A tunable light-transmitting wave-absorbing structure and manufacturing method

Abstract

The present invention provides a tunable light-transmitting wave absorbing structure, which is composed of multiple periods of tunable light-transmitting wave absorbing units arranged in an array, and the wave absorbing units of a single period include: a base, a transverse pillar is vertically arranged at one end of the top surface; a longitudinal deflection block is vertically arranged with the transverse pillar; the longitudinal deflection block includes: a longitudinal shaft assembly, which is vertically connected to the center of the transverse pillar and is arranged parallel to the base; a longitudinal pillar, which is nested and connected with the longitudinal shaft assembly; two conductive films, which are respectively attached to the transverse pillar and the longitudinal pillar; the longitudinal shaft assembly is rotated to drive the longitudinal pillar to rotate, so as to realize the tunable wave absorbing wavelength of the wave absorbing structure. The tunable light-transmitting wave absorbing structure and the manufacturing method provided by the present invention have the advantages of a wide wave absorbing range, light-weight wave absorbing structure materials, and strong adaptability.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic wave absorbing structures, and in particular relates to a tunable light-transmitting wave absorbing structure and a manufacturing method thereof. Background Art

[0002] With the development of modern military technology, the role of low-scattering technology in weapons and equipment has become increasingly prominent. Low-scattering equipment mainly adopts a unique shape design and is supplemented by the application of absorbing, wave-transmitting or conductive electromagnetic materials to reduce the reflection or transmission of radar waves by the equipment, thereby achieving the effect of wave absorption. The traditional design idea of ​​low-scattering equipment is mainly to first effectively suppress the strong scattering source of low-scattering equipment. At this time, the radar cross section (RCS) can be reduced by more than ten to dozens of dB, and then treat the weak scattering sources with greater influence with absorbing materials one by one. For materials such as solar panels and transparent hatches, there are currently few aerodynamic and material comprehensive designs for their wave-absorbing characteristics. Among them, most of the applications of solar panels are flat-plate materials. For their low-scattering design, not only the problem of radar absorption should be considered, but also the problem of visible light absorption or light transmission should be considered. Therefore, as a unique type of equipment material, solar electromagnetic panels usually need to be exposed on the outside of the equipment, and their low-scattering design is one of the parts that must be solved for low-scattering weapons and equipment.

[0003] From the perspective of the aerodynamic structure of the equipment surface, the absorption problem of solar cells and glass cabin sails requires not only that the absorbing materials maintain the maneuverability of the equipment and the characteristics of low wind resistance; from the perspective of electromagnetic scattering, the absorbing structure must also take into account the reduction of the scattering performance of the equipment. Although domestic and foreign scholars have proposed a series of solutions for the research on absorbing materials compatible with visible light and radar waves, various design concepts and application products still fail to meet the demand indicators of various types of equipment. There are still problems such as small absorbing bandwidth, limited absorbing performance at certain key frequency points, and high material surface density. The above problems that need to be solved make the development of tunable light-transmitting absorbing materials technology an urgent need at present, which can not only broaden the means of preparing electromagnetic materials, but also improve the designability of various electromagnetic materials. Summary of the invention

[0004] The purpose of the present invention is to provide a tunable light-transmitting wave absorbing structure and a preparation method, which combines the design and manufacture of electromagnetic materials to realize the preparation of electromagnetic materials with complex structures, improve the designability of electromagnetic materials, and improve the lightness, tunability, and convenient assembly performance of the materials based on the structural characteristics of electromagnetic materials. To achieve the above purpose, the present invention provides a tunable light-transmitting wave absorbing structure, which is composed of multiple periods of tunable light-transmitting wave absorbing units arranged in an array, and the wave absorbing units of a single period include: a base, a transverse pillar is vertically arranged at one end of the top surface; a longitudinal deflection block, which is arranged vertically with the transverse pillar; the longitudinal deflection block includes: a longitudinal shaft assembly, which is vertically connected to the center of the transverse pillar and arranged parallel to the base; a longitudinal pillar, which is nested and connected with the longitudinal shaft assembly; a conductive film, which is respectively applied to the transverse pillar and the longitudinal pillar; rotating the longitudinal shaft assembly drives the longitudinal pillar to rotate, so as to realize the tunable wavelength of the wave absorbing structure.

[0005] Preferably, the height H1 of the transverse pillars in the single-period absorbing unit is between 7 and 10 mm, the length is between 9 and 10 mm, and the thickness d1 is between 0.3 and 0.5 mm; the total length L1 of the transverse pillars of the absorbing structure formed by a periodic array of multiple absorbing units is between 150 and 300 mm; and a pore is provided at the center of each of the transverse pillars, and the pore diameter D1 is 1 mm for embedding the longitudinal rotating shaft.

[0006] Preferably, the height H2 of the longitudinal pillar is lower than the height H1 of the transverse pillar, and the height difference between the two is between 0.8 and 1.1 mm; the length L2 of the longitudinal pillar is less than the length P of the absorbing unit of a single period, the length P of the absorbing unit of a single period is 9 to 10 mm, and the difference between the length L2 of the longitudinal pillar and the length P of the absorbing unit of a single period is P-d1-s1, wherein the margin s1 is 0.1 mm; the thickness d2 of the longitudinal pillar is between 0.3 and 0.5 mm.

[0007] Preferably, a plurality of the longitudinal rotating shaft assemblies are connected to form a multi-period longitudinal rotating shaft, which is used to connect a plurality of absorbing units to form a periodic array of absorbing structures; the longitudinal rotating shaft assembly comprises: a solid shaft embedded in the pores of the transverse pillars and a hollow groove for embedding the longitudinal pillars; a gear for adjusting the rotation of the longitudinal rotating shaft assembly is connected to the starting end of the multi-period longitudinal rotating shaft; the diameter of the longitudinal rotating shaft assembly is equal to the pore diameter D1 at the center of the transverse pillar, and the width d5 ​​of the hollow groove is equal to d2+0.08mm~d2+0.1mm; the module of the gear is 0.3mm, the number of teeth is 18, and the thickness d3 is 1mm.

[0008] Preferably, the thickness d4 of the base is between 0.3 and 0.6 mm, the length of the base is equal to the length L1 of the transverse pillar, and the width L3 of the base is equal to the length of each longitudinal rotating shaft assembly; a rectangular groove is also provided on one side of the top surface of the base connected to the rack, the depth of the rectangular groove is 0.1 to 0.2 mm, and the width is the same as the thickness d1 of the transverse pillar, which is used for fixing and embedding the transverse pillar; the starting end absorbing unit of the tunable light-transmitting absorbing structure also includes a rack, which is slidably arranged at one end of the base connected to the transverse pillar and is on the same horizontal plane as the base; the module of the rack is equal to the module of the gear, and the number of teeth of the rack is greater than the number of teeth of the gear.

[0009] Preferably, the conductive film is in the shape of an x-shape or a symmetrical double-open resonant ring; the longitudinal conductive film applied to the surfaces of both sides of the longitudinal pillar is symmetrically arranged along the longitudinal rotating shaft assembly; the transverse conductive film applied to the adjacent surfaces of the transverse pillar and the longitudinal deflection block is located on both sides of the central pore of the transverse pillar; the width p of the conductive film is between 7.5 and 8.5 mm, the height h is between 4 and 6 mm, the filling area width w is between 0.9 and 1.1 mm, the opening width s is between 0.9 and 1.1 mm, the thickness d6 is between 0.02 and 0.04 mm, and the conductivity range is 500 to 700 S / m.

[0010] Preferably, the conductive film is made of one of the following materials, including: indium tin oxide, zinc aluminum oxide or conductive powder or graphene film, a mixture of metal nanowires and epoxy resin, ultraviolet light curing resin, and polyimide resin; the base, transverse pillars, and longitudinal pillars are made of one or more composites of polymethyl methacrylate PMMA, polyimide PI, polyvinyl alcohol PVA, polypropylene PP, polyethylene terephthalate PET, polycarbonate PC, and polystyrene PS; the longitudinal shaft assembly (301) is made of one or more composites of polyvinyl alcohol PVA, polypropylene PP, polyethylene terephthalate PET, polycarbonate PC, and polystyrene PS.

[0011] Preferably, the gears in the longitudinal shaft assembly are manufactured by a three-dimensional molding method, and the solid shaft and the hollow groove are manufactured by compression molding.

[0012] Preferably, if the material of the conductive film is a metal oxide such as indium tin oxide, zinc aluminum oxide, etc., it is manufactured by magnetron sputtering; if the material of the conductive film is a mixture of conductive powder or graphene film, metal nanowires, etc. with epoxy resin, ultraviolet light-curing resin, polyimide resin, etc., the conductive film is prepared on the dielectric plate by screen printing.

[0013] Preferably, the overall assembly process of the tunable light-transmitting wave absorbing structure comprises the following steps: Step S1, preparing a conductive film and applying it to the surfaces of the transverse pillars and the longitudinal pillars respectively;

[0014] Step S2, vertically embedding the transverse support with the conductive film applied in step S1 into the rectangular groove on the base;

[0015] Step S3, embedding the solid shaft of the longitudinal rotating shaft assembly into the central hole of the transverse support;

[0016] Step S4, embedding the longitudinal pillars coated with the conductive film in step S1 symmetrically into the hollow grooves along the longitudinal rotating shaft assembly;

[0017] The assembly of the absorbing unit at the starting end further includes step S5, fixing the gear to the solid shaft embedded in the central hole of the transverse support, and meshing the gear to the rack;

[0018] Repeat steps S1 to S4 to prepare a plurality of absorbing units with the same structure. When the plurality of absorbing units are arranged in a periodic array, the starting end absorbing units assembled in step S5 are first connected in columns, and then the absorbing units assembled in steps S1 to S4 are connected side by side with the starting end absorbing units by connecting the longitudinal rotating shaft assembly to obtain a periodically arranged tunable light-transmitting absorbing structure.

[0019] In summary, the tunable light-transmitting absorbing structure and preparation method proposed in the present invention are different from other conventional absorbing structures. On the basis of taking into account the high transmittance of visible light, it can not only realize the broadband radar absorbing characteristics, but also has the function of real-time regulation of absorbing performance. Compared with the prior art, the advantages of the present invention are as follows:

[0020] (1) The material of the light-transmitting absorbing structure designed by the present invention is composed of two dielectric structures of horizontally and vertically applied conductive films. The absorbing structure provided by the present invention has a large porosity, broadband absorbing and light-weight characteristics;

[0021] (2) The present invention can adjust the absorbing performance of the absorbing material by deflecting the lateral dielectric block, and has better adaptability to radar absorbing function. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the wave absorbing structure of a single-period tunable light-transmitting wave absorbing structure of the present invention;

[0023] Figure 2 It is a schematic diagram of a longitudinal rotating shaft assembly in the tunable light-transmitting wave-absorbing structure of the present invention;

[0024] Figure 3It is a schematic diagram of the conductive film structure in the tunable light-transmitting wave-absorbing structure of the present invention;

[0025] Figure 4 The reflectivity curve of the tunable light-transmitting absorbing structure under horizontal polarization with different angles of the deflection block;

[0026] Figure 5 It is the reflectivity curve of the tunable light-transmitting absorbing structure under vertical polarization with different angles of the deflection block;

[0027] Figure 6 Schematic diagram of the structure of a tunable light-transmitting absorbing structure comprising 9 periodic arrays. DETAILED DESCRIPTION

[0028] The following will be combined with the attached embodiment of the present invention Figure 1 ~Attached Figure 6 , the technical solutions, structural features, objectives achieved and effects in the embodiments of the present invention are described in detail.

[0029] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0030] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0031] 1. Tunable light-transmitting wave-absorbing structure design

[0032] The present invention provides a tunable light-transmitting wave absorbing structure, wherein the tunable light-transmitting wave absorbing structure is composed of a plurality of periodic tunable light-transmitting wave absorbing units arranged in an array, such as Figure 1As shown, the single-period tunable light-transmitting absorbing unit comprises: a base 1, a transverse pillar 2 is vertically arranged at one end of the top surface of which; a longitudinal deflection block 3 is vertically arranged with the transverse pillar 2; the longitudinal deflection block 3 comprises: a longitudinal rotation axis assembly 301, which is vertically connected to the center of the transverse pillar 2 and is arranged parallel to the base 1; a longitudinal pillar 302, which is nested and connected with the longitudinal rotation axis assembly 301; a conductive film, which is respectively applied to the transverse pillar 2 and the longitudinal pillar 302; rotating the longitudinal rotation axis assembly 301 drives the longitudinal pillar 302 to rotate, so as to realize the tunable absorbing wavelength of the absorbing structure.

[0033] Among them, Figure 1 As shown, the height H1 of the transverse pillar 2 is between 7 and 10 mm, the thickness d1 is between 0.3 and 0.5 mm, the length P of a single period of absorbing units is between 9 and 10 mm (equivalent to the length of the transverse pillar 2 in each absorbing unit), and the absorbing structure formed by arranging a plurality of absorbing units in a periodic array, the total length L1 of all transverse pillars 2 is between 150 and 300 mm (not shown in the figure); a hole (not shown in the figure) is opened in the center of each of the transverse pillars 2, and the hole diameter D1 is 1 mm for embedding the longitudinal shaft assembly 301.

[0034] Among them, Figure 1 As shown, the height H2 of the longitudinal pillar 302 is lower than the height H1 of the transverse pillar 2, and the height difference between the two is between 0.8 and 1.1 mm. The length L2 of the longitudinal pillar 302 is less than the length P of the absorbing unit of a single period. The difference between the length L2 of the longitudinal pillar 302 and the length P of the absorbing unit of a single period is P-d1-s1, wherein the margin s1 is 0.1 mm, and the thickness d2 of the longitudinal pillar 302 is between 0.3 and 0.5 mm.

[0035] Among them, Figure 2 As shown, a plurality of the longitudinal rotating shaft assemblies 301 are connected to form a multi-period longitudinal rotating shaft. Figure 2The longitudinal rotating shaft with two periods is shown, which is formed by connecting two longitudinal rotating shaft assemblies 301; the multi-period longitudinal rotating shaft can sequentially pass through the pores in the center of multiple transverse pillars 2, thereby connecting multiple absorbing units to form a wave absorbing structure arranged in a periodic array; each of the longitudinal rotating shaft assemblies includes a solid shaft 311 embedded in the pores of the transverse pillars 2 and a hollow groove 312 for embedding and setting the longitudinal pillars 302. The starting end of the multi-period longitudinal rotating shaft (equivalent to the first solid shaft 311 in the multi-period longitudinal rotating shaft) is also connected with a gear 313 for adjusting the rotation of the longitudinal rotating shaft assembly 301; further, the diameter of the longitudinal rotating shaft assembly 301 is equal to the pore diameter D1, the width of the hollow groove 312 is greater than the thickness d2 of the longitudinal pillar 302, and the width d5 ​​of the hollow groove 312 is d2+0.08mm~d2+0.1mm, the module of the gear 313 is 0.3mm, the number of teeth is 18, and the thickness d3 is 1mm.

[0036] Among them, Figure 1 As shown, the thickness d4 of the base 1 is between 0.3 and 0.6 mm, and the length and width of the base 1 match the length of the transverse pillar 2 and the length of the longitudinal shaft assembly 301, respectively, that is, the length of the base 1 is equal to the length L1 of the transverse pillar 2, and the width L3 of the base 1 is equal to the length of each longitudinal shaft assembly, that is, the total length of a solid shaft 311 and a hollow groove 312; further, a rectangular groove (not shown in the figure) is also opened on one side of the top surface of the base 1, and the depth of the rectangular groove is 0.1 to 0.2 mm, and the width is the same as the thickness d1 of the transverse pillar 2, which is used for fixing and embedding the transverse pillar 2.

[0037] Furthermore, if Figure 6As shown, the absorbing unit at the starting end of the tunable light-transmitting absorbing structure further includes a rack 5, which is slidably arranged at one end of the base 1 connected to the transverse pillar 2 and is on the same horizontal plane as the base 1, that is, the rack 5 is arranged at one end of the base 1 with a rectangular groove, that is, the back of the transverse pillar 2. When the gear 313 is rotated, the gear 313 and the rack 5 are meshed and connected, driving the rack 5 to slide along the side of the base 1 relative to the transverse pillar 2. The module of the rack 5 is equal to the module of the gear 313, and the number of teeth is greater than the number of teeth of the gear 313. When in use, first connect the gear 313 to the end of the longitudinal shaft, then insert the other end of the longitudinal shaft (composed of three longitudinal shaft assemblies 301 connected) into the hole from the back of the transverse pillar 2 of the absorbing unit at the starting end, and then further pass through the transverse pillars 2 of the two absorbing units in sequence, so that the gear 313 is engaged with the rack 5 arranged on the back of the transverse pillar 2 of the absorbing unit at the starting end, and the three solid shafts 311 on the longitudinal shaft are correspondingly embedded in the gaps of the transverse pillars 2 of each absorbing unit. Further, on the three hollow grooves 312 of the longitudinal shaft, the longitudinal pillars 302 are symmetrically embedded along the longitudinal shaft, and the rotating gear 313 drives the longitudinal shaft to rotate and then drives the longitudinal pillars 302 to rotate.

[0038] Among them, Figure 1 As shown, the conductive film is in an x-shape, or is called a symmetrical double-open resonant ring. The longitudinal conductive films 402 applied to the surfaces of both sides of the longitudinal pillar 302 are symmetrically arranged along the longitudinal shaft assembly 301, and the transverse conductive films 401 applied to the adjacent surfaces of the transverse pillar 2 and the longitudinal deflection block 3 are located on both sides of the central pore of the transverse pillar 2 (or the center of the transverse conductive film 401 coincides with the midpoint of the line connecting the central pores of two adjacent transverse pillars 2); further, as Figure 3 As shown, the structural dimensions of the conductive film include length p, height h, conductive film filling area width w, and conductive film opening width s. Among them, the width p of the conductive film is between 7.5 and 8.5 mm, the height h is between 4 and 6 mm, the filling area width w is between 0.9 and 1.1 mm, and the opening width s is between 0.9 and 1.1 mm. The film thickness d6 is between 0.02 and 0.04 mm (not shown in the figure), and the conductivity range of the conductive film is 500 to 700 S / m.

[0039] In this embodiment, if Figure 1As shown, in a single-period wave absorbing unit, the period length P is 10 mm, the height H1 of the transverse pillar 2 is 9 mm, the length L1 is equal to the period length P of 10 mm, and the thickness d1 is 0.5 mm; the diameter D1 of the pore opened in the center of the transverse pillar 2 is 1 mm. The height of the longitudinal pillar 302 is lower than the height of the transverse pillar 2, and its height is selected as 8 mm. The length L2 of the longitudinal pillar 302 is less than the period length P of the wave absorbing structure. The length L2 of the longitudinal pillar 302 is P-d1-s1=10 mm-0.5 mm-0.1 mm=9.4 mm, and the thickness d2 of the longitudinal pillar 302 is 0.5 mm. The diameter of the longitudinal rotating shaft assembly 301 is equal to the pore diameter D1 and is equal to 1 mm. The width of the hollow groove 312 is greater than the thickness d2 of the longitudinal pillar 302, and the width d5 ​​of the hollow groove 312 is equal to 0.56 mm. The module of the gear 313 is 0.3 mm, the number of teeth is 18, and the thickness d3 is 1 mm. The module of the rack 5 is equal to the module of the gear 313, which is 0.3 mm, and the number of teeth of the rack 5 is 40. The thickness d4 of the base 1 is 0.5 mm, the length of the base is equal to the length L1 of the transverse pillar, which is 10 mm, and the width L3 of the base is also equal to 10 mm; further, the rectangular groove depth on the top surface of the base 1 is 0.1 mm, and the width is the same as the thickness d1 of the transverse pillar 2, which is equal to 0.5 mm. The width p of the conductive film is 8 mm, the height h is 5 mm, the width w of the filling area is 1 mm, the opening width s is 1 mm, the film thickness d6 is 0.04 mm, and the conductivity range of the conductive film is 600 S / m.

[0040] 2. Simulation of reflectivity of tunable light-transmitting absorber structure

[0041] The single-cycle tunable light-transmitting absorber unit with parameter settings completed in this embodiment is imported into the CST software platform, and reflectivity simulation is performed on it to analyze the reflectivity of the material under vertical and horizontal polarizations. Through the positioning setting of the geometric model, the angle between the longitudinal deflection block 3 and the base 1 is adjusted, and the initial angle between the longitudinal deflection block 3 and the base 1 is set to 90°, that is, the longitudinal deflection block 3 and the base 1 are in a mutually perpendicular state. The adjustment range of the deflection angle of the longitudinal deflection block 3 is 0-360°. Deflection angle values ​​such as 0°, 45°, 75°, 135°, and 180° are selected for model setting. Electromagnetic simulation analysis is performed on the model with the longitudinal deflection block 3 at different deflection angles to observe the influence of the change in the deflection angle of the longitudinal deflection block 3 on the reflectivity of the absorber structure. The reflectivity results are shown in FIG. Figure 4 and Figure 5 shown.

[0042] from Figure 4It can be seen that the reflectivity of the tunable light-transmitting absorbing structure in the horizontal polarization state of electromagnetic waves changes significantly with the deflection angle of the longitudinal deflection block 3. When the longitudinal deflection block 3 is not deflected, the reflectivity of the absorbing structure reaches below -15dB in the range of 8-20GHz, and has a good absorbing effect; when the deflection angle of the longitudinal deflection block 3 is 15°, the reflectivity of the absorbing structure at 18-20GHz increases, the absorbing performance weakens, and the reflectivity at 10-16GHz decreases to a certain extent; when the deflection angle of the longitudinal deflection block 3 is turned to 45°, the reflectivity of the absorbing structure is reduced in the range of 6-18GHz, and increases in the range of 18-20GHz; when the longitudinal deflection block 3 is turned to 45°, the reflectivity of the absorbing structure is reduced in the range of 6-18GHz, and increases in the range of 18-20GHz; when the longitudinal deflection block 3 is turned to 50°, the reflectivity of the absorbing structure is reduced in the range of 18-20GHz, and increases in the range of 20-3 .... When the deflection angle of the rotating block 3 is 90°, the reflectivity absorption peak of the absorbing structure is significantly reduced in the range of 8-9 GHz; when the deflection angle of the longitudinal deflection block 3 is 135°, the reflectivity of the absorbing structure is reduced in the range of 9-19 GHz, and is most obvious in the range of 9-18 GHz, with the reflectivity below -25 dB; when the deflection angle of the longitudinal deflection block 3 is 150°, the reflectivity of the absorbing structure is reduced in the range of 8-18 GHz, and the reflectivity in the range of 9-20 GHz reaches below -20 dB; when the deflection angle of the longitudinal deflection block 3 is 180°, the corresponding reflectivity is close to that when the deflection angle of the longitudinal deflection block 3 is 0°, and the change is not obvious.

[0043] Likewise, from Figure 5 It can be seen that when the incident polarization of the electromagnetic wave is vertical polarization, the reflectivity of the tunable light-transmitting absorbing structure is greatly different from that of the horizontal polarization as the deflection angle of the longitudinal deflection block 3 changes, and the change amplitude of the reflectivity is basically within 10dB; specifically, when the longitudinal deflection block 3 is not deflected, the reflectivity of the absorbing structure has a minimum value of close to -25dB near 8GHz; when the deflection angle of the longitudinal deflection block 3 is 15°, the reflectivity of the absorbing structure increases at 6-8GHz and decreases at 9-20GHz; when the longitudinal deflection block 3 is deflected by 45°, the peak value of the reflectivity of the absorbing structure is near 9GHz, reaching -2 7.5dB, and the reflectivity decreases at 9-20GHz; when the longitudinal deflection block 3 is deflected by 90°, the reflectivity of the absorbing structure is close to that when the deflection angle of the longitudinal deflection block 3 is 0°, and the change is not obvious; when the deflection angle of the longitudinal deflection block 3 reaches 135°, the reflectivity of the absorbing structure is close to that when the deflection angle of the longitudinal deflection block 3 is 45°; when the longitudinal deflection block 3 is deflected by 150°, the reflectivity of the absorbing structure is reduced at the high frequency of 9-20GHz, and the peak frequency of the reflectivity is around 9.5GHz; when the deflection angle of the longitudinal deflection block 3 reaches 180°, the reflectivity of the absorbing structure is close to that when the longitudinal deflection block 3 is not deflected.

[0044] In general, by adjusting the deflection angle of the longitudinal deflection block 3 in the absorbing structure, the reflectivity of the absorbing structure can be significantly adjusted in the range of 8-12 GHz, and can be controlled in the range of -28 to -10 dB. For the range of 12-20 GHz, the material can be maintained at a broadband absorption of -20 dB through regulation.

[0045] 3. Selection and manufacturing of tunable light-transmitting absorbing structural materials

[0046] The manufacture of the tunable light-transmitting radar absorbing structure mainly includes four parts: selection of materials for the conductive film 4 and pillars (including the base 1, the transverse pillar 2 and the longitudinal pillar 302), manufacture of the longitudinal rotating shaft assembly 301, application of conductive films on the surfaces of the longitudinal pillars and the transverse pillars, and overall assembly of the absorbing structure.

[0047] 3.1 Selection of conductive film and support materials

[0048] The material of the conductive film can be selected from the following materials: (1) indium tin oxide, zinc aluminum oxide, etc.; (2) conductive powder (such as aluminum powder, carbon powder, silver powder, copper powder, etc.); (3) a mixture of graphene film, metal nanowires, etc. with epoxy resin, ultraviolet light curing resin, polyimide resin, etc.

[0049] The base 1 , the transverse support 2 , and the longitudinal support 302 may be made of one or more composites of polymethyl methacrylate PMMA, polyimide PI, polyvinyl alcohol PVA, polypropylene PP, polyethylene terephthalate PET, polycarbonate PC, and polystyrene PS.

[0050] 3.2 Longitudinal shaft manufacturing

[0051] The material of the longitudinal shaft assembly is a transparent medium, and the manufacturing material can be selected from one or more composites of polyvinyl alcohol PVA, polypropylene PP, polyethylene terephthalate PET, polycarbonate PC, and polystyrene PS. The processing of the longitudinal shaft includes the processing of the gear 313 based on three-dimensional molding, and the processing of the solid shaft 311 and the hollow groove 312 area based on compression molding.

[0052] The three-dimensional molding manufacturing steps mainly include:

[0053] (1) Three-dimensional model construction: Use CAD software (such as UG, Pro / E, I-DEAS, etc.) on a PC or workstation to design a three-dimensional model based on the structure of the gear 313.

[0054] (2) Layering of the 3D model: Import the STL file into the slicing software of the dedicated 3D molding equipment, and discretize the 3D model into a series of ordered 2D slices along the molding height direction to extract the cross-sectional contour. The discrete interval range is 0.05-0.2 mm, and the commonly used interval range is 0.1 mm, which can obtain a fairly smooth molding surface.

[0055] (3) Layer-by-layer three-dimensional molding: According to the cross-sectional contour of the layered processing, under computer control, the forming head (such as a laser scanning head or a nozzle) in the three-dimensional molding system is controlled by a numerical control system, and the cross-sectional contour is scanned in the xy plane to obtain layer-by-layer cross-sections. Finally, the shaft model can be prepared by superimposing each layer.

[0056] (4) Post-processing: After the model is formed, the workpiece is taken out and polished and coated to obtain a structural part with a smooth surface.

[0057] The steps of the molding-based manufacturing are as follows:

[0058] (1) Plastic injection: First add the plastic into the mold cavity, gradually heat and pressurize it, and stop heating when the plastic becomes a viscous flow and fills the entire cavity.

[0059] (2) Cooling molding: Turn on the cooling device, open the mold after the plastic cools to below the thermal deformation temperature, take out the product, and then grind the surface to obtain a smooth surface structural part.

[0060] According to the above processing steps, the processed gear 313 is bonded to the periodically distributed solid shaft 311 and the hollow groove 312 to obtain the entire rotating shaft component.

[0061] 3.3 Conductive film application on the surface of longitudinal support 302 and transverse support 2

[0062] The preparation of conductive films is carried out according to the materials used, and mainly includes two types of processing: metal film magnetron sputtering processing and conductive paste screen printing processing.

[0063] If the material of the conductive film is a metal oxide such as indium tin oxide, zinc aluminum oxide, etc., it is manufactured by magnetron sputtering. The magnetron sputtering chamber uses the corresponding metal oxide target as the raw material, prepares the corresponding mask layer according to the designed conductive film structure (that is, digs out the corresponding x-shaped conductive film pattern on the complete film surface), and then applies the mask layer to the surface of the transverse pillar 2 or the longitudinal pillar 302, and places various materials required for preparation in the magnetron sputtering chamber. The upper part of the magnetron sputtering chamber is provided with a magnetron cathode target holder, and the front of the magnetron sputtering chamber is provided with an observation window to observe the sputtering state of the sample during the sputtering process. After the machine is turned on for sputtering, the material in the magnetron sputtering chamber is sputtered on the surface of the transverse pillar 2 or the longitudinal pillar 302 that is not covered by the mask layer, the sputtering switch is turned off and gas is filled in, and after the system is stable, the sputtered transverse pillar 2 or the longitudinal pillar 302 is taken out, and the mask layer on the surface of the transverse pillar 2 or the longitudinal pillar 302 is torn off, and the x-shaped pattern conductive film can be applied to the surface of the dielectric block.

[0064] If the material of the conductive film is a conductive powder such as aluminum powder, carbon powder, silver powder, copper powder, or a mixture of graphene film, metal nanowire, etc. and epoxy resin, ultraviolet light curing resin, polyimide resin, etc., a screen printing process is used to complete the application of the conductive film on the dielectric plate, which specifically includes the following steps:

[0065] Step 1: Cut the conductive film to be applied to the transverse support 2 or the longitudinal support 302 into the required size, and clean the surface of the conductive film with alcohol to ensure that the surface of the conductive film is clean, flat, and has good adhesion;

[0066] Step 2: Fix the screen frame on the screen printing table, level the screen frame height, then fix the medium plate on the screen printing table, align the screen pattern and the medium plate and adjust the distance between the screen and the medium plate;

[0067] Step 3: Pour the prepared conductive film slurry on the left side of the screen, move the ink knife to the right to make the conductive slurry cover the pattern on the screen, and move the scraper to the left to make the conductive slurry on the screen evenly distributed on the dielectric plate;

[0068] Step 4: Take out the dielectric plate and let it stand for one minute to allow the conductive slurry to level out;

[0069] Step 5: Use an oven to heat and dry the conductive film slurry on the dielectric plate to form a conductive film, the drying temperature is 30-60° C., and the time is 5-20 minutes;

[0070] Repeat steps 1 to 5 to prepare multiple conductive films; apply the prepared conductive films to the transverse pillars 2 or the longitudinal pillars 302 to complete the preparation of various components of the absorbing structure.

[0071] 3.4 Overall assembly of the wave absorbing structure

[0072] The various components of the prepared absorbing unit are assembled, specifically including the following steps: step S1, preparing a conductive film and applying it to the surface of the transverse pillar 2 and the longitudinal pillar 302 respectively; step S2, vertically embedding the transverse pillar 2 with the conductive film applied in step S1 into the rectangular groove on the base 1; step S3, embedding the solid shaft 311 of the longitudinal rotating shaft assembly 301 into the central pore of the transverse pillar 2; step S4, symmetrically embedding the longitudinal pillar 302 applied with the conductive film in step S1 into the hollow groove 312 along the longitudinal rotating shaft assembly 301.

[0073] The assembly of the absorbing unit at the starting end further includes step S5 , fixing the gear 313 to the solid shaft 311 embedded in the central hole of the transverse support 2 , and meshing the gear 313 to the rack 5 .

[0074] Repeat steps S1 to S4 to prepare multiple absorbing units with the same structure; when multiple absorbing units are arranged in a periodic array, first connect the starting end absorbing units with gears 313 in a row, then connect the absorbing units without gears 313 to the starting end absorbing units in parallel by connecting the longitudinal shaft assembly 301, and finally obtain a periodically arranged tunable light-transmitting absorbing structure. Figure 6 In the embodiment shown, the starting end absorbing units of three periods are first connected into a row, and then two periods of absorbing units without gears 313 are connected side by side with each starting end absorbing unit through the longitudinal shaft assembly 301, and finally a tunable light-transmitting absorbing structure including a 9-period array structure is obtained, and the deflection angle of the longitudinal pillar 302 is adjusted by rotating the gear 313 to achieve the tunable characteristics of the absorbing structure. In another embodiment, the absorbing units are arranged in a plurality of periodic arrays to obtain a tunable light-transmitting absorbing structure, and the length of the base 1 of the absorbing structure is equal to the total length of the transverse pillars 2 of the plurality of periods, which is equal to 180 mm, and the width L3 of the base 1 of the absorbing structure is also equal to 180 mm.

[0075] In summary, compared with existing absorbing structures, the tunable light-transmitting absorbing structure and the manufacturing method provided by the present invention have the advantages of a wide absorbing range, light absorbing structure material, and strong adaptability.

[0076] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A tunable light-transmitting wave-absorbing structure, characterized in that: The tunable light-transmitting wave absorbing structure is composed of multiple periods of tunable light-transmitting wave absorbing units arranged in an array, and a single period of wave absorbing units includes: A base (1) having a transverse support (2) vertically arranged at one end of the top surface thereof; A longitudinal deflection block (3) disposed perpendicularly to the transverse support (2); The longitudinal deflection block (3) comprises: a longitudinal rotation shaft assembly (301) which is vertically connected to the center of the transverse support (2) and is arranged parallel to the base (1); a longitudinal support (302) which is nested and connected to the longitudinal rotation shaft assembly (301); Conductive films are respectively applied to the transverse pillar (2) and the longitudinal pillar (302); the conductive films are in the shape of an x-shape or a symmetrical double-open resonant ring; the longitudinal conductive films (402) applied to the surfaces on both sides of the longitudinal pillar (302) are symmetrically arranged along the longitudinal shaft assembly (301); the transverse conductive films (401) applied to the surfaces adjacent to the transverse pillar (2) and the longitudinal deflection block (3) are located on both sides of the central aperture of the transverse pillar (2); The longitudinal rotating shaft assembly (301) is rotated to drive the longitudinal support (302) to rotate, thereby achieving tunable wave absorption wavelength of the wave absorption structure.

2. The tunable light-transmitting absorbing structure according to claim 1, characterized in that: The height H1 of the transverse pillar (2) in the single-period wave absorbing unit is between 7 and 10 mm, the length is between 9 and 10 mm, and the thickness d1 is between 0.3 and 0.5 mm; The total length L1 of the transverse pillars (2) of the wave absorbing structure formed by the periodic array of multiple wave absorbing units is between 150 and 300 mm; A hole is provided at the center of each of the transverse pillars (2), and the hole diameter D1 is 1 mm, for embedding the longitudinal rotating shaft assembly (301).

3. The tunable light-transmitting absorbing structure according to claim 1, characterized in that: The height H2 of the longitudinal support (302) is lower than the height H1 of the transverse support (2), and the height difference between the two is between 0.8 and 1.1 mm; The length L2 of the longitudinal pillar (302) is less than the length P of the absorbing unit of a single period, the length P of the absorbing unit of a single period is 9 to 10 mm, and the difference between the length L2 of the longitudinal pillar (302) and the length P of the absorbing unit of a single period is P-d1-s1, wherein the margin s1 is 0.1 mm; The thickness d2 of the longitudinal support (302) is between 0.3 and 0.5 mm.

4. The tunable light-transmitting absorbing structure according to claim 2, characterized in that: A plurality of the longitudinal rotating shaft components (301) are connected to form a multi-periodic longitudinal rotating shaft, which is used to connect a plurality of absorbing units to form a periodic array absorbing structure; the longitudinal rotating shaft component comprises: A solid shaft (311) embedded in the pores of the transverse pillar (2) and a hollow groove (312) for embedding and setting the longitudinal pillar (302); The starting end of the multi-period longitudinal rotating shaft assembly (301) is connected to a gear (313) for adjusting the rotation of the longitudinal rotating shaft assembly (301); The diameter of the longitudinal rotating shaft assembly (301) is equal to the hole diameter D1 at the center of the transverse support (2), and the width d5 ​​of the hollow groove (312) is equal to d2+0.08mm~d2+0.1mm; The module of the gear (313) is 0.3 mm, the number of teeth is 18, and the thickness d3 is 1 mm.

5. The tunable light-transmitting absorbing structure according to claim 4, characterized in that: The thickness d4 of the base (1) is between 0.3 and 0.6 mm, the length of the base (1) is equal to the length L1 of the transverse support (2), and the width L3 of the base (1) is equal to the length of each longitudinal rotating shaft assembly (301); A rectangular groove is also provided on one side of the top surface of the base (1) connected to the rack (5), the depth of the rectangular groove is 0.1 to 0.2 mm, and the width is the same as the thickness d1 of the transverse support (2), and is used for fixing and embedding the transverse support (2); The starting end absorbing unit of the tunable light-transmitting absorbing structure further comprises a rack (5), which is slidably arranged at one end of the base (1) connected to the transverse support (2) and is located on the same horizontal plane as the base (1); the module of the rack (5) is equal to the module of the gear (313), and the number of teeth of the rack (5) is greater than the number of teeth of the gear (313).

6. The tunable light-transmitting absorbing structure according to claim 1, characterized in that: The conductive film has a width p of 7.5 to 8.5 mm, a height h of 4 to 6 mm, a filling area width w of 0.9 to 1.1 mm, an opening width s of 0.9 to 1.1 mm, a thickness d6 of 0.02 to 0.04 mm, and a conductivity range of 500 to 700 S / m.

7. The tunable light-transmitting absorbing structure according to claim 1, characterized in that: The conductive film is made of one of the following materials, including: a mixture of indium tin oxide, zinc aluminum oxide or conductive powder or graphene film, metal nanowires and epoxy resin, ultraviolet light curing resin, and polyimide resin; The base (1), the transverse support (2), and the longitudinal support (302) are made of one or more composites selected from polymethyl methacrylate (PMMA), polyimide (PI), polyvinyl alcohol (PVA), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), and polystyrene (PS); The longitudinal rotating shaft assembly (301) is made of one or more composites of polyvinyl alcohol (PVA), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), and polystyrene (PS).

8. The tunable light-transmitting absorbing structure according to claim 4, characterized in that: The gear (313) is manufactured by a three-dimensional molding method, and the solid shaft (311) and the hollow groove (312) in the longitudinal rotating shaft assembly (301) are manufactured by compression molding.

9. The tunable light-transmitting absorbing structure according to claim 8, characterized in that: When the material of the conductive film is a metal oxide such as indium tin oxide, zinc aluminum oxide, etc., it is manufactured by magnetron sputtering; When the material of the conductive film is a mixture of conductive powder or graphene film, metal nanowires, etc. and epoxy resin, ultraviolet light curing resin, polyimide resin, etc., the conductive film is prepared on the dielectric plate by using a screen printing process.

10. The tunable light-transmitting absorbing structure according to any one of claims 1 to 9, characterized in that: The overall assembly of the absorbing structure includes the following steps: Step S1, preparing a conductive film and applying it on the surface of the transverse pillar (2) and the longitudinal pillar (302) respectively; Step S2, vertically embedding the transverse support (2) with the conductive film applied in step S1 into the rectangular groove on the base (1); Step S3, embedding the solid shaft (311) of the longitudinal rotating shaft assembly (301) into the central hole of the transverse support (2); Step S4, embedding the longitudinal pillar (302) with the conductive film applied in step S1 symmetrically into the hollow groove (312) along the longitudinal rotating shaft assembly (301); The assembly of the absorbing unit at the starting end further includes step S5, fixing the gear (313) to the solid shaft (311) embedded in the central hole of the transverse support (2), and meshing the gear (313) with the rack (5); Repeat steps S1 to S4 to prepare a plurality of absorbing units with the same structure. When the plurality of absorbing units are arranged in a periodic array, the starting end absorbing units assembled in step S5 are first connected in columns, and then the absorbing units assembled in steps S1 to S4 are connected side by side with the starting end absorbing units by connecting a longitudinal rotating shaft assembly (301), thereby obtaining a periodically arranged tunable light-transmitting absorbing structure.

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