Simulation program, simulation method, and simulation device

Abstract

To solve a problem caused by increase in memory capacity and calculation time required for calculation of a far field due to complication of a shape of an analysis target model of a far electromagnetic field simulation and progress of a large-scale analysis model with increasing performance and density of electronic apparatuses and devices in recent years.SOLUTION: A simulation program causes a computer to execute processing of generating a thinned grid for electromagnetic current calculation in accordance with an electric field intensity distribution of an equivalent electromagnetic current region and calculating an equivalent electromagnetic current and a far field by using the thinned grid.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a simulation program, a simulation method, and a simulation device. [Background technology]

[0002] There is a method to quickly calculate the far electromagnetic field using few computational resources by using the equivalence theorem from the near electromagnetic field calculated by numerical calculation, etc. The far electromagnetic field is sometimes simply referred to as the far field. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-282516 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-092190 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the recent trend toward higher performance and higher density in electronic devices, the shapes of models to be analyzed in far-field simulations have become more complex, and the analytical models have become larger in scale, which has resulted in an increase in the memory capacity and calculation time required for far-field calculations.

[0005] In one aspect, an object of the present invention is to provide a simulation program, a simulation method, and a simulation device that can reduce the memory capacity and calculation time required for far-field calculations. [Means for solving the problem]

[0006] In one embodiment, the simulation program generates a thinned grid for calculating electromagnetic currents according to the electric field strength distribution in the equivalent electromagnetic current region, and causes the computer to execute a process of calculating the equivalent electromagnetic current and the far field using the thinned grid. [Effects of the Invention]

[0007] On the one hand, it reduces the memory capacity and computation time required for far-field calculations. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram for explaining a conventional method for calculating a far field using the equivalence theorem. [Figure 2] FIG. 2 is a diagram for explaining the memory capacity required for far-field calculation. [Figure 3] FIG. 3 is a diagram for explaining the amount of calculation required for calculating the far field. [Figure 4] FIG. 4 is a diagram for explaining calculation of the far field in a smartphone. [Figure 5] FIG. 5 is a diagram for explaining the refinement of the computational grid due to the complicated shape of the analysis object model. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of the simulation apparatus 10 according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the thinned grid data 33 according to the first embodiment. [Figure 8] FIG. 8 is a flowchart illustrating an example of the flow of the simulation process according to the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of the generation of an analysis model according to the first embodiment. [Figure 10] FIG. 10 is a flowchart illustrating an example of the flow of the thinned grid generation process according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a field intensity distribution output according to the first embodiment. [Figure 12] FIG. 12 is a flowchart illustrating an example of the flow of the thinned-grid generation determination process according to the first embodiment. [Figure 13] FIG. 13 is a diagram illustrating an example of thinning grid processing (1) according to the first embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of thinning grid processing (2) according to the first embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of the thinning grid processing (3) according to the first embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of the thinning grid processing (4) according to the first embodiment. [Figure 17] FIG. 17 is a diagram illustrating an example of the thinning grid processing (5) according to the first embodiment. [Figure 18] FIG. 18 is a diagram illustrating an example of cells when the thinned grid generation process according to the first embodiment is completed. [Figure 19] FIG. 19 is a diagram illustrating an example of the equivalent electromagnetic current calculation process according to the first embodiment. [Figure 20] FIG. 20 is a diagram illustrating an example of the far-field calculation process according to the first embodiment. [Figure 21] FIG. 21 is a diagram illustrating an example of the hardware configuration of the simulation device 10. As shown in FIG. [Figure 22] FIG. 22 is a diagram illustrating an example of an effect according to the first embodiment. [Figure 23] FIG. 23 is a diagram illustrating an example of a calculation result of the far field according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Examples of the simulation program, simulation method, and simulation device according to the present embodiment will be described in detail below with reference to the accompanying drawings. Note that the present embodiment is not limited to these examples. Furthermore, the examples can be combined as appropriate within a consistent range. [Example]

[0010] First, a conventional method for calculating the far field will be described. Figure 1 is a diagram for explaining a conventional method for calculating the far field using the equivalence theorem. The far field can be calculated by integrating the equivalent electromagnetic flow of S on a closed surface that surrounds the radiator or scatterer. For example, as shown in Figure 1, a rectangular parallelepiped that surrounds the radiator or scatterer is set as an equivalent electromagnetic flow region within the analysis domain, and the far field is calculated by integrating the equivalent electromagnetic flow on its surface.

[0011] More specifically, the equivalent current and the equivalent magnetic current are calculated from the magnetic field and the electric field using the following equations (1) and (2), respectively.

[0012]

number

[0013] In equation (1), the part indicated by Js represents the equivalent current, the part indicated by H represents the magnetic field, and the part indicated by n represents the unit normal vector of the equivalent electromagnetic flow surface.

[0014]

number

[0015] In equation (2), the part indicated by Ms represents the equivalent magnetic current, and the part indicated by E represents the electric field.

[0016] Then, for example, the far field in the time domain is calculated from the equivalent electromagnetic flow in the time domain using the following equation (3), and the far field in the frequency domain is calculated by performing a Fourier transform on the calculated far field in the time domain.

[0017]

number

[0018] Alternatively, for example, the equivalent electromagnetic current in the time domain is Fourier transformed using the following equation (4) to calculate the far field in the frequency domain.

[0019]

number

[0020] Next, the memory capacity and calculation amount required for far-field calculation will be explained, and a specific example of the memory capacity and calculation amount for a smartphone will be given.

[0021] FIG. 2 is a diagram for explaining the memory capacity required for far-field calculations. The memory capacity required for far-field calculations can be calculated, for example, using the formula "(number of cells in the equivalent electromagnetic flow region + number of distant observation points) x number of time-series data." This formula is based on the following ideas: (1) time-series data is required to reduce the far-field calculation time for multiple arbitrary frequencies, (2) a memory area for time-series data is required for each cell in the equivalent electromagnetic flow region, and (3) a memory area for time-series data is required for each distant observation point. Here, a cell refers to an area generated by dividing each plane of the equivalent electromagnetic flow region, which is, for example, a rectangular or cubic region.

[0022] A more specific formula is "memory capacity required for far-field calculation = {2 x (ab + bc + ac) + K} x 2 x n." In this formula, a, b, and c represent the number of cells in the X-axis direction, the Y-axis direction, and the Z-axis direction of the equivalent electromagnetic flow region, respectively. Also, in this formula, K represents the number of far-field observation points, and n represents the number of time-series data, for example, the number of samples.

[0023] Figure 3 is a diagram for explaining the amount of calculation required to calculate the far field. The amount of calculation required to calculate the far field can be calculated, for example, using the formula "number of distant observation points x number of cells in the equivalent electromagnetic flow region x number of time-series data." This formula is based on the idea that (1) the distance between each cell in the equivalent electromagnetic flow region and the distant observation point P is not uniform, and (2) the far field of the distant observation point P is calculated for each cell in the equivalent electromagnetic flow region, and an integral calculation is performed taking into account the phase difference.

[0024] A more specific formula is "calculation amount required for far-field calculation = K × 2 × (ab + bc + ac) × 2 × n", where each parameter in this formula is the same as that of the memory capacity required for far-field calculation.

[0025] Fig. 4 is a diagram for explaining calculation of the far field in a smartphone. For example, in the case of a smartphone, as shown in Fig. 4, electromagnetic waves are radiated from an antenna element at the bottom inside the housing.

[0026] For the smartphone shown in Figure 4, an equivalent electromagnetic flow region with 300 cells in the X-axis direction, 200 cells in the Y-axis direction, and 500 cells in the Z-axis direction, and an analysis region of 350 mm (millimeters) x 250 mm x 250 mm are set, and the far field is calculated. The number of distant observation points, analysis time, analysis time interval, and number of time-series data are as shown in the bottom right of Figure 4.

[0027] In this case, the memory capacity required for far-field calculations is approximately 313.4 GByte (gigabytes) when calculated by substituting each parameter value into the above formula "{2 x (ab+bc+ac)+K} x 2 x n." Similarly, the amount of calculation required for far-field calculations is approximately 40.5 PFlops when calculated using the above formula "K x 2 x (ab+bc+ac) x 2 x n" with 5 flops per calculation.

[0028] As described above, the memory capacity and amount of calculation required for far-field calculations are not small. However, the recent trend toward higher performance and higher density in electronic devices has led to more complex shapes for far-field simulation models, which has resulted in a further increase in the required memory capacity and amount of calculation.

[0029] Figure 5 is a diagram for explaining the refinement of the computational grid due to the increased complexity of the shape of the model to be analyzed. As shown in Figure 5, as the shape of the model to be analyzed becomes more complex, the computational grid becomes finer and the number of cells in the equivalent electromagnetic flow region increases. As the number of cells in the equivalent electromagnetic flow region increases, the value of the number of cells in the "ab+bc+ac" part in the above-mentioned formula used to calculate the memory capacity and calculation amount required for far-field calculation also increases, and therefore the required memory capacity and calculation amount also increase.

[0030] Therefore, conventional far-field calculation methods require large-scale computer resources and enormous calculation time to perform calculations for recent electronic devices. Therefore, one of the objectives of this embodiment is to reduce the memory capacity and calculation time required for far-field calculations.

[0031] It is well known that electromagnetic waves emitted from electronic devices radiate from the antenna's location, while leakage electromagnetic waves radiate from openings or gaps in the housing. Furthermore, it is well known that even if the shape of the antenna or printed circuit board (which serves as the wave source) changes and the amplitude of the wave source changes, the locations where electromagnetic waves are concentrated and not concentrated do not change. Therefore, in this embodiment, by utilizing this property, a computer thins out the computational grid for electromagnetic flow calculations according to the electric field strength distribution of the equivalent electromagnetic flow region to create a thinned grid, and then calculates the equivalent electromagnetic flow and far field using the created thinned grid. Note that thinning out the computational grid, as will be described in detail later, means dividing each plane of the equivalent electromagnetic flow region to generate multiple cells, and then combining some of the cells for each plane based on predetermined conditions to create a thinned grid. This reduces the number of computational grids. In this way, in this embodiment, by thinning out the computational grid, the memory capacity and computation time required for far-field calculations are reduced, while obtaining far-field calculation results equivalent to those of conventional techniques.

[0032] [Functional configuration of simulation device 10] Next, a functional configuration of a simulation apparatus 10, which is an information processing apparatus that executes the present embodiment, will be described. Fig. 6 is a diagram illustrating an example of the configuration of the simulation apparatus 10 according to Example 1. As shown in Fig. 6, the simulation apparatus 10 includes a communication unit 20, a storage unit 30, and a control unit 40.

[0033] The communication unit 20 is, for example, a processing unit that controls communication with other information processing devices via the network 50, and is, for example, a communication interface such as a network interface card.

[0034] The storage unit 30 is an example of a storage device, such as a memory or a hard disk, that stores various data and programs executed by the control unit 40. The storage unit 30 stores analysis target data 31, thinning condition data 32, thinning grid data 33, etc.

[0035] Data related to the analysis target of the far electromagnetic field simulation is stored as the analysis target data 31. Here, the data related to the analysis target is, for example, data related to the analysis region, equivalent electromagnetic flow region, number of distant observation points, analysis time, analysis time interval, number of time series data, etc., as shown on the right side of Fig. 4.

[0036] The thinning condition data 32 stores, for example, data related to the thinning conditions of the computational grid for electromagnetic current calculation. Here, the data related to the thinning conditions includes, for example, the number of vertical or horizontal grids in the range to be thinned out, the upper limit of the size, the upper limit of the electric field strength in the range to be thinned out, and the coefficient of variation of the electric field strength. Regarding the number of vertical or horizontal grids in the range to be thinned out, for example, if the number of vertical or horizontal grids is two and the number of horizontal grids is two, a thinned grid is generated that combines four 2x2 grids into one. The number of vertical or horizontal grids in the range to be thinned out does not have to be the same.

[0037] The thinned grid data 33 stores, for example, data related to thinned grids generated by thinning computational grids for electromagnetic flow calculation. Fig. 7 is a diagram showing an example of the thinned grid data 33 according to the first embodiment. As shown in Fig. 7, the thinned grid data 33 stores information such as the number of grids and intervals in each axial direction of each plane of the equivalent electromagnetic flow region, the number of connected cells, and the like, in association with each other.

[0038] The above-mentioned various types of information stored in the storage unit 30 are merely examples, and the storage unit 30 can store various types of information other than the above-mentioned information.

[0039] The control unit 40 is a processing unit, such as a processor, that controls the entire simulation device 10. The control unit 40 includes a generating unit 41 and a calculating unit 42. Each processing unit is an example of an electronic circuit included in the processor or an example of a process executed by the processor.

[0040] The generation unit 41 generates a thinned grid for electromagnetic flow calculation according to, for example, the electric field strength distribution of the equivalent electromagnetic flow region. More specifically, for example, the generation unit 41 calculates the electric field strength for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region, and generates a thinned grid by combining a predetermined number of cells based on the electric field strength.

[0041] Here, the process of generating a thinned grid may be, for example, a process of combining all cells in a thinned-out target range containing a predetermined number of cells to generate a thinned grid when the electric field strength of all cells in the thinned-out target range is equal to or less than a predetermined upper limit. Alternatively, this process may be a process of combining all cells in a thinned-out target range containing a predetermined number of cells to generate a thinned grid when the electric field strength of all cells in the thinned-out target range is equal to or less than a first upper limit and the coefficient of variation of the electric field strength is equal to or less than a second upper limit. Alternatively, this process may be a process of generating a thinned grid so that the vertical or horizontal size of the thinned-out target range is equal to or less than a predetermined upper limit.

[0042] Although the thinning conditions are exemplified by the electric field strength of the cells in the thinning range, the variation coefficient of the electric field strength, and the vertical or horizontal size of the thinning range, these conditions may be combined to form a composite condition. Furthermore, the conditions are not limited to these, and other conditions may be combined to form a composite condition.

[0043] The calculation unit 42 calculates the equivalent electromagnetic current and the far field using, for example, the thinned grid generated by the generation unit 41.

[0044] Here, the process of calculating the equivalent electromagnetic current may be, for example, a process of calculating the electromagnetic current for each cell that is not coupled due to the thinned-out lattice and for each thinned-out lattice. Furthermore, the process of calculating the electromagnetic current for each thinned-out lattice may be a process of integrating a first calculation result of the electric field corresponding to a cell in the thinned-out lattice to calculate a magnetic current when there are multiple first calculation results of the electric field corresponding to the cell in the thinned-out lattice. Alternatively, the process of calculating the electromagnetic current for each thinned-out lattice may be a process of integrating a second calculation result of the magnetic field corresponding to a cell in the thinned-out lattice to calculate a current when there are multiple second calculation results of the magnetic field corresponding to the cell in the thinned-out lattice.

[0045] Furthermore, the process of calculating the far field may be a process of calculating the far field for each cell that is not coupled due to the thinned grid and for each thinned grid.

[0046] [Function details] Next, a more detailed description will be given of the simulation process executed by the simulation device 10. Fig. 8 is a flowchart showing an example of the flow of the simulation process according to the first embodiment. The simulation process shown in Fig. 8 is a process of calculating the electromagnetic field of the analytical model of the electronic device, generating a thinned-out grid for electromagnetic current calculation according to the electric field intensity distribution in the equivalent electromagnetic current region, and calculating the equivalent electromagnetic current and the far field using the thinned-out grid.

[0047] First, as shown in Fig. 9, the simulation device 10 generates an analytical model of the target electronic device (step S101). Fig. 9 is a diagram showing an example of analytical model generation according to Example 1. As shown in Fig. 9, for example, when the target electronic device is a metal housing with a printed circuit board as a wave source, the simulation device 10 sets a predetermined range around the housing as an equivalent electromagnetic flow region based on data stored in the analysis target data 31, and generates an analytical model.

[0048] Next, the simulation device 10 calculates the electromagnetic field of the analysis model generated in step S101 (step S102). More specifically, for example, the simulation device 10 executes electromagnetic field calculations employing the FDTD (Finite-Difference Time-Domain) method, which is an existing technology, to calculate the electric field and magnetic field of the entire analysis space of the analysis model generated in step S101. The FDTD method is a technique for directly differentiating Maxwell's equations in the time domain.

[0049] Next, the simulation device 10 determines whether or not a thinned-out grid has been saved for the target electronic device (step S103). If a thinned-out grid has been saved (step S103: Yes), the saved thinned-out grid can be reused. Therefore, the simulation device 10 acquires the saved thinned-out grid from the thinned-out grid data 33, skips step S104 for generating the thinned-out grid, and proceeds to step S105.

[0050] On the other hand, if there is no saved thinned grid for the target electronic device (step S103: No), the simulation device 10 generates a thinned grid (step S104). The generation of the thinned grid is performed for each plane of the six-plane equivalent electromagnetic flow region based on the flowchart shown in Fig. 10. Fig. 10 is a flowchart showing an example of the flow of the thinned grid generation process according to the first embodiment.

[0051] First, as shown in Fig. 10, the simulation device 10 outputs an electric field intensity distribution based on the calculation result of the electromagnetic field calculated in step S102 (step S201). The output of the electric field intensity distribution will be described in detail. Fig. 11 is a diagram showing an example of the electric field intensity distribution output according to the first embodiment. As shown in Fig. 11, the six planes of the equivalent electromagnetic flow region are respectively designated as the X-plane, Y-plane, Z-plane, X+plane, Y+plane, and Z+plane. Each plane becomes an electric field intensity output region.

[0052] Then, the simulation device 10 calculates the maximum electric field strength value for each cell on each plane, which is the electric field strength output area. Furthermore, the simulation device 10 normalizes the maximum electric field strength value for each cell by the maximum value of all cells on the six planes, and outputs the normalized value. Expressed as a specific formula, for example, this is "output value = maximum electric field strength value for each cell / max (maximum electric field strength value of all cells on the six planes)".

[0053] Returning to the description of FIG. 10 , next, the simulation apparatus 10 generates a thinned grid based on the electric field intensity distribution output in step S201 (step S202). More specifically, for example, the simulation apparatus 10 determines a range that satisfies all predetermined conditions for each thinned grid size range in the grid of the six-plane equivalent electromagnetic flow region as a thinned-grid-capable range, and generates a thinned grid by combining cells in the thinned-grid target range. Note that the predetermined conditions for generating a thinned grid include, for example, the upper limit of the number of vertical or horizontal grids or size of the thinned-grid target range, the upper limit of the electric field intensity in the thinned-grid target range, and the coefficient of variation of the electric field intensity, which are stored in advance in the thinning condition data 32. The determination of whether to generate a thinned grid is performed based on, for example, the flowchart shown in FIG. 12 . FIG. 12 is a flowchart showing an example of the flow of a thinned-grid generation determination process according to the first embodiment.

[0054] First, as shown in FIG. 12, the simulation apparatus 10 sets various conditions for generating a thinning grid (step S301). This involves, for example, acquiring various condition data stored in advance in the thinning condition data 32 to be used as parameters for determining whether or not to generate a thinning grid. The condition data may include, for example, the upper limit of the number of vertical or horizontal grids in the thinning target range, the upper limit of the field strength in the thinning target range, and the coefficient of variation of the field strength. Based on the number of vertical or horizontal grids in the thinning target range acquired from the thinning condition data 32, the simulation apparatus 10 then determines the number of vertical grids x the number of horizontal grids for the thinning target range.

[0055] FIG. 13 is a diagram illustrating an example of the thinning grid process (1) according to the first embodiment. As shown in the lower part of FIG. 13, the example of FIG. 13 is an example in which the thinning target range is determined to be four cells, 2 cells in height and 2 cells in width. The subsequent processes of steps S302 to S306 are executed for each thinning target range. In the example of FIG. 13, first, the four cells in the upper left, 2 cells in height and 2 cells in width, are processed as the thinning target range, and then, for example, the thinning target range is shifted to the right, and the next thinning target range is processed. Therefore, the processes of steps S302 to S306 are repeated until the processes are executed for all thinning target ranges.

[0056] Returning to the description of FIG. 12, next, the simulation apparatus 10 determines whether the vertical and horizontal sizes of the thinning target range are within the upper limit values ​​of each size acquired from the thinning condition data 32 (step S302). This determination is made because the thinning target range is selected only when its vertical and horizontal sizes are equal to or less than the upper limit values, in order to minimize the impact on the analysis accuracy of the far electromagnetic field simulation. If either the vertical or horizontal size of the thinning target range is greater than the upper limit value (step S302: No), the simulation apparatus 10 determines not to generate a thinning grid for the thinning target range (step S306). After executing step S306, if there is no next thinning target range, the thinning grid generation determination process shown in FIG. 12 ends, and the process returns to the flowchart of FIG. 10 and proceeds to step S203. On the other hand, if there is a next thinning target range, the process returns to step S302, and steps S302 to S306 are repeated until the process has been executed for all thinning target ranges.

[0057] On the other hand, if the vertical and horizontal sizes of the thinning-out target range are within the upper limit values ​​(step S302: Yes), the simulation apparatus 10 determines whether the electric field intensity of the thinning-out target range is within the upper limit value of the electric field intensity acquired from the thinning-out condition data 32 (step S303). This determination is also made to minimize the impact on the analysis accuracy of the far electromagnetic field simulation. If the electric field intensity of the thinning-out target range is within the upper limit value (step S303: Yes), the simulation apparatus 10 combines the cells of the thinning-out target range to generate a thinning grid (step S304). After executing step S304, if there is still a next thinning-out target range, the process returns to step S302; if there is not a next thinning-out target range, the process returns to the flowchart of FIG. 10.

[0058] On the other hand, if the electric field strength in the thinning-out target range is higher than the upper limit (step S303: No), the simulation apparatus 10 determines whether the coefficient of variation of the electric field strength in the thinning-out target range is within the upper limit of the coefficient of variation acquired from the thinning condition data 32 (step S305). This determination is also made to minimize the impact on the analysis accuracy of the far electromagnetic field simulation. The coefficient of variation of the electric field strength in the thinning-out target range is, for example, the standard deviation of the electric field strength in the thinning-out target range divided by the average value of the electric field strength in the thinning-out target range. If the coefficient of variation in the thinning-out target range is within the upper limit (step S305: Yes), the simulation apparatus 10 combines the cells in the thinning-out target range to generate a thinning grid (step S304). On the other hand, if the coefficient of variation in the thinning-out target range is higher than the upper limit (step S305: No), the simulation apparatus 10 determines not to generate a thinning grid in the thinning-out target range (step S306).

[0059] This concludes the explanation of the flowchart of the thinned-grid generation determination process shown in Fig. 12, but this process will be explained in more detail using Figs. 13 to 18. Figs. 13 to 18 are diagrams for explaining the process of determining whether or not to generate a thinned-grid, and the flow of a series of processes in the thinned-grid generation process, as the thinned-grid process, which are executed by simulation device 10.

[0060] FIG. 13 is a diagram illustrating an example of thinning grid processing (1) according to the first embodiment. The initial grid shown in the upper part of FIG. 13 is an example of a group of cells obtained by dividing one plane of the equivalent electromagnetic flow region into 6 cells vertically and 10 cells horizontally. The numerical values ​​inside each cell indicate the electric field strength, and the shaded cells indicate cells that exceed the upper limit of the electric field strength, assuming that the upper limit is −20 dB (decibels). The upper limit of the variation coefficient of the electric field strength in the thinning target range is 0.05. The variation coefficient of the electric field strength in the thinning target range is, for example, the standard deviation of the electric field strength in the thinning target range divided by the average value of the electric field strength in the thinning target range. The thinning target range is assumed to be 2 cells vertically and 2 cells horizontally, as shown in the lower part of FIG. 13, and is assumed to be processed as a target range. The vertical and horizontal sizes of the thinning target range are assumed to be within the upper limit values.

[0061] First, in the example shown in the lower part of Fig. 13, the four cells in the upper left corner are set as the first thinning target range, and a determination is made as to whether or not to generate a thinned grid using the electric field strength of each cell in the target range. Because the electric field strength of each cell in the first thinning target range is within the upper limit, when applied to the flowchart in Fig. 12, the process proceeds from the Yes route in step S303 to step S304, where the cells in the first thinning target range are combined and a thinned grid is generated. In other words, it has been determined that a thinned grid will be generated for the first thinning target range.

[0062] Fig. 14 is a diagram illustrating an example of the thinning grid processing (2) according to the first embodiment. As shown in the upper part of Fig. 14, cells in the first thinning target range are combined to generate one thinning grid. Then, as shown in the lower part of Fig. 14, the thinning target range is shifted, and thinning grids are generated for the second to seventh thinning target ranges. Note that, as with the first thinning target range, the electric field intensity of each cell in the thinning target range is within the upper limit value of -20 dB for the second to seventh thinning target ranges as well, and therefore it is determined that a thinning grid should be generated.

[0063] FIG. 15 is a diagram illustrating an example of the thinning grid processing (3) according to the first embodiment. The upper part of FIG. 15 illustrates processing for the eighth thinning target range. Since the electric field strength of the bottom right cell in the eighth thinning target range exceeds the upper limit of −20 dB, applying the flowchart in FIG. 12 to the process results in the process proceeding from the No route in step S303 to step S305. Furthermore, the coefficient of variation of the electric field strength in the eighth thinning target range is calculated using the formula “(standard deviation of the electric field strength in the thinning target range / average value of the electric field strength in the thinning target range)” to approximately 4.33, which exceeds the upper limit of 0.05. Applying the flowchart in FIG. 12 to the determination of the coefficient of variation, the process also proceeds from the No route in step S305 to step S306, where it is determined that no thinning grid will be generated for the eighth thinning target range.

[0064] Therefore, four cells remain in the eighth thinning target range without being thinned out, as shown in the bottom of Figure 15. Also, like the eighth thinning target range, the electric field strength and coefficient of variation in the ninth thinning target range exceed the upper limit values, so no thinning grid is generated.

[0065] Fig. 16 is a diagram illustrating an example of the thinning grid process (4) according to the first embodiment. Fig. 15 illustrates the process for the 10th to 12th thinning target ranges. As with the 1st to 7th thinning target ranges, the 10th to 12th thinning target ranges have electric field strengths within the thinning target ranges that are within the upper limit of -20 dB, and therefore a thinning grid is generated.

[0066] Fig. 17 is a diagram showing an example of thinning grid processing (5) according to the first embodiment. Fig. 15 shows processing of the 13th to 15th thinning target ranges. As with the 8th and 9th thinning target ranges, the 13th and 14th thinning target ranges have electric field strengths and coefficients of variation within the thinning target ranges that exceed the upper limit, so thinning grids are not generated. As with the 1st to 7th thinning target ranges, the electric field strength of each cell within the thinning target range is within the upper limit of -20 dB, so a thinning grid is generated for the 15th thinning target range.

[0067] In this way, the thinning target range is shifted, and the process of determining whether or not to generate a thinning grid and the process of generating a thinning grid are executed for all thinning target ranges. Fig. 18 is a diagram showing an example of cells at the completion of the thinning grid generation process according to the first embodiment. Fig. 18 shows the thinning grid after the process of determining whether or not to generate a thinning grid and the process of generating a thinning grid are executed for the first to fifteenth thinning target ranges shown in Figs. 13 to 17. Comparing the thinning grid after each process shown in Fig. 18 with the initial grid shown in the upper part of Fig. 13, the initial grid has 60 cells, while the thinning grid after each process has 27 cells, meaning that 33 cells have been thinned out, resulting in a 55% reduction in the number of cells.

[0068] Returning to the explanation of Fig. 10, next, the simulation device 10 stores and saves the thinned grid generated in step S202, for example, as thinned grid data 33 (step S203). The saved thinned grid can be reused not only for the current simulation process, but also when simulating the same analytical model by changing parameters, etc. After step S203 is executed, the thinned grid generation process shown in Fig. 10 ends, and the process returns to the flowchart of Fig. 8 and proceeds to step S105.

[0069] Next, the simulation device 10 sets a thinned-out grid to be used for calculating the equivalent electromagnetic flow and the far field (step S105). Note that the thinned-out grid is set for each plane of the six-plane equivalent electromagnetic flow region. The thinned-out grid set here is the thinned-out grid generated in step S104 or the thinned-out grid acquired and saved via the Yes route in step S103.

[0070] Next, the simulation apparatus 10 calculates the equivalent electromagnetic current (step S106). More specifically, the simulation apparatus 10 calculates the equivalent electromagnetic current for each cell of the thinned grid set in step S105 for each plane of the six-plane equivalent electromagnetic current region based on the calculation results of the electromagnetic field calculated in step S102. The equivalent current is calculated, for example, by the formula "J = n × H". The equivalent magnetic current is calculated, for example, by the formula "M = - n × E". In each formula, J represents the equivalent current, M represents the equivalent magnetic current, H represents the magnetic field, E represents the electric field, and n represents the unit normal vector of the equivalent electromagnetic flow plane.

[0071] 19 is a diagram illustrating an example of the equivalent electromagnetic current calculation process according to the first embodiment. FIG. 19 illustrates an example of calculation of the equivalent current for the thinned grid after the thinned grid generation process shown in FIG. 18 is executed. For example, as shown in FIG. 19, the eighth thinning target range is not thinned out and four cells remain, so the magnetic field H of each cell is 24 , H 25 , H 34 , H 35 Using the equivalent current J 24 , J 25, J 34 , J 35 In this way, for the thinning target range where no thinned grid has been generated, the equivalent current of each cell is calculated using the magnetic field of each cell.

[0072] On the other hand, for example, when a thinned grid is generated as in the 15th thinned-out target range as shown in FIG. 19, the magnetic field H 48 , H 49 , H 58 , H 59 Integrating and calculating the equivalent current J 48 In this way, for the range to be thinned out in which the thinned out grid has been generated, the magnetic field corresponding to each cell of the thinned out grid is integrated to calculate the equivalent current of the thinned out grid.

[0073] Note that the equivalent magnetic current can be calculated in the same way by replacing the magnetic field H in FIG. 19 with the electric field E and the equivalent current J with the equivalent magnetic current M.

[0074] Returning to the description of FIG. 8, next, the simulation apparatus 10 calculates the far field (step S107). FIG. 20 is a diagram illustrating an example of the far field calculation process according to the first embodiment. The simulation apparatus 10 calculates the far field of the distant observation point P for each cell of the thinned lattice set in step S105, and performs an integral calculation in consideration of the phase difference in the far field. The memory capacity required for the far field calculation is calculated, for example, by the formula "memory capacity = {m + K} × 2 × n". The calculation amount of the far field is calculated, for example, by the formula "calculation amount = K × m × 2 × n". In each formula, K represents the number of distant observation points, n represents the number of time-series data (number of samples), and m represents the total number of cells in the equivalent electromagnetic flow region (thinned lattice). After step S107 is executed, the simulation process illustrated in FIG. 8 ends.

[0075] [effect] As described above, the simulation device 10 generates a thinned grid for calculating the electromagnetic flow in accordance with the electric field strength distribution in the equivalent electromagnetic flow region, and calculates the equivalent electromagnetic flow and the far field using the thinned grid.

[0076] In this way, the simulation device 10 calculates the equivalent electromagnetic current and the far field using a thinned grid generated by combining cells on each plane of the equivalent electromagnetic current region according to the electric field intensity distribution, thereby reducing the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0077] In addition, the process of generating a thinned grid, which is executed by the simulation device 10, includes a process of dividing each plane of the equivalent electromagnetic flow region, which is a rectangular or cubic region, to calculate the electric field strength for each cell generated, and combining a predetermined number of cells based on the electric field strength to generate a thinned grid.

[0078] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0079] Furthermore, the process executed by the simulation device 10 to combine a predetermined number of cells to generate a thinned grid includes a process of combining all cells in a thinned-out target range to generate a thinned-out grid when the electric field strength of all cells in the thinned-out target range including the predetermined number of cells is equal to or less than a predetermined upper limit value.

[0080] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0081] In addition, the process executed by the simulation device 10 to combine a predetermined number of cells to generate a thinned grid includes a process of combining all cells in a thinning target range to generate a thinned grid when the electric field strengths of all cells in the thinning target range including the predetermined number of cells are equal to or less than a first upper limit value and the coefficients of variation of the electric field strengths of all cells in the thinning target range are equal to or less than a second upper limit value.

[0082] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0083] Furthermore, the process executed by the simulation device 10 to combine a predetermined number of cells to generate a thinned grid includes a process of generating a thinned grid so that the vertical or horizontal size of the range to be thinned is equal to or smaller than a predetermined upper limit value.

[0084] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0085] Furthermore, the process of calculating the equivalent electromagnetic current, which is executed by the simulation device 10, includes a process of calculating the electromagnetic current for each cell that is not connected due to the thinned-out grid and for each thinned-out grid.

[0086] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0087] In addition, the process of calculating the electromagnetic current for each thinned-out lattice, which is executed by the simulation device 10, includes a process of integrating the first calculation results to calculate the magnetic current when there are multiple first calculation results of the electric field corresponding to the cells in the thinned-out lattice, and a process of integrating the second calculation results to calculate the current when there are multiple second calculation results of the magnetic field corresponding to the cells in the thinned-out lattice.

[0088] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0089] Furthermore, the process of calculating the far field, which is executed by the simulation apparatus 10, includes a process of calculating the far field for each cell that is not coupled due to the thinned grid and for each thinned grid.

[0090] This allows the simulation device 10 to reduce the required memory capacity and time while maintaining the calculation accuracy of the far field.

[0091] [system] The information, including the processing procedures, control procedures, specific names, various data, and parameters shown in the above documents and drawings, can be changed as desired unless otherwise specified. Furthermore, the specific examples, distributions, and numerical values ​​described in the embodiments are merely examples and can be changed as desired.

[0092] Furthermore, the components of each device shown in the figure are conceptual functional units and do not necessarily have to be physically configured as shown. In other words, the specific form of distribution or integration of each device is not limited to that shown. In other words, all or part of the devices can be functionally or physically distributed or integrated in any unit depending on various loads and usage conditions. Furthermore, all or any part of the processing functions performed by each device can be realized by a CPU (Central Processing Unit) or GPU (Graphics Processing Unit) and a program analyzed and executed by the CPU or GPU, or can be realized as hardware using wired logic.

[0093] [Hardware] FIG. 21 is a diagram illustrating an example of the hardware configuration of the simulation device 10. As shown in FIG. 21, the simulation device 10 includes a communication interface 10a, a hard disk drive (HDD) 10b, a memory 10c, and a processor 10d. The components shown in FIG. 21 are connected to each other via a bus or the like.

[0094] The communication interface 10a is a network interface card or the like, and communicates with other servers. The HDD 10b stores programs and DBs that operate the functions shown in FIG.

[0095] The processor 10d is a hardware circuit that operates a process that executes each function described in FIG. 6 and other figures by reading a program that executes the same processing as each processing unit shown in FIG. 6 from the HDD 10b or the like and expanding the program into the memory 10c. That is, this process executes the same functions as each processing unit of the simulation device 10. Specifically, the processor 10d reads a program having the same functions as the generation unit 41, the calculation unit 42, and the like from the HDD 10b or the like. Then, the processor 10d executes a process that executes the same processing as the generation unit 41, the calculation unit 42, and the like.

[0096] In this way, the simulation device 10 operates as an information processing device that executes operation control processing by reading and executing a program that executes processing similar to that of each processing unit shown in Fig. 6. The simulation device 10 can also realize functions similar to those of the above-described embodiment by reading a program from a recording medium using a medium reading device and executing the read program. Note that the program in these other embodiments is not limited to being executed by the simulation device 10. For example, this embodiment can also be applied in the same way to cases where another computer or server executes a program, or where these execute a program in cooperation with each other.

[0097] A program that executes the same processes as those of the processing units shown in Fig. 6 can be distributed via a network such as the Internet. This program can be recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, a magneto-optical disk (MO), or a digital versatile disc (DVD), and can be executed by being read from the recording medium by a computer.

[0098] For reference, the effects of the technology according to this embodiment are shown using actual calculation results. FIG. 22 is a diagram illustrating an example of the effects according to Example 1. FIG. 22 shows the results of calculating the far field of an analysis target model using a conventional calculation method and a calculation method according to this embodiment, with 720 distant observation points and 530 time-series data. The proposed technology portion of FIG. 22 shows the memory capacity, calculation amount, and calculation time required for calculation when calculating the far field using the calculation method according to this embodiment. Compared to the conventional calculation method, the calculation method according to this embodiment can reduce the required memory capacity and calculation amount by approximately 50% and the calculation time by 40%. Furthermore, the example shown in FIG. 22 is a calculation result for a relatively small-scale analysis target model, so even greater effects can be expected for larger models.

[0099] FIG. 23 is a diagram showing an example of the calculation results of the far field according to Example 1. FIG. 23 shows the frequency characteristics of the electric field strength of the far field when the far field of the analysis target model is calculated using both the conventional calculation method and the calculation method according to this embodiment. Referring to FIG. 23, it can be confirmed that the peak frequencies of the radio wave strength match between the conventional calculation method and the calculation method according to this embodiment, and that the frequency characteristics tend to be the same. From the results of FIGS. 22 and 23, it can be seen that the calculation method according to this embodiment can reduce the required memory capacity and time while maintaining the calculation accuracy of the far field. [Example]

[0100] Although the embodiments of the present invention have been described above, the present invention may be embodied in various different forms other than the above-described embodiments.

[0101] The following additional notes are provided regarding the embodiments including the above examples.

[0102] (Appendix 1) Generate thinned grids for electromagnetic flow calculations according to the electric field strength distribution in the equivalent electromagnetic flow region, Using the thinned grid, the equivalent electromagnetic current and the far field are calculated. A simulation program that causes a computer to execute a process.

[0103] (Supplementary Note 2) The process of generating the thinned grid is Calculating the electric field intensity for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region; Based on the electric field strength, a predetermined number of the cells are combined to generate the thinned grid. 2. The simulation program according to claim 1, further comprising:

[0104] (Supplementary Note 3) The process of combining a predetermined number of the cells to generate the thinned lattice is When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a predetermined upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. 3. The simulation program according to claim 2, further comprising:

[0105] (Supplementary Note 4) The process of combining a predetermined number of the cells to generate the thinned lattice is When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a first upper limit value and the coefficient of variation of the electric field strength of all the cells in the thinning-out target range is equal to or less than a second upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. 3. The simulation program according to claim 2, further comprising:

[0106] (Supplementary Note 5) The process of combining a predetermined number of the cells to generate the thinned lattice is The thinning grid is generated so that the vertical or horizontal size of the thinning target range is equal to or smaller than a predetermined upper limit. 3. The simulation program according to claim 2, further comprising:

[0107] (Supplementary Note 6) The process of calculating the equivalent electromagnetic current is Calculating electromagnetic currents for each of the unconnected cells for the thinned grid and for each of the thinned grids 3. The simulation program according to claim 2, further comprising:

[0108] (Supplementary Note 7) The process of calculating the electromagnetic current for each thinned-out grid is When there are a plurality of first calculation results of the electric field corresponding to the cell in the thinned lattice, integrating the first calculation results to calculate a magnetic current; When there are a plurality of second calculation results of the magnetic field corresponding to the cell in the thinned grid, the second calculation results are integrated to calculate the current. 7. The simulation program according to claim 6, further comprising:

[0109] (Appendix 8) The process of calculating the far field is Calculating the far field for each of the uncoupled cells for the decimated grid and for each of the decimated grids 3. The simulation program according to claim 2, further comprising:

[0110] (Appendix 9) Generate thinned grids for electromagnetic flow calculations according to the electric field strength distribution in the equivalent electromagnetic flow region, Using the thinned grid, the equivalent electromagnetic current and the far field are calculated. A simulation method characterized in that processing is executed by a computer.

[0111] (Supplementary Note 10) The process of generating the thinned grid includes: Calculating the electric field intensity for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region; Based on the electric field strength, a predetermined number of the cells are combined to generate the thinned grid. 10. The simulation method according to claim 9, further comprising the steps of:

[0112] (Supplementary Note 11) The process of combining a predetermined number of the cells to generate the thinned lattice includes: When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a predetermined upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. 11. The simulation method according to claim 10, further comprising the steps of:

[0113] (Supplementary Note 12) The process of combining a predetermined number of the cells to generate the thinned lattice is When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a first upper limit value and the coefficient of variation of the electric field strength of all the cells in the thinning-out target range is equal to or less than a second upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. 11. The simulation method according to claim 10, further comprising the steps of:

[0114] (Supplementary Note 13) The process of combining a predetermined number of the cells to generate the thinned lattice includes: The thinning grid is generated so that the vertical or horizontal size of the thinning target range including a predetermined number of the cells is equal to or smaller than a predetermined upper limit. 11. The simulation method according to claim 10, further comprising the steps of:

[0115] (Supplementary Note 14) The process of calculating the equivalent electromagnetic current is Calculating electromagnetic currents for each of the unconnected cells for the thinned grid and for each of the thinned grids 11. The simulation method according to claim 10, further comprising the steps of:

[0116] (Supplementary Note 15) The process of calculating the electromagnetic current for each thinned-out grid is When there are a plurality of first calculation results of the electric field corresponding to the cell in the thinned lattice, integrating the first calculation results to calculate a magnetic current; When there are a plurality of second calculation results of the magnetic field corresponding to the cell in the thinned grid, the second calculation results are integrated to calculate the current. 15. The simulation method according to claim 14, further comprising the steps of:

[0117] (Supplementary Note 16) The process of calculating the far field is Calculating the far field for each of the uncoupled cells for the decimated grid and for each of the decimated grids 11. The simulation method according to claim 10, further comprising the steps of:

[0118] (Appendix 17) Generate thinned grids for electromagnetic flow calculations according to the electric field strength distribution in the equivalent electromagnetic flow region, Using the thinned grid, the equivalent electromagnetic current and the far field are calculated. A simulation device comprising a control unit that executes processing.

[0119] (Supplementary Note 18) The process of generating the thinned grid comprises: Calculating the electric field intensity for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region; Based on the electric field strength, a predetermined number of the cells are combined to generate the thinned grid. 18. The simulation device according to claim 17, further comprising:

[0120] (Supplementary Note 19) The process of combining a predetermined number of the cells to generate the thinned lattice includes: When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a predetermined upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. 19. The simulation device according to claim 18, further comprising:

[0121] (Supplementary Note 20) The process of combining a predetermined number of the cells to generate the thinned lattice comprises: When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a first upper limit value and the coefficient of variation of the electric field strength of all the cells in the thinning-out target range is equal to or less than a second upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. 19. The simulation device according to claim 18, further comprising:

[0122] (Supplementary Note 21) The process of combining a predetermined number of the cells to generate the thinned lattice includes: The thinning grid is generated so that the vertical or horizontal size of the thinning target range including a predetermined number of the cells is equal to or smaller than a predetermined upper limit. 19. The simulation device according to claim 18, further comprising:

[0123] (Supplementary Note 22) The process of calculating the equivalent electromagnetic current is Calculating electromagnetic currents for each of the unconnected cells for the thinned grid and for each of the thinned grids 19. The simulation device according to claim 18, further comprising:

[0124] (Supplementary Note 23) The process of calculating the electromagnetic current for each thinned-out grid is When there are a plurality of first calculation results of the electric field corresponding to the cell in the thinned lattice, integrating the first calculation results to calculate a magnetic current; When there are a plurality of second calculation results of the magnetic field corresponding to the cell in the thinned grid, the second calculation results are integrated to calculate the current. 23. The simulation device according to claim 22, further comprising:

[0125] (Supplementary Note 24) The process of calculating the far field is Calculating the far field for each of the uncoupled cells for the decimated grid and for each of the decimated grids 19. The simulation device according to claim 18, further comprising:

[0126] (Appendix 25) A processor; a memory operatively connected to the processor; A simulation device comprising: Generate a thinned grid for electromagnetic flow calculation according to the electric field strength distribution in the equivalent electromagnetic flow region; Using the thinned grid, the equivalent electromagnetic current and the far field are calculated. A simulation device that executes processing. [Explanation of symbols]

[0127] 10 Simulation equipment 10a communication interface 10b HDD 10c memory 10d processor 20 Communications Department 30 Storage section 31 Data to be analyzed 32 Thinning condition data 33 Thinned grid data 40 Control Unit 41 Generation part 42 Calculation section

Claims

1. Generate a thinned grid for electromagnetic flow calculation according to the electric field strength distribution in the equivalent electromagnetic flow region; Calculating an equivalent electromagnetic current and a far field using the thinned grid; In the process of generating the thinned grid, Calculating the electric field intensity for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region; combining a predetermined number of the cells to generate the thinned grid based on the electric field strength; In the process of combining a predetermined number of the cells to generate the thinned lattice, When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a predetermined upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. A simulation program that causes a computer to execute a process.

2. The process of calculating the equivalent electromagnetic current includes: Calculating electromagnetic currents for each of the unconnected cells for the thinned grid and for each of the thinned grids 2. The simulation program according to claim 1, further comprising:

3. The process of calculating the electromagnetic current for each thinned-out grid includes: When there are a plurality of first calculation results of the electric field corresponding to the cell in the thinned lattice, integrating the first calculation results to calculate a magnetic current; When there are a plurality of second calculation results of the magnetic field corresponding to the cell in the thinned grid, the second calculation results are integrated to calculate the current.

3. The simulation program according to claim 2, further comprising a process.

4. The process of calculating the far field includes: Calculating the far field for each of the uncoupled cells for the decimated grid and for each of the decimated grids 2. The simulation program according to claim 1, further comprising:

5. Generate a thinned grid for electromagnetic flow calculation according to the electric field strength distribution in the equivalent electromagnetic flow region; Calculating an equivalent electromagnetic current and a far field using the thinned grid; In the process of generating the thinned grid, Calculating the electric field intensity for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region; combining a predetermined number of the cells to generate the thinned grid based on the electric field strength; In the process of combining a predetermined number of the cells to generate the thinned lattice, When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a predetermined upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. A simulation method characterized in that processing is executed by a computer.

6. Generate a thinned grid for electromagnetic flow calculation according to the electric field strength distribution in the equivalent electromagnetic flow region; Calculating an equivalent electromagnetic current and a far field using the thinned grid; In the process of generating the thinned grid, Calculating the electric field intensity for each cell generated by dividing each plane of the equivalent electromagnetic flow region, which is a rectangular parallelepiped or cubic region; combining a predetermined number of the cells to generate the thinned grid based on the electric field strength; In the process of combining a predetermined number of the cells to generate the thinned lattice, When the electric field strength of all the cells in a thinning-out target range including a predetermined number of the cells is equal to or less than a predetermined upper limit value, all the cells in the thinning-out target range are combined to generate the thinned grid. A simulation device comprising a control unit that executes processing.

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