High-altitude nuclear electromagnetic pulse simulator simulation method

Abstract

The application discloses a simulation method of high-altitude nuclear electromagnetic pulse simulator, comprising the following steps: step 1, a model of a strip-line type bounded wave simulator is established, the model comprising a front transition section, a working space and a rear transition section; step 2, a double exponential voltage waveform is loaded in the model as an excitation source; step 3, background material, boundary conditions and a terminal load of the model are set; step 4, a time domain solver is adopted to perform calculation in combination with hexahedral mesh division; and step 5, field probes are arranged in the working space, pulse waveforms are acquired and verified. The simulation method solves the problems of waveform control, field uniformity and load impedance mismatching of the existing numerical simulation method.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic field technology, specifically relating to a simulation method for a high-altitude nuclear electromagnetic pulse simulator. Background Technology

[0002] Bounded wave simulators, also known as guided wave simulators, are typical devices widely used in high-power electromagnetic environment effects tests such as high-altitude nuclear electromagnetic pulse (HEMP) and lightning electromagnetic pulse. For larger targets, conducting threat-level electromagnetic pulse assessments often requires even larger bounded wave simulators to provide the electromagnetic pulse environment. Although the internal space field analysis of bounded wave simulators has always been a research hotspot, for medium-sized threat-level bounded wave simulators, considering the potential hazards of their external space leakage fields to surrounding electronic equipment and personnel, research on radiation leakage fields and safe zones is equally important.

[0003] Traditional bounded wave simulators rely on physical construction, resulting in high costs, difficulties in parameter tuning, and limitations in the testing environment. Existing numerical simulation methods also have shortcomings in waveform control, field uniformity, and load impedance mismatch, as detailed below:

[0004] 1. The unreasonable aspect ratio design of the simulator's working area leads to impedance mismatch; 2. Imperfect load matching causes reflection interference; 3. Field uniformity is difficult to meet the ±3dB standard; 4. The unreasonable loading method of the excitation source, the connection between the stripline and the grounding plate cause the output waveform to fail to meet the RS105 standard waveform, with the pulse leading edge meeting 2.5ns±0.5ns and the half-width at half-maximum meeting 23ns±5ns. Summary of the Invention

[0005] The purpose of this invention is to provide a simulation method for a high-altitude nuclear electromagnetic pulse simulator, which solves the problems of waveform control, field uniformity and load impedance mismatch in existing numerical simulation methods.

[0006] The technical solution adopted in this invention is a simulation method for a high-altitude nuclear electromagnetic pulse simulator, comprising the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0007] The invention is further characterized by: Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounding metal plate located below the working space and a strip structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements.

[0008] In step 1, the working space is 4m×4m×4m in size. The grounding metal plate is made of an ideal conductor material and is placed 3-5m below the working space. The width of the grounding metal plate is 7-9m, which is greater than the horizontal dimension of the working space. There are 8-10 wires, and the width of a single wire is 0.4-0.6m.

[0009] Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1); V (t)= V 0(e αt e βt (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and half-width at half-maximum, respectively, where t is time.

[0010] Step 3 specifically involves setting the background material to air and the boundary conditions to open boundaries to simulate infinite free space; and loading a matching resistor at the end of the transition section to suppress reflection.

[0011] The matching resistor has a resistance value of 140-160Ω.

[0012] Step 4 specifically involves using a time-domain solver and combining it with a hexahedral mesh to perform subdivision calculations on the model. The mesh size is adaptively refined based on the rise time of the double exponential voltage waveform.

[0013] Step 5 specifically involves: setting up a 3×3 array of time-domain field probes in the workspace, verifying the field uniformity, and ensuring that the leading edge of the acquired pulse waveform is 2.5ns ± 0.5ns, the half-width at half-maximum (WHM) is 23ns ± 5ns, and the amplitude fluctuation of the field strength in the workspace is within ±3dB.

[0014] The beneficial effects of this invention are: The high-altitude nuclear electromagnetic pulse simulator simulation method provided by this invention achieves a smooth transition from spherical waves to plane waves through transition section design, with field uniformity reaching ±3dB; the adjustable dual-exponential source parameters meet the requirements of standards such as GJB 8848; open boundary and load matching reduce simulation errors and improve the reliability of results. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the high-altitude nuclear electromagnetic pulse simulator simulation method of the present invention. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0017] The high-altitude nuclear electromagnetic pulse simulator simulation method provided by this invention, such as... Figure 1 As shown, it includes the following steps: Step 1: Model building; First, a three-dimensional model of a stripline bounded wave simulator was established in the CST electromagnetic simulation software. This model consists of three parts: a front transition section, a working space, and a rear transition section. The working space is designed as a cube with dimensions of 4m × 4m × 4m, used to place the device under test and create a uniform electromagnetic pulse environment. The front transition section adopts a horn-shaped gradient structure with a spherical wavefront, used to smoothly convert the spherical wave input from the excitation source into a plane wave, ensuring a flat wavefront when the electromagnetic wave enters the working space. The rear transition section also adopts a gradient structure to achieve a gradual impedance transition from the working space to the terminal load, reducing reflections. During the model construction process, a grounding metal plate and a stripline structure also need to be set up. The grounding metal plate is made of ideal conductor (PEC) material and is set 4m directly below the workspace, with a width of 8m, as a ground plane reference for the simulator. The stripline structure consists of 9 evenly distributed wires, each with a width of 0.5m. The spacing between the wires is optimized according to the 50Ω impedance matching requirement to ensure that the simulator has good transmission characteristics in the working frequency band. Step 2: Loading the stimulus source; An excitation source is set in the model; a discrete port loading method is used to apply a double exponential voltage waveform at the beginning of the first transition section; the mathematical expression of this waveform is: V (t)= V 0(e αt e βt (1); in, V 0 is an adjustable amplitude value, which can be set according to the required field strength. α and β As waveform control parameters, by adjusting the values ​​of the two, the leading edge of the output pulse is 2.5ns ± 0.5ns and the half-width at half-maximum is 23ns ± 5ns, so as to meet the specification requirements of military standards such as GJB 8848 for high-altitude nuclear electromagnetic pulse waveforms. Step 3, Boundary and Load Settings; After completing the model construction and stimulus settings, configure the simulation environment; set the background material to air to simulate the actual atmospheric environment; use open boundary conditions to simulate infinite free space and avoid interference from boundary reflections on the simulation results; At the end of the transition section after the simulator, a matching resistor is loaded; in this implementation, the resistance value of the matching resistor is set to 150Ω; this resistance value is designed to match the characteristic impedance of the simulator, and is used to absorb the electromagnetic wave energy transmitted to the terminal, effectively suppress the reverse propagation of the reflected wave along the stripline, thereby ensuring the purity of the waveform in the workspace. Step 4: Solve the calculation; The simulation calculation was performed using a time-domain solver (transient solver); the model was discretized using a hexahedral mesh; to ensure calculation accuracy, the mesh size was adaptively refined according to the rise time of the double exponential voltage waveform, that is, the mesh was automatically refined in regions with drastic waveform changes (such as the early transition section and near the excitation source), and the mesh was appropriately coarsened in regions with gentle waveform changes, so as to achieve a balance between calculation efficiency and accuracy. Step 5: Result Verification; After the calculation is completed, field probes are set up in the workspace to verify the results; Specifically, a 3×3 array of time-domain field probes is arranged in the workspace, evenly distributed at 9 sampling points in the workspace; the pulse waveforms at each point are monitored by the time-domain field probes to verify the field uniformity in the workspace. The verification criteria are as follows: the leading edge of the acquired pulse waveform must meet the requirements of 2.5ns ± 0.5ns, and the full width at half maximum (FWHM) must meet the requirements of 23ns ± 5ns; the amplitude fluctuation of the field strength at each sampling point in the workspace must be within ±3dB. If both of the above requirements are met, the simulation results are deemed valid, and the simulator model can be used for subsequent simulation analysis of high-altitude nuclear electromagnetic pulse effects.

[0018] Example 1 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0019] Example 2 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0020] Example 3 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. In step 1, the working space dimensions are 4m×4m×4m. The grounding metal plate is made of an ideal conductor material and is placed 3-5m below the working space, with a width of 7-9m, which is greater than the horizontal dimension of the working space. The number of wires is 8-10, and the width of a single wire is 0.4-0.6m. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0021] Example 4 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. In step 1, the working space dimensions are 4m×4m×4m. The grounding metal plate is made of an ideal conductor material and is placed 3-5m below the working space, with a width of 7-9m, which is greater than the horizontal dimension of the working space. The number of wires is 8-10, and the width of a single wire is 0.4-0.6m. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1); V (t)= V 0(e αt e βt (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and full width at half maximum (FWHM), respectively, where t is time. Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0022] Example 5 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. In step 1, the working space dimensions are 4m×4m×4m. The grounding metal plate is made of an ideal conductor material and is placed 3-5m below the working space, with a width of 7-9m, which is greater than the horizontal dimension of the working space. The number of wires is 8-10, and the width of a single wire is 0.4-0.6m. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1); V (t)= V 0(e αt e βt (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and full width at half maximum (FWHM), respectively, where t is time. Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 3 specifically involves: setting the background material to air and the boundary conditions to open boundaries to simulate infinite free space; and loading a matching resistor at the end of the transition section to suppress reflection. The resistance of the matching resistor is 140-160Ω; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0023] Example 6 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. In step 1, the working space dimensions are 4m×4m×4m. The grounding metal plate is made of an ideal conductor material and is placed 3-5m below the working space, with a width of 7-9m, which is greater than the horizontal dimension of the working space. The number of wires is 8-10, and the width of a single wire is 0.4-0.6m. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1); V (t)= V 0(e αt e βt (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and full width at half maximum (FWHM), respectively, where t is time. Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 3 specifically involves: setting the background material to air and the boundary conditions to open boundaries to simulate infinite free space; and loading a matching resistor at the end of the transition section to suppress reflection. The resistance of the matching resistor is 140-160Ω; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 4 specifically involves using a time-domain solver and combining it with a hexahedral mesh to perform subdivision calculations on the model. The mesh size is adaptively refined based on the rise time of the double exponential voltage waveform. Step 5: Set up field probes in the workspace, acquire pulse waveforms, and verify them.

[0024] Example 7 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. In step 1, the working space dimensions are 4m×4m×4m. The grounding metal plate is made of an ideal conductor material and is placed 3-5m below the working space, with a width of 7-9m, which is greater than the horizontal dimension of the working space. The number of wires is 8-10, and the width of a single wire is 0.4-0.6m. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1); V (t)= V 0(e αt e βt (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and full width at half maximum (FWHM), respectively, where t is time. Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 3 specifically involves: setting the background material to air and the boundary conditions to open boundaries to simulate infinite free space; and loading a matching resistor at the end of the transition section to suppress reflection. The resistance of the matching resistor is 140-160Ω; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 4 specifically involves using a time-domain solver and combining it with a hexahedral mesh to perform subdivision calculations on the model. The mesh size is adaptively refined based on the rise time of the double exponential voltage waveform. Step 5: Set up the field probe in the workspace, acquire pulse waveforms, and verify them; Step 5 specifically involves: setting up a 3×3 array of time-domain field probes in the workspace, verifying the field uniformity, and ensuring that the leading edge of the acquired pulse waveform is 2.5ns ± 0.5ns, the half-width at half-maximum (WHM) is 23ns ± 5ns, and the amplitude fluctuation of the field strength in the workspace is within ±3dB.

[0025] Example 8 The high-altitude nuclear electromagnetic pulse simulator simulation method proposed in this embodiment, such as Figure 1 As shown, it includes the following steps: Step 1: Establish a model for the bandline bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section. Step 1 is as follows: The working space is a cubic structure, the wavefront of the front transition section is spherical, which is used to convert the spherical wave into a plane wave, and the rear transition section is used to realize the impedance gradual transition; the model also includes a grounded metal plate located below the working space and a strip line structure composed of multiple wires, with the wires evenly distributed and the spacing optimized according to the impedance matching requirements. In step 1, the working space dimensions are 4m×4m×4m. The grounding metal plate is made of an ideal conductor material and is placed 4m below the working space. Its width is 8m, which is greater than the horizontal dimension of the working space. There are 9 wires, and the width of each wire is 4m. Step 2: Load a double exponential voltage waveform as the excitation source into the model; Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1); V (t)= V 0(e αt e βt (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and full width at half maximum (FWHM), respectively, where t is time. Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 3 specifically involves: setting the background material to air and the boundary conditions to open boundaries to simulate infinite free space; and loading a matching resistor at the end of the transition section to suppress reflection. The matching resistor has a resistance of 150Ω; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 4 specifically involves using a time-domain solver and combining it with a hexahedral mesh to perform subdivision calculations on the model. The mesh size is adaptively refined based on the rise time of the double exponential voltage waveform. Step 5: Set up the field probe in the workspace, acquire pulse waveforms, and verify them; Step 5 specifically involves: setting up a 3×3 array of time-domain field probes in the workspace, verifying the field uniformity, and ensuring that the leading edge of the acquired pulse waveform is 2.5ns ± 0.5ns, the half-width at half-maximum (WHM) is 23ns ± 5ns, and the amplitude fluctuation of the field strength in the workspace is within ±3dB.

Claims

1. A simulation method for a high-altitude nuclear electromagnetic pulse simulator, characterized in that, Includes the following steps: Step 1: Establish a model of the strip-shaped bounded wave simulator, which includes a front transition section, a workspace, and a rear transition section; Step 2: Load a double exponential voltage waveform as an excitation source into the model; Step 3: Set the background material, boundary conditions, and terminal load of the model; Step 4: Perform calculations using a time-domain solver combined with hexahedral mesh generation; Step 5: Arrange a field probe in the workspace to acquire pulse waveforms and verify them.

2. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 1, characterized in that, Step 1 specifically involves: the workspace being a cubic structure, the wavefront of the front transition section being spherical to convert spherical waves into plane waves, and the rear transition section being used to achieve a gradual impedance transition; the model also includes a grounded metal plate located below the workspace and a strip structure composed of multiple conductors, the conductors being evenly distributed and the spacing being optimized according to impedance matching requirements.

3. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 2, characterized in that, In step 1, the working space has dimensions of 4m×4m×4m, the grounding metal plate is made of an ideal conductor material, and the grounding metal plate is set 3-5m below the working space with a width of 7-9m, which is greater than the lateral dimension of the working space; the number of wires is 8-10, and the width of a single wire is 0.4-0.6m.

4. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 1, characterized in that, Step 2 specifically involves: using a discrete port loading method, the double exponential voltage waveform is represented by equation (1). V (t)= V 0(e αt And βt ) (1); in, V 0 represents the amplitude. α , β These are used to control the pulse leading edge and half-width at half-maximum, respectively, where t is time.

5. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 1, characterized in that, Step 3 specifically involves: setting the background material to air and the boundary conditions to an open boundary to simulate an infinite free space; and loading a matching resistor at the end of the post-transition segment to suppress reflection.

6. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 5, characterized in that, The resistance of the matching resistor is 140-160Ω.

7. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 1, characterized in that, Step 4 specifically involves using a time-domain solver and combining it with a hexahedral mesh to perform subdivision calculations on the model. The mesh size is adaptively refined based on the rise time of the double exponential voltage waveform.

8. The simulation method for a high-altitude nuclear electromagnetic pulse simulator according to claim 1, characterized in that, Step 5 specifically involves: arranging a 3×3 array of time-domain field probes in the workspace to verify the field uniformity and ensure that the leading edge of the acquired pulse waveform is 2.5ns ± 0.5ns, the half-width at half-maximum is 23ns ± 5ns, and the amplitude fluctuation of the field strength in the workspace is within ±3dB.

Images