KR101698110B1 - Electromagnetic Absorber attached to object - Google Patents

Abstract

An electromagnetic absorber attached to an object according to the present invention includes: a dielectric to which an electromagnetic wave is inputted and which is attached to the object with a surface which is inclined in a longitudinal direction; and a plurality of metal elements which are arranged on the upper side of the dielectric in transverse and longitudinal directions. The size of the plurality of metal elements increases in the longitudinal direction in which the electromagnetic wave is inputted later, based on a specific column. The present invention can provide the electromagnetic absorber with optimum efficiency in an environment limited in the aspects of structural integrity, weight and costs.

Description

Electromagnetic absorbers attached to an object [

The present invention relates to a radio wave absorber to be attached to an object. More particularly, it relates to a radio wave absorber for reduction of RCS (Radar Cross Section) of an object or a structure.

In order to absorb / block unnecessary electromagnetic waves incident from the outside, electromagnetic wave absorbers having different performances composed of various materials have been developed and actively applied to various fields. However, these radio wave absorbers are susceptible to increase in thickness and weight in order to attain the lowered mechanical property of the material due to the addition of a specific material and the required radio wave absorption performance in order to achieve the radio wave absorption performance. Due to the above reasons, the radio wave absorbers are also applied to some areas of the object in which the vertical reflection area is assured in consideration of the RCS effect and cost of the structure. For example, air vehicles tend to be lightweight due to their own weight directly linked to performance. Therefore, researches are mainly being applied to the leading edge region where the vertical reflection region is largely present in the frontal incident electromagnetic wave in the air vehicle.

However, since the characteristics of the material between the applied portion and the non-applied portion are different, the electromagnetic scattering occurring at the boundary is caused by the RCS (Radar Cross Section). That is, the performance of the electromagnetic wave absorber designed due to the boundary effect can not be properly expressed.

Accordingly, an object of the present invention is to provide a radio wave absorber having an optimum efficiency in a limited environment in structural soundness, weight, and cost.

It is another object of the present invention to provide a radio wave absorber capable of realizing a low-pitched sound performance.

According to an aspect of the present invention, there is provided an electromagnetic wave absorber attached to an object, the electromagnetic wave absorber comprising: a dielectric to which an electromagnetic wave is incident and attached to an object having a surface inclined in the longitudinal direction; And a plurality of metal elements arranged on the upper surface of the dielectric in a lateral direction and a longitudinal direction, wherein the plurality of metal elements are arranged in the longitudinal direction in which the electromagnetic wave is incident on a specific column It is possible to provide an electromagnetic wave absorber having an optimum efficiency in a limited environment due to structural integrity, weight and cost.

According to an embodiment, when the electromagnetic wave is indexed to the first column from the first incident row, the specific column is indexed to the kth column, and the column in which the electromagnetic wave is finally incident is indexed to the Nth column, The first metal elements arranged in the (k-1) th column from the first column have the same size (w), and the second metal elements arranged in the kth column to the Nth column are monotonically increased in the column direction .

According to an embodiment of the present invention, the plurality of metal elements are arranged at a constant arrangement interval D in the transverse and longitudinal directions, and the second metal elements are spaced apart from each other as their size increases monotonically in the column direction, And to reduce scattering at a boundary due to incidence of the electromagnetic wave by making electromagnetic characteristics similar to the conductor surface of the object.

According to an embodiment, the plurality of metal elements may be arranged such that the third metal elements arranged in the m-th column to the N-th column having an index larger than the k-th column are formed of one metal element in the row direction, .

According to one embodiment, the dielectric is configured to increase in thickness in the longitudinal direction in which the electromagnetic wave is incident later, wherein an upper surface of the dielectric on which the plurality of metal elements are disposed has a slope that is less than a slope of the object have.

According to one embodiment, the dielectric is made of glass-fiber-reinforced plastic (GFRP), a metal layer is formed on the lower surface of the dielectric, the plurality of metal elements are printed on a polyimide film, Holes are formed in the non-patterned areas where the metal elements are not printed, and the first and second dielectric materials disposed on the upper and lower layers of the polyimide film are connected to each other through a resin impregnated through the holes The mechanical strength can be increased.

According to one embodiment, the first dielectric is implemented on an upper layer of the polyimide film by an outer mold line (OML) surface technique, and the metal layer implemented on the lower surface of the second dielectric is a carbon-fiber-reinforced plastic (CFRP) Lt; / RTI >

According to one embodiment, the dielectric corresponds to a wing leading edge structure, and further includes a metal bolt for fastening an existing structure corresponding to the wing leading edge structure and the internal structure. At this time, the metal bolt is disposed inside one element of the plurality of metal elements, and the screw head thickness of the metal bolt is equal to the metal thickness of the one element.

According to one embodiment, the metal bolt may be configured so that a plurality of metal bolts are arranged in a single device in the form of a band in which metal elements are arranged in a row direction in succession.

The radio wave absorber adhering to the object according to the present invention can be provided in a region where electromagnetic waves are incident rather than the entire area of the object to provide a radio wave absorber having optimum efficiency in a limited environment in terms of structural integrity, There are advantages.

On the other hand, the stealth weapon system is basically made to have a relatively sharp shape through the shape design. Therefore, the present invention is advantageous in that the electromagnetic characteristics at the boundary can be implemented similar to the electromagnetic characteristics of the object, thereby reducing the scattering effect in different media and realizing the low-pitched performance.

Fig. 1 shows a diagram in which a radio wave absorber is attached to an object according to the present invention.
2 shows a side view and a front view of a single element of a periodic lattice pattern type radio wave absorber according to the present invention.
Fig. 3 is a graph comparing electromagnetic wave characteristics in an object to which a periodic lattice pattern absorber and a gradient pattern absorber are attached, in the context of the present invention.
FIG. 4 illustrates a fastening structure between an object and an internal structure according to an embodiment of the present invention.
Fig. 5 shows the structure of a stacked type radio wave absorber applicable to an actual structure (object) according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It will be possible. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

The suffix "module "," block ", and "part" for components used in the following description are given or mixed in consideration of ease of specification only and do not have their own distinct meanings or roles .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, a radio wave absorber (Electromagnetic (EM) abosorber) attached to an object according to the present invention will be described.

Fig. 1 shows a diagram in which a radio wave absorber is attached to an object according to the present invention. 2 shows a side view and a front view of a single element of a periodic lattice pattern type radio wave absorber according to the present invention.

1 and 2, the radio wave absorber 1000 includes a dielectric 100, a plurality of metal elements 200 including a single element 200 ', and a metal layer 300 .

The dielectric 100 is attached to an object to which an electromagnetic wave is incident and which has a vertically inclined surface. In addition, the dielectric material 100 may be formed of glass fabric reinforced plastic (GFRP) corresponding to a low dielectric loss material used as a space, and the electromagnetic characteristics of the GFRP should be considered. On the other hand, GFRP can also play a structural role of external load support by being combined with composites or through internal mechanisms and fastening structures, in which case mechanical characteristics can be taken into consideration.

The single element 200 'is disposed on the top surface of the dielectric and is a metal pattern of size w in the longitudinal direction. Meanwhile, the single element 200 'may have a rectangular shape as well as an arbitrary lattice structure. For example, the single element 200 'may have various shapes such as circular, hexagonal, and octagonal.

The plurality of metal elements 200 are arranged on the upper surface of the dielectric body 100 in the horizontal and vertical directions. Meanwhile, the plurality of metal elements 200 may be arranged at a predetermined arrangement interval D in the horizontal and vertical directions. However, the present invention is not limited thereto, and they may be arranged at different arrangement intervals or may be offset by a predetermined position in the horizontal and vertical directions.

Referring to FIG. 1, the plurality of metal elements 200 is characterized in that the size increases in the longitudinal direction in which the electromagnetic waves are incident on a specific column. Here, it is assumed that the electromagnetic wave is indexed from the first incident row to the first column, the specific column is indexed to the kth column, and the last row of the electromagnetic wave is indexed to the Nth column. That is, the first metal elements arranged in the (k-1) th column from the first column among the plurality of metal elements may be configured to have the same size (w). In addition, the second metal elements disposed in the k-th column to the N-th column may be monototically increased in size in the column direction. At this time, the size of the second metal elements may increase linearly in size in the column direction or may increase in an arbitrary curve shape. On the other hand, the arrangement of the second metal elements arranged such that the size increases monotonically in the column direction can be referred to as a grained pattern shape.

Meanwhile, as shown in FIG. 1, the plurality of metal elements 200 may be arranged in the form of one metal strip on the surface of the object, on which the electromagnetic wave is finally incident, corresponding to the boundary of the object. That is, the second metal elements 200 are configured such that the spacing distance between the second metal elements 200 decreases as the size increases monotonically in the column direction. Thus, the electromagnetic characteristics of the second metallic elements 200 may be configured to resemble electromagnetic characteristics with the conductor surface of the object to reduce scattering at boundaries as a result of the incident electromagnetic waves have. Therefore, in the plurality of metal elements 200, the third metal elements arranged in the m-th column to the N-th column having an index larger than the k-th column are arranged with one metal element in the row direction, .

In addition, the metal layer 300 is disposed on the lower surface of the dielectric, and the PEC (perfect electric conductor) surface is formed of a metal layer or carbon fiber reinforced plastic (CFRP) to form an electromagnetic wave reflecting surface .

As described above, the electromagnetic wave absorber is applied only to the front region in order to absorb the electromagnetic wave that is incident on the object in front. The remaining area depends on the object, but generally CFRP is used for metal structures or composites for rigidity of the structure. Metal and CFRP play a role as reflecting surface (PEC) which reflects all incident waves when viewed from the electromagnetic point of view. When electromagnetic waves reach the object, various scattering phenomena occur. Among them, in the present invention, the scattering phenomenon between objects having different characteristics is reduced, so that the electromagnetic wave flows better along the surface (body) of the object . In this case, the electromagnetic waves arriving at the object are emitted to the rear, which is a relatively non-hazardous area, and an effect of decreasing forward RCS is realized.

As a method for implementing the above-described technique, a radio wave absorber having a superior performance at a target frequency is applied at the forefront, and the radio wave absorption performance is intentionally gradually relaxed by a certain interval gradually toward the boundary portion, So that a smooth transition can be achieved.

In this connection, Fig. 3 is a graph comparing electromagnetic wave characteristics in an object to which a periodic lattice pattern absorber and a gradient pattern absorber are attached, in the context of the present invention.

As shown in FIG. 3, some of the electromagnetic waves incident on the object proceed along the surface. On the other hand, as shown in FIG. 3A, the electromagnetic wave scattering effect at the boundary is large because the electromagnetic wave absorber between the microwave absorber and the conductor surface of the existing object is different from the electromagnetic wave absorber of the periodic lattice pattern. On the other hand, if the absorbing performance of the absorber is intentionally lowered toward the conductor surface as shown in FIG. 3 (b), the effect of reducing the scattering effect and reducing the amount of electromagnetic waves that return to the front, .

That is, in the periodic lattice pattern absorber shown in FIG. 3A, the periodic lattice pattern layer using the conductive paste exists at the outermost periphery, the dielectric material is located on the back surface of the pattern layer, and the reflective surface . The periodic lattice pattern absorber can be manufactured relatively thin and light, has an advantage that it can easily print a pattern, and various absorption performance can be easily realized according to the material and shape of the pattern. The proposed object is basically composed of PEC and the periodic lattice pattern absorber is applied to the front part. However, there is a disadvantage that the scattering of the electromagnetic wave is large in the region where the electromagnetic wave is incident later.

Fig. 3 (a) is an absorber printed in a predetermined pattern, and Fig. 3 (b) is applied so that the pattern gradually increases in size toward the boundary. As shown in FIG. 3 (b), in the periodic lattice pattern absorber applied in the present invention, when the thickness of the dielectric material is constant and the size of the metal pattern is designed to be gradually increased from the optimum value, the radio wave absorbing performance gradually decreases. In other words, it is configured to show characteristics similar to the PEC constituting the object from the electromagnetic point of view to the boundary. As described above, the radio wave absorber thus configured can mitigate the scattering phenomenon of electromagnetic waves due to the characteristics of different media at the boundary portion, thereby contributing to the reduction of forward RCS. Further, even if the size of the object becomes large and complicated, it can be applied to obtain an optimum effect in a required area.

FIG. 3 (b) is a simplified embodiment only for facilitating understanding of the present invention, and the present invention can also be implemented by other factors that change the wave absorption performance, such as the thickness adjustment of the pattern layer, have. Also, the application of the periodic lattice pattern absorber as well as other electromagnetic wave absorbers can be implemented in a similar manner.

In this regard, the dielectric 100 may be configured to increase in thickness in the longitudinal direction in which the electromagnetic wave is incident later. Therefore, the upper surface of the dielectric 300, on which the plurality of metal elements 200 are disposed, has an inclination that is smaller than the inclination of the object.

On the other hand, as shown in FIG. 3, the dielectric material 300 corresponding to the object may be a flat surface or may be a conformal shape having an arbitrary curved surface.

Meanwhile, FIG. 4 illustrates a fastening structure between an object and an internal structure according to an embodiment of the present invention. Referring to FIG. 4, the dielectric 300 corresponding to an object and the object internal structure may be fastened by an arbitrary fastening means. At this time, the optional fastening means may be a bolt and a nut formed in the object internal structure. Meanwhile, when the object corresponds to the wing leading edge structure, the existing structure corresponding to the wing leading edge structure and the internal structure is fastened as the metal bolt 210. At this time, radio waves are scattered due to different media between the metal bolts 210 and the radio wave absorber. At this time, referring to FIG. 2, the metal bolt is disposed in the single element 200 '. That is, since the metal bolt is a part of the single element 200 ', even when a radio wave is incident on the metal bolt, the metal bolt 210 operates as a radio wave absorber. In this connection, the thickness of the screw head of the metal bolt may be smaller than the thickness of the metal of the single element 200 '. For example, when the thickness of the screw head of the metal bolt 210 is set to be equal to the thickness of the metal of the single element 200 ', the discontinuity between the media is minimized in the incident electromagnetic wave.

Meanwhile, as shown in FIGS. 1 and 4 (b), the metal bolts 210 may be disposed in the single element 200 'arranged in the band shape. That is, the metal bolt 210 may be configured to be disposed in a plurality of band-shaped single elements in which metal elements are continuously arranged in the row direction.

In this regard, the metal bolt 210 is fastened to the upper or lower end of the object, which can increase the fastening strength structurally. Also, since the scattering of electromagnetic waves at the end of the object is large, it is effective to reduce scattering waves by being disposed in the single element 200 'arranged in the band shape. In addition, the area of the metal bolt 210 in the single element 200 'arranged in the band shape is minimized by the area occupied by the metal bolt 210 with respect to the area of the single element 200' Is effective.

Next, Fig. 5 shows the structure of a stacked type radio wave absorber applicable to an actual structure (object) according to the present invention. 4, the wave absorber 1000 'includes a first dielectric 50, a polyimide film 200a, a plurality of metal elements 200, a second dielectric 200, a metal layer 300, And a third dielectric (400).

The metal layer 300 may be formed on a lower surface of the second dielectric 200 and a hole may be formed in a non-patterned region where the metal elements 200 are not printed. Accordingly, the first and second dielectrics 50 and 200 disposed on the upper and lower layers of the polyimide film 200a are connected to each other through a resin impregnated through the holes to increase mechanical strength .

Meanwhile, the first dielectric layer 50 may be formed on the upper layer of the polyimide film by an OML (outer mold line) surface method. In addition, the metal layer formed on the lower surface of the second dielectric 200 may be formed of carbon fiber-reinforced plastic (CFRP).

The electromagnetic wave absorber according to at least one embodiment of the present invention can be provided in a region where electromagnetic waves are incident rather than the entire area of the object to provide an electromagnetic wave absorber having optimum efficiency in a limited environment in terms of structural integrity, .

Further, the radio wave absorber according to at least one embodiment of the present invention can realize the electromagnetic characteristics at the boundary similarly to the electromagnetic characteristics of the object, thereby reducing the scattering effect in different media, and realizing the low-pitched performance There are advantages.

According to a software implementation, not only the procedures and functions described herein, but also each component may be implemented as a separate software module. Each of the software modules may perform one or more of the functions and operations described herein. Software code can be implemented in a software application written in a suitable programming language. The software code is stored in a memory and can be executed by a controller or a processor.

1000, 1000 ': radio wave absorber 100: dielectric
200 ': single element 200: a plurality of metal elements
300: metal layer

Claims (8)

An electromagnetic wave absorber attached to an object,
A dielectric to which an electromagnetic wave is incident and which is attached to an object having a longitudinally inclined surface; And
And a plurality of metal elements disposed on the upper surface of the dielectric in the lateral and longitudinal directions,
Wherein the plurality of metal elements increase in size in the longitudinal direction in which the electromagnetic waves are incident on a specific column. The method according to claim 1,
When the electromagnetic wave is indexed in the first column from the first incident row, the specific column is indexed in the kth column, and the column in which the electromagnetic wave is finally incident is indexed to the Nth column,
Wherein the first metal elements disposed in the (k-1) th column from the first column among the plurality of metal elements have the same size (w)
And the second metal elements disposed in the kth column to the Nth column are monotonously increased in size in the column direction. 3. The method of claim 2,
Wherein the plurality of metal elements are arranged at a constant arrangement distance D in the transverse and longitudinal directions,
As the size of the second metal elements monotonously increases in the column direction, a distance between the first metal elements decreases, and the electromagnetic characteristics of the second metal elements become similar to the surface of the conductor of the object, thereby causing scattering at a boundary due to incidence of the electromagnetic waves Wherein the electromagnetic wave absorber is configured to reduce the electromagnetic wave. The method of claim 3,
Wherein the plurality of metal elements are composed of one metal element in the row direction, and the third metal elements arranged in the mth column to the Nth column having an index larger than the kth column are 0 apart from each other. The method according to claim 1,
Wherein the dielectric is configured to increase the thickness in the longitudinal direction in which the electromagnetic wave is incident later, wherein an upper surface of the dielectric on which the plurality of metal elements are disposed has a slope that is reduced from a slope of the object. The method according to claim 1,
The dielectric is made of GFRP (glass-fiber-reinforced plastic)
A metal layer is formed on the lower surface of the dielectric,
Wherein the plurality of metal elements are printed and implemented on a polyimide film,
Wherein the polyimide film has a first dielectric and a second dielectric disposed on an upper layer and a lower layer of the polyimide film and a resin impregnated through the hole, To increase the mechanical strength of the radio wave absorber. The method according to claim 6,
The first dielectric is implemented on an upper layer of the polyimide film by an outer mold line (OML)
And the metal layer implemented on the lower surface of the second dielectric is implemented as carbon fiber-reinforced plastic (CFRP). The method of claim 3,
The dielectric corresponds to a wing leading edge structure,
Further comprising a metal bolt for fastening an existing structure corresponding to the wing leading edge structure and the internal structure,
Wherein the metal bolt is disposed inside one element of the plurality of metal elements, the screw head thickness of the metal bolt being equal to the metal thickness of the one element,
Wherein the metal bolt is configured such that a plurality of metal bolts are arranged in a single band-shaped element in which metal elements are arranged continuously in the row direction.

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