JP2009294774A - Electromagnetic field analysis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic field analysis device that analyzes an electromagnetic field of a space including a thin film at high speed with high accuracy. <P>SOLUTION: The analysis device has: an analysis model construction part 312 creating an analysis model of the analysis space based on structure data 131 stored in a storage part 320; a thin film model mesh setting part 314 setting thin film model information 136 related to a thin film model wherein electromagnetic fields different from each other are respectively allocated to the surface and the backside on a boundary (a mesh) of a cell corresponding to a thin film structure; and an electromagnetic field analysis part 316 calculating the electromagnetic fields of the surface and the backside of the thin film model, based on analysis model information 135 and the thin film model information 136. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic field analysis apparatus, and more particularly, to an electromagnetic field analysis apparatus that performs electromagnetic field analysis by a time-domain finite difference method (Finite Difference Time Domain Method, FDTD method).

  In recent years, with the advancement of functions of digital home appliances typified by flat-screen televisions and mobile phones, the speed of circuit elements used in digital home appliances and the density of printed circuit boards are increasing. Accordingly, countermeasures against electromagnetic noise generated in circuit elements and substrates (for example, countermeasures against malfunction due to electromagnetic noise and suppression of electromagnetic noise radiation) are more important than ever.

  In order to effectively take measures against electromagnetic noise, techniques for analyzing electromagnetic noise of circuit elements and substrates on a computer have been actively developed.

  One technique for analyzing electromagnetic noise on a computer is the time domain finite difference method (FDTD method) (see Non-Patent Document 1).

  The electromagnetic field analysis by the FDTD method will be described. The FDTD method uses a Maxwell equation obtained by numerically subtracting time and space. Faraday's law and Ampere's law are expressed by the following equations (1) and (2), respectively.

  Substituting B = μH, D = εE, and J = σE into equations (1) and (2), the following equations (3) and (4) are obtained. Here, μ is magnetic permeability, ε is dielectric constant, and σ is conductivity. These are constants determined for each medium of the structure disposed in the space.

  Expressions (3) and (4) include a time derivative (δt) and a space derivative (δx). For this reason, Expression (3) and Expression (4) are numerically differentiated using the center difference. Assuming that the time step of the difference is Δt, equations (5) and (6) are obtained. The subscripts at the upper right of E and H indicate time. The electric field and the magnetic field are arranged so as to be offset from each other by a half hour.

  When Expression (5) is summarized for the electric field at time n, Expression (7) is obtained.

  Further, when Expression (6) is summarized for the magnetic field at time n + 1/2, Expression (8) is obtained.

  Expressions (7) and (8) indicate that the electric field and magnetic field at a certain time at a certain place can be calculated from its own value at that place before one step and the magnetic field / electric field in the vicinity before half a step. . As described above, in the FDTD method using the center difference, the electric field and the magnetic field at the time shifted by half an hour are calculated.

  In the FDTD method, the electric field and the magnetic field are arranged so as to be shifted from each other by a half cell, and the electric field and the magnetic field at a position shifted by a half cell are calculated. The arrangement of electric and magnetic fields in the FDTD method is shown in FIG. FIG. 1 is a diagram showing the arrangement of electric and magnetic fields in the FDTD method.

  In other words, the FDTD method updates the electric and magnetic fields arranged as shown in FIG. 1 with time using the equations (7) and (8), thereby changing the behavior of the electric and magnetic fields in the analysis region. It is a method of analysis.

  By the way, in order to perform a stable analysis by the FDTD method, the Courant condition shown in Expression (9) must be satisfied with respect to the time step Δt.

  From the Courant condition, in the FDTD method, if the cell size (Δx, Δy, Δz) is reduced, the time step needs to be reduced.

  When an analysis including a fine structure is performed by the FDTD method, it is necessary to select a small mesh size for modeling the fine structure. Therefore, in order to satisfy the Courant condition, it is necessary to perform analysis in a minute time step. As described above, the FDTD method has a drawback that the time required for the electromagnetic field analysis of a space including a fine structure increases.

  For example, consider performing an electric field analysis on a plastic structure whose surface is subjected to metal plating. While the thickness of normal structures (frames, shield boxes, etc.) is several millimeters, the thickness of the plating is several um or less, so when meshed so that the plating part can be made into cells, The number of analysis cells becomes enormous.

  On the other hand, if the cell size is determined in accordance with a normal structure, the plated portion cannot be modeled. Alternatively, the plated portion is modeled by handling the thickness significantly greater than the actual thickness.

  Conventionally, modeling using the subgrid method or the subcell method has also been proposed, but the subgrid method has a problem of stability, and the subcell method has poor analysis accuracy when a thin object is modeled. There was a drawback.

Non-Patent Document 2 discloses that a conductive thin film is modeled as a resistive film having a transmission coefficient equal to that of the conductive thin film assigned to the mesh surface of the cell, and simulation is performed by the FDTD method. According to this method, the above-mentioned drawbacks can be overcome.
Satoshi Uno, “Electromagnetic field and antenna analysis by FDTD method”, Corona, 1998, p. 1-13, 52-53 “Simulation of transmitted wave in multilayer conductor thin film by FDTD method”, IEICE Transactions, May 2000, B Vol. J83-B, p. 711-719

  The method described in Non-Patent Document 2 has a problem in that the magnetic field existing on the front and back of the structure is modeled as one magnetic field, and the analysis accuracy is lowered.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an electromagnetic field analysis apparatus that analyzes an electromagnetic field in a space including a thin film at high speed and with high accuracy.

  The present invention according to one aspect is an electromagnetic field analysis apparatus, comprising a storage means for storing structure data and analysis conditions of a structure having a thin film structure, and an analysis including the structure based on the structure data and the analysis conditions Model construction means to create an analysis model that divides space into multiple cells each assigned an electromagnetic field, and assigns different electromagnetic fields to the front and back surfaces of the boundary on the cell boundary corresponding to the thin film structure Thin film model setting means for setting the thin film model, and analysis means for calculating the electromagnetic field of each cell based on the electromagnetic field one step before each cell and the surrounding cells of each cell, The electromagnetic field value one step before on each surface of the boundary is determined based on a value obtained by multiplying the electromagnetic field value one step before on the front and back surfaces by a coefficient corresponding to the electromagnetic transmission characteristics of the thin film model. Using the effective electromagnetic field value.

  Preferably, the analysis means includes a value obtained by multiplying the electric field value on each surface of the boundary by the electric field reflectance of the thin film model, and a value obtained by multiplying the electric field value on a surface different from each surface by the electric field transmittance of the thin film model. The sum is used as the effective electric field value on each surface.

  More preferably, the analysis means calculates the magnetic field value on each surface of the boundary based on the magnetic field value one step before on each surface and the effective electric field value.

  More preferably, the thin film model setting means calculates the electric field transmittance and electric field reflectance based on the thickness and material of the thin film model.

  Preferably, the analysis unit uses a sum of a magnetic field value on each surface of the boundary and a magnetic field value on a surface different from each surface multiplied by the magnetic field attenuation factor of the thin film model as an effective magnetic field value on each surface. .

  More preferably, the analyzing means sets the electric field value on each surface of the boundary, the electric field value on one surface before one step multiplied by the electric field reflectance of the thin film model, and one step on a surface different from each surface. Calculation is based on the value obtained by multiplying the previous electric field value by the electric field transmittance of the thin film model and the effective magnetic field value.

  More preferably, the thin film model setting means calculates the magnetic field attenuation rate based on the thickness and material of the thin film model.

  According to the present invention, a minute structure is modeled as a thin film model, and the electromagnetic field on the thin film model is distinguished and updated. As a result, the electromagnetic field in the space including the thin film can be analyzed accurately without increasing the calculation time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

(1. Hardware configuration)
FIG. 2 is a block diagram showing the configuration of analysis apparatus 100 according to the present embodiment. Hereinafter, the configuration of the analysis apparatus 100 will be described with reference to FIG.

  The analysis apparatus 100 includes a computer main body 102, a monitor 104, a keyboard 106, and a mouse 108. The monitor 104 displays information inside the computer main body 102. The keyboard 106 and mouse 108 accept external instructions and send the instructions to the computer main body 102. A bus 170 connects the monitor 104, the keyboard 106, the mouse 108, and the computer main body 102.

  The computer main body 102 includes a CPU (central processing unit) 110, a memory 120 including a ROM (Read Only Memory) and a RAM (Random Access Memory), a hard disk 130, a flexible disk (hereinafter referred to as "FD"). Drive 140, optical disk drive 150, and communication interface 160 for exchanging data with the outside are included. The CPU 110, the memory 120, the hard disk 130, the FD drive 140, the optical disk drive 150, and the communication interface 160 are connected to each other via a bus 170.

  The CPU 110 functioning as an arithmetic processing unit executes processing corresponding to a program stored in the hard disk 130 using the memory 120 as a working memory.

  The FD drive 140 reads and writes information of the FD 142. The optical disc drive 150 reads information on an optical disc such as a CD-ROM (Compact Disc Read-Only Memory) 152. The analysis device 100 may include a drive device that can read other media, for example, a medium such as a DVD-ROM (Digital Versatile Disc) or a memory card.

  The hard disk 130 stores structure data 131, analysis conditions 134, analysis model information 135, thin film model information 136, analysis results 137, and an analysis program 138. The hard disk 130 is an example of a direct access memory device, and a flash memory or the like may be used instead of the hard disk 130.

  The structure data 131 is information representing the structure of an object included in a space to be analyzed (hereinafter referred to as an analysis space). The structure data 131 includes shape information 132 of an object in the analysis space and material information 133 of the object. The structure data 131 may be created, for example, when a user inputs to the keyboard 106, the mouse 108, or the like. Alternatively, the structure data 131 may be stored in the FD 142 or the CD-ROM 152. In this case, the FD drive 140 or the optical disk drive 150 reads the structure data 131 from the FD 142 or the CD-ROM 152 and stores the read structure data 131 in the hard disk. Alternatively, the structure data 131 may be supplied from the outside via the communication interface 160.

  The analysis condition 134 is a condition required for electromagnetic field analysis. The analysis condition 134 includes a mesh size, an absorption boundary condition, an end time, and the like. The analysis condition 134 may be set by the user using the mouse 108, the keyboard 106, or the like, or may be supplied via the FD drive 140, the optical disc drive 150, and the communication interface 160.

  The analysis model information 135 is data in which the coordinates of the cell formed by dividing the analysis space and the material are associated with each other. The thin film model information 136 is information on a thin film model obtained by modeling the thin film structure in the analysis space, and includes mesh coordinates, electric field transmittance, and magnetic field attenuation factor of the thin film model.

  The analysis result 137 is a result of electromagnetic field analysis, and consists of an electromagnetic field value at each point at each time. Note that the analysis result 137 is not necessarily stored in the hard disk 130. For example, the CPU 110 may store the analysis result 137 of the electromagnetic field analysis in an external storage device and read it to the memory 120 or the like as necessary.

  The analysis program 138 causes the CPU 110 to perform electromagnetic field analysis. That is, the analysis program 138 is software executed by the CPU 110. Generally, such software is stored and distributed in a storage medium such as a CD-ROM 152 or FD 142, read from the storage medium by the optical disk drive 150 or FD drive 140, and temporarily stored in the hard disk 130. Alternatively, when the analysis apparatus 100 is connected to a network, the analysis apparatus 100 may be temporarily copied from the server on the network to the hard disk 130. The analysis program 138 stored in the hard disk 124 in this way is read into the RAM in the memory 120 and executed by the CPU 110. However, when connected to the network, the analysis program 138 may be directly loaded into the RAM and executed without being stored in the hard disk 130.

  Note that the analysis program 138 may cause the external computer to execute electromagnetic field analysis via the communication interface 128 and store the analysis result in the analysis apparatus 100 in the external computer.

  The computer hardware itself shown in FIG. 2 and its operating principle are general. Therefore, an essential part for realizing the functions of the present invention is software stored in a storage medium such as the FD 142, the CD-ROM 152, and the hard disk 130.

(2. Functional configuration)
Next, the functional configuration of the analysis apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing a functional configuration of analysis apparatus 100 according to the present embodiment.

  The analysis apparatus 100 includes a calculation unit 310 for performing electromagnetic field analysis, a storage unit 320 for storing information necessary for calculation, and an interface unit for displaying information in the apparatus to the user and receiving instructions from the user. 330.

  The calculation unit 310 includes an analysis model construction unit 312 that creates an analysis model in which the analysis space is divided into cells according to the shape information and mesh size of the structure in the analysis space, and features (material, thickness, frequency, etc.) of the thin film model. ) Includes a thin film model mesh setting unit 314 that generates thin film model information 136 and an electromagnetic field analysis unit 316 that calculates an electromagnetic field in the analysis region based on the analysis model information 135 and the thin film model information 136. The electromagnetic field analysis unit 316 includes a magnetic field update unit 317 that calculates a magnetic field at the next time from the electromagnetic field at the already obtained time, and an electric field update unit 318 that calculates an electric field at the next time from the electromagnetic field at the already obtained time. Have

  The storage unit 320 stores the structure data 131, the analysis result 137, the analysis condition 134, the analysis model information 135, and the thin film model information 136 described with reference to FIG.

  The interface unit 330 displays a result display unit 332 that displays the analysis result 137 to the user, a thin film model designation unit 334 that accepts the material, thickness, and frequency assigned to the mesh handled as the thin film model from the user, and inputs analysis conditions 134 from the user. And an analysis condition input unit 336 to accept.

(3. Process flow)
A flow of processing performed by the analysis apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing processing performed by the calculation unit 310. Hereinafter, with reference to FIG. 4, processing performed by the calculation unit 310 will be described. In order to simplify the description, the two-dimensional TM-FDTD method will be described as an example.

  In step S401, the analysis model construction unit 312 included in the calculation unit 310 arranges the structure to be analyzed in the analysis space based on the structure data 131, and divides it by the cell size specified by the analysis condition 134, Create an analysis model. Each cell of the analysis model is assigned an electromagnetic field by a predetermined method (here, according to the electromagnetic field arrangement of the FDTD method). The calculation unit 310 stores the cell coordinates and material of the divided structure in the storage unit 320 as analysis model information 135.

  In step S403, the thin film model mesh setting unit 314 included in the calculation unit 310 receives the coordinates of the cell boundary (hereinafter referred to as a mesh) to which the thin film model is assigned corresponding to the thin film structure received by the thin film model specifying unit 334. Get material, thickness and frequency assigned to thin film model. Different electromagnetic fields are assigned to the front and back surfaces of the thin film model. The front and back electromagnetic fields are each updated according to different equations, as will be described in detail later.

  When there are a plurality of thin film structures handled as the thin film model, the thin film model designating unit 334 repeats the process of step S403 for the number of thin film structures. When the user inputs data regarding the thin film model, the user inputs data of the thin film model corresponding to each thin film model structure. Accordingly, the thin film model mesh setting unit 314 obtains all input data.

  The thin film model mesh setting unit 314 then determines the electric field transmittance (T) and the magnetic field representing the electromagnetic transmission characteristics of the thin film model from the thickness and material of the thin film model and the material information of the cells on both sides of the mesh to which the thin film model is assigned. An attenuation factor (A) is obtained. Here, an arrangement example of the thin film model and peripheral materials shown in FIG. 5 will be described. FIG. 5 is a diagram illustrating an arrangement example of a thin film model and peripheral materials.

  The thin film model mesh setting unit 314 acquires material information of two cells (air 510 and glass epoxy 530 in FIG. 5) facing the thin film model 520. Dielectric constant ε1, conductivity σ1, permeability μ1, air epoxy 530 dielectric constant ε3, conductivity σ3, permeability μ3, thin film model material permittivity ε2, conductivity σ2, permeability μ2, thickness d2 When the frequency is f, the thin film model mesh setting unit 314 calculates the electric field permeability T according to the equation (10) (see Non-Patent Document 2).

  Here, ηi and ki are defined by Equation (11), assuming that ω = 2πf.

  Further, the thin film model mesh setting unit 314 calculates the magnetic field attenuation factor A according to the equation (12). Here, ω is ω = 2πf as described above.

  The thin film model mesh setting unit 314 stores the electric field transmittance T and the magnetic field attenuation factor A calculated in the above procedure and the coordinates of the mesh to which the thin film model is assigned in the storage unit 320 as the thin film model information 136.

  Since the thin film model mesh setting unit 314 calculates the electric field transmittance and the magnetic field attenuation factor, the analysis apparatus 100 can perform an electromagnetic field analysis if there is a thickness / material as data on the thin film model. Therefore, in the electromagnetic field analysis, the user does not need to calculate or check the values of the electric field transmittance and the magnetic field attenuation factor. However, the electric field transmittance and the magnetic field attenuation factor may be prepared in advance. In this case, the thin film model mesh setting unit 314 does not calculate the electric field transmittance and the magnetic field attenuation rate.

  In step S405, the electromagnetic field analysis unit 316 included in the calculation unit 310 reads the mesh size from the analysis condition 134, and calculates an appropriate time step (Δt) from the read mesh size and coolant condition. The time step may be given in advance as an analysis condition. In this case, the electromagnetic field analysis unit 316 reads a time step from the analysis condition 134.

  Subsequently, the electromagnetic field analysis unit 316 secures an electromagnetic field calculation area according to the electromagnetic field allocation method.

  With reference to FIG. 6, how to assign the electromagnetic field in the present embodiment will be described. FIG. 6 is a diagram showing the arrangement of electric and magnetic fields in the analysis region in the two-dimensional TM-FDTD method. In regions other than the thin film model, an electric field (E (i, j), E (i + 4, j), etc. in FIG. 6) is arranged at the apex of the cell, and a magnetic field (H in FIG. 6) is placed on the side of the cell. (i, j), H (i + 4, j), etc.) are arranged. For the area on the thin film model, the electric field is secured separately on both sides of the thin film model. That is, in FIG. 6, Eleft (i + 2, j) and Eleft (i + 2, j + 1) are on the left side of the thin film model, and Eright (i + 2) is on the right side of the thin film model. , j) and Eright (i + 2, j + 1) are assigned. As with the electric field, the magnetic field is secured separately on the right and left sides of the thin film model (Hleft (i + 2, j), Hright (i + 2, j) in FIG. 6).

  In step S407, the magnetic field update unit 317 included in the calculation unit 310 performs the magnetic field of each cell other than on the thin film model (in FIG. 6, Hy (i, j), Hy (i + 3, j), Hy (i, j + 1), Hy (i + 3, j + 1), Hx (i, j), Hx (i + 1, j), Hx (i + 3, j), H (i + 4, j)) Is updated according to equation (13). That is, the magnetic field updating unit 317 obtains the magnetic field at the next time from the electromagnetic field obtained so far.

  However, CHXLY (i, j + 1) and CHYLY (i + 1, j) are given by the following equation (14).

  When obtaining the y component of the magnetic field of the cell adjacent to the thin film model, a part of the electric field component one step before (half time step before the time) appearing in Equation (13) becomes the electric field component on the thin film model. . However, the electric field component on the thin film model is different between the front side and the back side of the thin film model. Therefore, it is necessary to determine what value is used as the electric field component on the thin film model.

  In the present embodiment, as the electric field component on the thin film model, an effective electric field component obtained by multiplying the electric field component on the front and back surfaces of the thin film model by a coefficient corresponding to the electric field transmission characteristics of the thin film model is used. . Specifically, the electric field component on the side where the magnetic field is desired to be obtained is multiplied by the electric field reflectance (1-T), and the electric field component on the other side is multiplied by the electric field transmittance (T). The sum of these is the effective electric field component.

That is, the magnetic field updating unit 317 calculates H _y ^{n + 1/2} (i + 1, j) according to the equation (15).

In step S409, the magnetic field updating unit 317 obtains the magnetic field at the next time of the cell on the thin film model. The magnetic field updating unit 317 converts the H _x ^{n + 1/2} (i + 2, j) component into the components of each surface of the thin film model, that is, H _left ^{n + 1/2} (i + 2, j) and H _right ^{n + 1. / 2} (i + 2, j) are handled separately and each component is updated in a different manner.

Specifically, the magnetic field updating unit 317 calculates H _left ^{n + 1/2} (i + 2, j) and H _right ^{n + 1/2} (i + 2, j) according to the equations (16) and (17). . Note that CHXLY (i + 1, j) in the equations (16) and (17) is the same as that defined in the equation (14).

  As can be seen from these equations, the magnetic field updating unit 317 is effective as represented by the front-side and back-side electric field components and the electric field transmittance T as the electric field components one step before on the thin film model necessary for obtaining the magnetic field. Use an electric field component.

  Referring to Equation (16), the effective electric field component of the left surface is obtained by multiplying the electric field component of the left surface by the electric field reflectance (1-T), and the right electric field component by the electric field transmittance ( It is the sum of those multiplied by T). Also, referring to equation (17), the effective electric field component on the right side is obtained by multiplying the electric field component on the right side by the electric field reflectance (1-T), and the electric field transmission on the left side electric field component. It is the sum of the product of rate (T). That is, the effective electric field component of each surface is represented by (electric field component of each surface) × (1−T) + (electric field component of the opposing surface) × T. This determination method takes into consideration the influence of the electric field component of each surface one step before on the magnetic field component.

  As described above, the magnetic field updating unit 317 calculates the magnetic field component on each surface of the thin film model based on the magnetic field component one step before on the surface and the effective electric field value on the surface. The magnetic field updating unit 317 distinguishes and updates the magnetic field on one surface of the thin film and the magnetic field on the other surface, so that the electromagnetic field analysis accuracy is improved as compared with the case where the magnetic fields on both surfaces are handled together.

  In step S411, the electromagnetic field analysis unit 316 advances the time by a half-hour step in order to calculate the electric field.

  In step S413, the electric field updating unit 318 included in the electromagnetic field analysis unit 316 performs the electric field of the cell outside the thin film model (E (i, j), E (i + 1, j in FIG. 6) according to the equation (18). ), E (i + 3, j), E (i + 4, j), E (i, j + 1), E (i + 1, j + 1), E (i + 3, j + 1) , E (i + 4, j + 1)).

  However, CEZ (i, j), CEZLX (i, j), and CEZLY (i, j) are given by Expression (19).

  In step S415, the electric field updating unit 318 obtains the electric field of the cell on the thin film model according to the equations (20) and (21).

  The magnetic field attenuation factor A that appears in the third term on the right side of the equations (20) and (21) represents the contribution of the magnetic field component on the other surface to the magnetic field component on the other surface of the thin film model. In the contribution of the magnetic field component of the other surface to the magnetic field component of one surface expressed by the magnetic field attenuation index (generally called the skin effect) in the material, distinguishing the front and back magnetic fields of the thin film model By using the effective value of the magnetic field obtained based on this, the electromagnetic field analysis accuracy is improved.

  In step S417, the electromagnetic field analysis unit 316 advances the time by half an hour. In step S419, the electromagnetic field analysis unit 316 determines whether to end the electromagnetic field analysis. That is, the electromagnetic field analysis unit 316 determines whether the time t is less than the set analysis end time tmax.

  If t <tmax (Yes in step S419), the electromagnetic field analysis unit 316 repeats the processing from step S407.

  If t is equal to or greater than tmax (No in step S419), operation unit 310 ends the electromagnetic field analysis process.

(4. Verification results)
Verification was performed to show the effectiveness of the present invention. The model used for verification is shown in FIG. FIG. 7 is a diagram for explaining a model used for verification. The cell size in the model used for verification is 1 mm in both the X direction and the Y direction. The absorption boundary condition used is the Mur primary absorption boundary. Furthermore, the thin film model was copper having a thickness of 1 μm (conductivity 5.76e7, frequency 1 GHz), and was placed at a distance of 500 mm from the input source.

  The given input wave source is a 1 GHz sine plane wave propagating in the positive direction from the negative direction of x. The input electric field is shown in FIG.

  FIG. 9 is a diagram showing a simulation result and a theoretical value of the electric field of the cell nearest to the thin film model by the conventional method and the proposed method. The simulation is performed by a C language verification program created according to the proposed method. Here, the “theoretical value” is a value calculated using Expression (10).

  By adding the conditions of the above thin film model to the equation (10), the theoretical value of the attenuation rate can be obtained as −80.7 dB. The simulation result shows that the attenuation factor calculated by the conventional method is -65.9dB, whereas the attenuation factor calculated by this method is -77.5dB. Compared to the theoretical value (−80.7 dB), the error of the attenuation rate with the conventional method is 14.8 dB, whereas the error of the attenuation rate with this method is 3.1 dB, which improves the simulation accuracy. I understand that

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  Electromagnetic field analysis of a space containing a thin metal object such as a shield case or plating can be performed accurately and in a short time.

It is a figure which shows arrangement | positioning of the electric field and magnetic field in FDTD method. It is a figure which shows the structure of the analyzer 100 concerning this Embodiment in the block diagram format. It is a figure shown in the block diagram format which shows the functional structure of the analyzer 100 which concerns on this Embodiment. It is the flowchart which showed the process which the calculating part 310 performs. It is a figure which shows the example of arrangement | positioning of a thin film model and peripheral material. It is a figure which shows arrangement | positioning of the electric field and magnetic field of an analysis area | region in a 2-dimensional TM-FDTD method. It is a figure for demonstrating the model used for verification. It is a figure which shows an input electric field. It is a figure which shows the simulation result by the conventional method and this proposal method, and the theoretical value of the electric field of the cell nearest to a thin film model.

Explanation of symbols

  100 analysis device, 102 computer main body, 104 monitor, 106 keyboard, 108 mouse, 110 CPU, 112 mouse, 120 memory, 124 hard disk, 128 communication interface, 130 hard disk, 131 structure data, 132 shape information, 133 material information, 134 analysis Conditions, 135 analysis model information, 136 thin film model information, 137 analysis results, 138 analysis program, 140 FD drive, 142 FD, 150 optical disk drive, 152 CD-ROM, 160 communication interface, 170 bus, 310 operation unit, 312 analysis model Construction unit, 314 Thin film model mesh setting unit, 316 Electromagnetic field analysis unit, 317 Magnetic field update unit, 318 Electric field update unit, 320 Storage unit, 330 interface Chair unit, 332 result display unit, 334 a thin film model designation unit, 336 analysis condition input unit, 510 air, 520 thin model, 530 glass epoxy.

Claims (7)

An electromagnetic field analyzer,
Storage means for storing structure data and analysis conditions of a structure having a thin film structure;
Based on the structure data and the analysis conditions, model construction means for creating an analysis model in which an analysis space including the structure is divided into a plurality of cells each assigned an electromagnetic field;
Thin film model setting means for setting a thin film model in which different electromagnetic fields are respectively assigned to the front and back surfaces of the boundary on the boundary of the cell corresponding to the thin film structure;
Analyzing means for calculating the electromagnetic field of each of the cells based on the electromagnetic field one step before each of the cells and the cells around each of the cells;
The analysis unit multiplies the electromagnetic field value of one step before on the front surface and the back surface by a coefficient corresponding to the electromagnetic transmission characteristic of the thin film model as the electromagnetic field value of one step before on each surface of the boundary. An electromagnetic field analyzer that uses an effective electromagnetic field value determined based on a value.   The analysis means includes a value obtained by multiplying the electric field value on each surface of the boundary by the electric field reflectance of the thin film model, and a value obtained by multiplying the electric field value on a surface different from each surface by the electric field transmittance of the thin film model. The electromagnetic field analysis apparatus according to claim 1, wherein the sum is used as an effective electric field value of each surface.   The electromagnetic field analysis apparatus according to claim 2, wherein the analysis unit calculates a magnetic field value on each surface of the boundary based on a magnetic field value one step before on each surface and the effective electric field value. .   The electromagnetic field analysis apparatus according to claim 2, wherein the thin film model setting unit calculates the electric field transmittance and the electric field reflectance based on a thickness and a material of the thin film model.   The analysis means calculates the sum of the magnetic field value on each surface of the boundary and the value obtained by multiplying the magnetic field value on a surface different from each surface by the magnetic field attenuation factor of the thin film model, on the surface. The electromagnetic field analysis apparatus according to claim 1, which is used as   The analyzing means calculates an electric field value on each surface of the boundary, a value obtained by multiplying an electric field value of one step on each surface by the electric field reflectance of the thin film model, and 1 on a surface different from each surface. The electromagnetic field analysis apparatus according to claim 5, wherein the electromagnetic field analysis apparatus calculates based on a value obtained by multiplying an electric field value of the thin film model by an electric field value before the step and the effective magnetic field value.   The electromagnetic field analysis apparatus according to claim 5, wherein the thin film model setting unit calculates the magnetic field attenuation rate based on a thickness and a material of the thin film model.

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