Panel radome based on compounding of PP prepreg strip and PMI foam interlayer and preparation method

Abstract

The invention discloses a planar radome based on compounding of a PP prepreg strip and a PMI foam interlayer and a preparation method. The panel radome comprises a lower-layer skin, a core layer and an upper-layer skin which are sequentially stacked, each of the upper-layer skin and the lower-layer skin comprises a plurality of PP prepreg strip layers which are sequentially stacked, the PP prepreg strip layers are laid in a crossed mode, the core layer comprises a PMI foam core layer, and the PMI foam core layer comprises a PMI foam layer. The PP prepreg strip layer is a polypropylene fiber reinforced polypropylene resin prepreg strip, the fiber volume fraction is 40%-60%, the PMI foam core layer is polymethacrylimide foam, the density is 30-100 kg / m, and the percentage of closed area is larger than or equal to 95%; the preparation method sequentially comprises the steps of material preparation, cutting, laying, hot press molding, cooling demolding and processing molding. The antenna housing is applied to the technical field of antenna housings.

Description

Technical Field

[0001] This invention relates to radomes, and more particularly to a planar radome based on a composite of PP prepreg tape and PMI foam sandwich and its preparation method. Background Technology

[0002] Antenna radomes are crucial components that protect antenna systems from external environmental influences, finding wide and irreplaceable applications in numerous fields such as communications, radar, and navigation. They must not only provide reliable physical protection against harsh environments like wind, rain, dust, and extreme temperatures, but also must not significantly interfere with the antenna's electromagnetic signal transmission. Furthermore, they must possess sufficient structural strength to ensure long-term stable operation.

[0003] With the development of modern technology, the performance requirements for radomes are increasing. Traditional radome materials and manufacturing processes have many shortcomings: for example, radomes made of a single metal material, although strong, are heavy and have a strong shielding effect on electromagnetic signals, which seriously affects the communication performance of the antenna; ceramic radomes, although having good high temperature resistance and insulation properties, are brittle, have poor impact resistance, and are expensive to manufacture, which is not conducive to large-scale applications; some composite material radomes, such as glass fiber reinforced resin matrix composite radomes, have improved in terms of weight and strength, but still need to be improved in terms of weather resistance, fatigue resistance, and dielectric stability. Furthermore, traditional radome manufacturing processes are often complex and inefficient, failing to meet the demands of modern manufacturing for mass production and high precision. Therefore, developing a lightweight, high-strength radome with excellent dielectric properties, good weather resistance, and a simple manufacturing process, along with its fabrication method, has become a pressing technical challenge in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art. The primary objective is to provide a lightweight, high-strength, high-dielectric-performance, and weather-resistant planar radome based on a composite of PP prepreg tape and PMI foam interlayer. The second objective is to provide a simple method for preparing a flat panel radome.

[0005] The technical solution adopted in this invention is as follows: the flat panel radome based on PP prepreg tape and PMI foam sandwich is made of composite flat panel, the composite flat panel includes a lower skin, a core layer and an upper skin layer stacked in sequence, the upper skin and the lower skin each include multiple layers of PP prepreg tape stacked in sequence, the multiple layers of PP prepreg tape are cross-laid, the core layer includes a PMI foam core layer, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape, and the fiber volume fraction is 40%-60%, the PMI foam core layer is polymethacrylimide foam, and the density is 30-100kg / m³, and the closed cell rate is ≥95%.

[0006] Furthermore, the layup direction of each PP prepreg tape layer is one of 0°, 90° or ±45°.

[0007] Furthermore, a modified epoxy resin film is bonded between the upper skin and the core layer, as well as between the lower skin and the core layer.

[0008] Furthermore, the modified epoxy resin film contains 0.5-2 wt% nano-titanium dioxide.

[0009] Furthermore, the thickness of both the upper and lower skin layers is 0.3-0.5 mm, and the thickness of the core layer is 1-15 mm.

[0010] Furthermore, the present invention also provides a method for preparing the planar radome based on the composite of PP prepreg tape and PMI foam sandwich, which includes the following steps: Step S101: Select PP prepreg tape layer as the upper and lower skin layers, and select PMI foam core layer as the core layer; wherein, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 40%-60%, and the PMI foam core layer is polymethacrylimide foam with a density of 30-100kg / m³ and a closed cell rate of ≥95%; Step S102: According to the design dimensions of the radome, cut the PP prepreg tape layer and PMI foam core layer into the corresponding shapes and sizes; Step S103: Lay the lower skin, core layer and upper skin in sequence in the mold, and ensure that each layer is tightly bonded without air bubbles and wrinkles during the laying process; wherein, the number of PP prepreg tape layers for the lower skin and upper skin is determined according to the strength requirements of the radome, and multiple PP prepreg tape layers are laid crosswise. Step S104: Place the laid composite laminate material together with the mold into a hot press for hot pressing and molding; Step S105: After hot pressing, turn off the heating device of the hot press and allow the composite plate to cool naturally to room temperature under pressure. Then demold to obtain the composite plate of PP prepreg tape layer and PMI foam core layer. Step S106: According to the design requirements of the radome, the composite plate is processed to form the required radome.

[0011] Furthermore, in step 101, the PMI foam core layer is subjected to plasma treatment by a plasma device, wherein the power of the plasma device is 100-200W and the time is 30-60s.

[0012] Furthermore, during the hot pressing process in step 104, the hot pressing temperature is 160-190℃, the pressure is 2-5MPa, and the heat and pressure holding time is 30-60min.

[0013] Furthermore, in step 103, the layup direction of each layer of the PP prepreg tape is one of 0°, 90° or ±45°.

[0014] The beneficial effects of this invention are: 1. Lightweight: The finished product has a surface density of ≤0.5kg / m². Both the PP prepreg tape layer and the PMI foam core layer are lightweight materials. The weight of the radome made by combining the two is greatly reduced, which helps to reduce the overall load of the antenna system. It is especially suitable for weight-sensitive fields such as aerospace. 2. High strength: The polypropylene fibers in the PP prepreg tape layer have high strength and modulus. The sandwich structure formed with the PMI foam core layer works synergistically to give the radome good bending and impact resistance, and can effectively resist the impact and load of the external environment. 3. Excellent dielectric properties: X-band transmittance ≥92%, both the PP prepreg tape layer and the PMI foam core layer have stable dielectric properties and low dielectric constant, which have little impact on the electromagnetic signal transmission of the antenna and ensure the communication performance of the antenna. 4. Good weather resistance: The PP prepreg tape layer and PMI foam core layer have good resistance to high and low temperatures and aging, and can work stably for a long time under harsh environmental conditions, extending the service life of the radome. It has passed the thermal cycling test from -55℃ to 85℃ without delamination. 5. Simple preparation process: The preparation method of the present invention adopts hot pressing molding process, which is simple to operate, has high production efficiency, is easy to realize large-scale production, and reduces production costs. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is an exploded view of the composite plate of the present invention; Figure 2 This is an oscilloscope test diagram of an existing radome. Figure 3 This is an oscilloscope test diagram of the flat panel antenna radome of the present invention.

[0017] The attached figures are labeled as follows: 1. Upper skin layer; 2. Core layer; 3. Lower skin layer.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, clockwise, counterclockwise, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0021] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0022] like Figure 1As shown, in this embodiment, the planar radome based on PP prepreg tape and PMI foam sandwich is made of a composite planar sheet. The composite planar sheet includes a lower skin 3, a core layer 2, and an upper skin 1 stacked sequentially. Both the upper skin 1 and the lower skin 3 include multiple layers of PP prepreg tape stacked sequentially, with cross-lays between the multiple PP prepreg tape layers. The core layer 2 includes a PMI foam core layer. The PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 40%-60%. The PMI foam core layer is polymethacrylamide foam with a density of 30-100 kg / m³ and a closed-cell rate ≥95%. The single-layer thickness of the PP prepreg tape layer is 0.1-0.3 mm, and the width is 10-100 mm. The thickness of both the upper skin 1 and the lower skin 3 is 0.3-0.5 mm. The core layer 2 has a pore size of 50-300 μm and a thickness of 1-15 mm. It should be noted that, as Figure 2 As shown, the waveform diagram of the existing radome differs significantly from that without a radome. Both wall thickness and material have a significant impact on the antenna's wave transmission. Meanwhile, the radome made of this composite flat plate in this invention has an X-band wave transmission rate ≥92%. Both the PP prepreg tape layer and the PMI foam core layer have stable dielectric properties and low dielectric constants, minimizing their impact on the antenna's electromagnetic signal transmission and ensuring its communication performance. Specifically, as... Figure 3 As shown, the red markings at the top of the figure represent the waveform of the flat radome of the present invention, and the red markings at the bottom of the figure represent the waveform without the radome. It can be understood that the waveform of the flat radome of the present invention is very similar to that of the waveform without the radome, and the wall thickness has a negligible impact on the wave transmission, which facilitates structural design and ensures the communication performance of the antenna.

[0023] Compared with the shortcomings of the prior art, in this invention, since the finished surface density of the composite plate is ≤0.5kg / m², and both the PP prepreg tape layer and the PMI foam core layer are lightweight materials, the weight of the radome made by combining the two is significantly reduced, which is beneficial to reducing the overall load of the antenna system, and is especially suitable for weight-sensitive fields such as aerospace; secondly, the polypropylene fibers in the PP prepreg tape layer have high strength and modulus, and the sandwich structure formed with the PMI foam core layer works synergistically to give the radome made by the composite plate good bending and impact resistance, and can effectively resist the impact and load of the external environment; Furthermore, the radome made from this composite flat panel has an X-band transmittance of ≥92%. Both the PP prepreg tape layer and the PMI foam core layer have stable dielectric properties and low dielectric constants, which have little impact on the electromagnetic signal transmission of the antenna and ensure the antenna's communication performance. Moreover, the PP prepreg tape layer and the PMI foam core layer have good resistance to high and low temperatures and aging, and can work stably for a long time under harsh environmental conditions, extending the service life of the radome. It does not delaminate after passing the thermal cycling test of -55℃~85℃. Therefore, the flat panel radome has the advantages of being lightweight, high-strength, having excellent dielectric properties, and good weather resistance.

[0024] In this embodiment, the layup direction of each PP prepreg tape layer is one of 0°, 90°, or ±45°. Specifically, to avoid insufficient strength in other directions due to multiple PP prepreg tape layers being arranged in the same direction, the present invention ensures the strength of the upper skin 1 and the lower skin 3 in multiple directions by cross-laying multiple PP prepreg tape layers. Preferably, when the layup direction of each PP prepreg tape layer is one of 0°, 90°, or ±45°, the upper skin 1 and the lower skin 3 can have a better strength structure at the above angles. Specifically, when the number of PP prepreg tape layers is two, the layup directions are cross-layed at 0° and 90°. Assume that the upper skin 1 and the lower skin 3 have sufficient structural strength in the 0° and 90° directions; when the number of PP prepreg tape layers is three, the layup directions are 0°, 90° and 45°, respectively, so that the upper skin 1 and the lower skin 3 have sufficient structural strength in the 0°, 90° and 45° directions; when the number of PP prepreg tape layers is four, the layup directions are 0°, 90°, 45° and -45°, respectively, so that the upper skin 1 and the lower skin 3 have sufficient structural strength in the 0°, 90°, 45° and -45° directions.

[0025] In this embodiment, the thickness of the upper skin and the lower skin is 0.3-0.5 mm, and the thickness of the core layer is 1-15 mm; a modified epoxy resin film is bonded between the upper skin 1 and the core layer 2, and between the lower skin 3 and the core layer 2; the modified epoxy resin film contains 0.5-2 wt% nano titanium dioxide.

[0026] Furthermore, the present invention also provides a method for preparing the planar radome based on the composite of PP prepreg tape and PMI foam sandwich, which includes the following steps: Step S101: Select PP prepreg tape layer as upper skin 1 and lower skin 3, and select PMI foam core layer as core layer 2; wherein, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 40%-60%, and the PMI foam core layer is polymethacrylamide foam with a density of 30-100kg / m³ and a closed cell rate of ≥95%; Preferably, the PP prepreg tape layer is made of commercially available continuous polypropylene fiber reinforced polypropylene resin prepreg tape, with fibers arranged in one direction, a single filament diameter of 15-25μm, and a resin melt index of 10-30g / 10min (230℃ / 2.16kg); the PMI foam core layer needs to be dried at 80℃ for 2-4 hours before use to remove adsorbed moisture.

[0027] Step S102: According to the design dimensions of the radome, cut the PP prepreg tape layer and PMI foam core layer into the corresponding shapes and sizes; Step S103: Lay the lower skin 3, core layer 2 and upper skin 1 in sequence in the mold, and ensure that each layer is tightly bonded without air bubbles or wrinkles during the laying process; wherein, the number of PP prepreg tape layers for the lower skin 3 and upper skin 1 is determined according to the strength requirements of the radome, and multiple PP prepreg tape layers are laid crosswise. Preferably, during the laying process, air bubbles are removed layer by layer by roller pressing, with a roller pressing pressure of 0.1-0.5 MPa and a roller pressing speed of 0.5-2 m / min. For radomes with complex shapes, release cloth and breathable felt can be pre-laid on the mold surface to improve molding quality.

[0028] Step S104: Place the laid composite laminate material together with the mold into a hot press for hot pressing and molding; Specifically, the mold is a steel flat mold with a surface finish Ra≤0.8μm and is coated with a release agent.

[0029] Step S105: After hot pressing, turn off the heating device of the hot press and allow the composite plate to cool naturally to room temperature under pressure. Then demold to obtain the composite plate of PP prepreg tape layer and PMI foam core layer. Specifically, the hot press is a flat vulcanizing machine with a temperature control system and a pressure control system. The temperature control accuracy is ±2℃, and the pressure control accuracy is ±0.1MPa.

[0030] Step S106: According to the design requirements of the radome, the composite plate is processed to form the required radome.

[0031] In this embodiment, in step 101, the PMI foam core layer is subjected to plasma treatment by a plasma device, wherein the power of the plasma device is 100-200W and the time is 30-60s.

[0032] In this embodiment, during the hot pressing process in step 104, the hot pressing temperature is 160-190℃, the pressure is 2-5MPa, and the heat and pressure holding time is 30-60min.

[0033] In this embodiment, in step 103, the layup direction of each PP prepreg tape layer is one of 0°, 90° or ±45°.

[0034] The preparation method of the present invention adopts a hot pressing molding process, which is simple to operate and has high production efficiency, making it easy to achieve large-scale production and reducing production costs.

[0035] Example 1: In this embodiment, the flat panel radome based on PP prepreg tape and PMI foam sandwich is made of a composite flat panel. The composite flat panel includes a lower skin 3, a core layer 2, and an upper skin 1 stacked sequentially. Both the upper skin 1 and the lower skin 3 include multiple layers of PP prepreg tape stacked sequentially, with cross-lays between the multiple PP prepreg tape layers. The core layer 2 includes a PMI foam core layer. The PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 40%. The PMI foam core layer is polymethacrylamide foam with a density of 30 kg / m³ and a closed-cell rate of 95%. Its preparation method includes the following steps: Step S101: Select PP prepreg tape layer as upper skin 1 and lower skin 3, and select PMI foam core layer as core layer 2; wherein, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 40%, and the PMI foam core layer is polymethacrylimide foam with a density of 30kg / m³ and a closed cell rate of 95%. Step S102: According to the design dimensions of the radome, cut the PP prepreg tape layer and PMI foam core layer into the corresponding shapes and sizes; Step S103: Lay the lower skin 3, core layer 2, and upper skin 1 sequentially in the mold, ensuring that each layer is tightly bonded without air bubbles or wrinkles during the laying process; wherein, the lower skin 3 has two layers of PP prepreg tape, and the two layers are laid in a 0° and 90° cross direction; the upper skin 1 has two layers of PP prepreg tape, and the two layers are laid in a 0° and 90° cross direction, ensuring that each layer is tightly bonded. Step S104: Place the laid composite laminate material together with the mold into a hot press for hot pressing; the hot pressing temperature is 160℃, the pressure is 2MPa, and the holding time is 60min. Step S105: After hot pressing, turn off the heating device of the hot press and allow the composite plate to cool naturally to room temperature under pressure. Then demold to obtain the composite plate of PP prepreg tape layer and PMI foam core layer. Step S106: According to the design requirements of the radome, the composite plate is processed to form the required radome.

[0036] Example 2: In this embodiment, the planar radome based on PP prepreg tape and PMI foam sandwich is made of a composite planar sheet. The composite planar sheet includes a lower skin 3, a core layer 2, and an upper skin 1 stacked sequentially. Both the upper skin 1 and the lower skin 3 include multiple layers of PP prepreg tape stacked sequentially, with cross-lays between the multiple PP prepreg tape layers. The core layer 2 includes a PMI foam core layer. The PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 50%. The PMI foam core layer is polymethacrylamide foam with a density of 60 kg / m³ and a closed-cell rate of 96%. Its preparation method includes the following steps: Step S101: Select PP prepreg tape layer as upper skin 1 and lower skin 3, and select PMI foam core layer as core layer 2; wherein, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 50%, and the PMI foam core layer is polymethacrylimide foam with a density of 60kg / m³ and a closed cell rate of 96%. Step S102: According to the design dimensions of the radome, cut the PP prepreg tape layer and PMI foam core layer into the corresponding shapes and sizes; Step S103: Lay the lower skin 3, core layer 2, and upper skin 1 sequentially in the mold, ensuring that each layer is tightly bonded without air bubbles or wrinkles during the laying process; wherein, the lower skin 3 has three layers of PP prepreg tape, and the laying directions of the three layers are 0°, 90°, and 45° intersecting; the upper skin 1 has three layers of PP prepreg tape, and the laying directions of the three layers are 0°, 90°, and -45° intersecting, ensuring that each layer is tightly bonded; Step S104: Place the laid composite laminate material together with the mold into a hot press for hot pressing; the hot pressing temperature is 175℃, the pressure is 3.5MPa, and the holding time is 45min. Step S105: After hot pressing, turn off the heating device of the hot press and allow the composite plate to cool naturally to room temperature under pressure. Then demold to obtain the composite plate of PP prepreg tape layer and PMI foam core layer. Step S106: According to the design requirements of the radome, the composite plate is processed to form the required radome.

[0037] Example 3: In this embodiment, the planar radome based on PP prepreg tape and PMI foam sandwich is made of a composite planar sheet. The composite planar sheet includes a lower skin 3, a core layer 2, and an upper skin 1 stacked sequentially. Both the upper skin 1 and the lower skin 3 include multiple layers of PP prepreg tape stacked sequentially, with cross-lays between the multiple PP prepreg tape layers. The core layer 2 includes a PMI foam core layer. The PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 60%. The PMI foam core layer is polymethacrylamide foam with a density of 100 kg / m³ and a closed-cell rate of 97%. Its preparation method includes the following steps: Step S101: Select PP prepreg tape layer as upper skin 1 and lower skin 3, and select PMI foam core layer as core layer 2; wherein, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 60%, and the PMI foam core layer is polymethacrylimide foam with a density of 100kg / m³ and a closed cell rate of 97%. Step S102: According to the design dimensions of the radome, cut the PP prepreg tape layer and PMI foam core layer into the corresponding shapes and sizes; Step S103: Lay the lower skin 3, core layer 2, and upper skin 1 sequentially in the mold, ensuring that each layer is tightly bonded without air bubbles or wrinkles during the laying process; wherein, the lower skin 3 has four layers of PP prepreg tape, and the four layers are laid in a cross pattern of 0°, 90°, 45°, and -45°; the upper skin 1 has four layers of PP prepreg tape, and the four layers are laid in a cross pattern of 0°, 90°, 45°, and -45°, ensuring that each layer is tightly bonded. Step S104: Place the laid composite laminate material together with the mold into a hot press for hot pressing; the hot pressing temperature is 190℃, the pressure is 5MPa, and the holding time is 30min. Step S105: After hot pressing, turn off the heating device of the hot press and allow the composite plate to cool naturally to room temperature under pressure. Then demold to obtain the composite plate of PP prepreg tape layer and PMI foam core layer. Step S106: According to the design requirements of the radome, the composite plate is processed to form the required radome.

[0038] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A planar radome based on a composite of PP prepreg tape and PMI foam sandwich, characterized in that: It is made of composite flat plate, which includes a lower skin, a core layer and an upper skin layer stacked in sequence. Both the upper skin and the lower skin include multiple layers of PP prepreg tape stacked in sequence, with cross-laying between the multiple PP prepreg tape layers. The core layer includes a PMI foam core layer. The PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape, and the fiber volume fraction is 40%-60%. The PMI foam core layer is polymethacrylimide foam, and the density is 30-100 kg / m³, with a closed-cell rate of ≥95%.

2. The planar radome based on PP prepreg tape and PMI foam interlayer composite as described in claim 1, characterized in that: The layup direction of each PP prepreg tape layer is one of 0°, 90° or ±45°.

3. The planar radome based on PP prepreg tape and PMI foam interlayer composite as described in claim 1 or 2, characterized in that: A modified epoxy resin film is bonded between the upper skin and the core layer, as well as between the lower skin and the core layer.

4. The planar radome based on PP prepreg tape and PMI foam interlayer composite as described in claim 3, characterized in that: The modified epoxy resin film contains 0.5-2 wt% nano-titanium dioxide.

5. The planar radome based on PP prepreg tape and PMI foam sandwich composite as described in claim 1, characterized in that: The thickness of the upper and lower skin layers is 0.3-0.5 mm, and the thickness of the core layer is 1-15 mm.

6. A method for preparing a planar radome based on a composite of PP prepreg tape and PMI foam sandwich as described in any one of claims 1-5, characterized in that: It includes the following steps: Step S101: Select PP prepreg tape layer as the upper and lower skin layers, and select PMI foam core layer as the core layer; wherein, the PP prepreg tape layer is polypropylene fiber reinforced polypropylene resin prepreg tape with a fiber volume fraction of 40%-60%, and the PMI foam core layer is polymethacrylimide foam with a density of 30-100kg / m³ and a closed cell rate of ≥95%; Step S102: According to the design dimensions of the radome, cut the PP prepreg tape layer and PMI foam core layer into the corresponding shapes and sizes; Step S103: Lay the lower skin, core layer and upper skin in sequence in the mold, and ensure that each layer is tightly bonded without air bubbles and wrinkles during the laying process; wherein, the number of PP prepreg tape layers for the lower skin and upper skin is determined according to the strength requirements of the radome, and multiple PP prepreg tape layers are laid crosswise. Step S104: Place the laid composite laminate material together with the mold into a hot press for hot pressing and molding; Step S105: After hot pressing, turn off the heating device of the hot press and allow the composite plate to cool naturally to room temperature under pressure. Then demold to obtain the composite plate of PP prepreg tape layer and PMI foam core layer. Step S106: According to the design requirements of the radome, the composite plate is processed to form the required radome.

7. The method for preparing a planar radome based on a composite of PP prepreg tape and PMI foam sandwich as described in claim 6, characterized in that: In step 101, the PMI foam core layer is subjected to plasma treatment by a plasma device with a power of 100-200W and a treatment time of 30-60s.

8. The method for preparing a planar radome based on a composite of PP prepreg tape and PMI foam sandwich as described in claim 6, characterized in that: During the hot pressing process in step 104, the hot pressing temperature is 160-190℃, the pressure is 2-5MPa, and the heat and pressure holding time is 30-60min.

9. The method for preparing a planar radome based on a composite of PP prepreg tape and PMI foam sandwich as described in claim 6, characterized in that: In step 103, the layup direction of each layer of the PP prepreg tape is one of 0°, 90° or ±45°.

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