A Method for Analyzing Experimental Data on the Effect of Composite Shielding Materials

Abstract

This invention discloses a method for analyzing experimental data on the effectiveness of composite shielding materials, specifically relating to the field of material shielding effectiveness analysis. The method includes: measuring key data such as the dielectric constant, permeability, conductivity, and thickness of each layer of the composite shielding material using an electromagnetic performance measuring instrument; establishing an electromagnetic wave propagation model based on Maxwell's equations to describe the propagation of electromagnetic waves within a multilayer medium, and defining the boundary conditions of the test sample; simulating the time and frequency domain characteristics of the electromagnetic interference source using Fourier transform to simulate actual input interference; analyzing the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals to form an electromagnetic wave interference response propagation model; adjusting the model parameters by comparing with actual shielding effectiveness test data to ensure that the model calculation error is within an acceptable range; and generating a full-band shielding effectiveness prediction spectrum for the composite shielding material based on this model, providing theoretical support for material design and optimization.

Description

Technical Field

[0001] This invention relates to the field of material shielding effect analysis technology, and more specifically, to a method for analyzing experimental data on the effect of composite shielding materials. Background Technology

[0002] In multi-band broadband electromagnetic environments, the shielding performance of composite shielding materials faces multi-level and multi-dimensional evaluation requirements. Testing methods based on single frequencies or idealized interference conditions are insufficient to fully reflect shielding effectiveness in practical applications. For predicting the electromagnetic shielding effectiveness of composite shielding materials under complex electromagnetic interference conditions, traditional methods mainly rely on material property measurements and static assessments at single frequencies, failing to encompass the synergistic mechanisms of reflection, transmission, and absorption during multi-frequency electromagnetic wave propagation. Furthermore, existing research on the nonlinear response behavior of multilayer composite materials largely focuses on static calculations with separated variables, neglecting the relationship between the transient response and steady-state power loss of multilayer media under dynamic interference conditions.

[0003] Therefore, a modeling method capable of integrating multi-frequency interference and the nonlinear coupling effects of multi-layered media is needed to accurately describe the shielding characteristics of composite shielding materials in complex electromagnetic interference scenarios. This method aims to achieve a full-band interference shielding effectiveness prediction spectrum, providing theoretical support for the performance optimization and application design of composite shielding materials in broadband electromagnetic environments.

[0004] To address the aforementioned problems, a technical solution is provided. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a method for analyzing experimental data on the effect of composite shielding materials to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] S1: Use electromagnetic performance measuring instruments to measure the dielectric constant, permeability, thickness, and conductivity of each layer of the composite shielding material;

[0008] S2: Define the boundary conditions of the test sample and establish an electromagnetic wave propagation model based on Maxwell's equations to describe the propagation characteristics of electromagnetic waves inside the multilayer medium of the composite shielding material.

[0009] S3: Set the electromagnetic interference source with a frequency range coverage, describe the time and frequency domain characteristics of the electromagnetic interference through Fourier transform, and simulate real input interference;

[0010] S4: Analyze the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals to form an electromagnetic wave interference response propagation model;

[0011] S5: Compare the output results of the electromagnetic interference response propagation model with the actual shielding effectiveness test data, and adjust the model parameters based on the comparison error until the calculation error of the electromagnetic interference response propagation model is within an acceptable range.

[0012] S6: Generate a full-band shielding effectiveness prediction spectrum of composite shielding materials under simulated interference conditions based on the electromagnetic wave interference response propagation model.

[0013] In a preferred embodiment, in S1, measuring the dielectric constant, permeability, thickness, and conductivity of each layer of the composite shielding material using an electromagnetic performance measuring instrument specifically includes:

[0014] The composite shielding material was cut into test samples in layers, and the thickness of each shielding layer was measured using a mechanical measuring device according to the set accuracy requirements.

[0015] A dielectric analysis device with a non-fixed frequency range is used to scan the response of the test sample by applying an alternating electric field, thereby generating frequency distribution data of the dielectric constant of each layer;

[0016] The response characteristics of the test sample material to magnetic fields of different frequencies were extracted using a vector network analyzer, and the frequency distribution data of the permeability of each layer were obtained.

[0017] A constant current is applied to the surface of the test sample material, and the voltage change is measured in real time to calculate the conductivity of each layer of material.

[0018] The thickness, dielectric constant, magnetic permeability, and electrical conductivity of the composite shielding material were measured multiple times. The measured results were then digitally converted and corrected to establish a standardized material property parameter library.

[0019] In a preferred embodiment, in S2, the boundary conditions of the test sample are defined, and an electromagnetic wave propagation model describing the propagation characteristics of electromagnetic waves within the multilayer dielectric of the composite shielding material is established based on Maxwell's equations. Specifically, this includes:

[0020] Based on the relationship between electric field, electric displacement field, magnetic induction intensity and magnetic field intensity in Maxwell's equations, continuous boundary conditions are set at each layer interface of the test sample material.

[0021] Based on the material properties of each medium in the standardized material property parameter library and its actual spatial distribution, an electromagnetic wave equation is constructed to describe the relationship between the reflection, transmission, and absorption processes of electromagnetic waves in each medium. The electromagnetic wave equation is as follows:

[0022]

[0023] In the formula, For electric field strength, For time variables, The spatial second derivative of the electric field, It is the change of electric field over time. , , These are the magnetic permeability, dielectric constant, and conductivity of the medium, respectively.

[0024] Based on the changes in the input and output electromagnetic field intensity of each medium layer, the power density distribution and electromagnetic wave propagation trajectory of each medium layer are calculated using the wave equation combined with the phase change of the electric field. The calculation results are then incorporated into the electromagnetic wave propagation characteristic data inside the medium to establish an electromagnetic wave propagation model.

[0025] The electromagnetic wave propagation characteristics of each layer of the medium are converted into a transmission matrix in the frequency domain, and the overall shielding effectiveness of the material is expressed by the product of the matrices.

[0026] In a preferred embodiment, in S3, an electromagnetic interference source covering a frequency range is set, and the time-domain and frequency-domain characteristics of the electromagnetic interference are described by Fourier transform. The simulation of real input interference specifically includes:

[0027] The frequency range of the interference signal is preset, and the frequency characteristics and pulse shape of the interference signal are dynamically set within the frequency range. The pulse width of the transient signal and the frequency range and amplitude change of the steady-state signal are used as the input conditions of the interference signal.

[0028] Based on Fourier transform, the time distribution of transient signals is transformed into frequency distribution, and the frequency characteristics of steady-state signals are superimposed to generate a joint model of interference signals that includes spectral energy and phase distribution.

[0029] The spatial intensity distribution of a signal is described by defining a directional function based on the propagation path, and the change in signal intensity with propagation distance is expressed by a distance attenuation factor, thus forming the spatial propagation characteristics of electromagnetic waves.

[0030] The amplitude and frequency distribution of the generated interference signal are dynamically adjusted by the joint model of the interference signal to generate a dynamic multidimensional interference signal containing transient and steady-state signal characteristics.

[0031] The time-domain waveform, frequency-domain amplitude, and spatial distribution of the interference signal are tested using spectrum analysis methods to verify the integrity of its spectrum within the preset interference signal frequency range.

[0032] In a preferred embodiment, in S4, analyzing the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals to form an electromagnetic wave interference response propagation model specifically includes:

[0033] A plane wave is input as the excitation condition at the outermost boundary of the electromagnetic wave propagation model. A multidimensional interference signal containing transient and steady-state signal characteristics is generated as input to drive the dynamic simulation of the interference response of the electromagnetic wave propagation model.

[0034] The finite-difference time-domain method was used to analyze transient interference signals. The dynamic changes of electric and magnetic fields of each layer of the composite shielding material were continuously calculated with a fixed time step, and the propagation trajectory and energy distribution of internal electromagnetic waves under transient signal interference were recorded.

[0035] Based on the frequency domain finite element method, a set of electromagnetic field equations under steady-state signal interference is established. Combining the material's dielectric constant, permeability, and thickness distribution, the field distribution and power loss of the internal electromagnetic wave under steady-state signal interference within the preset interference signal frequency range are recorded.

[0036] The electromagnetic wave propagation characteristics in the electromagnetic wave propagation model are transformed and interpolated by using the spatial propagation characteristics in the time domain and the corresponding field distribution and power loss data in the frequency domain of the multidimensional interference signal, so as to establish an electromagnetic wave interference response propagation model.

[0037] In a preferred embodiment, in S5, the output results of the electromagnetic interference response propagation model are compared with the actual shielding effectiveness test data, and the model parameters are adjusted based on the comparison error until the calculation error of the electromagnetic interference response propagation model is within an acceptable range. Specifically, this includes:

[0038] The actual propagation characteristics of the internal electromagnetic waves of the composite shielding material under real external electromagnetic interference scenarios are used as experimental data.

[0039] By comparing the experimental data under the same interference conditions with the output results of the electromagnetic wave interference response propagation model in the same frequency domain, the deviation distribution of the electromagnetic wave propagation characteristic data of the two is obtained by difference calculation.

[0040] Based on the deviation distribution of electromagnetic wave propagation characteristic data, the boundary condition parameters in the electromagnetic wave interference response propagation model are adjusted item by item.

[0041] The adjusted boundary condition parameters are re-input into the electromagnetic wave interference response propagation model for iterative calculation. The output results are then compared with the experimental data, and the verification is continued until the deviation converges to the predetermined tolerance range.

[0042] In a preferred embodiment, in S6, generating a full-band shielding effectiveness prediction spectrum of the composite shielding material under simulated interference conditions based on the electromagnetic wave interference response propagation model specifically includes:

[0043] Generate a full-band multi-dimensional interference signal on the composite shielding material within a preset interference signal frequency range;

[0044] The interference signal is input into the electromagnetic wave interference response propagation model, which outputs electromagnetic wave propagation characteristic data for each layer. The electromagnetic wave propagation characteristic data is then converted into a transmission matrix in the frequency domain to generate a shielding effectiveness prediction spectrum for the full-band interference mode.

[0045] The technical effects and advantages of the experimental data analysis method for composite shielding materials of this invention are as follows:

[0046] The electromagnetic interference response propagation model constructed based on this method effectively addresses the insufficient adaptability of traditional shielding material performance evaluation under complex interference conditions. By combining the finite-difference time-domain method and the finite-element frequency-domain method, this model can simultaneously capture the dynamic characteristics of transient signals and the power loss distribution of steady-state signals, thus comprehensively analyzing the propagation behavior of multi-band interference signals within the composite shielding material. Through dynamic adjustment of model parameters and comparison and optimization with actual shielding effectiveness test data, the accuracy and reliability of the model prediction results are significantly improved. The generation of a full-band shielding effectiveness prediction spectrum can accurately reflect the material's shielding capability against signals of different frequencies in a wide-band electromagnetic interference scenario, providing a scientific basis for the design and optimization of composite shielding materials.

[0047] This method, by considering the multilayer dielectric structure and combining the frequency and time domain characteristics of complex signals, can effectively improve the characterization ability of nonlinear electromagnetic responses, making the performance evaluation of shielding materials closer to the actual application requirements, and ultimately improving the shielding effectiveness and engineering applicability of materials in complex electromagnetic environments. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of an experimental data analysis method for the effect of composite shielding materials according to the present invention; Detailed Implementation

[0049] 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 some embodiments of the present invention, and not all 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.

[0050] Example 1

[0051] Figure 1 This invention provides a method for analyzing experimental data on the effectiveness of composite shielding materials, which includes the following steps:

[0052] S1: Use electromagnetic performance measuring instruments to measure the dielectric constant, permeability, thickness, and conductivity of each layer of the composite shielding material;

[0053] S2: Define the boundary conditions of the test sample and establish an electromagnetic wave propagation model based on Maxwell's equations to describe the propagation characteristics of electromagnetic waves inside the multilayer medium of the composite shielding material.

[0054] S3: Set the electromagnetic interference source with a frequency range coverage, describe the time and frequency domain characteristics of the electromagnetic interference through Fourier transform, and simulate real input interference;

[0055] S4: Analyze the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals to form an electromagnetic wave interference response propagation model;

[0056] S5: Compare the output results of the electromagnetic interference response propagation model with the actual shielding effectiveness test data, and adjust the model parameters based on the comparison error until the calculation error of the electromagnetic interference response propagation model is within an acceptable range.

[0057] S6: Generate a full-band shielding effectiveness prediction spectrum of composite shielding materials under simulated interference conditions based on the electromagnetic wave interference response propagation model.

[0058] In S1, the measurement of the dielectric constant, permeability, thickness, and conductivity of each layer of the composite shielding material using electromagnetic performance measuring instruments specifically includes:

[0059] The composite shielding material is cut according to its layered structure, ensuring that the shape of the cut sample matches the size requirements of the testing equipment. The thickness of each layer is measured using a high-precision mechanical measuring device (such as a laser thickness gauge or micrometer). To meet the set accuracy requirements (e.g., 0.001 mm), the equipment is calibrated before measurement, and multiple measurements are taken for each sample to reduce the influence of surface irregularities on the thickness measurement. Finally, the average thickness value of each layer of shielding material is recorded and calculated.

[0060] A dielectric analysis device with a non-fixed frequency range (such as a dielectric spectrometer) is used to apply an alternating electric field to the test sample and record the sample's response to electric fields of different frequencies. Within a frequency range (e.g., 10 Hz to 1 MHz), the dielectric constant of each layer of the sample is scanned, and the frequency distribution data of the dielectric constant at different frequencies are recorded.

[0061] The response characteristics of sample materials to magnetic fields of different frequencies were tested using a vector network analyzer (VNA) with an adapter fixture. The frequency distribution data of the sample's permeability were progressively scanned within a frequency range (e.g., 100 kHz to 10 GHz). During the test, a high-frequency magnetic fixture was used to ensure good contact between the magnetic field and the sample, and to eliminate the influence of high-frequency noise interference on the data.

[0062] A constant current is applied to the surface of the test sample, and the voltage change is recorded in real time using a digital multimeter or conductivity meter. The conductivity data is calculated using the conductivity calculation formula based on the sample's current, voltage, and geometry.

[0063] The thickness, dielectric constant, magnetic permeability, and electrical conductivity of the composite shielding material were measured multiple times. The measured results were then digitally converted and corrected to establish a standardized material property parameter library.

[0064] In S2, the boundary conditions of the test sample are defined, and an electromagnetic wave propagation model describing the propagation characteristics of electromagnetic waves inside the multilayer medium of the composite shielding material is established based on Maxwell's equations.

[0065] Based on the relationships between electric field, electric displacement field, magnetic induction, and magnetic field strength in Maxwell's equations, a continuous boundary condition is set at the layered interface of the test sample material. The electromagnetic field continuity at the interface is described by the following formula:

[0066]

[0067] In the formula, , It refers to the electric and magnetic fields of the first layer of medium. 2. It refers to the electric and magnetic fields of the second layer of medium. and Let n represent the difference in electric displacement field and magnetic induction intensity between the first and second dielectric layers, respectively, and n be the interface normal vector. For the interface charge density, To determine the interfacial current density, these continuity conditions are applied to each layered interface of the material, providing constraints for the subsequent solution of the wave equation.

[0068] Based on the material properties of each medium in the standardized material property parameter library and its actual spatial distribution, an electromagnetic wave equation is constructed to describe the relationship between the reflection, transmission, and absorption processes of electromagnetic waves in each medium. The electromagnetic wave equation is as follows:

[0069]

[0070] In the formula, For electric field strength, For time variables, The spatial second derivative of the electric field, It is the change of electric field over time. , , These are the magnetic permeability, dielectric constant, and conductivity of the medium, respectively.

[0071] Based on the changes in input and output electromagnetic field intensity of each medium layer, the power density distribution and electromagnetic wave propagation trajectory of each medium layer are calculated using the wave equation combined with the phase change of the electric field. The calculation results are then incorporated into the electromagnetic wave propagation characteristic data within the medium (including at least power density distribution, propagation trajectory, reflection, transmission, and absorption characteristic data) to establish an electromagnetic wave propagation model. The power density is calculated as follows:

[0072]

[0073] In the formula, Power density represents the intensity of electromagnetic wave energy flow. Indicates the magnetic field Inverting the imaginary part is used to calculate the actual power in a complex field. This indicates that the real part of the calculation result is taken. By analyzing the changes in power density with space and time, the propagation trajectory and energy distribution of electromagnetic waves in materials can be analyzed.

[0074] The electromagnetic wave propagation characteristics of each layer of the medium are converted into a transmission matrix in the frequency domain, and the overall shielding effectiveness of the material is expressed by the product of the matrices.

[0075] The transfer matrix is ​​expressed as: For wave impedance, The thickness of this medium layer. For electromagnetic wave vector, Let be the transmission matrix of the i-th layer of the medium. For multilayer media, the overall transmission matrix is ​​obtained by multiplying the matrices of each individual layer. The transmission coefficient is calculated using the overall transmission matrix between the medium layers, and then the shielding effectiveness is calculated. The expression is:

[0076]

[0077] In the formula, This represents the element in the 2nd row and 2nd column of the overall transfer matrix. The transmittance is the coefficient of light. It refers to shielding effectiveness.

[0078] In S3, electromagnetic interference sources covering a frequency range are set, and the time-domain and frequency-domain characteristics of electromagnetic interference are described by Fourier transform to simulate real input interference.

[0079] Based on the experimental scenario, the frequency range of the interference signal was set from 1 MHz to 1 GHz, covering multiple frequency bands from low frequency to high frequency. The amplitude of the interference signal changed with time, and the amplitude was set to increase or decrease exponentially with time to simulate the signal attenuation or enhancement effect in the actual environment and dynamically set the frequency characteristics of the interference signal.

[0080] The transient signal has a pulse width of 5 μs and uses a Gaussian pulse shape, while the steady-state signal uses a continuous wave (CW) signal with a fixed frequency of 500 MHz. The transient and steady-state signals are superimposed within the same frequency range. The signal sources include a single-frequency steady-state signal and a narrowband pulse signal, with random variations in signal strength and phase to ensure the complexity and diversity of the interference.

[0081] The time-domain changes of transient signals (such as Gaussian pulses) are transformed into frequency-domain characteristics. The Discrete Fourier Transform (DFT) is used to transform the time distribution of the signal into a frequency distribution, and the frequency characteristics of the steady-state signal are superimposed. The frequency components of the two are then superimposed by weighted averaging to generate a joint model of the interference signal that includes spectral energy and phase distribution.

[0082] Using typical radiation modes, simplified directionality functions are employed. The spatial intensity distribution of the signal is described as follows:

[0083]

[0084] in, The distance between the signal source and the receiving point. Considering the propagation angle, the signal strength attenuates with distance during propagation. The distance attenuation factor is set as follows: That is, the signal strength is inversely proportional to the square of the propagation distance.

[0085] Based on the needs of different time periods, the amplitude of the signal is adjusted by simulating the dynamic changes of interference signals in real-world scenarios (such as power spikes or attenuation). For example, the transient signal is set to increase in amplitude between 0 and 5 μs, and then gradually attenuate to zero after 5 μs. By adjusting the frequency distribution of the signal, the frequency ranges of the transient and steady-state signals are dynamically switched. The steady-state signal is maintained around 500 MHz, while the frequency range of the transient signal is adaptively adjusted according to the test requirements.

[0086] Experiments show that the signal propagation strength is greater near the shielding layer or interference source, while the signal strength gradually attenuates at greater distances. The spatial intensity distribution of the signal is dynamically adjusted based on the propagation path and attenuation factor.

[0087] By using Fourier transform, the frequency domain amplitude distribution of the interference signal is tested to ensure the integrity of the spectrum within the frequency range, covering the preset frequency range (1MHz to 1GHz).

[0088] In S4, the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals is analyzed, and an electromagnetic wave interference response propagation model is formed.

[0089] A plane wave is set as the excitation condition at the outermost boundary of the electromagnetic wave propagation model. The input multidimensional interference signal consists of transient and steady-state signals. The generated interference signal is used as the input condition of the electromagnetic wave propagation model to drive the electromagnetic wave interference response simulation of the composite shielding material.

[0090] The finite-difference time-domain (FDTD) method is used to analyze the dynamic electromagnetic field under transient signal interference. The composite shielding material is layered, and the spatial grid (e.g., 1 μm grid spacing) and time step (satisfying the CFL condition, e.g., 1 ps) are set for each layer to ensure computational accuracy and stability. Within each time step, the electric and magnetic fields of each layer are continuously solved, and the propagation trajectory and energy distribution of the internal electromagnetic waves under transient signal interference are recorded. Based on the time-dimensional variation data of the energy distribution (i.e., energy flow rate), the power density distribution in the propagation characteristic data is calculated.

[0091] Based on the frequency domain finite element method, a set of electromagnetic field equations under steady-state signal interference is established. Combining the material's dielectric constant, permeability, and thickness distribution, the field distribution and power loss of the internal electromagnetic waves under steady-state signal interference within a preset interference signal frequency range are recorded.

[0092] This paper integrates the spatial propagation characteristics data of transient signals in the time domain and the field distribution and power loss data of steady-state signals in the frequency domain. An interpolation method is used to establish a mapping relationship between the two, ensuring consistency in the data conversion between the time and frequency domains. Linear interpolation is employed to replace the frequency domain calculation results with the time series of the transient calculations, filling in and redefining the propagation characteristics of each medium layer (including at least the electromagnetic wave field distribution, power loss, power density distribution, propagation trajectory, reflection, transmission, and absorption characteristics). Through interpolation and replacement, an electromagnetic wave interference response propagation model incorporating both transient and steady-state characteristics is established to describe the dynamic response of the composite shielding material under multidimensional interference signals.

[0093] In S5, the output results of the electromagnetic interference response propagation model are compared with the actual shielding effectiveness test data. The model parameters are adjusted based on the comparison error until the calculation error of the electromagnetic interference response propagation model is within an acceptable range.

[0094] Under the same interference conditions, the electromagnetic wave interference response propagation model was run, and the electromagnetic wave propagation characteristics data output by the model were recorded, including power density distribution, field strength distribution, and energy attenuation characteristics. The experimental data and model output results were compared point-by-point using frequency domain matching. Based on the deviation distribution results, parameters in the propagation model that need optimization were identified, and the boundary condition settings were adjusted item by item. Simultaneously, the amplitude, frequency range, and phase distribution of the input interference signal were checked to ensure consistency with the experimental conditions.

[0095] Common boundary conditions include: for interfaces with large deviations, adjusting the boundary parameters of the electric and magnetic fields, such as the permittivity and permeability at the material interface. For the outermost boundary conditions of the model, optimizing the absorption characteristics of the perfectly matched layer reduces the interference of boundary reflections on the model calculation.

[0096] The adjusted boundary condition parameters are re-input into the electromagnetic wave interference response propagation model for iterative calculation. The output results are then compared with the experimental data, and the verification is continued until the deviation converges to the predetermined tolerance range.

[0097] In S6, a full-band shielding effectiveness prediction spectrum of composite shielding materials under simulated interference conditions is generated based on the electromagnetic wave interference response propagation model. According to a preset interference signal frequency range (e.g., 1 MHz to 1 GHz), a multi-dimensional interference signal pattern with dynamic combinations of transient and steady-state signals is generated.

[0098] The interference signal is input into the electromagnetic wave interference response propagation model, which outputs electromagnetic wave propagation characteristic data for each layer. The electromagnetic wave propagation characteristic data is converted into a transmission matrix in the frequency domain. The shielding effectiveness at each frequency point is calculated based on the transmission matrix, and a shielding effectiveness prediction spectrum is generated. The horizontal axis represents frequency, and the vertical axis represents shielding effectiveness. The prediction spectrum can intuitively reflect the material's shielding ability against interference at different frequencies, providing a reference for material performance evaluation and design optimization.

[0099] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters and thresholds in the formulas are set by those skilled in the art according to the actual situation.

[0100] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0101] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0102] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0104] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0106] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0108] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for analyzing experimental data on the effectiveness of composite shielding materials, characterized in that, Includes the following steps: S1: Use electromagnetic performance measuring instruments to measure the dielectric constant, permeability, thickness, and conductivity of each layer of the composite shielding material; S2: Define the boundary conditions of the test sample and establish an electromagnetic wave propagation model based on Maxwell's equations to describe the propagation characteristics of electromagnetic waves inside the multilayer medium of the composite shielding material. S3: Set the electromagnetic interference source covering the frequency range, describe the time and frequency domain characteristics of the electromagnetic interference through Fourier transform, and simulate the real input interference; S4: Analyze the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals to form an electromagnetic wave interference response propagation model; S5: Compare the output results of the electromagnetic interference response propagation model with the actual shielding effectiveness test data, and adjust the model parameters based on the comparison error until the calculation error of the electromagnetic interference response propagation model is within an acceptable range. S6: Generate a full-band shielding effectiveness prediction spectrum of composite shielding materials under simulated interference conditions based on the electromagnetic wave interference response propagation model; In S3, electromagnetic interference sources covering a frequency range are set, and the time-domain and frequency-domain characteristics of the electromagnetic interference are described using Fourier transform. The simulation of real input interference specifically includes: The frequency range of the interference signal is preset, and the frequency characteristics and pulse shape of the interference signal are dynamically set within the frequency range. The pulse width of the transient signal and the frequency range and amplitude change of the steady-state signal are used as the input conditions of the interference signal. The transient signal of electromagnetic interference is transformed into frequency domain characteristics. The time distribution of the signal is transformed into frequency distribution using discrete Fourier transform. The frequency characteristics of the steady-state signal are superimposed, and the frequency components of the two are superimposed to generate a joint model of the interference signal that includes spectral energy and phase distribution. The spatial intensity distribution of a signal is described by defining a directional function through the propagation path, and the change in signal intensity with propagation distance is expressed by a distance attenuation factor, thus forming the spatial propagation characteristics of electromagnetic waves. Directional function The spatial intensity distribution of the signal is described as follows: in, The distance between the signal source and the receiving point. From a communication perspective, This is the distance attenuation factor, which means that the signal strength is inversely proportional to the square of the propagation distance.

2. The method for analyzing experimental data on the effect of composite shielding materials according to claim 1, characterized in that, In S1, the measurement of the dielectric constant, permeability, thickness, and conductivity of each layer of the composite shielding material using electromagnetic performance measuring instruments specifically includes: The composite shielding material was cut into test samples in layers, and the thickness of each shielding layer was measured using a mechanical measuring device according to the set accuracy requirements. A dielectric analysis device with a non-fixed frequency range is used to scan the response of the test sample by applying an alternating electric field, thereby generating frequency distribution data of the dielectric constant of each layer; The response characteristics of the test sample material to magnetic fields of different frequencies were extracted using a vector network analyzer, and the frequency distribution data of the permeability of each layer were obtained. A constant current is applied to the surface of the test sample material, and the voltage change is measured in real time to calculate the conductivity of each layer of material. The thickness, dielectric constant, magnetic permeability, and electrical conductivity of the composite shielding material were measured multiple times. The measured results were then digitally converted and corrected to establish a standardized material property parameter library.

3. The method for analyzing experimental data on the effect of composite shielding materials according to claim 2, characterized in that, In S2, the boundary conditions of the test sample are defined, and an electromagnetic wave propagation model describing the propagation characteristics of electromagnetic waves within the multilayer dielectric of the composite shielding material is established based on Maxwell's equations. Specifically, this includes: Based on the relationship between electric field, electric displacement field, magnetic induction intensity and magnetic field intensity in Maxwell's equations, continuous boundary conditions are set at each layer interface of the test sample material. Based on the material properties of each medium in the standardized material property parameter library and its actual spatial distribution, an electromagnetic wave equation is constructed to describe the relationship between the reflection, transmission, and absorption processes of electromagnetic waves in each medium. The electromagnetic wave equation is as follows: In the formula, For electric field strength, For time variables, The spatial second derivative of the electric field, It is the change of electric field over time. , , These are the magnetic permeability, dielectric constant, and conductivity of the medium, respectively. Based on the changes in the input and output electromagnetic field intensity of each medium layer, the power density distribution and electromagnetic wave propagation trajectory of each medium layer are calculated using the wave equation combined with the phase change of the electric field. The calculation results are then incorporated into the electromagnetic wave propagation characteristic data inside the medium to establish an electromagnetic wave propagation model. The electromagnetic wave propagation characteristics of each layer of the medium are converted into a transmission matrix in the frequency domain, and the overall shielding effectiveness of the material is expressed by the product of the matrices.

4. The method for analyzing experimental data on the effect of composite shielding materials according to claim 3, characterized in that, In S3, electromagnetic interference sources covering a frequency range are set, and the time-domain and frequency-domain characteristics of the electromagnetic interference are described using Fourier transform. Simulating real input interference further includes: The amplitude and frequency distribution of the generated interference signal are dynamically adjusted by the joint model of the interference signal to generate a dynamic multidimensional interference signal containing transient and steady-state signal characteristics. The time-domain waveform, frequency-domain amplitude, and spatial distribution of the interference signal are tested using spectrum analysis methods to verify the integrity of its spectrum within the preset interference signal frequency range.

5. The method for analyzing experimental data on the effect of composite shielding materials according to claim 4, characterized in that, In S4, the dynamic response of the electromagnetic wave propagation model under transient and steady-state interference signals is analyzed, forming the electromagnetic wave interference response propagation model, which specifically includes: A plane wave is input as the excitation condition at the outermost boundary of the electromagnetic wave propagation model. A multidimensional interference signal containing transient and steady-state signal characteristics is generated as input to drive the dynamic simulation of the interference response of the electromagnetic wave propagation model. The finite-difference time-domain method was used to analyze transient interference signals. The dynamic changes of electric and magnetic fields of each layer of the composite shielding material were continuously calculated with a fixed time step, and the propagation trajectory and energy distribution of internal electromagnetic waves under transient signal interference were recorded. Based on the frequency domain finite element method, a set of electromagnetic field equations under steady-state signal interference is established. Combining the material's dielectric constant, permeability, and thickness distribution, the field distribution and power loss of the internal electromagnetic wave under steady-state signal interference within the preset interference signal frequency range are recorded. The electromagnetic wave propagation characteristics in the electromagnetic wave propagation model are transformed and interpolated by using the spatial propagation characteristics in the time domain and the corresponding field distribution and power loss data in the frequency domain of the multidimensional interference signal, so as to establish an electromagnetic wave interference response propagation model.

6. The method for analyzing experimental data on the effect of composite shielding materials according to claim 5, characterized in that, In S5, the output results of the electromagnetic interference response propagation model are compared with the actual shielding effectiveness test data. The model parameters are adjusted based on the comparison error until the calculation error of the electromagnetic interference response propagation model is within an acceptable range. Specifically, this includes: The actual propagation characteristics of the internal electromagnetic waves of the composite shielding material under real external electromagnetic interference scenarios are used as experimental data. By comparing the experimental data under the same interference conditions with the output results of the electromagnetic wave interference response propagation model in the same frequency domain, the deviation distribution of the electromagnetic wave propagation characteristic data of the two is obtained by difference calculation. Based on the deviation distribution of electromagnetic wave propagation characteristic data, the boundary condition parameters in the electromagnetic wave interference response propagation model are adjusted item by item. The adjusted boundary condition parameters are re-input into the electromagnetic wave interference response propagation model for iterative calculation. The output results are then compared with the experimental data, and the verification is continued until the deviation converges to the predetermined tolerance range.

7. The method for analyzing experimental data on the effect of composite shielding materials according to claim 6, characterized in that, In S6, the generation of a full-band shielding effectiveness prediction spectrum for composite shielding materials under simulated interference conditions based on the electromagnetic wave interference response propagation model specifically includes: Generate a full-band multi-dimensional interference signal on the composite shielding material within a preset interference signal frequency range; The interference signal is input into the electromagnetic wave interference response propagation model, which outputs electromagnetic wave propagation characteristic data for each layer. The electromagnetic wave propagation characteristic data is then converted into a transmission matrix in the frequency domain to generate a shielding effectiveness prediction spectrum for the full-band interference mode.

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