Transparent electromagnetic wave absorber

Abstract

The present invention relates to a transparent electromagnetic wave absorber and includes a reflective layer, a first dielectric layer, a first resonance layer, a second dielectric layer, and a second resonance layer. The first dielectric layer is laminated on the reflective layer. The first resonance layer is laminated on the first dielectric layer to resonate electromagnetic waves to cause loss of the electromagnetic waves. The second dielectric layer is laminated on the first resonance layer. The second resonance layer is laminated on the second dielectric layer to resonate electromagnetic waves to cause loss of the electromagnetic waves. The second resonance layer includes a pattern region formed of a conductive material and a blank region not formed of a conductive material, and the entire surface of the first resonance layer is formed of a conductive material.

Description

transparent electromagnetic wave absorber

[0001] The present invention relates to a transparent electromagnetic wave absorber, and more particularly, to a transparent electromagnetic wave absorber that can be implemented with a thin thickness and is transparent while being capable of absorbing electromagnetic waves over a wide band.

[0002] The frequency bands of various electrical and electronic devices and components used in the telecommunications industry are expanding both to broader bandwidths and across diverse frequency ranges. Furthermore, many components are being densely packed into confined spaces. This is leading to electromagnetic interference between devices, resulting in malfunctions and other functional issues.

[0003] Especially in the field of mobile communications, related devices are becoming lighter, thinner, smaller, less power-hungry, and more digitalized for portability and long-term use, making them highly vulnerable to electromagnetic interference from outside.

[0004] Existing electromagnetic wave absorbers can be categorized by their absorption mechanism. Among these, the most common method used to date in the design of resonant electromagnetic wave absorbers is the Salisbury screen with a thickness of 1 / 4 wavelength (λ / 4). However, this technology has limitations in reducing thickness because the dielectric thickness must satisfy λ / 4, and the problem is that absorption performance is not very high at frequencies other than λ / 4.

[0005] Accordingly, the problem to be solved by the present invention is to solve the above-mentioned conventional problem, and to provide a transparent electromagnetic wave absorber capable of improving the absorption performance of electromagnetic waves in a desired frequency band by configuring the transparent electromagnetic wave absorber to include both a resonant layer on which a pattern is formed and a resonant layer on which a pattern is not formed.

[0006] In order to achieve the above object, the transparent electromagnetic wave absorber of the present invention comprises: a reflective layer; a first dielectric layer laminated on the reflective layer; a first resonant layer laminated on the first dielectric layer and causing electromagnetic waves to resonate and cause loss; a second dielectric layer laminated on the first resonant layer; and a second resonant layer laminated on the second dielectric layer and causing electromagnetic waves to resonate and cause loss; wherein the second resonant layer has a pattern region formed of a conductive material and a blank region not formed of a conductive material, and the first resonant layer is characterized in that the entire surface is formed of a conductive material.

[0007] In the transparent electromagnetic wave absorber according to the present invention, the first resonant layer can be formed of graphene or ITO (Indium Tin Oxide) material.

[0008] In the transparent electromagnetic wave absorber according to the present invention, a third dielectric layer laminated on the second resonant layer may be further included.

[0009] In the transparent electromagnetic wave absorber according to the present invention, the higher the surface resistance of the second resonant layer, the lower the center frequency of the frequency band absorbed by the transparent electromagnetic wave absorber.

[0010] In the transparent electromagnetic wave absorber according to the present invention, the higher the surface resistance of the first resonant layer, the higher the absorption performance of the transparent electromagnetic wave absorber.

[0011] According to the transparent electromagnetic wave absorber of the present invention, the absorption performance of electromagnetic waves in a desired frequency band can be improved.

[0012] According to the transparent electromagnetic wave absorber of the present invention, the compatibility of the transparent electromagnetic wave absorber can be improved by adjusting the surface resistance of the first resonant layer or the second resonant layer.

[0013] FIG. 1 is a schematic drawing of a transparent electromagnetic wave absorber according to one embodiment of the present invention.

[0014] FIG. 2 is a drawing showing the first resonant layer and the second resonant layer of the transparent electromagnetic wave absorber of FIG. 2,

[0015] Figure 3 is a graph comparing the reflection performance of a transparent electromagnetic wave absorber without a first resonance layer, a transparent electromagnetic wave absorber without a second resonance layer, and the transparent electromagnetic wave absorber of Figure 2.

[0016] Figure 4 is a graph comparing the reflection performance according to the surface resistance of the second resonant layer.

[0017] Figure 5 is a graph comparing reflection performance according to surface resistance of the first resonant layer.

[0018] Hereinafter, embodiments of a transparent electromagnetic wave absorber according to the present invention will be described in detail with reference to the attached drawings.

[0019] FIG. 1 is a schematic diagram illustrating a transparent electromagnetic wave absorber according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a first resonant layer and a second resonant layer of the transparent electromagnetic wave absorber of FIG. 2, FIG. 3 is a graph comparing the reflection performance of a transparent electromagnetic wave absorber without a first resonant layer, a transparent electromagnetic wave absorber without a second resonant layer, and the transparent electromagnetic wave absorber of FIG. 2, FIG. 4 is a graph comparing the reflection performance according to the sheet resistance of the second resonant layer, and FIG. 5 is a graph comparing the reflection performance according to the sheet resistance of the first resonant layer.

[0020] Referring to FIGS. 1 to 5, a transparent electromagnetic wave absorber (100) according to the present embodiment can be implemented with a thin thickness and is capable of absorbing electromagnetic waves in a wide band, and includes a reflective layer (110), a first dielectric layer (120), a first resonant layer (130), a second dielectric layer (140), a second resonant layer (150), and a third dielectric layer (160).

[0021] The above reflective layer (110) reflects electromagnetic waves that pass through the first dielectric layer (120). The reflective layer (110) may be formed of a conductive material, and preferably may be formed of a metal material.

[0022] The first dielectric layer (120) is laminated on the reflective layer (110) and may be formed in a thin film form. The first dielectric layer (120) is not limited to a specific material and may be formed of a polymer material, glass material, etc., and examples of polymer materials that may be used include polyethylene terephthalate (PET), acrylic, epoxy, etc. The first dielectric layer (120) may be formed transparently, but is not necessarily limited thereto.

[0023] The first resonant layer (130) is laminated on the first dielectric layer (120) and causes electromagnetic waves to resonate and be lost. The band of electromagnetic waves absorbed by the first resonant layer (130) may be a broadband within the range of 7 to 20 GHz.

[0024] The first resonant layer (130) of the present invention may be formed entirely of a conductive material, preferably formed of a transparent or flexible material such as graphene or ITO (Indium Tin Oxide), and may be formed in a form in which multiple layers are stacked.

[0025] The first resonant layer (130) can be formed in the form of a thin film of a conductive material over the entire surface without any blank areas that are not formed of a conductive material.

[0026] The second dielectric layer (140) may be laminated on the first resonant layer (130) and formed in a film form. The second dielectric layer (140) is not limited to a specific material, and may be formed of a polymer material, glass material, etc., and examples of polymer materials that may be used include polyethylene terephthalate (PET), acrylic, epoxy, etc. The second dielectric layer (140) may be formed transparently, but is not necessarily limited thereto.

[0027] The second resonant layer (150) is laminated on the second dielectric layer (140) and causes electromagnetic waves to resonate and be lost. The band of electromagnetic waves absorbed by the second resonant layer (150) may be a wide band within the range of 7 to 20 GHz, and may be a low-frequency band different from the band of electromagnetic waves absorbed by the first resonant layer (130).

[0028] The second resonant layer (150) of the present invention may have a pattern region (151) formed of a conductive material and a blank region (152) not formed of a conductive material. The pattern region (151) may preferably be formed of a transparent or flexible conductive material such as graphene or ITO (Indium Tin Oxide), and may be formed in a form in which multiple layers are stacked.

[0029] Referring to FIG. 2, the pattern area (151) of the second resonant layer (150) is composed of a conductive material, and the conductor is formed in a pattern (size, shape, etc.) corresponding to a predetermined electromagnetic wave frequency band.

[0030] The pattern area (151) of the second resonant layer (150) illustrated in FIG. 2 only represents an example of the pattern area (151) of the second resonant layer (150), and the pattern area (151) of the second resonant layer (150) may be formed in various pattern shapes to correspond to the frequency band to be absorbed.

[0031] The third dielectric layer (160) may be laminated on the second resonant layer (150) and formed in a film form. The third dielectric layer (160) is not limited to a specific material, and may be formed of a polymer material, glass material, etc., and examples of polymer materials that may be used include polyethylene terephthalate (PET), epoxy, etc. The third dielectric layer (160) may be formed transparently, but is not necessarily limited thereto.

[0032] In this way, the present invention is characterized by a structure in which a first resonant layer (130) formed entirely of a thin film-shaped conductive material without a blank area is disposed on the lower side, and a second resonant layer (150) having a pattern area (151) formed of a conductive material and a blank area (152) not formed of a conductive material is disposed on the upper side.

[0033] Referring to FIG. 3, a graph comparing the reflection performance of a transparent electromagnetic wave absorber (single-dotted line) having only a second resonant layer (150) and no first resonant layer (130), a transparent electromagnetic wave absorber (double-dotted line) having only a first resonant layer (130) and no second resonant layer (150), and a transparent electromagnetic wave absorber of the present embodiment (solid line) is shown.

[0034] It can be confirmed that the reflection performance of the transparent electromagnetic wave absorber (100) (solid line) of the present embodiment including both the first resonant layer (130) and the second resonant layer (150) is improved compared to the reflection performance of the transparent electromagnetic wave absorber (single-dotted line) having only the second resonant layer (150) and no first resonant layer (130), and is improved compared to the reflection performance of the transparent electromagnetic wave absorber (double-dotted line) having only the first resonant layer (130) and no second resonant layer (150).

[0035] Accordingly, it can be confirmed that the absorption performance of the transparent electromagnetic wave absorber (100) including both the first resonant layer (130) and the second resonant layer (150) is relatively superior compared to the transparent electromagnetic wave absorber including only the second resonant layer (150) and not the first resonant layer (130).

[0036] Figure 4 is a drawing for explaining the change in reflection performance according to the change in surface resistance of the second resonant layer.

[0037] Referring to FIG. 4, it can be confirmed that the higher the sheet resistance of the second resonant layer (150), the more the center frequency of the frequency band reflected (i.e., absorbed) by the transparent electromagnetic wave absorber (10) moves toward a lower frequency. For example, when the sheet resistance of the second resonant layer (150) is 50 ohm / sq., the center frequency is approximately 14 GHz, when the sheet resistance of the second resonant layer (150) is 250 ohm / sq., the center frequency is approximately 11 GHz, and when the sheet resistance of the second resonant layer (150) is 1000 ohm / sq., the center frequency is approximately 10 GHz.

[0038] At this time, a method of making the thickness of the second resonant layer (150) thinner can be used as a method of increasing the surface resistance of the second resonant layer (150). For example, the surface resistance of the second resonant layer (150) can be increased by reducing the number of layers of the second resonant layer (150) laminated in multiple layers.

[0039] In this way, the frequency band absorbed by the transparent electromagnetic wave absorber (10) can be adjusted by changing the surface resistance of the second resonant layer (150). By configuring the surface resistance of the second resonant layer (150) to match the target frequency band of the product in which the transparent electromagnetic wave absorber (10) is used, the compatibility of the transparent electromagnetic wave absorber (10) can be improved.

[0040] Figure 5 is a drawing for explaining the change in reflection performance according to the change in surface resistance of the first resonant layer.

[0041] Referring to FIG. 5, it can be confirmed that the higher the sheet resistance of the first resonant layer (130), the better the reflection performance (i.e., the higher the absorption performance) of the transparent electromagnetic wave absorber (100). For example, when the sheet resistance of the first resonant layer (130) is 50 ohm / sq., the maximum reflection performance is approximately -21 dB, when the sheet resistance of the second resonant layer (150) is 250 ohm / sq., the maximum reflection performance is approximately -35 dB, and when the sheet resistance of the second resonant layer (150) is 500 ohm / sq., the maximum reflection performance is approximately -45 dB.

[0042] At this time, a method of making the thickness of the first resonant layer (130) thinner can be used as a method of increasing the surface resistance of the first resonant layer (130). For example, the surface resistance of the first resonant layer (130) can be increased by reducing the number of layers of the first resonant layer (130) laminated in multiple layers.

[0043] In this way, the absorption performance of the transparent electromagnetic wave absorber (10) can be adjusted by changing the surface resistance of the first resonant layer (130). By configuring the surface resistance of the first resonant layer (130) to match the target absorption performance of the product in which the transparent electromagnetic wave absorber (10) is used, the compatibility of the transparent electromagnetic wave absorber (10) can be improved.

[0044] The transparent electromagnetic wave absorber of the present invention, configured as described above, can obtain the effect of improving the absorption performance of electromagnetic waves in a desired frequency band by configuring the transparent electromagnetic wave absorber to include both a resonant layer on which a pattern is formed and a resonant layer on which a pattern is not formed.

[0045] The scope of the present invention is not limited to the embodiments and modifications described above, but can be implemented in various forms within the scope of the appended claims. Any person skilled in the art, without departing from the spirit of the invention as claimed in the claims, may make various modifications to the invention, which are deemed to fall within the scope of the claims.

[0046] The present invention can be implemented with a thin thickness, is transparent, and is capable of absorbing electromagnetic waves in a wide band, and can be used in the fields of electronics and mobile communication technology.

Claims

1. Reflective layer; A first dielectric layer laminated on the above reflective layer; A first resonant layer laminated on the first dielectric layer and causing loss by resonating electromagnetic waves; A second dielectric layer laminated on the first resonant layer; and A second resonant layer is laminated on the second dielectric layer and causes loss by resonating electromagnetic waves; The second resonant layer has a pattern region formed of a conductive material and a blank region not formed of a conductive material. A transparent electromagnetic wave absorber characterized in that the first resonant layer is formed entirely of a conductive material.

2. In paragraph 1, A transparent electromagnetic wave absorber, characterized in that the first resonant layer is formed of graphene or ITO (Indium Tin Oxide) material.

3. In paragraph 1, A transparent electromagnetic wave absorber, characterized in that it further includes a third dielectric layer laminated on the second resonant layer.

4. In paragraph 1, A transparent electromagnetic wave absorber, characterized in that the higher the surface resistance of the second resonant layer, the lower the center frequency of the frequency band absorbed by the transparent electromagnetic wave absorber.

5. In paragraph 1, A transparent electromagnetic wave absorber, characterized in that the higher the surface resistance of the first resonant layer, the higher the absorption performance of the transparent electromagnetic wave absorber.

Images