Equivalent dielectric parameter calculation method for truss type structure

Abstract

The invention discloses an equivalent dielectric parameter calculation method for a truss type structure, and belongs to the technical field of electronic science. The method solves the problem that an existing equivalent medium theory cannot directly perform equivalent calculation on a truss structure model, constructs a general expression from the equivalent medium theory, can improve the calculation universality and portability, considers the influence of material composition and structure on equivalent dielectric parameters, and improves the calculation accuracy. A precise tool is provided for analyzing electromagnetic behaviors, undetermined indexes are discretized in an interval range at equal intervals, processing and analysis can be facilitated, a scattering result data set of an equivalent model corresponding to each discrete index can be calculated, comparison data can be accumulated, a typical actual model can be established, and a scattering result is calculated by adopting an area integral equation method. According to the method, data can be ensured to be close to reality and reliable, accurate parameters are determined through fitting, equivalent conversion from a complex truss structure to a simple homogeneous medium model is achieved, and main electromagnetic characteristics of an original structure can be reserved while the complexity of the model is simplified.

Description

Technical Field

[0001] The present invention relates to the field of electronic science and technology, and in particular to a method for calculating equivalent dielectric parameters of a truss structure. Background Art

[0002] Ceramic-based materials, with their low density, high specific strength, high-temperature oxidation resistance, and excellent chemical stability, have gradually become important candidates for electromagnetic stealth. In recent years, structural design has endowed ceramic materials with multi-scale and multifunctional electromagnetic control capabilities. Within the structural design system of ceramic materials, ceramic truss structures have attracted widespread attention due to their unique topological configuration and adjustable mechanical and thermal properties.

[0003] With breakthroughs in numerical electromagnetic algorithms and advanced computing resources, electromagnetic simulation technology is becoming increasingly integrated into the research and development of novel material configurations. Rapid simulation of the electromagnetic properties of ceramic-based truss structures, the development of theoretical models, and the optimization of structural designs through parameterization are all key areas of advancement in material and structural design.

[0004] Currently, the main methods for analyzing the electromagnetic characteristics of truss structures are full-wave numerical methods and experimental measurement methods, but the following problems still exist:

[0005] 1. The unit size of the truss structure is small. The actual target composed of this type of material is mostly a unit periodic structure with a large electrical size. When using full-wave numerical methods for simulation calculations, it is easy to cause multi-scale problems and difficult to calculate. In addition, the computational efficiency of the full-wave numerical method is limited by the meshing accuracy. When the truss unit size is close to the electromagnetic wavelength, the computing resource consumption increases exponentially.

[0006] 2. Among experimental measurement techniques, the free-space method is limited by the test environment and sample size requirements, making it difficult to analyze the local modulation effect of the truss microunits on the electromagnetic field. Although near-field scanning microscopy can detect local field enhancement phenomena at truss nodes, the spatial resolution is limited by the probe size, and the measurement accuracy is significantly reduced at the subwavelength scale, and continuous scanning across the entire frequency band cannot be achieved. The transmission line method uses waveguide or coaxial line testing, which is more difficult to process samples. Furthermore, since the sample size is generally large in the low-frequency band, processing is often a problem.

[0007] 3. Currently, there are many methods for calculating equivalent parameters. Different equivalent medium theories have certain limitations in their applicability to complex structural materials. For example, the MG formula is applicable to spherical particle-doped composite materials, the Bruggeman formula is applicable to symmetrical effective media with no obvious enclosure between two phases, and the Li formula is suitable for analyzing asymmetric microstructures. However, as a typical periodic structure, there is currently no clear theoretical formula that can be directly applied to the equivalent prediction of truss structures.

[0008] Therefore, it does not meet the existing needs. We propose a calculation method for equivalent dielectric parameters of truss structures. Summary of the Invention

[0009] The purpose of the present invention is to provide a method for calculating the equivalent dielectric parameters of truss structures. By providing clear calculation formulas for typical structures such as SC and BCC, an efficient conversion of complex micro-geometry to a uniform medium model is achieved. After the complex structure is equivalent to a uniform medium, the electromagnetic characteristics analysis can be completed quickly while ensuring accuracy. The undetermined parameters are determined through scientific and rigorous steps such as discrete sampling, data set establishment, and fitting errors, ensuring the high accuracy of the equivalent results, which are highly consistent with the results of the full-wave numerical method. This provides a reliable theoretical tool for the electromagnetic characteristics analysis of electromagnetic stealth materials and solves the problems raised in the above-mentioned background technology.

[0010] To achieve the above object, the present invention provides the following technical solution: a method for calculating equivalent dielectric parameters of a truss structure, the method comprising the following steps:

[0011] Step 1: For N-phase material mixtures, according to the equivalent medium theory, establish a general expression for the equivalent dielectric parameters of the truss structure to be calculated;

[0012] Step 2: Calculate the volume fraction of the ceramic truss base material. The ceramic-based truss lattice structure material is considered to be a two-phase mixture of air and ceramic material. Assuming the volume fraction of the ceramic material is c, the volume fraction of air is 1-c. By dividing the ceramic material into tetrahedral meshes separately, the sum of the volumes of all tetrahedrons is calculated to obtain the total volume occupied by the ceramic material, and then the volume fraction c is obtained.

[0013] Step 3: Perform uniform discrete sampling of the exponential unknowns in the general expression within the range of 0 and 1, establish a uniform dielectric body with the same dimensions as the original model, and use the surface integral equation method to calculate the far-field single-station RCS scattering result data set within the axial range of ±45° for each equivalent parameter corresponding to the equivalent model;

[0014] Step 4: Place the actual ceramic truss lattice structure material model into the FEKO software, set the calculation conditions and calculation methods, obtain the VV polarization scattering results of the actual model through simulation calculation, and output the results for storage;

[0015] Step 5: By fitting the calculation result curves of the actual model and the equivalent model, the root mean square error between the actual model results and each data in the data set is calculated, the minimum error is taken, and the final parameter expression is determined.

[0016] Furthermore, in step 1, a general expression for the equivalent dielectric parameters of the truss structure to be calculated is established as follows:

[0017]

[0018] Among them, ε ef represents the equivalent dielectric parameter; ε i represents the dielectric constant of the i-th component; c i represents the volume fraction of the i-th component; for ceramic truss structures, α is an exponential coefficient to be determined, and its value range is [0, 1].

[0019] Furthermore, in step 2, in order to calculate the volume fraction of each component, the ceramic material is divided into a tetrahedral grid separately. During the division, the sparsity of the grid is adjusted according to the shape of the material. Then, the volume of each tetrahedron is calculated based on the four vertex information of the tetrahedral grid. The volumes of all tetrahedrons are added together to obtain the total area occupied by the material, and finally the volume fraction occupied by the ceramic material is obtained.

[0020] Furthermore, the volume of the tetrahedron is calculated as follows:

[0021]

[0022] Wherein, V represents the volume of the tetrahedron; X1, X2, X3, X4, Y1, Y2, Y3, Y4 and Z1, Z2, Z3, Z4 represent the coordinates of the four vertices of the tetrahedron in three-dimensional space.

[0023] Furthermore, in step three, the parameter α in the general expression is uniformly discretely valued between 0 and 1 at intervals of 0.02, and is substituted into the general expression to obtain an equivalent dielectric parameter data set.

[0024] Furthermore, in step 3, the RCS results of a homogeneous medium with the same size as the actual model are calculated, and the frequency and azimuth angle settings are consistent with those in the FEKO software. The dielectric parameters of the homogeneous medium are the equivalent dielectric parameters in the data set. After calculating all the data, the RCS result library is obtained.

[0025] Furthermore, in step 4, the calculation conditions include frequency range, scanning angle range and interval, and VV polarization.

[0026] Furthermore, in step 5, the calculation results of the FEKO software moment method are used as reference data, and the calculation results after equivalent are used as comparison data. The error between the two is calculated to obtain a relationship diagram of the error changing with the parameter α.

[0027] Furthermore, based on the obtained error versus parameter α relationship graph, parameter values ​​were selected from the graph to obtain the equivalent formulas for SC structural materials and BCC structural materials, as shown below:

[0028] The equivalent formula of SC structural material is:

[0029]

[0030] The equivalent formula for BCC structural materials is:

[0031]

[0032] Furthermore, the general expression established in step 1 is applicable to different types of truss structures, including simple cubic lattice structures, body-centered cubic lattice structures, and other customized truss structures.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. Starting from the equivalent medium theory, the present invention establishes a relationship between the exponent of the equivalent electromagnetic parameters of the truss structure to be calculated, multiplied by the volume fraction of each phase material and the exponent of the corresponding dielectric constant, and then summed. This can provide a universal model for subsequent calculations, eliminating the need to rebuild the basic theory for each truss structure, greatly improving the versatility and portability of the calculation. Incorporating the volume fraction and dielectric constant of each phase material into the relationship fully considers the proportion of different materials in the truss structure and the differences in their electromagnetic properties, allowing the calculation results to more accurately reflect the impact of material composition and structure on the equivalent dielectric parameters, thereby making it possible to accurately analyze and predict the electromagnetic behavior of truss structures.

[0035] 2. The present invention discretizes the undetermined exponents into equally spaced values ​​within the interval [0, 1], thereby concretizing the originally uncertain exponential parameters into a series of operable discrete values, thereby facilitating subsequent processing and analysis. Furthermore, by calculating the scattering result data set of the equivalent model corresponding to each discrete exponent, rich comparative data can be accumulated for the fitting process.

[0036] 3. By establishing a typical actual finite-period truss structure model, the present invention makes the calculated scattering results closer to the real physical scene and reflects the electromagnetic characteristics of the truss structure in actual engineering. The scattering results of the actual model are calculated using the surface integral equation method, which can provide accurate target data for the subsequent fitting process and ensure the reliability and effectiveness of the entire calculation method.

[0037] 4. By fitting the calculation result curves of the actual model and the equivalent model, the present invention can accurately find the value of the undetermined exponential parameter that minimizes the error between the two, thereby determining the equivalent dielectric parameters that best conform to reality, so that the equivalent model can accurately reflect the electromagnetic characteristics of the actual truss structure. The final determined parameters are substituted back into the original undetermined equivalent formula to obtain the final equivalent parameters, thereby achieving the goal of equivalentizing the complex truss structure to a simple uniform medium model, which not only retains the main electromagnetic characteristics of the original structure but also simplifies the model complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flow chart of a method for calculating equivalent dielectric parameters of a truss structure according to the present invention;

[0039] Figure 2 A schematic diagram of the tetrahedron mesh and vertex coordinates of the present invention;

[0040] Figure 3 Schematic diagram of the truss structure entity modeling unit of two typical structures of SC and BCC of the present invention;

[0041] Among them, (a) is the SC lattice unit structure model, (b) is the BCC lattice unit structure model;

[0042] Figure 4 This is a graph showing the error value of the present invention changing with the parameter α;

[0043] Among them, (a) is the result of SC structure material, (b) is the result of BCC structure material;

[0044] Figure 5 Schematic diagram of the homogeneous equivalent model of the SC and BCC structures of the present invention;

[0045] Among them, (a) is the SC crystal structure, (b) is the BCC crystal structure;

[0046] Figure 6 Schematic diagram of the comparison between the SC structure, the present method and the FEKO single-station scattering results (VV polarization 3GHz);

[0047] Figure 7 Schematic diagram of the comparison between the SC structure of the present invention and the FEKO single-station scattering results (VV polarization 5GHz);

[0048] Figure 8 Schematic diagram of the comparison between the BCC structure of the present invention and the FEKO single-station scattering results (VV polarization 3GHz);

[0049] Figure 9 Schematic diagram of the comparison between the BCC structure, this method and the FEKO single-station scattering results (VV polarization 5GHz). DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] In order to solve the technical problem that the existing equivalent medium theory cannot directly perform equivalent calculations on truss structure models, please refer to Figure 1-Figure 3 , this embodiment provides the following technical solutions:

[0052] A method for calculating equivalent dielectric parameters of a truss structure, comprising the following steps:

[0053] Step 1: For N-phase material mixtures, according to the equivalent medium theory, establish a general expression for the equivalent dielectric parameters of the truss structure to be calculated;

[0054] The general expression for the equivalent dielectric parameters of the truss structure to be calculated is as follows:

[0055]

[0056] Among them, ε ef represents the equivalent dielectric parameter; ε i represents the dielectric constant of the i-th component; c i represents the volume fraction of the i-th component; for ceramic truss structures, α is an exponential coefficient to be determined, and its value range is [0, 1];

[0057] The established general expressions are applicable to different types of truss structures, including simple cubic lattice structures, body-centered cubic lattice structures, and other customized truss structures;

[0058] Step 2: Calculate the volume fraction of the ceramic truss base material. The ceramic-based truss lattice structure material is considered to be a two-phase mixture of air and ceramic material. Assuming the volume fraction of the ceramic material is c, the volume fraction of air is 1-c. By dividing the ceramic material into tetrahedral meshes separately, the sum of the volumes of all tetrahedrons is calculated to obtain the total volume occupied by the ceramic material, and then the volume fraction c is obtained.

[0059] Step 3: Perform uniform discrete sampling of the exponential unknowns in the general expression within the range of 0 and 1, establish a uniform dielectric body with the same dimensions as the original model, and use the surface integral equation method to calculate the far-field single-station RCS scattering result data set within the axial range of ±45° for each equivalent parameter corresponding to the equivalent model;

[0060] Step 4: Place the actual ceramic truss lattice structure material model into the FEKO software, set the calculation conditions and methods, and obtain the VV polarization scattering results of the actual model through simulation calculations and output the results for storage. The calculation conditions include the frequency range, scanning angle range and interval, and VV polarization. By clearly specifying the calculation conditions and methods, the accuracy, standardization, and repeatability of the simulation calculations are ensured, thus providing a reliable data foundation for subsequent parameter fitting and model verification.

[0061] Step 5: By fitting the calculation result curves of the actual model and the equivalent model, the root mean square error between the actual model results and each data in the data set is calculated, the minimum error is taken, and the final parameter expression is determined.

[0062] The technical effects of the above technical scheme are as follows: First, for a mixture of N-phase materials, a general expression for the equivalent dielectric parameters of the truss structure to be calculated can be established based on the equivalent medium theory, thereby laying a theoretical foundation for subsequent calculations. Compared with the traditional full-wave numerical method, this method avoids the excessive consumption of computing resources and low computing efficiency caused by problems such as the small size of the truss structure unit, the large electrical size, and multiple scales, thereby effectively improving the computing efficiency, especially when dealing with complex truss structure models. Secondly, by dividing the ceramic material into tetrahedral meshes separately, the sum of the volumes of all tetrahedrons is calculated to obtain the total volume occupied by the ceramic material, and then the volume fraction is obtained, thereby providing accurate material volume ratio data for the subsequent calculation of equivalent dielectric parameters. Afterwards, the exponential unknowns in the general expression are uniformly discretely sampled in the interval [0,1], which can make the originally uncertain exponential parameters concretized into a series of operable discrete values, thereby facilitating subsequent processing and analysis, and then a uniform dielectric body consistent with the original model size is established, and the surface integral equation method is used to calculate the equivalent model corresponding to each equivalent parameter. The far-field single-station RCS scattering result data set within the axial ±45° range of the model is obtained, thereby accumulating rich comparative data for the fitting process. Afterwards, the actual ceramic truss lattice structure material model is placed in the FEKO software, and the calculation conditions and calculation methods are set. The VV polarization scattering results of the actual model can be obtained through simulation calculation and the results are output and saved, making the calculated scattering results closer to the real physical scene, thereby reflecting the electromagnetic characteristics of the truss structure in the actual engineering and providing accurate target data for the subsequent fitting process, ensuring the reliability and effectiveness of the entire calculation method. Finally, by fitting the calculation result curves of the actual model and the equivalent model, and statistically calculating the root mean square error between the actual model results and the data in the dataset, and taking the minimum error, the value of the undetermined exponential parameter that minimizes the error between the two can be accurately found, thereby determining the final parameter expression, so that the goal of equivalentizing the complex truss structure to a simple uniform medium model can be achieved, which not only retains the main electromagnetic characteristics of the original structure but also simplifies the model complexity, thereby providing an efficient and accurate tool for subsequent electromagnetic simulation and design.

[0063] In step 2, in order to calculate the volume fraction of each component, the ceramic material is divided into tetrahedral meshes separately. When dividing, the sparsity of the mesh is adjusted according to the shape of the material (the information of the tetrahedral mesh is as follows Figure 2 As shown in the figure, the calculation method can adapt to ceramic truss structures of different shapes and complexities, improving the applicability and versatility of the method and ensuring that the volume fraction can be accurately calculated in various cases. The volume of each tetrahedron is then calculated based on the four vertex information of the tetrahedron mesh, and the volumes of all tetrahedrons are added together to obtain the total area occupied by the material, and finally the volume fraction occupied by the ceramic material is obtained.

[0064] The volume of a tetrahedron is calculated as follows:

[0065]

[0066] Wherein, V represents the volume of the tetrahedron; X1, X2, X3, X4, Y1, Y2, Y3, Y4 and Z1, Z2, Z3, Z4 represent the coordinates of the four vertices of the tetrahedron in three-dimensional space.

[0067] The technical effect of the above technical solution is: by dividing the ceramic material into a tetrahedral mesh separately, calculating the volume of each tetrahedron based on the vertex information of the tetrahedral mesh, and then adding up the volumes of all tetrahedrons to obtain the total volume occupied by the ceramic material, the volume fraction of the ceramic material can be accurately obtained. This method can accurately reflect the actual composition ratio of the material, thereby providing accurate basic data for the subsequent calculation of equivalent dielectric parameters.

[0068] In step 3, the parameter α in the general expression is uniformly discretized between 0 and 1 at intervals of 0.02, and then substituted into the general expression to obtain the equivalent dielectric parameter data set;

[0069] Calculate the RCS results of a homogeneous medium with the same size as the actual model, and keep the frequency and azimuth angle settings consistent with those in the FEKO software. The dielectric parameters of the homogeneous medium are the equivalent dielectric parameters in the data set. Complete the calculation of all data to obtain the RCS result library.

[0070] The technical effect of the above technical solution is: by further refining the specific operations of discretizing the parameters in the general expression, the method of uniformly discrete values ​​at intervals of 0.02 is clarified. This systematic discretization method ensures the comprehensiveness and uniformity of the parameter values, avoids the deviation of the calculation results caused by improper discrete intervals, and thus provides detailed and systematic data support for the subsequent establishment of the scattering result data set of the equivalent model, so that the data set can more accurately reflect the scattering characteristics under different parameter conditions. By substituting the discretized parameters into the general expression to obtain the equivalent dielectric parameter data set and calculating the RCS results of the corresponding uniform medium, a large amount of comparative data can be generated, thereby providing rich samples for the fitting process, helping to improve the accuracy and reliability of the subsequent fitting results, and thus accelerating the process of determining the optimal parameter values.

[0071] In step 5, the calculation results of the FEKO software moment method are used as reference data, and the calculation results after equivalent are used as comparison data. The error between the two is calculated to obtain the relationship diagram of the error as the parameter α changes (such as Figure 4 shown);

[0072] Based on the obtained error versus parameter α relationship diagram (such as Figure 4As shown in the figure), the parameter values ​​are selected from the figure to obtain the equivalent formulas of SC structural materials and BCC structural materials, which are shown as follows:

[0073] The equivalent formula of SC structural material is:

[0074]

[0075] The equivalent formula for BCC structural materials is:

[0076]

[0077] At this point, the complex microscopic geometries of simple cubic structure materials (i.e., SC structure materials) and body-centered cubic lattice structure materials (i.e., BCC structure materials) are equivalent to homogeneous medium models of the same size (e.g., Figure 5 shown).

[0078] In this example, a flat plate model composed of SC structural material and BCC structural material units is used. The model size of the SC structural model is 40mm*40mm*8mm, and the size of the BCC structural flat plate model is 56mm*56mm*4mm. The relative dielectric parameter of the ceramic material is set to 6. The moment method of FEKO software is used to calculate the flat plate structural model and the corresponding equivalent model respectively. At the 3GHz and 5GHz frequencies, the VV polarization monostatic RCS of the two structural plates is calculated. The results are shown as follows: Figure 6-Figure 9 As shown, this equivalent method is proven to have good accuracy.

[0079] The technical effect of the above technical solution is: a method for determining parameter values ​​by fitting the calculation result curves of the actual model and the equivalent model is clarified, providing a reliable error analysis and parameter optimization method for the entire calculation process. The calculation results of the FEKO software moment method are used as reference data, and the calculation results after equivalent are used as comparison data. The error between the two is calculated and a relationship diagram of the error versus parameter change is obtained, which can intuitively present the impact of parameter changes on the calculation results, thereby providing a clear basis for parameter selection. Through the error analysis and fitting process, the optimal parameter combination can be quickly found within limited computing resources and time. Based on the parameters determined by the above error analysis and fitting, the final equivalent dielectric parameters are closer to the electromagnetic characteristics of the actual model. Based on the error versus parameter change relationship diagram, the parameter values ​​are selected to obtain equivalent formulas for SC structural materials and BCC structural materials, providing specific equivalent dielectric parameter calculation formulas for these two typical truss structures, making the equivalent dielectric parameter calculation for these two common truss structures more direct and efficient, without the need for complex fitting and error analysis processes.

[0080] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0081] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for calculating equivalent dielectric parameters of a truss structure, characterized in that: The following steps are involved: Step 1: For N-phase material mixtures, according to the equivalent medium theory, establish a general expression for the equivalent dielectric parameters of the truss structure to be calculated; Step 2: Calculate the volume fraction of the ceramic truss base material. The ceramic-based truss lattice structure material is considered to be a two-phase mixture of air and ceramic material. Assuming the volume fraction of the ceramic material is c, the volume fraction of air is 1-c. By dividing the ceramic material into tetrahedral meshes separately, the sum of the volumes of all tetrahedrons is calculated to obtain the total volume occupied by the ceramic material, and then the volume fraction c is obtained. Step 3: Perform uniform discrete sampling of the exponential unknowns in the general expression within the range of 0 and 1, establish a uniform dielectric body with the same dimensions as the original model, and use the surface integral equation method to calculate the far-field single-station RCS scattering result data set within the axial range of ±45° for each equivalent parameter corresponding to the equivalent model; Step 4: Place the actual ceramic truss lattice structure material model into the FEKO software, set the calculation conditions and calculation methods, obtain the VV polarization scattering results of the actual model through simulation calculation, and output the results for storage; Step 5: By fitting the calculation result curves of the actual model and the equivalent model, the root mean square error between the actual model results and each data in the data set is calculated, the minimum error is taken, and the final parameter expression is determined.

2. The method for calculating equivalent dielectric parameters of a truss structure according to claim 1, characterized in that: In step 1, the general expression for the equivalent dielectric parameters of the truss structure to be calculated is established as follows: Among them, ε ef represents the equivalent dielectric parameter; ε i represents the dielectric constant of the i-th component; c i represents the volume fraction of the i-th component; for ceramic truss structures, α is an exponential coefficient to be determined, and its value range is [0, 1].

3. The method for calculating equivalent dielectric parameters of a truss structure according to claim 1, wherein: In step 2, in order to calculate the volume fraction of each component, the ceramic material is divided into a tetrahedral mesh separately. During the division, the sparsity of the mesh is adjusted according to the shape of the material. Then, the volume of each tetrahedron is calculated based on the four vertex information of the tetrahedral mesh. The volumes of all tetrahedrons are added together to obtain the total area occupied by the material, and finally the volume fraction occupied by the ceramic material is obtained.

4. The method for calculating equivalent dielectric parameters of a truss structure according to claim 3, wherein: The volume of a tetrahedron is calculated as follows: Wherein, V represents the volume of the tetrahedron; X1, X2, X3, X4, Y1, Y2, Y3, Y4 and Z1, Z2, Z3, Z4 represent the coordinates of the four vertices of the tetrahedron in three-dimensional space.

5. The method for calculating equivalent dielectric parameters of a truss structure according to claim 2, wherein: In the step three, the parameter α in the general expression is uniformly discretely valued between 0 and 1 at intervals of 0.02, and is substituted into the general expression to obtain an equivalent dielectric parameter data set.

6. The method for calculating equivalent dielectric parameters of a truss structure according to claim 1, characterized in that: In step 3, the RCS results of a homogeneous medium with the same size as the actual model are calculated, and the frequency and azimuth angle settings are consistent with those in the FEKO software. The dielectric parameters of the homogeneous medium are the equivalent dielectric parameters in the data set. After calculating all the data, the RCS result library is obtained.

7. The method for calculating equivalent dielectric parameters of a truss structure according to claim 1, wherein: In step 4, the calculation conditions include frequency range, scanning angle range and interval, and VV polarization.

8. The method for calculating equivalent dielectric parameters of a truss structure according to claim 2, wherein: In the step 5, the calculation result of the FEKO software moment method is used as the reference data, and the calculation result after equivalent is used as the comparison data. The error between the two is calculated to obtain a relationship diagram of the error changing with the parameter α.

9. The method for calculating equivalent dielectric parameters of a truss structure according to claim 8, characterized in that: Based on the obtained error versus parameter α relationship graph, parameter values ​​are selected from the graph to obtain the equivalent formulas for SC structural materials and BCC structural materials, as shown below: The equivalent formula of SC structural material is: The equivalent formula for BCC structural materials is:

10. The method for calculating equivalent dielectric parameters of a truss structure according to claim 1, wherein: In the step 1, the general expression established is applicable to different types of truss structures, including a simple cubic lattice structure, a body-centered cubic lattice structure, and other customized truss structures.

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