X-axis of the sixth branch 216 ranges from 0.5mm to 0.9mm, and the optimal parameter is selected as 0.7mm after optimization; the length L7 extending along the positive Y-axis of the seventh branch 217 ranges from 0.2mm to 0.6mm, and the optimal parameter is selected as 0.4mm after optimization; the arc angle of the eighth branch 218... θThe arc is 40 degrees, and it is formed by scanning around the Z-axis, which is perpendicular to the Z-axis. Figure 4 The X-axis and Y-axis in the diagram.

[0029] The regular hexagonal dielectric substrate 11 has a side length of 3 mm and a thickness of 0.1 mm. The regular hexagonal dielectric substrate 11 adopts a regular hexagonal base structure with good symmetry. The key geometric parameters of this structure have been rigorously optimized and verified by electromagnetic simulation: the distance from each vertex of the regular hexagonal dielectric substrate 11 to its center ranges from 2.5 mm to 3.5 mm. Through optimization analysis, the optimal value was finally determined to be 3 mm; the radius of the circular hole 110 ranges from 0.5 mm to 1.1 mm. Through optimization analysis, the optimal value was finally determined to be 0.8 mm.

[0030] The sidewall 12 has a height of 2 mm and a thickness d ranging from 0.1 mm to 0.3 mm. The sidewall extends inward along the edge of the regular hexagonal dielectric substrate 11 at a precise 0-degree angle. The extension thickness d, as one of the most sensitive structural parameters affecting electromagnetic properties, was found to exhibit optimal electromagnetic control performance in the Ka band (center wavelength 10 mm, corresponding to a frequency of 30 GHz) after a systematic parameter scan ranging from 0.1 mm to 0.3 mm. This optimization result can be attributed to the fact that a smaller extension thickness allows for a more gradual impedance transition between the sidewall 12 and the regular hexagonal dielectric substrate 11, effectively suppressing field reflection at the substrate edge and significantly reducing system transmission loss.

[0031] The multifunctional holographic tunable metamaterial structure provided in this embodiment adopts the form of rotationally symmetric extended dielectric walls (segmentation units 20 extending from sidewall 12), which orderly divide a complete cavity into six sub-cavities to form a stable resonant mode. In electromagnetism, electromagnetic waves pass through the unit structure of polylactic acid material, where the different dielectric constants of the internal air and the material change the propagation of electromagnetic waves. In acoustics, sound waves entering the structure are canceled out by the cavity structure, which generates sound waves similar to echoes, thus forming sound wave absorption and achieving adjustment of the sound frequency and electromagnetic field distribution. The structure is constructed using a bio-inspired mechanical metamaterial framework made of polylactic acid material with a dielectric constant of 2.5 (the structure is designed as a hexagonal honeycomb arrangement similar to a beehive, which provides excellent mechanical stability in nature, and the multi-cavity coupling design simulates the acoustic resonant cavity of some insects). This material features an innovative three-dimensional, multi-layered, periodic honeycomb cavity structure. Each cavity unit comprises a regular hexagonal dielectric substrate and sidewalls. The hexagonal dielectric substrate consists of a 3mm side length and 0.1mm thick regular hexagonal base platform, with a 0.8mm diameter through-hole at the center of the platform. The cavity is precisely divided into six sub-cavities through six 2mm high sidewalls and specifically designed dividing branches, forming a microstructure with electromagnetic control properties. This structure is fabricated using precision injection molding, achieving a good balance of mechanical and dielectric properties through strict control of molecular chain orientation and crystal distribution. Figure 1 The overall array is arranged in a 10×7 compact array. Through optimized geometric parameters, it achieves synergistic mechanical and electromagnetic effects, mainly targeting the 28-32GHz millimeter wave band for effective control. At the same time, it maintains excellent lightweight and high-strength characteristics and environmental stability. Furthermore, it can meet different application requirements by adjusting the unit size and arrangement.

[0032] Working principle: This invention achieves intelligent control of multiple physical fields through innovative multi-layer cavity design and material walls with special morphology (branches extending from the outer wall into the interior). It adopts a multi-chamber, multi-layer pure dielectric adjustable metamaterial structure. The adjustment of the cavity structure can affect the sound wave of ultrasound, the field distribution of electromagnetic fields, and the temperature in thermodynamics. Different material structures affect the force and tensile strength in mechanics.

[0033] In the field of thermal engineering, multiple cavity structures can generate appropriate turbulence to improve heat transfer efficiency. In electromagnetics, the propagation of electromagnetic waves is altered by the difference in dielectric constant between the internal air and the material itself, which occurs through a polylactic acid (PLA) unit structure. This invention employs a multi-cavity synergistic resonance mechanism to construct a multiple Helmholtz resonant cavity system, achieving highly efficient absorption of sound waves. In acoustics, sound waves entering a structure are absorbed due to echo-like sound wave cancellation generated by the cavity structure, a process that generates heat.

[0034] In acoustics, the wavelength of a sound wave With frequency and speed of sound The relationship is determined by the following formula:

[0035] The material's acoustic transmission properties exhibit a significant metamaterial modulation effect, with a sound velocity of approximately 370 m / s, achieving effective ultrasonic modulation at a frequency of approximately 37 kHz. This specific frequency band allows for precise matching of the ultrasonic wavelength to a size of approximately 10 mm, a wavelength that highly matches the dimensions of the material's periodic microstructure features (the structural feature size of each cavity unit matches the acoustic wavelength). Experimental tests show that when the acoustic wavelength and the material's structural feature size are on the same order of magnitude (i.e.,...), the material exhibits significant metamaterial modulation effects. This will induce a significant Bragg scattering effect, while simultaneously exciting complex local resonant modes within the cavity array. This wavelength-structure matching mechanism enables the material to exhibit excellent acoustic modulation performance in the target frequency band, including directional acoustic wave guidance and acoustic energy localization enhancement. Furthermore, the acoustic impedance gradient generated by the honeycomb porous structure of the material further optimizes the energy coupling efficiency of sound waves propagating within it, thus achieving efficient modulation of ultrasound in the 37kHz frequency band while maintaining a lightweight structure. When a sound wave of a specific frequency passes through the resonant cavity, the cavity structure achieves efficient energy dissipation and attenuation of the target frequency sound wave through a multi-physics coupling mechanism. Its core technical principle lies in the impedance mismatch formed at the branch structure of the precisely tuned Helmholtz resonant cavity, converting acoustic energy into heat energy through the viscous friction loss of air molecules at the neck; simultaneously, the multi-mode resonance within the cavity produces an interference destructive effect, further attenuating the sound wave energy in the specific frequency band.

[0036] In electromagnetism, this material exhibits significant electromagnetic wave modulation characteristics at a wavelength of 10 mm (corresponding to a frequency of approximately 30 GHz). At this wavelength, the phase propagation speed of the electromagnetic wave approaches the speed of light in a vacuum (c ≈ 3 × 10⁻⁶). 8 This specific wavelength precisely matches the characteristic dimensions of the material's periodic microstructure. When the electromagnetic wave wavelength and the structural unit size are both on the order of 10 mm, a unique metamaterial response mechanism is excited. Through a carefully designed hexagonal cavity array, this can be achieved at the subwavelength scale (m / s). This allows for the artificial manipulation of electromagnetic wave absorption (on a scale of [number]). This precise wavelength-structure matching not only maximizes the near-field coupling effect between units but also proposes the possibility of wavefront shaping of electromagnetic waves through gradient refractive index distribution.

[0037] In the field of thermal engineering, this invention proposes a highly efficient heat dissipation mechanism based on the synergistic effect of a porous cavity structure and a central through-hole. The core innovation of this heat dissipation system lies in its intelligent control of the heat transfer path through a specially designed geometric structure. The entire system employs a composite architecture combining a peripheral porous resonant cavity and a central axial through-hole; this unique spatial arrangement exhibits significant advantages in thermal performance. When the system is heated, the air medium within the porous cavity naturally forms a temperature gradient, thereby inducing stable convection circulation. Simultaneously, the central through-hole creates a low-pressure zone due to hydrodynamic effects, which not only accelerates airflow but also promotes the effective stripping and renewal of the thermal boundary layer.

[0038] The key to this design lies in the ingenious utilization of the confinement effect of porous media and the fluid dynamics of open channels, enabling the system to simultaneously leverage the combined advantages of conductive and convective heat dissipation. The peripheral porous structure not only increases the heat exchange area but also guides the orderly transfer of heat through precisely designed channels; while the central through-hole further enhances the active heat dissipation effect of airflow. More importantly, because different temperatures lead to different pressures, a large internal and external temperature difference results in a large pressure difference and improved heat dissipation efficiency, while a small temperature difference results in a small pressure difference and slightly lower efficiency. Therefore, this system relies entirely on its physical structure for heat regulation, automatically adjusting its heat dissipation efficiency based on temperature changes without external driving force. This adaptive heat flow management approach makes this technology widely applicable in various fields such as electronic device heat dissipation, building energy conservation, and industrial thermal management.

[0039] In the field of electromagnetic wave manipulation, this invention can achieve phase control and amplitude modulation of electromagnetic waves. This manipulation method not only expands the application range of traditional electromagnetic wave manipulation, but also shows unique advantages in the field of holographic imaging.

[0040] Example 2 The difference between this embodiment and Embodiment 1 is as follows: See Figure 6 In the multifunctional holographic tunable metamaterial structure provided in this embodiment, the honeycomb cavity structure includes multiple honeycomb units, and each honeycomb unit includes a cavity unit. The structures of the separating units are different, and a dielectric substrate is also disposed above the cavity unit. The dielectric substrate is a regular hexagon. The structure is described in detail below: See Figures 7 to 9 There is a gap between adjacent sidewalls 12; the partition unit includes a circular column 23 and a first connecting arm 22 located between the sidewall and the circular column, and a second connecting arm 24 located between the circular column 23 and the central axis of the overall structure. A regular hexagonal cover plate 30 is provided above the cavity. In this embodiment, the partition unit 20 evenly divides the cavity into six sub-cavities of the same size, that is, the cavity 13 in this embodiment includes six third sub-cavities 133.

[0041] See Figure 10 The geometric parameters of the structure underwent rigorous optimization calculations and electromagnetic simulation verification. The straight-line distance from the center of the circular ring cylinder 23 to the central axis of the overall structure ranged from 16.75mm to 20.75mm, and the optimal parameter was selected as 18.75mm. The outer radius R1 of the circular ring cylinder 23 ranged from 1.2mm to 1.8mm, and the optimal parameter was selected as 1.5mm; the inner radius R2 of the circular ring cylinder ranged from 0.3mm to 0.7mm, and the optimal parameter was selected as 0.5mm. Figure 10 Taking a dividing unit as an example, the length b1 of the first connecting arm 22 extending along the positive Y-axis ranges from 2.5mm to 3.5mm, and the optimal parameter is selected as 3mm after optimization. The length b2 of the second connecting arm 24 extending along the positive X-axis ranges from 2.5mm to 3.5mm. The width a of the first connecting arm 22 or the second connecting arm 24 ranges from 0.3mm to 0.7mm, and the optimal parameter is selected as 0.5mm after optimization. In the direction perpendicular to the length direction of the first connecting arm 22 (i.e., the X-axis direction), the length b3 of the sidewall ranges from 8mm to 12mm, and the optimal parameter is selected as 10mm after optimization.

[0042] In this embodiment, the distance from each vertex of the regular hexagonal dielectric substrate 11 to its center ranges from 2.5 mm to 3.5 mm; the thickness of the sidewalls ranges from 0.1 mm to 0.3 mm (the optimal parameter is 0.2 mm).

[0043] This embodiment of the multifunctional holographic tunable metamaterial structure achieves adjustment of the acoustic and electromagnetic field distribution through the interplay of rotationally symmetrical cuboids and annular walls. The cuboid sidewalls provide structural support, ensuring the material's mechanical stability; the annular cylinders, through their annular cavity structure, regulate the electromagnetic field distribution, forming specific resonant modes. These two different structures achieve synergistic enhancement of mechanical load-bearing capacity and electromagnetic functionality through optimized spatial arrangement. This modular design also allows for dynamic control of the material's electromagnetic response characteristics by adjusting the unit size, arrangement, and proportions.

[0044] Working principle: The dielectric plate is composed of dielectric materials of different shapes. By changing the shape, resonance is formed, thereby affecting the sound wave of ultrasound, the electromagnetic field distribution, and the temperature in thermodynamics. The different material structures affect the force and tensile strength in mechanics.

[0045] This structure is an electromagnetically modulated functional material based on the chiral structure of polylactic acid (PLA). It is a bio-inspired chiral mechanical metamaterial framework composed of PLA with a dielectric constant of 2.5, consisting of a combination of conventional cuboids and toroidal cylinders. The cuboid units provide basic support as the main load-bearing components, while the toroidal cylinder units serve as functional connection nodes, and their annular cavity structure can induce specific electromagnetic field distribution patterns. This modular design not only simplifies the manufacturing process but also enables intelligent control of the material's macroscopic properties by adjusting the arrangement of the basic units. All structural units are made from L-type PLA raw materials with strictly controlled molecular weight distribution, and optimized injection molding process parameters ensure isotropic dielectric properties and stable mechanical characteristics.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multifunctional holographic tunable metamaterial structure, characterized by: include: Multiple periodically and closely arranged cavity units form a honeycomb-like cavity structure. The cavity units are made of polylactic acid material. The structural characteristic dimensions of the cavity units are on the same order of magnitude as the wavelengths of sound waves and electromagnetic waves. Each cavity unit includes a regular hexagonal dielectric substrate and sidewalls perpendicularly disposed on each side of the regular hexagonal dielectric substrate. The sidewalls and the regular hexagonal dielectric substrate form a gradually changing impedance transition. All sidewalls enclose the cavity to form a cavity. From each sidewall, a partition unit extends towards the center of the cavity. All partition units divide the cavity into six sub-cavities. The six sub-cavities form a resonant mode.

2. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: The air inside the cavity has a different dielectric constant than the cavity unit, so electromagnetic waves will change their propagation direction when they pass through the cavity unit.

3. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: When a sound wave enters a cavity, it generates an echo-like sound wave within the cavity, which cancels out the incoming sound wave, resulting in sound wave absorption.

4. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: A circular hole is formed in the center of a regular hexagonal dielectric substrate. The partition unit includes partition branches. Two partition branches extend from each sidewall to the outer edge of the circular hole. The partition branches include a first branch to a seventh branch that are vertically connected in sequence. The end of the first branch is vertically connected to the sidewall, and the end of the seventh branch is connected to an arc-shaped eighth branch.

5. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: After the structure absorbs electromagnetic waves and sound waves, its temperature rises, and the temperature of the air medium in each sub-cavity rises. The temperature inside the circular hole is lower than the temperature inside the sub-cavity, and a convection circulation is formed between the sub-cavity and the circular hole.

6. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: The honeycomb cavity structure is a multi-layered structure, which includes multiple honeycomb units, and each honeycomb unit includes multiple cavity units arranged in layers.

7. The multifunctional holographic tunable metamaterial structure according to claim 4, characterized in that: The radius of the circular hole ranges from 0.5mm to 1.1mm; the length of the first branch ranges from 0.2mm to 0.4mm, the length of the second branch ranges from 0.8mm to 1.2mm, the length of the third branch ranges from 0.2mm to 0.4mm, the length of the fourth branch ranges from 0.5mm to 0.9mm, the length of the fifth branch ranges from 0.2mm to 0.4mm, the length of the sixth branch ranges from 0.5mm to 0.9mm, the length of the seventh branch ranges from 0.2mm to 0.6mm, and the arc angle of the eighth branch is 40 degrees.

8. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: There is a gap between adjacent sidewalls; the partition unit includes a circular column and a first connecting arm located between the sidewall and the circular column, and a second connecting arm located between the circular column and the central axis of the overall structure. A regular hexagonal cover plate is provided above the cavity.

9. The multifunctional holographic tunable metamaterial structure according to claim 8, characterized in that: The outer radius of the annular cylinder ranges from 1.2mm to 1.8mm, and the inner radius of the annular cylinder ranges from 0.3mm to 0.7mm; the length of the first connecting arm ranges from 2.5mm to 3.5mm, the length of the second connecting arm ranges from 2.5mm to 3.5mm, the width of the first or second connecting arm ranges from 0.3mm to 0.7mm, and the length of the sidewall in the direction perpendicular to the length direction of the first connecting arm ranges from 8mm to 12mm.

10. The multifunctional holographic tunable metamaterial structure according to claim 1, characterized in that: The distance from each vertex of the regular hexagonal dielectric substrate to its center ranges from 2.5 mm to 3.5 mm; the thickness of the sidewalls ranges from 0.1 mm to 0.3 mm.

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