Low-noise box type 6G standardized test platform based on pyramid-like wave-absorbing foam

Abstract

The invention belongs to the technical field of electromagnetic wave darkrooms, provides a low-noise box type 6G standardized test platform based on pyramid-like wave-absorbing foam, and aims to solve the problems of large size, heavy weight, high cost, environmental sensitivity, insufficient durability and the like in the prior art. The test box comprises a test box body, a terahertz wave transmitting and receiving assembly and pyramid-like wave absorbing foam, an electromagnetic isolation space is formed in the test box body, and the pyramid-like wave absorbing foam is attached to the inner wall of the test box body; the pyramid-like wave-absorbing foam adopts a periodic structure and is formed by splicing a plurality of pyramid-like unit structures, and each pyramid-like unit structure adopts a stepped pointed cone structure and is loaded with a wave-absorbing two-dimensional material Mxene. Through creative structural design of the wave-absorbing foam and selection of the wave-absorbing material, effective shielding of terahertz electromagnetic waves and accurate control of an internal electromagnetic environment are realized, and a reliable and efficient solution is provided for related fields.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic wave darkroom, and specifically provides a low-noise box-type 6G standardized test platform based on pyramid-shaped absorbing foam. Background Art

[0002] Terahertz wave (THz wave for short) is a section of electromagnetic wave between microwave and infrared in the electromagnetic spectrum, with a frequency range of approximately 0.1THz to 10THz, and a corresponding wavelength range of approximately 0.03mm to 3mm. Due to its unique physical properties, such as high frequency, short wavelength, strong penetration and non-ionizing radiation, THz wave has the advantages of high data transmission rate and high spatial resolution, and shows great application potential in imaging and detection, security inspection, medical treatment and biomedicine.

[0003] The sixth generation of mobile communication technology (6G) is expected to use the terahertz wave band to achieve faster data transmission speeds and lower latency; the development of terahertz wave technology is crucial to realizing the vision of 6G communication, which will support higher network capacity, faster transmission rates and a wider range of application scenarios. However, the power of terahertz waves is too small, and the noise in space is enough to drown out the terahertz signal. In order to eliminate the interference signal, there is an urgent need for a terahertz test darkroom that can shield the interference of external signals to ensure the normal operation of the equipment, which is of great significance for the development of sky survey satellites, networked drones and other related applications.

[0004] Traditional electromagnetic test environments are often affected by external electromagnetic interference, resulting in inaccurate test results. The low-noise box-type 6G standardized test platform uses high-performance absorbing materials to effectively absorb and eliminate indoor electromagnetic waves, providing a low-noise, low-interference environment for testing. It can not only improve the accuracy of the test, but also reduce errors and interference during the test process, thereby improving test efficiency. However, the current low-noise box-type 6G standardized test platform has some drawbacks and challenges: 1) Limitation of absorbing performance: Many existing absorbing materials have low absorption efficiency in the terahertz frequency band, resulting in residual electromagnetic waves in the test box that may interfere with the test results; 2) Material weight and volume: Traditional absorbing materials are often large in size and heavy in weight, which limits the portability and flexibility of the test box; 3) Cost issues: High-performance absorbing materials may be expensive, resulting in expensive construction and maintenance costs of the test box; 4) Durability and reliability: Frequent testing and operation may cause wear of the absorbing materials in the test box, affecting long-term stability; In response to these problems, the present invention provides a low-noise box-type 6G standardized test platform based on pyramid-shaped absorbing foam, which aims to overcome the problems of large size, heavy weight, high cost, environmental sensitivity and insufficient durability of the existing low-noise box-type 6G standardized test platform. Summary of the Invention

[0005] The object of the present invention is to provide a low-noise box-type 6G standardized test platform based on a pyramid-like absorbing foam, so as to solve the problems existing in the existing low-noise box-type 6G standardized test platform, such as large volume, heavy weight, high cost, environmental sensitivity and insufficient durability.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A low-noise box-type 6G standardized test platform based on a pyramid-like absorbing foam, comprising: a test box body, a terahertz wave transceiver component and a pyramid-like absorbing foam; characterized in that an electromagnetic isolation space is formed inside the test box body, and the pyramid-like absorbing foam is attached to the inner wall of the test box body and completely covers the inner wall of the test box body; the pyramid-like absorbing foam adopts a periodic structure and is composed of a plurality of pyramid-like unit structures spliced together, and the pyramid-like unit structure adopts a stepped tapered structure and is loaded with an absorbing two-dimensional material Mxene.

[0008] Further, the bottom of the stepped tapered structure is square and the four side surface morphologies are exactly the same.

[0009] Further, the test box body includes: an outer shell, a box door and a signal transmission port. The box door is connected to the outer shell through a hinge to jointly form the box body of the test box, and the signal transmission port is arranged on the side wall of the outer shell to correspondingly install the terahertz wave transceiver component.

[0010] Furthermore, inside the test box body, at least four signal transmission ports are provided on one side or multiple sides of the electromagnetic isolation space for installing the terahertz wave transceiver component, and one or more metal isolation plates are configured outside the signal transmission port and fixed by manual fasteners.

[0011] Furthermore, inside the test box body, an electric rotary adjustment platform is installed on the top of the electromagnetic isolation space, and the electric rotary adjustment platform is connected to the sample to be measured through a low-reflection slender connecting piece.

[0012] Further, the pyramid-like absorbing foam adopts polyurethane sponge foam, and the absorbing two-dimensional material Mxene specifically adopts Ti2CT x .

[0013] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0014] 1. The present invention proposes a new type of low-noise box-type 6G standardization test platform, which has the characteristics of being strong and durable and highly practical; the electromagnetic wave absorbing material assembled inside the test platform is a pyramid-shaped absorbing foam. Compared with conventional absorbing materials, this material can provide better electromagnetic shielding performance while maintaining a relatively thin thickness, which enables a more spacious available test space inside the test box;

[0015] 2. The pyramid-shaped absorbing foam material used in the low-noise box-type 6G standardization test platform of the present invention has excellent shielding and absorption effects, and at the same time has a light weight and a thin thickness, good processability, and the characteristic of being closely attached at the contact points. These characteristics work together to effectively avoid the leakage of terahertz waves through the edge gaps of the test platform, and at the same time ensure the high-efficiency absorption ability of terahertz electromagnetic waves;

[0016] 3. The low-noise box-type 6G standardization test platform of the present invention adopts a lightweight design, making its overall weight light and volume small, which is convenient for carrying and handling, so that it can be flexibly tested in a variety of different environments;

[0017] In summary, through the creative structural design of the absorbing foam and the selection of the absorbing material, the present invention has successfully solved the technical problems existing in the electromagnetic shielding box in the terahertz frequency band, realized the effective shielding of terahertz electromagnetic waves and the precise control of the internal electromagnetic environment, and provided a reliable and efficient solution for related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the pyramid-shaped absorbing foam in the present invention.

[0019] Figure 2 It is a schematic structural diagram of the test box body in the present invention.

[0020] Figure 3 It is a SEM morphology diagram of the high-performance absorbing two-dimensional material MXene (Ti2CT x ) used in the pyramid-shaped absorbing foam in the present invention.

[0021] Figure 4 It is a test diagram of the reflection performance of the absorbing foam on the inner side of the box wall for electromagnetic waves in the terahertz frequency band when the low-noise box-type 6G standardization test platform based on the pyramid-shaped absorbing foam in the present invention is closed. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives, technical solutions and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0023] This embodiment provides a low-noise box-type 6G standardization test platform based on a class pyramid-shaped absorbing foam, including: a test box body, a transmitting antenna, a receiving antenna, and a class pyramid-shaped absorbing foam; the test box body is as Figure 2 shown, including: a housing, a box door, and an antenna port. The box door is connected to the housing through a hinge to jointly form the box body of the test box. The antenna port is arranged on the side wall of the housing to correspondingly install the transmitting antenna and the receiving antenna; the class pyramid-shaped absorbing foam is attached to the inner wall of the test box and completely covers the inner wall of the test box; the class pyramid-shaped absorbing foam adopts a periodic structure and is composed of a plurality of class pyramid-shaped unit structures spliced together. The class pyramid-shaped unit structure is as Figure 1 shown, Figure 1 from left to right are the left view, the right view, and the top view. The class pyramid-shaped unit structure adopts a stepped cone structure, and the bottom of the stepped cone structure is square and the four side surface morphologies are exactly the same.

[0024] Furthermore, an electromagnetic isolation space is formed inside the test box. At least four signal transmission ports are provided on one side or multiple sides of the electromagnetic isolation space for installing terahertz transmitting and receiving components to realize the detection of the reflection and transmission characteristics of the sample; a metal isolation plate or multiple metal isolation plates are configured outside the signal transmission port and fixed by manual fasteners; an electric rotary adjustment platform is installed on the top of the electromagnetic isolation space, and the electric rotary adjustment platform is connected to the sample to be measured through a low-reflection slender connecting piece.

[0025] Furthermore, the class pyramid-shaped absorbing foam is loaded with a high-performance absorbing two-dimensional material Mxene, specifically Ti2CT x , and the loading process is as follows:

[0026] Step 1: Preparation of the absorbing two-dimensional material Mxene dispersion liquid;

[0027] First, add 1 g of Ti2AlC to 20 mL of an etching agent, which contains 18 mL of 9M HCl, 3 mL of 49 wt.% HF, and 9 mL of deionized water, and then stir at room temperature for 24 h with a stirring speed of 400 revolutions per minute to obtain Ti2C;

[0028] Then, centrifuge Ti2C with deionized water at a speed of 3500 rpm for multiple times, with each centrifugation time of 5 minutes, until the pH value of the supernatant is equal to 6, then multilayer Ti2C can be obtained. Dry the multilayer Ti2CT x in vacuum at 60 °C for 6 h to obtain multilayer Ti2CT x powder, as Figure 3 shown;

[0029] Finally, the dried multilayer Ti2CTx The powder is dispersed in deionized water, stirred evenly and ultrasonically treated to form a uniform Mxene dispersion;

[0030] Step 2: Loading of the wave-absorbing two-dimensional material Mxene;

[0031] Soak the pyramid-shaped polyurethane sponge foam in the Mxene dispersion for 30 min to 60 min, and repeatedly squeeze the polyurethane sponge foam with tweezers no less than 3 times during the soaking process; Take out the conical polyurethane sponge foam and let it stand for 3 h to 4 h under normal temperature and pressure; Then dry the conical polyurethane sponge foam after standing in a vacuum drying oven to obtain the pyramid-shaped wave-absorbing foam.

[0032] In terms of the working principle: The present invention creatively proposes a pyramid-shaped wave-absorbing foam, and its impedance matching mechanism with a stepped design is as follows:

[0033] 1. Discrete impedance transition;

[0034] The stepped structure is composed of multiple steps with different heights / widths, and each step corresponds to a specific impedance value (Z1, Z2,..., Z n ), and the impedance between layers changes according to a certain rule (such as linear increase or exponential change) to achieve gradual matching from free space (Z0 = 377 Ω) to the inside of the wave absorber (Z absorber );

[0035] Specifically, if N layers of steps are designed, the impedance of each step satisfies;

[0036]

[0037] Among them, Z k represents the impedance of the k-th step, Z0 represents the free space impedance, and Z absorber represents the internal characteristic impedance of the wave-absorbing foam;

[0038] This ensures a smooth impedance gradient and reduces the reflection coefficient at each layer interface;

[0039] 2. Multi-band resonance coupling;

[0040] The geometric dimensions (height h k , width w k ) of each step correspond to the resonant absorption of a specific frequency band, and the resonance condition is specifically:

[0041]

[0042] Among them, h k represents the height of the k-th step, λ k represents the center wavelength of the frequency band corresponding to the k-th step, c is the speed of light, and fk denotes the resonant frequency of the k-th step, ε k denotes the relative permittivity of the k-th step, μ k denotes the relative permeability of the material of the k-th step;

[0043] Superposition effect: The resonant peaks of multiple steps are coupled with each other to form a broadband absorption band;

[0044] The advantage of using a stepped pyramid-like shape in the present invention is that the gradient impedance design can make waves with different incident angles experience a similar impedance transition on the material surface, suppressing the reflection mutation. In this embodiment, the stepped pyramid-shaped absorbing foam is designed with the number of steps N = 3.

[0045] More specifically:

[0046] Through the synergistic effect of the intrinsic broadband absorbing performance of the MXene material and the three-dimensional impedance matching design of the stepped pyramid-like structure, the limitations of traditional test platforms can be systematically broken through:

[0047] Firstly, solve the problem of insufficient frequency band coverage;

[0048] Broadband characteristics of MXene: Ti2CT x Through surface functional group regulation (such as -OH, -O groups) and interlayer spacing optimization of MXene, the intrinsic limit absorption with a reflection loss ≤ -50 dB is achieved in the frequency band of 0.1 - 10 THz, covering the D band (110 - 170 GHz), H band (220 - 325 GHz) and higher frequency bands of the 6G core;

[0049] Frequency band expansion of the pyramid-like structure: The pyramid-like absorbing foam realizes multi-frequency point impedance matching in the terahertz frequency band through the gradient distribution of the permittivity, suppresses the resonant reflection (voltage standing wave ratio ≤ 1.2), and expands the effective absorption bandwidth to more than 1000 GHz;

[0050] Moreover, the combination of the high conductivity (> 20000 S / cm) of MXene and the geometric scattering of the pyramid structure significantly enhances the electromagnetic loss efficiency in the high frequency band (> 300 GHz);

[0051] Secondly, improve the adaptability to extreme environments;

[0052] Antioxidant modification of MXene: Through montmorillonite composite and vacuum packaging technologies, the shielding effectiveness retention rate of the MXene material is ≥ 90% at -196 °C to 300 °C, solving the problem of oxidation failure of traditional absorbing materials at extreme temperatures;

[0053] Structural weather resistance design: The pyramid-shaped absorbing foam uses a polymer substrate resistant to high and low temperatures (such as polyimide), combined with a composite shielding mechanism of a metal shell to ensure that the box has no deformation or cracking under thermal expansion and contraction; after testing, in the high-temperature cycle test (300 °C / 48 h), the reflectivity fluctuation of the MXene absorbing layer is <1 dB, meeting the test requirements of spacecraft high-frequency antennas in the extreme deep-space environment;

[0054] Thirdly, reduce volume and weight and improve portability;

[0055] Material lightweighting: The density of the pyramid-shaped absorbing foam is only 0.2 g / cm 3 , with a thickness of <5 mm, reducing the weight by 80% compared to traditional ferrite absorbing materials (thickness > 50 mm), and the overall weight of the test box ≤ 60 kg;

[0056] Compact structural design: The pyramid-shaped absorbing foam is precisely formed by 3D printing, maximizing the use of the internal space of the box (effective quiet zone 440×440×440 mm), and the volume is only 1 / 10 of that of a traditional anechoic chamber.

[0057] To further illustrate the performance of the terahertz test box, in the W band of 75 - 110 GHz, with a vector network analyzer of model AV3672, a millimeter-wave frequency extension module of model AV3640A, two S-parameter test modules of model AV3645A, and a Hengda microwave standard gain horn antenna, incident from one antenna port on the same side of the box and received at the other antenna port to examine the echo loss level of the box. The test results are as Figure 4 shown. As can be seen from the figure, the effective absorption in air at 75 - 110 GHz is only -25 dB, and the test box shell can further increase it to -30 dB, indicating that the high-conductivity metal shell can effectively block external clutter. After pasting pyramid-shaped absorbing foam on all six sides inside the box, the absorbing performance of the absorbing test box is greatly improved, reaching -77.2 dB at 75.9 GHz and 78.6 GHz, and the absorbing performance in the remaining frequency bands can at least reach -45 dB, showing excellent absorbing performance.

[0058] The above is only the specific implementation manner of the present invention. Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or similar-purpose alternative features; all the features disclosed, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A low-noise box-type 6G standardized test platform based on a class pyramid-shaped absorbing foam, comprising: Test chamber body, terahertz wave transceiver assembly and pyramid-shaped absorbing foam; characterized in that an electromagnetic isolation space is formed inside the test chamber body, the pyramid-shaped absorbing foam is attached to the inner wall of the test chamber body and completely covers the inner wall of the test chamber body; the pyramid-shaped absorbing foam adopts a periodic structure and is composed of a plurality of pyramid-shaped unit structures spliced together, and the pyramid-shaped unit structure adopts a stepped taper structure and is loaded with an absorbing two-dimensional material Mxene.

2. The low-noise box-type 6G standardized test platform based on the pyramid-shaped absorbing foam according to claim 1, characterized in that The bottom of the stepped taper structure is square and the four side surface morphologies are exactly the same.

3. The low-noise box-type 6G standardized test platform based on a pyramid-shaped absorbing foam according to claim 1, characterized in that, The test chamber body includes: an outer shell, a chamber door and a signal transmission port. The chamber door is connected to the outer shell through a hinge to jointly form the body of the test chamber, and the signal transmission port is arranged on the side wall of the outer shell to correspondingly install the terahertz wave transceiver assembly.

4. The low-noise box-type 6G standardization test platform based on a class pyramid-shaped absorbing foam according to claim 3, characterized in that, Inside the test chamber body, at least four signal transmission ports are provided on one or more sides of the electromagnetic isolation space for installing the terahertz wave transceiver assembly, and one or more metal isolation plates are configured outside the signal transmission ports and fixed by manual fasteners.

5. The low-noise box-type 6G standardization test platform based on the class pyramid-shaped absorbing foam according to claim 3, characterized in that Inside the test chamber body, an electric rotary adjustment platform is installed at the top of the electromagnetic isolation space, and the electric rotary adjustment platform is connected to the sample to be measured through a low-reflection slender connecting piece.

6. The low-noise box-type 6G standardized test platform based on a class pyramid-shaped absorbing foam according to claim 1, characterized in that, The pyramid-shaped wave-absorbing foam uses polyurethane sponge foam, and the wave-absorbing two-dimensional material Mxene specifically uses Ti2CT x .

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