Pointed cone for optimizing large-angle oblique incidence wave-absorbing performance

Abstract

The invention relates to a pointed cone for optimizing large-angle oblique incidence wave-absorbing performance, which comprises a cone body and a magnetic loss interlayer, the magnetic loss interlayer is arranged at the bottom of the cone body, and the cone body is integrally formed by a foamed conductive mixture. The microwave anechoic chamber has the advantages that the low-frequency large-angle oblique incidence performance of the wave-absorbing pointed cone can be remarkably optimized, then the reflection level of a low-frequency quiet zone of the anechoic chamber is improved, and the testing capacity and testing precision of the microwave anechoic chamber are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field, and in particular to a pointed cone with optimized large-angle oblique-incident wave-absorbing performance. Background Art

[0002] Microwave darkrooms mainly simulate "free space" without electromagnetic interference through metal shielding and absorbing materials, and are widely used in high-precision tests such as stealth performance testing, antenna performance testing, and electronic product testing. The electromagnetic performance of absorbing materials is one of the decisive factors for the final performance of the darkroom.

[0003] At present, in microwave darkrooms, especially in compact darkrooms, due to the wide illumination range of low-frequency feed sources, there is a common problem that the feed source transmission signal passes through the absorbing materials on the ground, side walls, and top surface, resulting in multipath scattering and deterioration of the quiet zone performance. For the darkroom absorbing materials located on these walls, the electromagnetic waves incident on the main reflection area are mostly obliquely incident at a large angle of 50~70°, while the low-frequency absorbing performance of conventional absorbing materials is poor. At the same time, the large-angle oblique incident absorbing performance is significantly weaker than the normal incident absorbing performance, making it difficult to reduce the scattering intensity to the required level, resulting in interference with the quiet zone performance, which greatly limits the low-frequency quiet zone size and test accuracy of the microwave darkroom. Therefore, in order to further improve the test capability and test accuracy of the darkroom, it is urgent to optimize the oblique incident absorbing performance of the absorbing material. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a pointed cone with optimized large-angle oblique incidence absorbing performance, which can significantly optimize the low-frequency large-angle oblique incidence performance of the absorbing cone, thereby improving the reflection level of the low-frequency quiet zone of the darkroom, and significantly improving the test capability and test accuracy of the microwave darkroom.

[0005] The purpose of the present invention is achieved through the following technical solutions: A pointed cone with optimized large-angle oblique-incident wave-absorbing performance comprises a cone body and a magnetic loss interlayer, wherein the magnetic loss interlayer is arranged at the bottom of the cone body, and the cone body is integrally formed of a foamed conductive mixture.

[0006] Furthermore, the magnetic loss interlayer includes at least one of ferrite, alloy powder, and carbonyl iron.

[0007] Furthermore, the magnetic loss interlayer is bonded to the bottom of the cone or fixed to the bottom of the cone through a connecting layer.

[0008] Furthermore, the thickness of the magnetic loss interlayer is 1 mm to 20 mm.

[0009] Furthermore, the conductive mixture is formed by melt blending polypropylene, high molecular polymer and conductive agent.

[0010] Furthermore, the high molecular polymer is composed of one or more of polystyrene, ethylene-vinyl acetate copolymer, polylactic acid, polycarbonate, polyamide, polyetheretherketone, and polyimide.

[0011] Furthermore, the conductive agent is composed of one or more of graphite, flaky graphite, carbon black, highly conductive carbon black, acetylene black, nano carbon black particles, carbon nanotubes, multi-walled carbon nanotubes, carbon fibers, carbon nanofibers, graphite nanosheets, graphene, single-layer graphene, few-layer graphene, multi-layer graphene, nickel-coated graphite powder, nickel-coated carbon fiber carbon black, metal powder, liquid metal, flaky iron-based metal powder, flaky iron-based alloy powder, flaky iron-silicon-aluminum alloy powder, flaky iron-silicon alloy powder, flaky iron-silicon-chromium alloy powder, flaky cobalt-based alloy powder, and flaky iron-nickel alloy powder.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention loads a magnetic loss interlayer at the bottom of the absorbing cone, so that electromagnetic waves with different incident angles will reach the magnetic loss interlayer after loss in the absorbing cone and will be further absorbed by the magnetic loss interlayer, so that the low-frequency, large-angle oblique incident performance of the absorbing cone is significantly optimized, thereby reducing the reflection level in the quiet zone of the darkroom and improving the darkroom testing capability and testing accuracy.

[0013] 2. Under the same quiet zone reflection level requirement, the present invention can reduce the height of the wave-absorbing cone required on the wall, thereby saving the required size of the darkroom and reducing costs.

[0014] 3. The present invention is easy to implement and can be used to optimize the reflection level of an existing anechoic chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 The oblique incident angle in the present invention is 50 o The comparison chart of the simulation effect of oblique incidence reflectivity of P-band electromagnetic waves; Figure 3 The oblique incident angle in the present invention is 60 o The comparison chart of the simulation effect of oblique incidence reflectivity of P-band electromagnetic waves; Figure 4 The oblique incident angle in the present invention is 70 o Comparison chart of simulation effects of oblique incidence reflectivity of P-band electromagnetic waves.

[0016] In the figure: 1. cone; 2. magnetic loss interlayer; 3. connecting layer. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0018] like Figure 1 As shown, a pointed cone with optimized large-angle oblique-incident wave absorbing performance comprises a cone body 1 and a magnetic loss interlayer 2. The magnetic loss interlayer 2 is arranged at the bottom of the cone body 1. The cone body 1 is integrally formed of a foamed conductive mixture.

[0019] The conductive mixture is formed by melt blending polypropylene, high molecular polymer and conductive agent. The high molecular polymer is composed of one or more of polystyrene, ethylene-vinyl acetate copolymer, polylactic acid, polycarbonate, polyamide, polyetheretherketone and polyimide; the conductive agent is composed of one or more of graphite, flaky graphite, carbon black, high conductive carbon black, acetylene carbon black, nano carbon black particles, carbon nanotubes, multi-walled carbon nanotubes, carbon fiber, carbon nanofiber, graphite nanosheet, graphene, single-layer graphene, few-layer graphene, multi-layer graphene, nickel-coated graphite powder, nickel-coated carbon fiber carbon black, metal powder, liquid metal, flaky iron-based metal powder, flaky iron-based alloy powder, flaky iron-silicon-aluminum alloy powder, flaky iron-silicon alloy powder, flaky iron-silicon-chromium alloy powder, flaky cobalt-based alloy powder and flaky iron-nickel alloy powder.

[0020] In this embodiment, the magnetic loss interlayer 2 includes at least one of ferrite, alloy powder, and carbonyl iron; the thickness of the magnetic loss interlayer 2 is 1 mm to 20 mm. The magnetic loss interlayer 2 is bonded to the bottom of the cone 1 or fixed to the bottom of the cone 1 through the connecting layer 3. The connecting layer 3 can be made of metal, wood or acrylic board, etc., and is fixed to the bottom of the cone 1 by plugging, screwing or gluing, and the magnetic loss interlayer 2 is clamped between the connecting layer 3 and the cone 1.

[0021] The incident angle is 50 o , 60 o , 70 o Taking the P-band electromagnetic waves (including transverse electric waves TE and transverse magnetic waves TM) of the present invention as an example, the oblique incidence reflectivity of the optimized large-angle oblique incidence wave absorbing performance cone (referred to as the oblique incidence optimized cone) and the unoptimized original cone are simulated and compared. The comparison results are as follows: Figure 2-Figure 4 As shown, the comparison results show that after loading the magnetic loss interlayer 2, the large-angle oblique-incidence wave absorbing performance of the wave absorbing cone is significantly optimized. Based on the optimized large-angle oblique-incidence wave absorbing performance cone of the present invention and the conventional wave absorbing cone, the reflection level of the ground quiet zone in the P-band compact field darkroom is simulated and compared, and the comparison results are shown in the following Table 1: Table 1: Comparison of simulation results of reflection levels in the ground quiet zone of a P-band compact field darkroom It can be seen from Table 1 that the optimized large-angle oblique-incidence wave-absorbing performance cone of the present invention optimizes the quiet zone reflection level of the ground by 2 to 14 dB, thereby significantly improving the quality of the quiet zone.

[0022] With an oblique incident angle of 45o Taking the P-band electromagnetic wave as an example, based on the optimized large-angle oblique-incidence wave absorbing performance cone of the present invention and the conventional wave absorbing cone, the reflection level of the vertical polarization quiet area on the ground of the P-band antenna darkroom is tested and compared, and the comparison results are shown in Table 2 below: Table 2: Comparison of P-band antenna test results in vertical polarization quiet area reflection level test in darkroom It can be seen from Table 2 that the optimized large-angle oblique-incidence wave-absorbing performance cone of the present invention optimizes the reflection level by 6 to 13 dB, and can optimize the reflection level in the low-frequency quiet zone on the ground to below -30 dB.

[0023] Based on the optimized large-angle oblique-incidence wave absorbing performance sharp cone of the present invention and the conventional sharp cone, the reflection level of the ground quiet zone in the P-band compact field darkroom is simulated and compared, and the comparison results are shown in Table 3 below: Table 3: Comparison of P-band compact field darkroom ground vertical polarization quiet zone reflection level test results It can be seen from Table 3 that the optimized large-angle oblique-incident wave-absorbing performance cone of the present invention optimizes the reflection level by 2 to 6 dB.

[0024] Based on the above simulation and test comparison results, the optimized large-angle oblique-incidence absorbing performance cone of the present invention can significantly optimize the low-frequency large-angle oblique-incidence performance of the absorbing cone by loading the magnetic loss interlayer 2 at the bottom of the cone 1, reduce the reflection level in the quiet zone of the darkroom, improve the darkroom testing capability and test accuracy, and the overall structure is easy to implement. Under the same quiet zone reflection level requirement, the required height of the absorbing cone on the wall can be reduced, thereby saving the required size of the darkroom and reducing costs.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A sharp cone with optimized large-angle oblique-incidence wave absorbing performance, characterized in that: The cone (1) comprises a cone (1) and a magnetic loss interlayer (2), wherein the magnetic loss interlayer (2) is arranged at the bottom of the cone (1), and the cone (1) is integrally formed from a foamed conductive mixture.

2. The sharp cone with optimized large-angle oblique-incidence wave-absorbing performance according to claim 1, characterized in that: The magnetic loss interlayer (2) comprises at least one of ferrite, alloy powder and carbonyl iron.

3. The sharp cone with optimized large-angle oblique-incidence wave-absorbing performance according to claim 1, characterized in that: The magnetic loss interlayer (2) is bonded to the bottom of the cone (1) or fixed to the bottom of the cone (1) via a connecting layer (3).

4. The sharp cone with optimized large-angle oblique-incidence wave-absorbing performance according to claim 1, characterized in that: The thickness of the magnetic loss interlayer (2) is 1 mm to 20 mm.

5. The sharp cone with optimized large-angle oblique-incidence wave-absorbing performance according to claim 1, characterized in that: The conductive mixture is formed by melt-blending polypropylene, high molecular polymer and conductive agent.

6. The sharp cone with optimized large-angle oblique-incidence wave-absorbing performance according to claim 5, characterized in that: The high molecular polymer is composed of one or more of polystyrene, ethylene-vinyl acetate copolymer, polylactic acid, polycarbonate, polyamide, polyetheretherketone and polyimide.

7. The sharp cone with optimized large-angle oblique-incidence wave-absorbing performance according to claim 5, characterized in that: The conductive agent is composed of one or more of graphite, flaky graphite, carbon black, highly conductive carbon black, acetylene black, nano carbon black particles, carbon nanotubes, multi-walled carbon nanotubes, carbon fibers, carbon nanofibers, graphite nanosheets, graphene, single-layer graphene, few-layer graphene, multi-layer graphene, nickel-coated graphite powder, nickel-coated carbon fiber carbon black, metal powder, liquid metal, flaky iron-based metal powder, flaky iron-based alloy powder, flaky iron-silicon-aluminum alloy powder, flaky iron-silicon alloy powder, flaky iron-silicon-chromium alloy powder, flaky cobalt-based alloy powder, and flaky iron-nickel alloy powder.

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