KR102633849B1 - Electromagnetic wave absorbers and design methods with multiple surface resistance - Google Patents

Abstract

It relates to an electromagnetic wave absorber and design method for absorbing electromagnetic waves, comprising a periodic pattern layer consisting of a combination of one or more empty portions on the upper surface of a structural layer and one or more occupied portions coated with a conductive material, and the occupied portions are electromagnetic. It is characterized by having different sheet resistance depending on the thickness or material to which the material is applied. This has the advantage of being able to design an optimized pattern by considering the surrounding environment such as target frequency and allowable structural thickness and weight.

Description

{Electromagnetic wave absorbers and design methods with multiple surface resistance}

The present invention relates to an electromagnetic wave absorber and a design method, and more specifically, to an electromagnetic wave absorber and a design method in which an electromagnetic wave absorber made of a conductive material absorbs electromagnetic waves.

As the number of environments using electromagnetic waves increases, much research is being conducted on ways to deal with unnecessarily radiated electromagnetic waves. A variety of technical approaches for effective shielding/absorbing have been proposed.

To improve the radio wave absorption performance of radio wave absorbers, various design techniques using metapatterns have been studied. Conventional pattern shapes have been proposed with specific shapes such as square, cross, and ring types. As various electromagnetic properties are implemented depending on the shape of the pattern, increasingly more complex patterns are being studied to obtain more effective properties.

Pixelated pattern design techniques were also proposed to obtain electromagnetic properties that are difficult to obtain in the basic form. However, existing pixelated technology only suggests pattern formation using a single material, making it difficult to implement an electromagnetic wave absorber that satisfies the required electromagnetic wave absorption performance.

Republic of Korea Patent No. 10-2358017

Therefore, the present invention was created to solve the problems of the prior art as described above. Various patterns were studied to improve the performance of the electromagnetic wave absorber, but due to the limitations of a single material, it was difficult to design an electromagnetic wave absorber with the required performance. To solve this problem, we propose an electromagnetic wave absorber and design method with multi-surface resistance.

The present invention includes a periodic pattern layer consisting of a combination of one or more empty portions on the upper surface of a structural layer and one or more occupied portions coated with a conductive material, wherein the occupied portions have different surfaces depending on the thickness of the electromagnetic material applied. It is characterized by resistance.

In addition, it includes a periodic pattern layer composed of a combination of one or more empty portions on the upper surface of the structural layer and one or more occupied portions coated with a conductive material, and the occupied portions have different sheet resistances depending on the material to which the electromagnetic material is applied. It is characterized by having a.

In addition, the periodic pattern layer is characterized in that it is symmetrical in the up and down, left and right, and diagonal directions with respect to the center.

In addition, the radio wave absorber is characterized in that the radio wave absorption performance is determined by an integrated variable including a structural variable including any one of the thickness, length, and number of layers of the structural layer and a pattern design variable of the periodic pattern layer. .

In addition, the periodic pattern layer is characterized in that when blank portions are disposed on the upper, lower, left, and right sides of the occupied portion, the blank portions are disposed in a diagonal direction.

In addition, a pixelization step of dividing the unit cells formed on the design program into N x N to form a plurality of divided surfaces, a variable setting step of setting the range of sheet resistance for each row or column of the divided unit cells, respectively A modeling step in which a model is created by applying sheet resistance to the divided surface, an analysis step in which electromagnetic analysis is performed on the generated model through an analysis program, and a comparative evaluation of the radio wave absorption performance of the analyzed model and the required radio wave absorption performance. It includes an evaluation step, and a correction step in which the model is modified and reinterpreted if the required radio wave absorption performance is not satisfied.

In addition, the variable setting step is characterized by setting variables for variable areas divided up, down, left, right, and diagonally based on the center of the unit cell.

Additionally, the variable setting step is characterized by setting the minimum and maximum values of the rows or columns of the variable area.

In addition, the variable setting step is characterized by setting the variable including the middle split surface when the variable area has an odd number of rows or columns.

In addition, the modeling step is characterized in that the thickness or material of the applied conductive material is different depending on the sheet resistance given to the divided surface.

In addition, the modeling step is characterized in that a pattern consisting of occupied portions and blank portions is formed according to sheet resistance, and when the blank portions are disposed on the top, bottom, left, and right sides of the occupied portion, the blank portions are set to be arranged diagonally.

The present invention has the advantage of being able to design an optimized pattern in consideration of the surrounding environment, such as the target frequency and the allowable thickness and weight of the structure.

Additionally, it can be used in structures with electromagnetic properties such as radomes.

Figure 1 is an example of a radio wave absorber.
Figure 2 is a design flow chart of a radio wave absorber.
Figure 3 is a design block diagram.
Figure 4 is an example diagram of the pixelization step.
Figure 5 is an example diagram of the variable setting step.
Figure 6 is an example diagram of whether a vertex is in contact.
Figure 7 is an exemplary diagram of a unit cell with multi-surface resistance.
Figure 8 is an example diagram of a crossover operation.
Figure 9 is an example diagram of a mutation operation.
Figure 10 is an example of manufacturing using lamination technology.
Figure 11 is an example of manufacturing using deposition technology.
Figure 12 is a resistance graph according to deposition time.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes included in the spirit and technical scope of the present invention.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains.

Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless clearly defined in the present application, should not be interpreted in an ideal or excessively formal sense. It shouldn't be.

The technology of the present invention deals with content related to electromagnetic wave absorbers. Electromagnetic wave absorbers can be designed by combining information on dielectric constant and permeability, which are electromagnetic properties of electromagnetic loss materials, and thickness. Single-layer and multi-layer designs are possible using homogeneous materials. Depending on the electromagnetic properties and thickness, a resonance characteristic can be generated at the target frequency, and this resonance characteristic is said to absorb electromagnetic waves at that frequency.

Another way to design an absorber is to use a metasurface, or periodic pattern layer. This periodic pattern layer can be inserted on top or in the middle of the medium to provide absorption performance using the filter characteristics and loss characteristics of the pattern.

Hereinafter, an electromagnetic wave absorber and design method with multi-planar resistance according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

Figure 1 is an example of a radio wave absorber with multi-planar resistance. A radio wave absorber with multiple sheet resistance refers to a radio wave absorber with multiple sheet resistances, and the pixelated periodic pattern layer 100 is characterized by a combination of a plurality of pixels with different sheet resistances. Referring to FIG. 1, the structural layer 1 includes a periodic pattern layer 100 composed of a combination of one or more empty portions 110 having a void on the upper surface of the structure layer 1 and one or more occupied portions 120 coated with a conductive material; , the occupied portion 120 is characterized in that it has different sheet resistance depending on the thickness to which the electromagnetic material is applied.

The structural layer 1 corresponds to the main body of the radio wave absorber and is the structure in which the periodic pattern layer 100 is formed. The shape and material of the structural layer 1 may be changed to satisfy the required radio wave absorption performance. For example, the structural layer 1 may be formed as a polyhedron or its upper surface may be formed as a curved surface. Additionally, it may be made of a flexible material.

The blank portion 110 of the periodic pattern layer 100 formed on the upper surface of the structural layer 1 is formed as an empty space. Radio waves incident on the blank portion 110 may be affected by structural variables such as the material and curvature of the structural layer 1. The structural variables of the structural layer 1 will be described later.

The periodic pattern layer 100 is formed on the upper surface of the structural layer 1. The periodic pattern layer 100 may be divided into various shapes and formed. The present invention will be explained using a square unit cell as an example. A split surface divided into N x N is formed on the upper surface of the structural layer (1). The dividing surface is a virtual dividing surface that divides the two-dimensional space. The divided shape and size of the dividing surface may be modified.

The performance of the periodic pattern layer 100 as a radio wave absorber is determined depending on whether each divided surface is an occupied space or an empty space. Here, the divided surface forming the empty space will be referred to as the empty part 110, and the divided surface on which the conductive material is applied and occupies the space will be referred to as the occupied part 120.

The blank portion 110 refers to a space in which a conductive material is not applied to the upper surface of the structural layer 1, and the upper surface of the structural layer 1 is exposed to the outside. The structural layer 1 has a certain radio wave absorption performance depending on the material. However, in the present invention, the blank portion 110 is described and illustrated with a blank space or the number 0 to distinguish it from the occupied portion 120.

The occupied portion 120 is a space where a conductive material is applied to the upper surface of the structural layer 1. The blank portion 110 and the occupied portion 120 form a pattern to form the periodic pattern layer 100. The sheet resistance of the occupied portion 120 appears differently depending on the type or thickness of the electromagnetic material applied to the occupied portion 120. For example, the occupied portion 120 has a first pixel 121 and a second pixel 122 having different sheet resistances. The first pixel 121 and the second pixel 122 have different sheet resistances due to different types of applied electromagnetic materials or differences in applied thickness. The present invention utilizes this to form the periodic pattern layer 100 to have a plurality of sheet resistances.

In the periodic pattern layer 100, the empty portion 110 and the occupied portion 120 form a certain pattern, and the pattern formed on the periodic pattern layer 100 forms a more complex pattern to obtain more effective characteristics. do. The radio wave absorber of the present invention has multi-surface resistance through the structure described above, and forms the required radio wave absorber by using the pattern shape of the periodic pattern layer 100 and the sheet resistance of each divided surface as variables.

The present invention presents a method for designing an electromagnetic wave absorber with multi-planar resistance. The design of the present invention is accomplished through a computer operation device. More precisely, it is done through a design program such as MATLAB and an analysis program such as CST (CST Studio Suite) installed on the computer.

Figure 2 is a design flow chart of a radio wave absorber. The computer receives input through input devices such as a mouse and keyboard, and the results processed through the program are output through an output device such as a monitor. Referring to Figure 2, a pixelization step of forming a plurality of divided surfaces by dividing the unit cells formed on the design program into N x N, and a variable that sets the range of sheet resistance for each row or column of the divided unit cells. Setting step, modeling step of generating a model by applying sheet resistance to each of the divided surfaces, analysis step in which electromagnetic analysis is performed on the generated model through an analysis program, radio wave absorption performance and required radio wave absorption of the analyzed model. It includes an evaluation step to compare and evaluate performance, and a correction step to modify and reinterpret the model if the required radio wave absorption performance is not met.

The pixelization step divides the two-dimensional space of the periodic pattern layer into N x N to form a plurality of division surfaces. The pixelated periodic pattern layer has a certain pattern. Considering the polarization component of the incident electromagnetic wave, the pattern must be symmetrical to minimize polarization characteristics. That is, it is formed to be symmetrical in the up and down, left and right, and diagonal directions with respect to the center. Since the periodic pattern layer is symmetrical up and down, left and right, and diagonally, it can be designed by setting 1/8 of the pattern (upper triangle) as the pattern design variable area. A detailed explanation will be provided later with reference to FIG. 4.

The variable setting step is the step of setting conditions in the set pattern design variable area. Reduce variables by setting the range of maximum and minimum values for each column or each row in the pattern design variable area. The divided surface is divided into a blank part and an occupied part depending on whether electromagnetic material is applied. The blank part is set to 0, the occupied part 120 is set to 1, and the range of the maximum and minimum values for the sum of each column or each row is set. For example, when formed with three dividing surfaces, the minimum value is 1 and the maximum value is set to 2, (1,0,0), (0,1,0), (0,0,1) , (1,1,0), (1,0,1), (1,1,0). In this way, the calculation time is reduced by limiting variables for each column or each row. The maximum and minimum values are set by referring to existing accumulated data. At this time, if the number of columns or rows is odd, set the design variables including the center.

The modeling step develops the pattern design variable area to shape the periodic pattern layer. The pattern design variable area in which the variables of each division surface are determined is expanded symmetrically in the top, bottom, left, right, and diagonal directions to form one periodic pattern layer. If the periodic pattern layer has an odd number of columns and rows, it is expanded based on the center column or row. At this time, the modeling step can be modeled together with the structural layer.

The analysis step is to analyze the modeled periodic pattern layer and radio wave absorber. The modeling stage is carried out through a design program, and the analysis stage is carried out through an analysis program. The analysis program evaluates the radio wave absorption performance of the modeled periodic pattern layer. The analysis step is carried out through an analysis program such as CST (CST Studio Suite). When proceeding with analysis, the conditions required for analysis are entered into the program. For necessary conditions, refer to existing accumulated data. Here, the necessary conditions include the electromagnetic properties and thickness of the periodic pattern layer and the structural layer, and the frequency range irradiated to the periodic pattern layer.

The evaluation step determines whether to make modifications by comparing the radio wave absorption performance of the modeled periodic pattern layer with the required absorption performance.

As a result of the analysis step, absorption performance results according to frequency are derived. The evaluation stage evaluates the absorption performance analysis results for the radio wave absorber that combines the modeled periodic pattern layer and the structural layer. Evaluation results may vary depending on the evaluation method. The evaluation method can be flexibly set by the user, such as whether absorption performance is maximized at a single frequency, or whether all preset absorption performances are satisfied in a specific frequency range. Evaluation results are accumulated and stored, sorted in order of excellence, and a revision stage is performed for excellent designs. The design technique proposed in this specification is based on the Genetic Algorithm.

The modification step changes the modeled pattern and re-performs the modeling step. Examples of modification methods include crossover operations and mutation operations, and detailed modification steps will be described later. Repeat the modification steps to create a model that satisfies the required radio wave absorption performance.

The correction method is performed independently for each variable classification. Variables can be divided into structural variables and pattern design variables. Structural variables are physical quantities with scalar values, and include period, sheet resistance, and thickness of each structural layer. Pattern design variables are variables for forming a pattern and are defined according to the number of dividing surfaces and the number and thickness of materials in the pattern-occupied portion. Structural variables and pattern design variables are implemented independently in the modification method, and are independently reflected in the modeling after implementation.

Figure 3 is a design block diagram. Referring to Figure 3, modeling is performed through a design program such as MATLAB. The target radio wave absorption performance or the problem to be solved is defined, and the variables are organized. After initializing the previously entered variable values, modeling proceeds through variable selection.

The formed model is input into an analysis program such as CST studio and analysis is performed. The result of the analysis is input into the design program, and evaluation is carried out within the design program. The result of the evaluation determines whether the termination criteria are met. If the termination criteria are met, the modeling work is terminated and the modeling is saved. At this time, not only modeling but also variable values and analysis values are stored together. Saved modeling data is used when creating other models.

If the modeling termination criteria are not met, modeling is performed by reselecting variable values. At this time, the variable value can be reselected through methods such as crossover and mutation. A detailed explanation of crossover and mutation methods will be provided later.

Figure 4 is an example diagram of the pixelization step. Referring to FIG. 4, the structural layer 1 and the periodic pattern layer 100 are modeled through a design program. The periodic pattern layer 100 is formed of one unit cell, and the unit cell consists of a plurality of divided surfaces. The design program is modeled by selecting variables for 1/8 of the variable area (A) formed based on the center of the periodic pattern layer 100 among the plurality of division surfaces. At this time, if each row or each column is formed with an odd number, it is modeled including a center split surface.

The design program proceeds with modeling by developing a 1/8 model with variable values injected so that it is symmetrical in the top, bottom, left, right, and diagonal directions. The performance of the developed model is analyzed through an analysis program, and modeling is re-run according to the derived results.

Figure 5 is an example diagram of the variable setting step. Referring to Figure 5, the radio wave absorption performance of the radio wave absorber is determined according to integrated variables including structural variables and pattern design variables. Structural variables are variables such as the thickness, length, and number of layers of the structural layer (1), and pattern design variables are variables for the pattern formed on the upper surface of the structural layer (1).

The pattern design variable enters the variable value for the variable area that is 1/8 of the radio wave absorber. For example, a pixelated slice sets a range of maximum and minimum values for each column. It is modeled by combining the empty part 110 and the occupied part 120 to satisfy the set variable range.

Figure 6 is an example diagram of setting whether or not a vertex is in contact. Figure 6(a) is an example diagram in which vertex contact between occupied parts is allowed. Referring to FIG. 6(a), the periodic pattern layer 100 is patterned according to set variables. At this time, the pattern formed on the periodic pattern layer 100 may have blank portions 110 formed on the top, bottom, left, and right sides, and may include diagonally adjacent portions (B) between occupied portions 120 .

During actual manufacturing, diagonally adjacent occupied portions 120 are manufactured so that their vertices touch or separate. If the vertices are manufactured to be in contact, they are manufactured to invade the occupied portion 120, and if the vertices are manufactured to be spaced apart, the applied amount is small. In this way, when the occupied portions 120 are adjacent only in the diagonal direction, differences in the vertex portion result in differences in radio wave absorption performance from the model for which modeling and analysis have been performed. To solve this, vertex contact can be limited as shown in Figure 6(b).

FIG. 6(b) is an example in which vertex contact between occupied portions 120 is limited. Referring to FIG. 6(b), the periodic pattern layer 100 is patterned according to set variables. At this time, the periodic pattern layer 100 limits vertex contact between the occupied portions 120. Occupied portions 120 adjacent to each other are arranged to contact each other in the up and down and left and right directions. This has the advantage of allowing the actually produced pattern to correspond to the modeled pattern.

Figure 7 is an example diagram with multi-facet resistance. Referring to FIG. 7, the periodic pattern layer 100 is divided into N x N dividing planes. This is an example diagram of one row of the divided periodic pattern layers 100. One row is formed by a plurality of split surfaces, and each split surface has different sheet resistance depending on set variables. Each division surface is designated as a blank portion 110 or an occupied portion 120 depending on the set variable.

At this time, the occupied portion 120 has one or more resistances depending on the thickness or material to which the material is applied. The resistance value can be adjusted depending on the thickness applied to the divided surface. For example, it is divided into a blank part 110 and an occupied part 120 depending on whether it is applied, and divided into a first pixel 121, a second pixel 122, and a third pixel 123 according to the applied thickness. do. The thicker the applied thickness of the split surface, the lower the sheet resistance. This is supported through Figure 12. Through this, it is possible to form a pattern of a radio wave absorber with the required radio wave absorption performance.

In the present invention, if the radio wave absorption performance of the radio wave absorber modeled through a design program and analyzed through an analysis program does not satisfy the required radio wave absorption performance, it is re-implemented through redesign. Several methods are used to adjust variables during redesign. Examples of redesign include crossover and mutation operations.

Figure 8 is an example diagram of a crossover operation. Figure 8(a) is the state before the crossover operation, and Figure 8(b) is the state after the crossover operation. A random dividing point is selected among the plurality of dividing surfaces forming a row. Rows are divided based on the split point, and are combined with split planes from other rows.

Let me explain in detail with an example. The division point is selected based on the second division plane from the left. One row is formed by combining the left dividing surfaces of the first row divided based on the dividing point and the right dividing surfaces of the second row divided based on the dividing point.

Figure 9 is an example diagram of a mutation operation. Figure 9(a) is an example of a reversal operation that changes the resistance of one or more split surfaces. Referring to FIG. 9(a), one of the plurality of split surfaces forming the periodic pattern layer is shifted. When each division surface is designated as a blank part or an occupied part 120, the dividing surface that is transformed is a transition from the empty part 110 to the occupied part 120 or a transition from the occupied part 120 to the empty part 110. do.

Figure 9(b) is an example of a switching operation for switching a plurality of division surfaces. Referring to FIG. 9(b), the resistance of two of the plurality of split surfaces forming the periodic pattern layer 100 is changed. For example, when the first split surface, which is the empty part 110, and the second split surface, which is the occupied part 120, are selected, the first split surface is converted to the occupied part 120 and the second split surface is blank. It is designed to be converted to unit 110.

As shown above, in the modification stage, the model that does not satisfy the radio wave absorption performance is redesigned by changing the pattern through crossover operation and mutation calculation. Design a model that satisfies radio wave absorption performance through continuous modification steps.

If a model with the required radio wave absorption performance is designed, an actual product is manufactured and evaluated for comparison. Figures 10 and 11 are examples for implementation, and other methods may be applied to implement. The present invention has the feature of implementing different sheet resistances on split surfaces formed on the same two-dimensional plane.

Figure 10 is an example of manufacturing using lamination technology. Referring to FIG. 10, a periodic pattern layer is formed on the upper surface of the structural layer 1 using the stacking device 200. Specifically, it is a technology that precisely coats carbon on the surface of a substrate using a laser. The amount of carbon can be controlled by the power of the laser.

Different sheet resistances are implemented depending on the amount of carbon laminated on the split surface, that is, the thickness of the carbon. For example, if a split surface is designed to have a relatively low sheet resistance, the designed sheet resistance value can be satisfied by implementing a thick carbon thickness. In this way, a radio wave absorber with multi-surface resistance can be implemented by controlling the thickness of the carbon layer.

Figure 11 is an example of manufacturing using deposition technology. It uses metal coating technology and has the feature of being able to adjust the size of sheet resistance depending on the deposition time. Referring to FIG. 11, the printed pattern portion 2 is placed on the upper surface of the structural layer 1 to mask each area requiring required sheet resistance. Afterwards, deposition is performed in a masked state. The printed pattern portion 2 is removed to form a periodic pattern layer 100 on the upper surface of the structural layer 1.

As the metal coating deposition time increases on a divided surface, the coating thickness becomes thicker, and a divided surface with low sheet resistance can be realized. Sheet resistance according to deposition time will be explained in detail through the graph in FIG. 12.

Figure 12 is a resistance graph according to deposition time. Referring to FIG. 12, an increase in deposition time means an increase in the thickness of the deposited pattern. Accordingly, as the deposition time increases, a lower sheet resistance value can be obtained. For example, when nickel (Ni) is deposited for about 5.5 seconds, a split surface with a sheet resistance value of about 50Ω/square can be created. Additionally, when deposition is performed for about 7.5 seconds, a split surface with a sheet resistance value of about 40Ω/square can be created.

At this time, the thickness can be deposited to hundreds of nm. Depending on the deposition equipment and conditions, the sheet resistance of each metal deposit may vary. Referring to Table 1 below, the sheet resistance measurement results for each metal material when deposition was performed for the same time are as follows. If the deposition time is adjusted, sheet resistance can be obtained within a certain range based on the values below.

Metal Al ITO Ti W Ni Sheet Resistance (Ω/□) 0.297 64.4 567.2 59.1 49.4

As explained above, a radio wave absorber with multi-surface resistance can be formed by varying the deposition time on each divided surface through masking.

In addition, the present invention can control the sheet resistance value of the divided surface depending on the material applied or deposited, and through this, a radio wave absorber with multi-planar resistance can be implemented. For example, a radio wave absorber is formed using at least one of materials such as carbon ink, copper, silver, gold, and graphene. When a single material is used, sheet resistance can be adjusted by controlling the thickness applied to each divided surface.

Additionally, when multiple materials are used, sheet resistance can be adjusted by varying not only the thickness but also the material applied to each divided surface. For example, at 0℃, the electrical resistivity of silver (Ag) is 15.87 nΩ*m, and that of gold (Au) is 22.14 nΩ*m. Since the electrical resistance and sheet resistance of each material are different, it is possible to implement a designed radio wave absorber.

The present invention is not limited to the above-described embodiments, and the scope of application is diverse. Of course, various modifications and implementations are possible without departing from the gist of the present invention as claimed in the claims.

1: first layer
2: Printing pattern section
100: periodic pattern layer
110: blank part
120: occupied area
121: 1st pixel 122: 2nd pixel
123: 3rd pixel
200: Lamination device

Claims (11)

It includes a periodic pattern layer composed of a combination of one or more empty portions having a void on the upper surface of the structural layer and one or more occupied portions coated with a conductive material,
The occupied portion has different sheet resistance depending on the thickness to which the electromagnetic material is applied,
A radio wave absorber, characterized in that each of the occupied parts is independently designed with a thickness of electromagnetic material applied thereto to satisfy the required radio wave absorption performance.
It includes a periodic pattern layer composed of a combination of one or more empty portions having a void on the upper surface of the structural layer and one or more occupied portions coated with a conductive material,
The occupied portion has different sheet resistance depending on the material to which the electromagnetic material is applied,
Each of the occupied portions is a radio wave absorber, characterized in that the material on which the electromagnetic material is independently applied is designed to satisfy the required radio wave absorption performance.
According to claim 1 or 2,
The periodic pattern layer is a radio wave absorber, characterized in that it is symmetrical in the up and down, left and right, and diagonal directions with respect to the center.
According to claim 1 or 2,
The radio wave absorber is a radio wave absorber whose radio wave absorption performance is determined by an integrated variable including a structural variable including any one of the thickness, length, and number of layers of the structural layer and a pattern design variable of the periodic pattern layer. .
According to claim 1 or 2,
The periodic pattern layer is a radio wave absorber, characterized in that when blank portions are disposed on the top, bottom, left, and right sides of the occupied portion, blank portions are disposed in a diagonal direction.
A pixelization step in which a processing unit divides a unit cell into N x N so that a plurality of division surfaces are formed in the unit cell;
A variable setting step of setting the range of sheet resistance for each row or column of the divided unit cells,
A modeling step of generating a model by assigning sheet resistance to each of the divided surfaces,
An analysis step in which a computing device electromagnetically analyzes the generated model,
An evaluation step to compare and evaluate the radio wave absorption performance of the analyzed model and the required radio wave absorption performance, and
A radio wave absorber design method that includes a modification step of modifying and reinterpreting the model when the required radio wave absorption performance is not met.
According to clause 6,
The variable setting step is a radio wave absorber design method characterized in that the variables are set for variable areas divided up, down, left, right, and diagonally based on the center of the unit cell.
In clause 7,
The variable setting step is a radio wave absorber design method, characterized in that setting the minimum and maximum values of the rows or columns of the variable area.
In clause 7,
The variable setting step is a method of designing a radio wave absorber, characterized in that when the rows or columns of the variable area are odd numbers, the variables are set including a center split surface.
According to clause 6,
The modeling step is a radio wave absorber design method, wherein the thickness or material of the applied conductive material is different depending on the sheet resistance given to the divided surface.
According to clause 6,
In the modeling step, a pattern consisting of occupied parts and empty parts is formed according to sheet resistance, and when the empty parts are disposed on the top, bottom, left, and right sides of the occupied part, the empty parts are set to be arranged in a diagonal direction. A radio wave absorber design method.

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