Lightweight conformal antenna and processing method of lightweight conformal antenna

Abstract

The invention discloses a light-weight conformal antenna and a processing method of the light-weight conformal antenna, and relates to the technical field of antennae, the light-weight conformal antenna comprises an antenna protection layer, a metal layer, a dielectric layer and a PMI foam layer which are laminated in sequence, the PMI foam layer is used as a core bearing structure, a composite design of a metal grid structure and a dielectric grid structure is adopted, and the PMI foam layer is used as a core bearing structure. The processing method comprises the following steps: performing hot press molding on the curved surface of the PMI foam board; a medium layer and a metal layer are printed on a curved surface layer by layer by using printing equipment, post-treatment thermocuring is carried out, a PMI foam lightweight material is adopted, large-curvature conformal is realized by combining a 3D printing technology, and a metal grid and medium grid composite structure is adopted on a third antenna metal layer to enhance the bonding strength, so that the antenna has a wide application prospect. The composite material has the advantages of high structural strength, good dielectric property, light weight, short processing period and the like.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, specifically to a lightweight conformal antenna and a method for fabricating a lightweight conformal antenna. Background Technology

[0002] Conformal antennas, which can conform perfectly to the shape of the carrier structure, have advantages such as high concealment, high integration, and good communication capabilities. They are widely used in ground communication base stations, airborne radar payloads, and radio frequency sensors for electronic information systems.

[0003] In existing technologies, printed circuit boards (PCBs) are commonly used to fabricate multilayer PCBs for antennas. Depending on the antenna structure and performance requirements, materials such as ordinary epoxy, low-dielectric PTFE, or hydrocarbon systems can be selected. On the one hand, these PCB materials are relatively heavy, which cannot meet the requirements for lightweight antennas; on the other hand, PCBs are mostly rigid structures, and traditional PCB lamination processes can only achieve planar or slightly curved multilayer PCB fabrication for antennas, which cannot meet the requirements for conformal antennas with large curvature. Summary of the Invention

[0004] In view of the above problems, the present invention provides a lightweight conformal antenna and a method for fabricating a lightweight conformal antenna, which can fully utilize the advantages of PMI foam material as the dielectric layer structure in the antenna circuit structure, namely its lightweight, high strength and good dielectric properties.

[0005] In a first aspect, embodiments of the present invention provide a lightweight conformal antenna, comprising: an antenna protective layer, a first antenna metal layer, a first dielectric layer, a PMI foam layer, a second dielectric layer, a second antenna metal layer, a third dielectric layer, and a third antenna metal layer stacked sequentially. The PMI foam layer has a curved structure and serves as a load-bearing structure. The first dielectric layer, the second dielectric layer, the third dielectric layer, and the antenna protective layer are all made of the same photosensitive resin material; The first antenna metal layer, the second antenna metal layer, and the third antenna metal layer all contain nano-metal materials and photosensitive resin materials, and the nano-metal materials are the same nano-metal materials. The third antenna metal layer comprises a metal mesh structure occupying the main area and a dielectric mesh structure occupying the secondary area, the dielectric mesh structure being made of photosensitive resin material.

[0006] In some embodiments, the photosensitive resin material includes acrylates, polyimides, epoxy resins, polyurethanes, or polyarylethers; the nanomaterial includes nanosilver, nanocopper, or nanogold.

[0007] In some embodiments, the third dielectric layer is provided with an interconnect circuit structure that electrically connects the second antenna metal layer and the third antenna metal layer.

[0008] In some embodiments, the minimum radius of curvature of the PMI foam layer is ≤100mm.

[0009] Secondly, applying the first aspect, embodiments of the present invention provide a method for fabricating a lightweight conformal antenna, comprising the following steps: The original planar PMI foam board is subjected to curved hot pressing molding to obtain a curved PMI foam layer; Using the PMI foam layer as the supporting structure, a 3D printing device is used to spray and deposit medium material and metal material layer by layer on one side and perform photocuring to form a second medium layer, a second antenna metal layer, a third medium layer and a third antenna metal layer in sequence; Using 3D printing equipment, deposited medium material and metal material are sprayed layer by layer onto the other side of the PMI foam layer and then photocured to form the first medium layer, the first antenna metal layer and the antenna protective layer in sequence. The printed conformal antennas are then thermosetting and fixed using tooling.

[0010] In some embodiments, the thickness and curvature of the PMI foam layer are controlled by the concave mold 9, the convex mold 10 and the limiting structure; the thermosetting post-treatment includes curing the photosensitive resin material by controlling the heating curve.

[0011] In some embodiments, the thickness of the original planar PMI foam board is 5% to 15% greater than the thickness of the PMI foam layer after hot pressing; the curved hot pressing is controlled by the concave mold 9, the convex mold 10 and the mold guide pin 11, and the mold guide pin 11 controls the thickness of the PMI foam layer after hot pressing.

[0012] In some embodiments, the process parameters for the curved surface hot pressing forming include: The heating program is as follows: hold at 80℃ for 30 minutes, hold at 150℃ for 20 minutes, hold at 200℃ for 10 minutes, with a heating rate ≤5℃ / min; The pressurization procedure is as follows: initial pressure of 0.5 MPa at 80°C, pressure increase to 2 MPa at 150°C, and final pressure of 5 MPa at 200°C, with a holding time of 15 minutes.

[0013] In some embodiments, the light source for photocuring is a UVLED light source with a wavelength of 365nm, wherein the single-layer exposure time is 5s and the interlayer cooling time is 10s.

[0014] In some embodiments, the process parameters for the thermosetting post-treatment are: holding at 80℃ for 30 min to 120℃ for 60 min to 160℃ for 120 min, with a heating rate of 2℃ / min; the curvature of the straightening fixture is consistent with that of the PMI foam layer, the pressure is 0.1MPa, and it is unloaded after cooling to 60℃, with a curvature rebound amount ≤0.1mm.

[0015] The lightweight conformal antenna and its fabrication method provided in this invention have at least the following advantages: Using PMI foam board as the curved dielectric layer that bears the main load in lightweight conformal antennas has the advantages of high structural strength, good dielectric properties, and light weight. Furthermore, the curved hot pressing process of PMI foam board is easy to control, the molding curvature is adjustable, the internal structure of the foam material has little impact, and the processing feasibility is high, which is conducive to improving the electrical performance of conformal antennas.

[0016] Simultaneously, it performs online printing and photocuring of photosensitive resin materials and nano-metal materials, with high printing precision, selectable material types, and suitability for conformal printing on surfaces with large curvature. It enables precise layer-by-layer manufacturing of each metal layer and dielectric layer in a conformal antenna on a single device, solving the problem that traditional rigid PCBs cannot adapt to structures with large curvature. Compared with traditional multilayer PCB processing methods, the overall processing technology is simpler, the cycle is shorter, there is almost no material waste, and it is environmentally friendly. In particular, it can meet the needs of rapid processing, testing, iteration and optimization in the product development stage.

[0017] During the 3D printing process, all dielectric layers and antenna protective layers use the same photosensitive resin material, and the metal layers use the same nano-metal material, ensuring the uniformity of material properties and the strength of interfacial bonding. Furthermore, the third antenna metal layer innovatively adopts a composite structure combining a metal mesh and a dielectric mesh, significantly enhancing the bonding strength between the metal layer and the dielectric layer while ensuring electrical performance, thus overcoming the bottleneck of easy peeling of metal layers in traditional large-area printing.

[0018] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0019] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0020] Figure 1 A schematic cross-sectional view of an exemplary lightweight conformal antenna structure proposed in one embodiment of the present invention is shown. Figure 2A schematic diagram of the structural relationship of an exemplary PMI foam board curved surface hot pressing molding process according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of an exemplary third antenna metal layer mesh structure proposed in one embodiment of the present invention is shown; Figure 4 A flowchart illustrating a method for fabricating a lightweight conformal antenna according to an embodiment of the present invention is shown. Figure 5 A flowchart of a lightweight conformal antenna fabrication process according to an embodiment of the present invention is shown. Figure 6 The measured radiation pattern of the sample at the working center frequency in one embodiment of the present invention is shown.

[0021] Figure label: 1-Antenna protective layer, 2-First antenna metal layer, 3-First dielectric layer, 4-PMI foam layer, 5-Second dielectric layer, 6-Second antenna metal layer, 7-Third dielectric layer, 8-Third antenna metal layer, 9-(PMI foam board curved surface hot pressing forming) concave mold 9, 10-(PMI foam board curved surface hot pressing forming) convex mold 10, 11-Mold guiding limit pin 11, 801-(Third antenna metal layer) metal mesh structure, 802-(Third antenna metal layer) dielectric mesh structure. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0023] In the prior art, some antenna PCBs use PMI (polymethacrylimide) foam material as dielectric substrate in the stacked structure. PMI foam material has the characteristics of excellent dielectric properties, light weight and high strength, which can solve the antenna lightweight requirement to a certain extent.

[0024] However, as a cross-linked porous material, PMI foam is prone to changes in its internal pore structure when bonded with printed circuit boards and prepregs under high temperature and pressure, which leads to deterioration of dielectric properties and affects the electrical performance of antennas. Moreover, the existing technology has relatively complex processing methods.

[0025] To address the aforementioned issues, the applicant proposed a lightweight conformal antenna and its fabrication method. This method fully leverages the advantages of PMI foam material as the dielectric layer in the antenna circuit structure, including its lightweight, high strength, and excellent dielectric properties. Furthermore, it optimizes the lightweight conformal antenna fabrication method by combining PMI foam board curved surface molding and curved multilayer circuit board 3D printing technologies.

[0026] The lightweight conformal antenna improved in this application includes an antenna protective layer 1, a first antenna metal layer 2, a first dielectric layer 3, a PMI foam layer 4, a second dielectric layer 5, a second antenna metal layer 6, a third dielectric layer 7, and a third antenna metal layer 8 stacked in sequence.

[0027] The antenna in this application is a classic two-layer microstrip patch array antenna structure. The thickness of each layer, the shape of the metal pattern, the number of arrays, and the array spacing are obtained through simulation.

[0028] PMI foam layer 4 has a curved structure and serves as a load-bearing structure; The first dielectric layer 3, the second dielectric layer 5, the third dielectric layer 7, and the antenna protective layer 1 are all made of the same photosensitive resin material; The first antenna metal layer 2, the second antenna metal layer 6, and the third antenna metal layer 8 all contain nano-metal materials and photosensitive resin materials, and the nano-metal materials are the same nano-metal materials. See Figure 3 The third antenna metal layer 8 includes a metal mesh structure 801 occupying the main area and a dielectric mesh structure 802 occupying the secondary area. The dielectric mesh structure 802 is made of photosensitive resin material.

[0029] Photosensitive resin materials include acrylates, polyimides, epoxy resins, polyurethanes, or polyarylethers; nanomaterials include nanosilver, nanocopper, or nanogold.

[0030] The third dielectric layer 7 contains an interconnect circuit structure that electrically connects the second antenna metal layer 6 and the third antenna metal layer 8.

[0031] The minimum radius of curvature of the PMI foam layer 4 is ≤100mm.

[0032] For fabrication methods of lightweight conformal antennas, please refer to [link / reference]. Figure 4 ,include: S110: Perform curved hot pressing molding on the original planar PMI foam board to obtain a curved PMI foam layer 4; S120: Using PMI foam layer 4 as the supporting structure, 3D printing equipment is used to spray and deposit medium material and metal material layer by layer on one side and perform photocuring to form the second medium layer 5, the second antenna metal layer 6, the third medium layer 7 and the third antenna metal layer 8 in sequence. S130: Using 3D printing equipment, deposited medium material and metal material are sprayed layer by layer on the other side of PMI foam layer 4 and then cured to form the first medium layer 3, the first antenna metal layer 2 and the antenna protective layer 1 in sequence. S140: The printed conformal antenna is fixed by tooling after heat curing.

[0033] For details, please refer to Figure 5 As shown, it may include the following steps: S1: PMI foam board curved surface hot pressing molding.

[0034] In this process, a suitable original flat PMI foam board with appropriate thickness is selected according to the size design requirements of PMI foam layer 4. Corresponding concave mold 9, convex mold 10 and mold guide limit pin 11 are made according to the curved PMI foam board structure to be formed, which are used for hot pressing of PMI foam board curved surface.

[0035] Considering the dimensional shrinkage of PMI foam material during hot pressing, the thickness of the original flat PMI foam board usually needs to be 5% to 15% larger than the thickness of the PMI foam board after hot pressing. The thickness of the PMI foam board after hot pressing is controlled by the mold guide pin 11.

[0036] S2: The second dielectric layer 5 is printed.

[0037] In this process, the prepared curved PMI foam board is used as the supporting structure. Photosensitive resin material is used, and a multi-station five-axis inkjet printer is used to spray and deposit resin material on one side of the curved PMI foam board as needed, while simultaneously performing photocuring to complete the printing of the second medium layer 5.

[0038] The photosensitive resin materials include systems such as acrylates, polyimides, epoxy resins, polyurethanes, and polyarylethers, which can complete the reaction and fix the size and shape after short-time photocuring. For the same antenna product, the first, second, and third dielectric layers 7 and the antenna protective layer 1 should use the same photosensitive resin material. During printing, the curved PMI foam board needs to be clamped and fixed to the printing equipment using special tooling.

[0039] S3: The second antenna metal layer 6 is printed.

[0040] In this process, by using photosensitive resin materials and nano-metal materials, a multi-station five-axis inkjet printing device is used to spray and deposit resin materials and nano-metal materials on the second medium layer 5 as needed, and simultaneously perform photocuring to complete the printing of the second antenna metal layer 6.

[0041] It should be noted that in this step, for the 3D printing method, the metal portion of the antenna metal layer is composed of nanomaterials, while the remaining portion is composed of resin materials. The consistency of this layer's thickness is ensured to provide a foundation for the next layer's printing. Nanomaterials include systems such as nano-silver, nano-copper, and nano-gold, which can achieve a fixed size and shape after short-term photocuring. For the same antenna product, the first, second, and third antenna metal layers 8 should use the same nanomaterial.

[0042] S4: The third dielectric layer 7 is printed.

[0043] Specifically, by employing photosensitive resin materials and nano-metal materials, a multi-station five-axis inkjet printer is used to spray and deposit resin materials and nano-metal materials on the second antenna metal layer 6 as needed, while simultaneously performing photocuring to complete the printing of the third dielectric layer 7. The third dielectric layer 7 is mainly composed of resin materials, while the remaining interconnect circuitry is composed of nano-metal materials. S5: The third antenna metal layer 8 is printed.

[0044] Among them, by using photosensitive resin materials and nano-metal materials, a multi-station five-axis inkjet printing device is used to spray and deposit resin materials and nano-metal materials on the basis of the third dielectric layer 7 as needed, and simultaneously perform photocuring to complete the printing of the third antenna metal layer 8.

[0045] It should be noted that in this step, the third antenna metal layer 8 is mainly composed of nano-metal materials, with the remaining part composed of resin materials. In order to improve the bonding strength between the third antenna metal layer 8 and the third dielectric layer 7, without affecting the electrical performance, the third antenna metal layer 8 is divided into a metal mesh structure 801 occupying the main area and a dielectric mesh structure 802 occupying the secondary area.

[0046] S6: First dielectric layer 3 is printed.

[0047] In this process, by using photosensitive resin material, a multi-station five-axis inkjet printer is used to spray and deposit resin material on the other side of the curved PMI foam board as needed, while simultaneously performing photocuring, to complete the printing of the first medium layer 3.

[0048] S7: The first antenna metal layer 2 is printed.

[0049] In this process, by using photosensitive resin materials and nano-metal materials, a multi-station five-axis inkjet printing device is used to spray and deposit resin materials and nano-metal materials on the first medium layer 3 as needed, and simultaneously perform photocuring to complete the printing of the first antenna metal layer 2.

[0050] S8: Antenna protection layer 1 is printed.

[0051] In this process, by using photosensitive resin material and employing a multi-station five-axis inkjet printing device, the resin material is deposited on the first antenna metal layer 2 as needed and simultaneously photocured to complete the printing of the antenna protective layer 1.

[0052] S9: Perform thermosetting post-processing on the printed conformal antenna.

[0053] In this process, the antenna is placed in a thermosetting oven, and the resin material in the antenna is fully thermoset by controlling the heating time and temperature curve to improve the dielectric properties. In the post-processing, a shaping fixture is used to fix the shape of the conformal antenna structure and suppress its deformation.

[0054] In the specific implementation method, see [reference] Figure 1 and Figure 2 As shown: The lightweight conformal antenna structure consists of an 8-layer stacked structure, including an antenna protective layer 1, a first antenna metal layer 2, a first dielectric layer 3, a PMI foam layer 4, a second dielectric layer 5, a second antenna metal layer 6, a third dielectric layer 7, and a third antenna metal layer 8.

[0055] Among them, the PMI foam layer 4 serves as the core carrier layer, with a minimum curvature radius of ≤100mm. The remaining dielectric and metal layers are conformally covered by 3D printing. The first antenna metal layer 2 is the first microstrip patch layer, the second antenna metal layer 6 is the second microstrip patch layer, and the third antenna metal layer 8 is a metal ground layer. The third dielectric layer 7 contains interconnecting circuit structures that electrically connect the patch unit of the second antenna metal layer 6 and the feed pad in the third antenna metal layer 8.

[0056] In the specific implementation steps, the PMI foam layer 4 in S1 is hot-pressed: The initial board material selection was as follows: a 6.0mm thick flat PMI foam board (model ROHACELL 71HF, target thickness 5.5mm, pre-compensated shrinkage rate 8.3%) with a density of 75. dielectric constant Loss tangent (Test frequency 10GHz) In the mold design, the concave mold 9 and the convex mold 10 are made of 304 stainless steel, the curvature radius of the curved surface R=500mm, and the mold clearance is controlled to be 5.5±0.05mm by the guide limit pin.

[0057] The hot pressing process is as follows: Heating program: 80℃ (30min) → 150℃ (20min) → 200℃ (10min), heating rate ≤ 5℃ / min.

[0058] Pressurization procedure: initial pressure 0.5MPa (80℃), increase to 2MPa (150℃), final pressure 5MPa (200℃), pressure holding time 15min.

[0059] The printing of the second dielectric layer 5 in S2 specifically includes: Fixture fixing: The curved PMI foam layer 4 (4) is clamped to the five-axis printing platform and fixed with a contoured aluminum alloy fixture (curvature tolerance ±0.05mm).

[0060] Printing equipment configuration: Inkjet printer model 5X-3DPES-200, equipped with piezoelectric resin material printhead (100μm diameter).

[0061] Materials: Modified acrylic photosensitive resin (viscosity 1000 cP, ε=3.2 after curing, tanδ=0.02@10GHz), single layer thickness 5μm, total thickness 150μm.

[0062] Photopolymerization process: UVLED light source wavelength 365nm, power density is Single-layer exposure time is 5 seconds, and interlayer cooling is 10 seconds.

[0063] The subsequent steps involve the same resin material printing process.

[0064] The printing process of the second antenna metal layer 6 in S3 specifically includes: Printing equipment configuration: Switch to piezoelectric nano-metal material nozzle (50μm diameter).

[0065] Materials: Nano silver ink, solid content 85%, average particle size 50nm, single layer thickness 1μm, total thickness 15μm.

[0066] Hybrid printing mode: Resin material printing and nano-metal material printing are performed simultaneously.

[0067] UV curing process: The UV curing parameters for the resin material are the same as in step 2, and the metal areas are NIR cured.

[0068] The subsequent steps involve the same printing process for nanomaterials.

[0069] The printing of the third dielectric layer 7 in S4 specifically includes: Hybrid printing mode: Resin material printing and nano-metal material printing are carried out simultaneously, with a total thickness of 200μm.

[0070] Interconnect circuit structure: Interconnect metal pillars with a diameter of 300μm and a height of 200μm.

[0071] The printing process of the third antenna metal layer 8 in S5 specifically includes: Hybrid printing mode: Resin material printing and nano-metal material printing are carried out simultaneously, with a total thickness of 15μm.

[0072] Metal mesh design: Metal mesh accounts for 70%; Medium mesh filled with resin (see details). Figure 4 ) The first dielectric layer 3 in S6 is printed, specifically including: Print on the curved back side, flip the PMI foam layer 4, repeat the S2 process on the other curved surface, and print the first dielectric layer 3 with a total thickness of 150μm.

[0073] The first antenna metal layer 2 in S7 is printed, specifically including: Hybrid printing mode: Resin material printing and nano-metal material printing are carried out simultaneously, with a total thickness of 15μm.

[0074] The antenna protective layer 1 in S8 is printed and includes: Encapsulation layer printing: Pure resin material covers the first antenna metal layer 2 with a total thickness of 50μm and a surface smoothness Ra≤1μm.

[0075] Step 9, antenna post-processing, specifically includes: Curing process: Place the printed antenna in a thermosetting oven and process it according to the following curve: 80℃ (30min) → 120℃ (60min) → 160℃ (120min), with a heating rate of 2℃ / min. Maintain the temperature at 160℃ for 4 hours and remove it after it cools naturally to 60℃.

[0076] Deformation suppression: The curvature of the straightening tool is consistent with that of PMI foam layer 4. The pressure is 0.1MPa. After cooling to 60℃, the curvature rebound amount is ≤0.1mm.

[0077] The conformal antenna fabricated using the above steps is more than 30% lighter than the planar antenna fabricated using traditional PCB methods. (See [link / reference]). Figure 6 As can be seen from the measured radiation pattern data of the antenna sample at the working center frequency, the antenna radiation performance meets the design specifications.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lightweight conformal antenna, characterized in that, include: The antenna protective layer, the first antenna metal layer, the first dielectric layer, the PMI foam layer, the second dielectric layer, the second antenna metal layer, the third dielectric layer, and the third antenna metal layer are stacked in sequence. The PMI foam layer has a curved structure and serves as a load-bearing structure. The first dielectric layer, the second dielectric layer, the third dielectric layer, and the antenna protective layer are all made of the same photosensitive resin material; The first antenna metal layer, the second antenna metal layer, and the third antenna metal layer all contain nano-metal materials and photosensitive resin materials, and the nano-metal materials are the same nano-metal materials. The third antenna metal layer comprises a metal mesh structure occupying the main area and a dielectric mesh structure occupying the secondary area, the dielectric mesh structure being made of photosensitive resin material.

2. The lightweight conformal antenna according to claim 1, characterized in that, The photosensitive resin material includes acrylates, polyimides, epoxy resins, polyurethanes, or polyarylethers; the nanomaterial includes nanosilver, nanocopper, or nanogold.

3. A lightweight conformal antenna according to claim 1, characterized in that, The third dielectric layer is provided with an interconnect circuit structure, which electrically connects the second antenna metal layer and the third antenna metal layer.

4. A lightweight conformal antenna according to claim 1, characterized in that, The minimum radius of curvature of the PMI foam layer is ≤100mm.

5. A method for fabricating a lightweight conformal antenna, characterized in that, The method for manufacturing a lightweight conformal antenna according to any one of claims 1-4 is characterized by comprising the following steps: The original planar PMI foam board is subjected to curved hot pressing molding to obtain a curved PMI foam layer; Using the PMI foam layer as the supporting structure, a 3D printing device is used to spray and deposit medium material and metal material layer by layer on one side and perform photocuring to form a second medium layer, a second antenna metal layer, a third medium layer and a third antenna metal layer in sequence; Using 3D printing equipment, deposited medium material and metal material are sprayed layer by layer onto the other side of the PMI foam layer and then photocured to form the first medium layer, the first antenna metal layer and the antenna protective layer in sequence. The printed conformal antennas are then thermosetting and fixed using tooling.

6. The method for fabricating a lightweight conformal antenna according to claim 5, characterized in that, The thickness and curvature of the PMI foam layer are controlled by a concave mold, a convex mold, and a limiting structure; the thermosetting post-treatment includes curing the photosensitive resin material by controlling the temperature rise curve.

7. The method for fabricating a lightweight conformal antenna according to claim 5, characterized in that, The thickness of the original planar PMI foam board is 5% to 15% greater than the thickness of the PMI foam layer after hot pressing; the curved hot pressing is controlled by a concave mold, a convex mold and a mold guide pin, and the mold guide pin controls the thickness of the PMI foam layer after hot pressing.

8. The method for fabricating a lightweight conformal antenna according to claim 5, characterized in that, The process parameters for the curved surface hot pressing forming include: The heating program is as follows: hold at 80℃ for 30 minutes, hold at 150℃ for 20 minutes, hold at 200℃ for 10 minutes, with a heating rate ≤5℃ / min; The pressurization procedure is as follows: initial pressure of 0.5 MPa at 80°C, pressure increase to 2 MPa at 150°C, and final pressure of 5 MPa at 200°C, with a holding time of 15 minutes.

9. The method for fabricating a lightweight conformal antenna according to claim 5, characterized in that, The light source for photocuring is a UVLED line light source with a wavelength of 365nm. The single-layer exposure time is 5s, and the interlayer cooling time is 10s.

10. The method for fabricating a lightweight conformal antenna according to claim 5, characterized in that, The process parameters for the thermosetting post-treatment are: 80℃ for 30 min, 120℃ for 60 min, 160℃ for 120 min, with a heating rate of 2℃ / min; the curvature of the straightening fixture is consistent with that of the PMI foam layer, the pressure is 0.1MPa, and it is unloaded after cooling to 60℃, with a curvature rebound amount ≤0.1mm.

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