A three-dimensional metamaterial, unit structure, preparation method and equipment

Abstract

This invention discloses a three-dimensional metamaterial unit structure, which sequentially comprises an electromagnetic loss three-dimensional metastructure, a first dielectric structure layer, an electromagnetic loss metasurface, a second dielectric structure layer, and a lossless bandpass metastructure bonded together. The electromagnetic loss three-dimensional metastructure has a hollow truncated structure, which is square in shape with one side having a convex cross-section. The electromagnetic loss metasurface has a substrate on which a periodic composite ring structure is fabricated. This composite ring structure includes an outer square ring and an inner regular octagonal ring. The composite ring is made of any one or any combination of gold, silver, or copper. The substrate material of the electromagnetic loss metasurface is any one of a PI film, a PEN film, an FR4 plate, or an F4B plate.

Description

Technical Field

[0001] This disclosure belongs to the field of microwave technology, specifically relating to an absorption-transmission-absorption type of integrated three-dimensional metamaterial, unit structure, preparation method and equipment. Background Technology

[0002] The development of wireless communication technology and the widespread adoption of intelligent interactive electronic devices have brought convenience to daily life, but have also introduced harmful electromagnetic radiation and safety hazards in various scenarios. A common technique for eliminating electromagnetic radiation is electromagnetic absorption, which typically uses electromagnetic absorbing coatings or structures to absorb electromagnetic energy in specific frequency bands, thereby protecting targets without information interaction capabilities. For electronic devices that require information interaction, a combined absorbent and penetrating structure is often used to simultaneously ensure in-band communication and out-of-band electromagnetic energy absorption. This design has significant application value in complex signal interaction systems.

[0003] Traditional integrated absorber-permeable structures typically consist of a lossy frequency selective surface with a passband, a supporting medium, and a lossless frequency selective surface with the same passband as the lossy frequency selective surface. The lossy frequency selective surface is the sole functional layer for energy loss, while the lossless frequency selective surface acts as a reflective layer for the lossy frequency selective surface in the absorption band. It is important to note that current integrated absorber-permeable structures suffer from a trade-off between absorption and transmission performance. Specifically, to improve absorption performance in the absorption band (reflection coefficient less than -10dB, absorptivity greater than 90%), the transmission coefficient in the transmission band is reduced (transmission coefficient only reaches -3dB); or to improve the transmission coefficient in the transmission band (transmission coefficient greater than -1dB), the absorption performance in the absorption band is reduced (reflection coefficient less than -10dB, absorptivity between 80% and 90%). Therefore, developing integrated absorber-permeable materials that simultaneously possess excellent absorption and transmission performance not only meets current application needs but also has clear commercial value. Summary of the Invention

[0004] One aspect of this disclosure is a permeable three-dimensional metamaterial structure, which sequentially comprises an electromagnetic loss three-dimensional metastructure, a first dielectric structure layer, an electromagnetic loss metasurface, a second dielectric structure layer, and a lossless bandpass metastructure bonded together.

[0005] The electromagnetic loss three-dimensional superstructure has a hollow platform structure, which is square in shape, with one side of the platform having a convex cross-section.

[0006] The electromagnetic loss metasurface has a substrate on which a periodic composite ring structure is fabricated, the composite ring structure comprising an outer square ring and an inner regular octagonal ring.

[0007] The lossless bandpass superstructure has a substrate on which a periodically symmetric three-dimensional structure is fabricated.

[0008] Preferably, the surface of the electromagnetic loss three-dimensional superstructure is coated with a resistive film.

[0009] The material of the first or second dielectric structure layer is any one of PMI foam, PI foam or honeycomb board. Attached Figure Description

[0010] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:

[0011] Figure 1 A schematic diagram of an electromagnetic loss three-dimensional metamaterial based on one embodiment of the present disclosure.

[0012] Figure 2 A schematic diagram of an electromagnetic loss metasurface structure of an integrated three-dimensional metamaterial based on one embodiment of the present disclosure.

[0013] Figure 3 The reflection coefficient, transmission coefficient, and absorptivity of an integrated three-dimensional metamaterial electromagnetic loss metasurface according to one embodiment of the present disclosure under perpendicular incidence.

[0014] Figure 4 A schematic diagram of a cuboid non-destructive bandpass superstructure in a three-dimensional metamaterial with integrated absorption and permeation according to one embodiment of the present disclosure.

[0015] Figure 5 The reflection coefficient and transmission coefficient of a cuboid non-destructive bandpass superstructure in a three-dimensional metamaterial according to one embodiment of the present disclosure under vertical incidence.

[0016] Figure 6 A schematic diagram of an integrated three-dimensional metamaterial structure based on one embodiment of the present disclosure.

[0017] Figure 7 The reflection coefficient, transmission coefficient, and absorptivity of a three-dimensional metamaterial with integrated absorption and permeability according to one embodiment of the present disclosure under vertical incidence.

[0018] Figure 8 A schematic diagram of an integrated three-dimensional metamaterial structure based on one embodiment of the present disclosure.

[0019] Figure 9 A schematic diagram of an electromagnetic loss three-dimensional metamaterial based on one embodiment of the present disclosure.

[0020] Figure 10A schematic diagram of a cone-shaped non-destructive bandpass superstructure in an integrated three-dimensional metamaterial according to one embodiment of the present disclosure.

[0021] Figure 11 The reflection coefficient and transmission coefficient of a cone-shaped non-destructive bandpass superstructure in an integrated absorbent-permeable three-dimensional metamaterial according to one embodiment of the present disclosure under vertical incidence.

[0022] Figure 12 The reflection coefficient, transmission coefficient, and absorptivity of a three-dimensional metamaterial with integrated absorption and permeability according to one embodiment of the present disclosure under vertical incidence.

[0023] Wherein, 1—electromagnetic loss three-dimensional superstructure, 2—dielectric structure layer I, and 3—electromagnetic loss metasurface.

[0024] 4—Electromagnetic loss metasurface substrate, 5—Dielectric structure layer II, 6—Three-dimensional lossless bandpass superstructure

[0025] 7—Three-dimensional lossless bandpass superstructure substrate,

[0026] 8 – Resistor 1 (loaded on the electromagnetic loss supersurface), 9 – Resistor 2 (loaded on the electromagnetic loss supersurface), 10 – Resistor 3 (loaded on the electromagnetic loss supersurface), 11 – Resistor 4 (loaded on the electromagnetic loss supersurface), 12 – Resistor film (loaded on the electromagnetic loss three-dimensional superstructure). Detailed Implementation

[0027] According to one or more embodiments, an absorption-transmission-absorption type three-dimensional metamaterial integrating absorption and transmission solves the problem that absorption performance and wave transmission performance cannot be ideally balanced in current absorption-transmission integrated structures.

[0028] A three-dimensional metamaterial integrating absorption and permeation includes, from top to bottom, an electromagnetic loss three-dimensional metastructure, a dielectric structure layer I, an electromagnetic loss metasurface, an electromagnetic loss metasurface substrate, a dielectric structure layer II, a three-dimensional lossless bandpass superstructure, and a three-dimensional lossless bandpass superstructure substrate. Among these,

[0029] The materials used for the electromagnetic loss three-dimensional superstructure can be FR4, PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, PET, Carbon / Glass Fiber Reinforced PLA, PPA-CF / GF, PPS, PPS-CF / GF, and other materials with certain electromagnetic loss characteristics. The relative permittivity ranges from 2.0 to 20.0, the dielectric loss ranges from 0.001 to 0.1, and the total thickness is 0.5 to 5.0 mm. The corresponding material names include:

[0030] FR4 – Glass fiber reinforced epoxy resin

[0031] PI—Polyimide

[0032] PLA—Polyllactic acid,

[0033] PETG—Polyethylene terephthalate,

[0034] TPU—Thermoplastic Polyurethane

[0035] PVA—Polyvinyl alcohol,

[0036] BVOH – Polyvinyl butyral.

[0037] ABS—Acrylonitrile-butadiene-styrene copolymer

[0038] ASA—Acrylonitrile-styrene-acrylate copolymer,

[0039] PC – Polycarbonate

[0040] PA—Polyamide,

[0041] PET—Polyethylene terephthalate

[0042] Carbon / Glass Fiber Reinforced PLA — Polylactic acid reinforced with carbon fiber / glass fiber

[0043] PPA-CF / GF — Polyphthalamide-carbon fiber / glass fiber

[0044] PPS – Polyphenylene sulfide

[0045] PPS-CF / GF – Polyphenylene sulfide-carbon fiber / glass fiber.

[0046] In this design, both dielectric structure layer I and dielectric structure layer II are made of common dielectric materials with a dielectric constant of 1.0-2.0, such as PMI foam, PI foam, or honeycomb panels. The thickness of dielectric structure layer I is 0.5-5.0 mm, and the thickness of dielectric structure layer II is 1.5-7.5 mm. The English abbreviations and their corresponding Chinese terms include:

[0047] PMI foam – polymethacrylamide foam

[0048] PI foam – polyimide foam

[0049] Honeycomb panels – honeycomb panels.

[0050] The period of the metal structural unit of the electromagnetic loss metasurface is 18-22 mm. The composite ring structure mainly consists of square rings connected by a grid type, with regular octagonal rings embedded within them. The four corner rings of the square rings are connected to the four corners of the octagonal rings by curved branches. The outer square ring has a side length of 14.0-18.0 mm and a line width of 0.2-0.6 mm; the inner regular octagonal ring has a side length of 2.0-6.0 mm and a line width of 0.2-0.6 mm.

[0051] The value of resistor 8 loaded on the square ring is 350-900Ω, the value of resistor 9 loaded on the curved branch connecting the square ring and the regular octagonal ring is 100-300Ω, and the value of resistors 10 and 11 loaded on the regular octagonal ring is 500-1000Ω.

[0052] Preferably, the substrate of the electromagnetic loss metasurface is one of a PI film, a PEN film, an FR4 plate, or an F4B plate, with a relative permittivity of 2.0-6.5 and a thickness of 0.1-0.6 mm. Here,

[0053] PI film – polyimide film

[0054] PEN membrane – Poly(ethylene naphthalate) membrane.

[0055] FR4 board – glass fiber reinforced epoxy resin board.

[0056] F4B board – Polytetrafluoroethylene board (modified).

[0057] Preferably, the metal structural unit of the electromagnetic loss metasurface is made of one of the following metals: gold, silver, or copper; it can be prepared on the electromagnetic loss metasurface substrate by means of inkjet printing, electrochemical etching, or magnetron sputtering.

[0058] The lumped resistance can be obtained by one or any combination of commercial electronic resistor components, magnetron sputtering, screen printing, and inkjet printing.

[0059] Preferably, the three-dimensional lossless bandpass superstructure substrate is divided into two parts: the first part is a flat plate structure with a thickness of 0.1-1.0 mm, and the second part is an arbitrary regular three-dimensional structure with a bottom symmetrical pattern and a height of 1.5-7.5 mm.

[0060] The substrate material of the three-dimensional lossless bandpass superstructure is a material with low electromagnetic loss characteristics, such as PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, and PET, with a relative permittivity ranging from 2.0 to 20.0 and a dielectric loss ranging from 0.001 to 0.01. The English abbreviations here correspond to the following Chinese terms:

[0061] PI—Polyimide

[0062] PLA—Polyllactic acid,

[0063] PETG—Polyethylene terephthalate,

[0064] TPU—Thermoplastic Polyurethane

[0065] PVA—Polyvinyl alcohol,

[0066] BVOH – Polyvinyl butyral.

[0067] ABS—Acrylonitrile-butadiene-styrene copolymer

[0068] ASA—Acrylonitrile-styrene-acrylate copolymer,

[0069] PC – Polycarbonate

[0070] PA—Polyamide,

[0071] PET—Polyethylene terephthalate.

[0072] The first part consists of a flat plate structure with conductive units having a period of 9.0-11.0 mm, an outer diameter of 9.0-11.0 mm for the conductive grid structure, a line width of 0.1-3.0 mm for the grid rings, and a gap width of 0.1-0.6 mm. The second part is an arbitrary regular three-dimensional structure with a symmetrical bottom surface covered with a metallic material.

[0073] The three-dimensional lossless bandpass superstructure conductive units are all made of copper or silver.

[0074] Preferably, the multi-layered structure of the metamaterial is formed by single-layer hot pressing or integral hot pressing.

[0075] The three-dimensional structure of the ultrawideband thin-layer three-dimensional absorbing metamaterial disclosed herein is prepared by 3D printing or engraving.

[0076] The design principle of this disclosure embodiment is:

[0077] (a) The high-loss functional layer of this disclosure is an electromagnetic loss metasurface, in which a square ring with a grid type connected and an embedded regular octagonal ring structure achieves a high transmission coefficient in the passband while having high loss performance on both sides of the passband.

[0078] (b) The weak loss functional layer disclosed herein is an electromagnetic loss three-dimensional superstructure. Its loss characteristics come from two parts: its own material loss and the loss of uniform resistive film attached to different interfaces of the three-dimensional structure. When the basic material of the electromagnetic loss three-dimensional superstructure is selected, its own loss characteristics and impedance matching characteristics can be adjusted by adding resistive film or changing the sheet resistance of resistive film.

[0079] (c) The dielectric structure layer I is made of a material with near-vacuum dielectric constant and dielectric loss. It is mainly used for adjusting the equivalent dielectric constant and impedance matching state of the upper structure, including the electromagnetic loss three-dimensional superstructure, and is also used for high-frequency absorption compensation.

[0080] (d) The dielectric structure layer II is made of a material with near-vacuum dielectric constant and dielectric loss, and is mainly used for adjusting the absorption intensity of the low-frequency and high-frequency absorption bands.

[0081] (e) The three-dimensional lossless bandpass superstructure design can improve its reflection performance in the low-frequency and high-frequency absorption bands while achieving a high transmission coefficient in the passband, thereby improving the absorption intensity in the absorption band.

[0082] The beneficial effects of this disclosure include:

[0083] (a) The three-dimensional metamaterial with absorption and permeation provided in this disclosure has a high transmission band located between strong absorption bands, and can achieve a bandwidth of more than 1.4 GHz with a transmission coefficient of more than -1 dB in the 7.5-11.0 GHz frequency band, a bandwidth of more than 2.2 GHz with a transmission rate of more than -2 dB, and a bandwidth of more than 2.8 GHz with a transmission coefficient of more than -3 dB.

[0084] (b) The metamaterial disclosed herein has two strong absorption bands, enabling absorption rates of over 90% in the frequency bands of 4.6-5.7 GHz and 12.4-21.6 GHz; and absorption rates of over 80% in the frequency bands of 3.8-7.0 GHz and 11.5-22.0 GHz (above).

[0085] (c) The 3D superstructure-enhanced transmissive metamaterial disclosed herein has a reflectivity of less than -10dB in the range of 4.0-21.7GHz and an absolute bandwidth of less than -15dB for a reflectivity coefficient greater than 14.5GHz.

[0086] (d) The electromagnetic loss three-dimensional metastructure in the integrated absorbent-permeable three-dimensional metamaterial disclosed herein can be adjusted by adding a uniform resistive film or changing the sheet resistance of the resistive film according to the requirements of the absorption rate and transmission coefficient in the actual application scenario, and has good adaptability and flexibility in practical applications.

[0087] (e) The three-dimensional non-destructive bandpass superstructure in the three-dimensional metamaterial of the present invention can adjust the three-dimensional geometry at any time according to the process conditions, and has good adaptability and flexibility in practical applications.

[0088] According to one or more embodiments, a three-dimensional metamaterial with integrated absorption and permeation includes, from top to bottom, an electromagnetic loss three-dimensional metastructure, a dielectric structure layer I, an electromagnetic loss metasurface, an electromagnetic loss metasurface substrate, a dielectric structure layer II, a three-dimensional lossless bandpass superstructure, and a three-dimensional lossless bandpass superstructure substrate.

[0089] The material of the electromagnetic loss three-dimensional superstructure can be FR4, PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, PET, Carbon / Glass Fiber Reinforced PLA, PPA-CF / GF, PPS, PPS-CF / GF, etc., which have certain electromagnetic loss characteristics. The relative permittivity ranges from 2.0 to 20.0, the dielectric loss ranges from 0.001 to 0.1, and the total thickness is 0.5 to 5.0 mm.

[0090] Electromagnetic loss three-dimensional superstructures can enhance their loss characteristics and impedance matching characteristics by loading a resistive film onto them. The sheet resistance of the loaded resistive film is 10-5000Ω / square, and the resistive film can be loaded by magnetron sputtering, inkjet printing, or direct pasting of commercial resistive films.

[0091] Both dielectric structure layer I and dielectric structure layer II are made of a common dielectric material with a dielectric constant of 1.0-2.0, such as PMI foam, PI foam, or honeycomb board. The thickness of dielectric structure layer I is 0.5-5.0 mm, and the thickness of dielectric structure layer II is 1.5-7.5 mm.

[0092] The period of the metal structural unit of the electromagnetic loss metasurface is 18-22 mm. The composite ring structure mainly consists of square ring structures connected by a grid type, with regular octagonal ring structures embedded within them. The four corner rings of the square rings are connected to the four corners of the octagonal rings through curved branches. The outer ring square ring has a side length of 14.0-18.0 mm and a line width of 0.2-0.6 mm; the inner ring regular octagonal ring has a side length of 2.0-6.0 mm and a line width of 0.2-0.6 mm. Here, "grid" refers to the connection form between the metal structural units, similar to a grid structure. A grid structure is a mesh structure composed of repeating cells, which can be used to achieve specific electromagnetic properties. The cells can be simple geometric shapes (such as squares, circles, etc.) connected together to form complex geometric shapes, that is, different geometric shapes are combined together through specific connection points.

[0093] The resistance values ​​applied to the square ring range from 350 to 900 Ω, the resistance values ​​applied to the regular octagonal ring range from 500 to 1000 Ω, and the resistance values ​​applied to the curved branches connecting the square ring and the regular octagonal ring range from 100 to 300 Ω.

[0094] The substrate of the electromagnetic loss metasurface is one of PI film, PEN film, FR4 plate, or F4B plate, with a relative permittivity of 2.0-6.5 and a thickness of 0.1-0.6 mm.

[0095] The metallic structural units of the electromagnetic loss metasurface are made of one of the following metals: gold, silver, or copper. They can be fabricated on the electromagnetic loss metasurface substrate by methods such as inkjet printing, electrochemical etching, or magnetron sputtering.

[0096] The lumped resistance can be obtained by one or any combination of commercial electronic resistor components, magnetron sputtering, screen printing, and inkjet printing.

[0097] The three-dimensional lossless bandpass superstructure substrate is divided into two parts. The first part is a flat plate structure with a thickness of 0.1-1.0 mm, and the second part is an arbitrary regular three-dimensional structure with a bottom symmetrical pattern and a height of 1.5-7.5 mm.

[0098] The substrate material of the three-dimensional lossless bandpass superstructure is a material with low electromagnetic loss characteristics such as PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, and PET, with a relative permittivity ranging from 2.0 to 20.0 and a dielectric loss ranging from 0.001 to 0.01.

[0099] The first part consists of a flat plate structure with conductive units having a period of 9.0-11.0 mm, an outer diameter of 9.0-11.0 mm for the conductive grid structure, a line width of 0.1-3.0 mm for the grid rings, and a gap width of 0.1-0.6 mm. The second part is an arbitrary regular three-dimensional structure with a symmetrical bottom surface covered with a metallic material.

[0100] The three-dimensional lossless bandpass superstructure conductive units are all made of copper or silver.

[0101] According to one or more embodiments, a schematic diagram of an integrated absorbent-permeable three-dimensional metamaterial structure is shown below. Figure 6 As shown, from top to bottom, a three-dimensional metamaterial with integrated absorption and permeation comprises, in order from top to bottom, an electromagnetic loss three-dimensional metastructure I, a dielectric structure layer I, an electromagnetic loss metasurface, an electromagnetic loss metasurface substrate, a dielectric structure layer II, a cuboid lossless bandpass superstructure, and a cuboid lossless bandpass superstructure substrate.

[0102] This 3D metamaterial, which integrates absorption and permeation, was simulated and verified using the electromagnetic simulation software CST 2025. It adopted a floquet port and used a unit cell to simulate an infinitely large plane with a period of 18.0~22.0 mm.

[0103] The material of the electromagnetic loss three-dimensional superstructure I can be FR4, PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, PET, Carbon / Glass Fiber Reinforced PLA, PPA-CF / GF, PPS, PPS-CF / GF and other materials with certain electromagnetic loss characteristics, with a relative permittivity ranging from 2.0 to 20.0, a dielectric loss ranging from 0.001 to 0.1, and a total thickness of 0.5 to 5.0 mm.

[0104] Both dielectric structure layer I and dielectric structure layer II are made of PMI foam with a dielectric constant of 1.05; the thickness of dielectric structure layer I is 0.5-5.0 mm, and the thickness of dielectric structure layer II is 1.5-7.5 mm.

[0105] The electromagnetic loss metasurface used is, for example... Figure 2 As shown, the period of the metal structural unit is 18-22mm. The composite ring structure mainly consists of square rings connected by a grid type, with regular octagonal rings embedded within them. The four corner rings of the square rings are connected to the four corners of the octagonal rings through curved branches. The outer square ring has a side length of 14.0-18.0mm and a line width of 0.2-0.6mm; the inner regular octagonal ring has a side length of 2.0-6.0mm and a line width of 0.2-0.6mm.

[0106] The value of resistor 8 loaded on the square ring is 350-900Ω, the value of resistor 9 loaded on the curved branch connecting the square ring and the regular octagonal ring is 100-300Ω, and the value of resistors 10 and 11 loaded on the regular octagonal ring is 500-1000Ω.

[0107] The substrate of the electromagnetic loss metasurface is one of PI film, PEN film, FR4 plate, or F4B plate, with a relative permittivity of 2.0-6.5 and a thickness of 0.1-0.6 mm.

[0108] The three-dimensional metamaterial with integrated absorption and permeation is a metallic structural unit of an electromagnetic loss metasurface, made of one of the following metals: gold, silver, or copper. It can be prepared on an electromagnetic loss metasurface substrate by means of inkjet printing, electrochemical etching, or magnetron sputtering. The lumped resistance can be obtained by one or any combination of commercial electronic resistor components, magnetron sputtering, screen printing, and inkjet printing.

[0109] The cuboid lossless bandpass superstructure in the integrated absorbent-permeable 3D metamaterial comprises a substrate as the first part, a flat plate structure with a thickness of 0.2-0.5 mm. The second part, fabricated on the substrate, is a cuboid structure with a square base, side lengths of 4.0-8.0 mm, and a height of 1.0-2.5 mm. The substrate material is a low electromagnetic loss material such as PTFE, TPU, PVA, BVOH, ABS, ASA, PC, PA, or PET, with a relative permittivity ranging from 2.0 to 20.0 and a dielectric loss ranging from 0.001 to 0.01. The period of the conductive units on the flat plate structure of the first part is 9.0-11.0 mm, the outer diameter of the conductive grid structure is 9.0-11.0 mm, the linewidth of the grid rings is 0.1-3.0 mm, and the gap width is 0.1-0.6 mm. The surface of the cuboid structure of the second part is coated with a metallic material. The conductive units of the cuboid lossless bandpass superstructure are all made of copper or silver.

[0110] Figure 3 The present invention discloses an embodiment of a three-dimensional metamaterial electromagnetic loss metasurface with integrated absorption and transmission properties, showing its reflection coefficient, transmission coefficient, and absorptivity under perpendicular incidence. It can be seen that its reflection coefficient is -7 dB in the 2.0-18.4 GHz range and generally within -6 dB in the 18.4-22.0 GHz range. The transmission coefficient is above -1 dB in the 8.3-9.9 GHz range, above -2 dB in the 7.8-10.7 GHz range, and above -3 dB in the 7.5-11.4 GHz range. Its absorptivity is greater than 40% in the 4.2-7.4 GHz and 11.9-22.0 GHz ranges. Therefore, the three-dimensional metamaterial electromagnetic loss metasurface possesses ideal transmission and absorption characteristics.

[0111] Figure 5 The present invention discloses the reflection and transmission coefficients of a cuboid lossless bandpass superstructure in an integrated absorption-transmission three-dimensional metamaterial under perpendicular incidence. It can be seen that the frequency bands with reflection coefficients above -1dB are 2.0-5.2GHz and 14.3-22.0GHz, and the frequency bands with reflection coefficients above -2dB are 2.0-6.1GHz and 12.0-22.0GHz. The frequency bands with transmission coefficients above -1dB are 7.5-9.7GHz, the frequency bands with transmission coefficients above -2dB are 7.0-10.5GHz, and the frequency bands with transmission coefficients above -3dB are 6.6-11.1GHz. Therefore, the cuboid lossless bandpass superstructure possesses ideal transmission and reflection characteristics, and corresponds to the transmission and absorption bands of the electromagnetic loss metasurface of the three-dimensional metamaterial.

[0112] Figure 7The present invention discloses the reflection coefficient, transmission coefficient, and absorptivity of the integrated absorptivity and transmissivity three-dimensional metamaterial under vertical incidence. It can be seen that the frequency band with a reflection coefficient below -10dB is 4.2-21.5GHz; the frequency band with a transmission coefficient above -1dB is 8.2-9.7GHz, the frequency band with a transmission coefficient above -2dB is 7.9-10.2GHz, and the frequency band with a transmission coefficient above -3dB is 7.8-10.6GHz; the frequency bands with an absorptivity greater than 90% are 5.0-5.5GHz and 12.5-21.4GHz, and the frequency bands with an absorptivity greater than 80% are 4.0-6.8GHz and 11.6-22.0GHz. It exhibits broadband strong transmission characteristics in the transmission frequency band, with a relatively ideal low-frequency absorption intensity band, and strong absorption characteristics in the high-frequency band.

[0113] According to one or more embodiments, a schematic diagram of an integrated absorbent-permeable three-dimensional metamaterial structure is shown below. Figure 8 As shown, from top to bottom, a three-dimensional metamaterial with integrated absorption and permeation comprises, in order from top to bottom, an electromagnetic loss three-dimensional metastructure (resistive film absorption enhancement), a dielectric structure layer I, an electromagnetic loss metasurface, an electromagnetic loss metasurface substrate, a dielectric structure layer II, a cone-shaped lossless bandpass superstructure, and a cone-shaped lossless bandpass superstructure substrate.

[0114] This 3D metamaterial, which integrates absorption and permeation, was simulated and verified using the electromagnetic simulation software CST 2025. It adopted a floquet port and used a unit cell to simulate an infinitely large plane with a period of 18.0-22.0 mm.

[0115] The materials used for the electromagnetic loss three-dimensional superstructure (resistive film absorption enhancement) can be FR4, PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, PET, Carbon / Glass Fiber Reinforced PLA, PPA-CF / GF, PPS, PPS-CF / GF, etc., which have certain electromagnetic loss characteristics. The relative permittivity ranges from 2.0 to 20.0, the dielectric loss ranges from 0.001 to 0.1, and the total thickness is 0.5 to 5.0 mm.

[0116] The loading form of the resistive film on the electromagnetic loss three-dimensional superstructure I (resistive film absorption enhancement) is as follows: Figure 9 As shown, resistive films can be obtained by directly pasting commercial uniform resistive films, spraying conductive ink, magnetron sputtering, etc., with sheet resistance of 200-600Ω / square.

[0117] Both dielectric structure layer I and dielectric structure layer II are made of PMI foam with a dielectric constant of 1.05; the thickness of dielectric structure layer I is 0.5-5.0 mm, and the thickness of dielectric structure layer II is 1.5-7.5 mm.

[0118] The electromagnetic loss metasurface used can be as described in the foregoing embodiments. Figure 2 As shown, the period of the metal structural unit is 18-22mm. The composite ring structure mainly consists of square rings connected by a grid type, with regular octagonal rings embedded within them. The four corner rings of the square rings are connected to the four corners of the octagonal rings through curved branches. The outer square ring has a side length of 14.0-18.0mm and a line width of 0.2-0.6mm; the inner regular octagonal ring has a side length of 2.0-6.0mm and a line width of 0.2-0.6mm.

[0119] The value of resistor 8 loaded on the square ring is 350-900Ω, the value of resistor 9 loaded on the branch connecting the square ring and the regular octagonal ring is 100-300Ω, and the value of resistors 10 and 11 loaded on the regular octagonal ring is 500-1000Ω.

[0120] The substrate of the electromagnetic loss metasurface is one of PI film, PEN film, FR4 plate, or F4B plate, with a relative permittivity of 2.0-6.5 and a thickness of 0.1-0.6 mm.

[0121] The metallic structural unit of the electromagnetic loss metasurface is made of one of the following metals: gold, silver, and copper. It can be prepared on the electromagnetic loss metasurface substrate by means of inkjet printing, electrochemical etching, or magnetron sputtering. The lumped resistance can be obtained by one or any combination of commercial electronic resistor components, magnetron sputtering, screen printing, and inkjet printing.

[0122] The cone-shaped lossless bandpass superstructure in this integrated 3D metamaterial comprises a substrate as the first part, a flat plate structure with a thickness of 0.2-0.5 mm. The second part on the substrate is a cone structure with a base radius of 2.0-4.0 mm and a height of 1.0-2.5 mm. The substrate is made of materials with low electromagnetic loss characteristics, such as PTFE, TPU, PVA, BVOH, ABS, ASA, PC, PA, and PET, with a relative permittivity ranging from 2.0 to 20.0 and a dielectric loss ranging from 0.001 to 0.01. The conductive units on the flat plate structure of the first part have a period of 9.0-11.0 mm, an outer diameter of 9.0-11.0 mm for the conductive grid structure, a linewidth of 0.1-3.0 mm for the grid rings, and a gap width of 0.1-0.6 mm. The surface of the cone-shaped structure of the second part is coated with a metallic material. The conductive units of the cone-shaped lossless bandpass superstructure are all made of copper or silver.

[0123] Figure 11The present invention discloses the reflection and transmission coefficients of a cone-shaped lossless bandpass superstructure in a three-dimensional metamaterial with integrated absorption and transmission under perpendicular incidence. It can be seen that the frequency bands with reflection coefficients above -1dB are 2.0-5.4GHz and 14.4-22.0GHz, and the frequency bands with reflection coefficients above -2dB are 2.0-6.3GHz and 12.3-22.0GHz. The frequency bands with transmission coefficients above -1dB are 7.7-10.1GHz, the frequency bands with transmission coefficients above -2dB are 7.2-10.7GHz, and the frequency bands with transmission coefficients above -3dB are 6.7-11.4GHz. Therefore, the cone-shaped lossless bandpass superstructure possesses ideal transmission and reflection characteristics, and corresponds to the transmission and absorption bands of the electromagnetic loss metasurface of the three-dimensional metamaterial.

[0124] Figure 12 The present invention discloses an embodiment of a transmissive three-dimensional metamaterial with reflectivity and transmittance, and its absorptivity under vertical incidence. It can be seen that the frequency band with a reflectivity below -10dB is 4.1-21.5GHz, and the frequency band with a reflectivity below -15dB is 4.6-6.0GHz / 8.0-20.9GHz. The frequency band with a transmittance above -1dB is 8.5-9.4GHz, the frequency band with a transmittance above -2dB is 8.1-10.0GHz, and the frequency band with a transmittance above -3dB is 7.9-10.5GHz. The frequency bands with an absorptivity greater than 90% are 4.5-5.9GHz and 12.3-21.4GHz, and the frequency bands with an absorptivity greater than 80% are 3.8-7.0GHz and 11.5-22.0GHz. It exhibits broadband strong transmittance characteristics in the transmittance frequency bands and strong absorption characteristics at both low and high frequencies.

[0125] As can be seen from the foregoing embodiments, the integrated absorption-transmission three-dimensional metamaterial provided in this disclosure, through impedance matching and loss compensation design of the top-layer electromagnetic loss three-dimensional metastructure, design of high-transmittance and strong absorption bands of the electromagnetic loss metasurface, and design of a three-dimensional lossless bandpass metastructure for the reflective backplate, enables it to achieve a passband transmittance of over -1dB with a bandwidth greater than 1.4GHz, while simultaneously achieving absorption performance of over 90% in both absorption bands over a wide bandwidth. This meets the current demand for integrated absorption-transmission electromagnetic metamaterials with both excellent absorption and transmission performance, making it extremely valuable in complex signal interaction systems, electromagnetic protection, and electromagnetic compatibility.

[0126] It should be understood that in the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0127] It is worth noting that although the foregoing has described the spirit and principles of this disclosure with reference to several specific embodiments, it should be understood that this disclosure is not limited to the disclosed specific embodiments, and the division of aspects does not imply that the features in these aspects cannot be combined; such division is merely for the convenience of expression. This disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A three-dimensional metamaterial unit structure, characterized in that, The structure comprises, in sequence, an electromagnetic loss three-dimensional superstructure, a first dielectric structure layer, an electromagnetic loss metasurface, a second dielectric structure layer, and a lossless bandpass superstructure that are bonded together with each other. The electromagnetic loss three-dimensional superstructure has a hollow enclosure structure, which is square in shape, with one side of the enclosure having a convex cross-section. The surface of the electromagnetic loss three-dimensional superstructure is covered with a resistive film. The electromagnetic loss metasurface has a substrate on which a periodic composite ring structure is fabricated. The composite ring structure includes an outer square ring and an inner regular octagonal ring. The four corner rings of the square ring are connected to the four corners of the octagonal ring through curved branches. The side length of the outer square ring is 14.0-18.0 mm and its line width is 0.2-0.6 mm. The side length of the inner regular octagonal ring is 2.0-6.0 mm and its line width is 0.2-0.6 mm. The lossless bandpass superstructure has a substrate on which a periodically symmetrical three-dimensional structure is fabricated. The periodically symmetrical three-dimensional structure is a cuboid structure or a cone structure with a square base and a metal coating on the surface. The material of the first or second dielectric structure layer is any one of PMI foam, PI foam or honeycomb board.

2. The unit structure according to claim 1, characterized in that, The material of the electromagnetic loss three-dimensional superstructure is one or any combination of FR4, PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA, PET, Carbon / Glass Fiber Reinforced PLA, PPA-CF / GF, PPS, or PPS-CF / GF.

3. The unit structure according to claim 1, characterized in that, The sheet resistance of the resistive film is 10-5000Ω / square.

4. The unit structure according to claim 1, characterized in that, The composite ring is made of any or any combination of gold, silver, or copper.

5. The unit structure according to claim 1, characterized in that, The substrate material of the electromagnetic loss metasurface is any one of PI film, PEN film, FR4 board or F4B board.

6. The unit structure according to claim 1, characterized in that, The substrate of the lossless bandpass superstructure is divided into two parts. The first part is a flat plate structure with a thickness of 0.1-1.0 mm, and the second part is the periodically symmetrical three-dimensional structure with a height of 1.5-7.5 mm. The substrate is made of any one of PI, PLA, PETG, TPU, PVA, BVOH, ABS, ASA, PC, PA or PET.

7. The unit structure according to claim 1, characterized in that, The periodically symmetrical three-dimensional structure is a cuboid structure with a square base, a side length of 4.0-8.0 mm, and a height of 1.0-2.5 mm.

8. The unit structure according to claim 1, characterized in that, The periodically symmetrical three-dimensional structure is a cone structure with a base radius of 2.0-4.0 mm and a height of 1.0-2.5 mm.

9. The unit structure according to claim 1, characterized in that, The electromagnetic loss supersurface is loaded with a lumped resistor. The resistance value of the square ring is 350-900Ω, the resistance value of the curved branch connecting the square ring and the regular octagonal ring is 100-300Ω, and the resistance value of the regular octagonal ring is 500-1000Ω.

10. A method for preparing three-dimensional metamaterials, characterized in that, For preparing a three-dimensional metamaterial composed of the unit structure described in claim 1, the electromagnetic loss three-dimensional metastructure and the non-destructive bandpass metastructure are prepared by 3D printing or engraving processes, and the metal structural units of the electromagnetic loss metasurface are prepared on the substrate of the electromagnetic loss metasurface by inkjet printing, electrochemical etching or magnetron sputtering.

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