A radio wave scatterer and a member for attenuating radio waves having a radio wave scatterer

Abstract

A component capable of transmitting and attenuating incident radio waves without the need to mix dielectric loss materials such as carbon particles or magnetic loss materials such as iron oxide, or radio wave absorbing materials or scattering materials, by means of a novel composition. A radio wave scattering body characterized by being composed of a resin composition having a resin as the main component, configured such that at least a portion of the incident radio waves are transmitted and the transmitted radio waves are emitted in a scattered state.

Description

Technology Field

[0001] The present invention relates to a radio wave scatterer for attenuating incident radio waves and a member for attenuating radio waves having a radio wave scatterer. Background Technology

[0002] Recently, the study of information detection means using radio waves (especially millimeter waves) as an information and communication medium is being conducted in fields such as automobiles, home appliances, and life sciences. For example, in the field of automotive technology, there are collision avoidance systems that use radar with radio waves of frequencies ranging from 24 to 81 GHz to detect obstacles and automatically apply the brakes, or to measure the speed or distance of surrounding vehicles and control the speed or distance of the vehicle itself. For collision avoidance systems to operate normally, it is important to avoid receiving unnecessary radio waves (noise) as much as possible to prevent misidentification.

[0003] FIG. 1 illustrates an example of a radar installation used in such a collision prevention system, in which a radar (36) and a cover member (31) for the radar (36) are placed within the bumper (38) of a vehicle. The radar (36) is mounted to be surrounded by the side wall (34) of the cover member (31). Radio waves β1 emitted from the radar (36) usually pass through the bumper (38), but some of them are reflected from the bumper (38) (including multiple reflections) and reach the radar (36) or the vicinity of the radar (36) (radio waves β2). Because of this, there are cases where the radar malfunctions.

[0004] To prevent such malfunctions, a technique has been proposed to prevent malfunctions of the radar (36) by forming a radio wave absorber on the surface of the cover member (31) to absorb and exclude unnecessary radio waves and suppress the amount of radio wave β2 reaching the radar (36). As for the radio wave absorber, for example, as shown in Patent Document 1 below, a radio wave absorber mixed with carbon particles that absorb radio waves has been proposed. Also, for example, as shown in Patent Document 2 below, a radio wave absorber mixed with a scattering agent that scatters radio waves has been proposed. Additionally, it is described that a plurality of concave portions are formed on the radio wave incident surface, but this is based on the premise of containing a scattering agent.

[0005] In addition, a technique has been proposed to disperse the energy of reflected waves by forming a member with a shape that diffusely reflects incident waves at the reflection point of the bumper (38) or at a necessary point of the shielding plate so that the reflected waves from the bumper (38) do not propagate strongly in a specific direction (Patent Document 3 below). Prior art literature

[0006] Japanese Published Patent Application No. 2001-230587, Japanese Published Patent Application No. 2004-153135, Japanese Patent Application No. 5696781 The problem to be solved

[0007] However, the electromagnetic wave absorber as described in Patent Document 1 is expensive because it involves mixing carbon particles, and the weight of the electromagnetic wave absorber increases because the carbon particles mixed are heavy.

[0008] In addition, the electromagnetic wave absorber as described in Patent Document 2 is expensive because it mixes a scatterer (second dielectric material), and research is required to disperse and arrange the scatterer within the electromagnetic wave absorber.

[0009] The inventors have discovered that even if a member is composed solely of a resin composition that transmits incident radio waves, by studying its shape, it is possible to scatter radio waves emitted from the member and thereby attenuate the intensity of the emitted radio waves per unit area. That is, they discovered that incident radio waves can be attenuated without the need to mix dielectric loss materials such as carbon particles, magnetic loss materials such as iron oxide, or scattering agents into the resin composition through which incident radio waves transmit, and that incident radio waves can be attenuated with a configuration different from that which diffusely reflects incident radio waves. FIG. 2 is a conceptual diagram showing the scattering of emitted radio waves by such a novel configuration.

[0010] One of the objectives of the present invention is to provide a member capable of transmitting and attenuating incident electromagnetic waves without the need to mix dielectric loss materials such as carbon particles, magnetic loss materials such as iron oxide, or scattering agents through a novel composition. means of solving the problem

[0011] One aspect of the present invention provides a radio wave scatterer composed of a resin composition having a resin as the main component, configured such that at least a portion of the incident radio waves are transmitted and the transmitted radio waves are emitted in a scattered state.

[0012] The resin composition above can transmit at least 20% of electromagnetic waves incident perpendicularly to a 3 mm thick plate made of the resin composition.

[0013] The above-mentioned radio wave scattering body may have at least two surfaces, one of which is a radio wave incident surface and the other is an exit surface, and a structural part that generates scattering of radio waves may be formed on at least one of the two surfaces.

[0014] The above structural part may be composed of at least one convex part and / or hole part.

[0015] When the wavelength of the incident electromagnetic wave is λ, the height of the convex portion may be 0.26λ or more, the width of the convex portion may be 0.12λ or more, and the spacing of the convex portion may be 5.1λ or less, and / or, the depth of the hole portion may be 0.26λ or more, the width of the hole portion may be 5.1λ or less, and the spacing of the hole portion may be 0.12λ or more.

[0016] The resin composition above may have a complex relative permittivity, and the imaginary part ε" of the relative permittivity may be 0.1 or less at any frequency of 10 to 300 GHz.

[0017] The above resin composition may have a real part ε' of the relative permittivity of 2 or more and 4 or less at any frequency of 10 to 300 GHz.

[0018] One aspect of the present invention is to provide a member for attenuating radio waves having the radio wave scatterer.

[0019] The member for attenuating the above-mentioned radio waves is a molded body, and the above-mentioned radio wave scattering body may be formed in at least a part thereof.

[0020] The component for attenuating the above-mentioned radio waves may be a cover component of the radar.

[0021] One aspect of the present invention provides a radar assembly in which a radar is mounted on a cover member of the radar.

[0022] One aspect of the present invention provides a bumper comprising a member for attenuating the radio waves.

[0023] One aspect of the present invention is to provide a vehicle having the member, the radar assembly, and / or the bumper.

[0024] As described above, techniques for absorbing (attenuating) unwanted radio waves have existed for some time. The technique described in Patent Document 1 involves actively introducing a radio wave loss material into a resin layer into which radio waves are incident, and absorbing (attenuating) unwanted radio waves through this radio wave loss material. The technique described in Patent Document 2 involves incorporating a scattering agent (e.g., air) that scatters radio waves into a resin layer into which radio waves are incident, thereby causing internal scattering within the resin layer to absorb (attenuate) unwanted radio waves. The technique described in Patent Document 3 involves suppressing unwanted radio waves by actively scattering the incident radio waves to attenuate them, or by changing the angle of the reflected wave relative to the incident wave through reflection.

[0025] As such, the conventionally known technology described in Patent Documents 1 to 3 and the technology of the present invention for scattering and attenuating radio waves penetrating a resin layer are considered to be different technologies. Effects of the invention

[0026] According to the present invention, by means of a novel composition, a member capable of attenuating incident electromagnetic waves without the need to mix dielectric loss materials such as carbon particles, magnetic loss materials such as iron oxide, or scattering agents can be provided.

[0027] Hereinafter, an embodiment of a radio wave scatterer according to the present invention will be described in detail with reference to the drawings. Brief explanation of the drawing

[0028] FIG. 1 is a drawing showing an example of the installation of a radar used in a collision prevention system. FIG. 2 is a conceptual diagram showing the scattering of emitted radio waves by a novel configuration. FIG. 3 is a perspective view showing one embodiment of a radio wave scatterer according to the present invention. FIG. 4 is a plan view showing one embodiment of a radio wave scatterer according to the present invention. FIG. 5 is a cross-sectional view of FIG. 4. FIG. 6 is a diagram explaining the schematic of a method for measuring the scattering rate. FIG. 7 is a conceptual diagram showing the relationship between the scattering state and the method for measuring the scattering rate. FIG. 8 is a diagram showing the relationship between the transmission attenuation amount based on actual values ​​and the height of the convex portion. FIG. 9 is a diagram showing the relationship between the transmittance based on scalar diffraction theory and the height of the convex portion. FIG. 10 is a cross-sectional view of an example of a radio wave scatterer having a shape in which units with convex portions of different widths are repeated. FIG. 11 shows a sample of Example 14 and an Example This is a drawing showing a comparison of the transmission attenuation amount at each angle for sample 3. Fig. 12 is a drawing showing a cross-sectional view of another embodiment of a radio wave scatterer according to the present invention. Fig. 13 is a drawing showing a cross-sectional view of another embodiment of a radio wave scatterer according to the present invention. Fig. 14 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 15 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 16 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 17 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 18 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 19 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 20 is a drawing showing a plan view of another embodiment of a radio wave scatterer according to the present invention. Fig. 21 is a plan view of another embodiment of a radio wave scatterer according to the present invention It is a drawing that represents.FIG. 22 is a plan view of another embodiment of a radio wave scatterer according to the present invention. FIG. 23 is a plan view and a cross-sectional view of an example configuration in which a hole is formed in a support portion of a radio wave scatterer. FIG. 24 is a cross-sectional view of another embodiment of a radio wave scatterer according to the present invention. FIG. 25 is a cross-sectional view of another embodiment of a radio wave scatterer according to the present invention. FIG. 26 is a drawing explaining the concept of the volume fraction of a convex portion. FIG. 27 is a perspective view of one embodiment of a member for attenuating radio waves according to the present invention. FIG. 28a is a plan view of one embodiment of a member for attenuating radio waves according to the present invention. FIG. 28b is a YY cross-sectional view of FIG. 28a. FIG. 28c is a ZZ cross-sectional view of FIG. 28b. FIG. 29a is a plan view of another embodiment of a member for attenuating radio waves according to the present invention. FIG. 29b is FIG. FIG. 29a is a cross-sectional view of GG. FIG. 30a is a drawing illustrating a convex ridge formed on the inner surface of a side wall of one embodiment of a member for attenuating radio waves according to the present invention. FIG. 30b is a drawing illustrating a modified example of a convex ridge formed on the inner surface of a side wall of one embodiment of a member for attenuating radio waves according to the present invention. FIG. 30c is a drawing illustrating a modified example of a convex ridge formed on the inner surface of a side wall of one embodiment of a member for attenuating radio waves according to the present invention. FIG. 31 is a perspective view of one embodiment of a radar assembly according to the present invention. FIG. 32 is a drawing showing an overview of one embodiment of a bumper according to the present invention. FIG. 33 is a drawing showing an overview of one embodiment of a vehicle according to the present invention. FIG. 34 is a drawing illustrating an overview of a method for measuring the amount of reflection attenuation. FIG. 35a is a drawing showing an example of curve fitting in the calculation of transmittance. 35b is a diagram showing an example of curve fitting in the calculation of transmittance. Specific details for implementing the invention

[0029] [Radio wave scatterer]

[0030] The radio wave scatterer of the present invention is configured such that at least a portion of the incident radio waves are transmitted and the transmitted radio waves are emitted in a scattered state, and is composed of a resin composition having a resin as the main component.

[0031] The radio wave scatterer of the present invention is such that the resin composition transmits at least 50% of the radio waves incident perpendicularly to a 3 mm thick plate made of the resin composition. This transmittance is preferably 65% ​​or higher, and more preferably 85% or higher. At least, by achieving this preferred transmittance, the addition of dielectric loss materials becomes unnecessary, making lightweight and low-cost production possible. The reason the transmittance of the radio wave scatterer is defined as the transmittance of radio waves incident perpendicularly to a 3 mm thick plate made of the resin composition constituting the radio wave scatterer is due to the following reasons. One is that the ratio of total incident power to total emitted power changes depending on the shape of the radio wave scatterer. Another is that it is difficult to measure the total emitted power. As described above, since the present invention scatters radio waves emitted from the member by studying its shape, even if the member is composed solely of a resin composition that transmits incident radio waves, it is reasonable to define the characteristics by the transmittance of a member composed of a planar resin composition, which is a representative shape that does not cause scattering of emitted radio waves.

[0032] FIG. 3 is a perspective view showing one embodiment of a radio wave scatterer according to the present invention. FIG. 4 is a plan view showing one embodiment of a radio wave scatterer according to the present invention. FIG. 5 is a cross-sectional view of the VV of FIG. 4.

[0033] The radio wave scatterer (1) has a support member (4) having a first main surface (2) and a second main surface (3), and a structural member (5) that generates scattering of radio waves is formed on the first main surface (2). The structural member (5) is composed of a plurality of convex members (6). In this embodiment, the convex members (6) are convex, all extend in the same direction, and are formed parallel to each other.

[0034] The width (Q) and length (P) (see FIG. 4) of the radio wave scatterer (1) vary depending on the size of the object being mounted, but are typically formed to be 1 to 50 cm, more preferably 1.5 to 40 cm, and even more preferably 3 to 30 cm. Also, the thickness (T1) of the support member (4) shown in FIG. 5 is typically preferably designed to be in the range of 0.5 to 10 mm, more preferably in the range of 0.7 to 5 mm, and even more preferably in the range of 1 to 3 mm, in terms of the balance of strength and weight. Also, the thickness (T2) of the radio wave scatterer (1), including the height (H) of the convex portion (6), is typically preferably designed to be in the range of 0.5 to 20 mm, more preferably in the range of 1 to 15 mm, and even more preferably in the range of 2 to 10 mm, in order to produce a sufficient radio wave scattering effect.

[0035] The height (H) of the convex portion (6) is preferably designed to be in the range of 0.26λ or more when the wavelength of the incident wave is λ, more preferably in the range of 0.51λ or more and 1.5λ or less, and even more preferably in the range of 0.77λ or more and 1.3λ or less.

[0036] The width dimension (W) of the portion rising from the first main surface (2) of the convex portion (6) is preferably designed to be in a range of 0.26λ or more when the wavelength of the incident electromagnetic wave is λ, more preferably in a range of 0.26λ or more and 3.1λ or less, and if the convex portion (6) is a dot shape, it is even more preferably designed to be in a range of 0.51λ or more and 3.1λ or less.

[0037] In addition, the spacing (S) of adjacent convex parts (6) is preferably designed to be in the range of 5.1λ or less when the wavelength of the incident wave is λ, more preferably in the range of 0.26λ or more and 3.1λ or less, and even more preferably in the range of 0.51λ or more and 2.6λ or less. Here, the more preferable range of spacing (S) is 0.26λ or more and 2.8λ or less when the convex part (6) is a convex shape, and 0.51λ or more and 2.6λ or less when the convex part (6) is a dot shape. Also, the spacing (S) is a value measured between the parts of the opposing convex parts (6) that rise from the first main surface (2).

[0038] The height (H), width (W), and spacing (S) of the convex portion (6) are preferably designed to be in the range of 0.26λ or more, 0.12λ or more, and 5.1λ or less when the wavelength of the incident wave is λ, more preferably designed to be in the range of 0.51λ or more and 1.5λ or less, 0.26λ or more and 3.1λ or less, and 0.26λ or more and 3.1λ or less, and even more preferably designed to be in the range of 0.51λ or more and 1.5λ or less, 0.26λ or more and 3.1λ or less, and 0.51λ or more and 2.6λ or less. Here, the more desirable ranges of height (H), width (W), and spacing (S) are 0.51λ or more and 1.5λ or less, 0.26λ or more and 3.1λ or less, and 0.26λ or more and 2.8λ or less when the convex portion (6) is convex, and 0.51λ or more and 1.5λ or less, 0.51λ or more and 3.1λ or less, and 0.51λ or more and 2.6λ or less when the convex portion (6) is dot-shaped.

[0039] The performance of the radio wave scatterer with respect to the height (H), width (W), and spacing (S) of the convex portion (6) may be verified by manufacturing and evaluating a sample in the manner described in the present embodiment, or by electromagnetic field analysis simulation.

[0040] As described above, the radio wave scatterer of the present invention is configured such that at least a portion of the incident radio waves is transmitted, and the transmitted radio waves are emitted in a scattered state. The phrase “transmitted radio waves are emitted in a scattered state” means that the scattering rate is a predetermined value (where the “scattering rate III” described below is 1.0% or more) based on a measurement value obtained by the following measurement. Here, the scattering rates are considered to include “scattering rate I,” which is the ratio of the scattered wave to the straight-transmitted wave of the radio waves incident on the radio wave scatterer, and “scattering rate II” or “scattering rate III,” which is the ratio of the scattered wave to the total transmitted wave.

[0041] The method for measuring the scattering rate is described. FIG. 6 is a diagram illustrating the schematic of the method for measuring the scattering rate. FIG. 7 is a conceptual diagram showing the relationship between the scattering state and the method for measuring the scattering rate. The amount of transmission attenuation is measured at 60 to 90 GHz using a radio transceiver (EAS03, manufactured by Kicom Co., Ltd.) in accordance with the following sequence, with reference to JIS R 1679. The amount of transmission attenuation is expressed as the absolute value of the value calculated by the following equation (1).

[0042] 10Log|P i / P0| … (1) (P i : Received power, P0: Transmitted power)

[0043] As shown in the schematic of FIG. 6, a sample holder (11), a millimeter wave lens (12), a transmitter (9), and a receiver (10) are arranged. From the transmitter (9), a radio wave with a diameter of 150 mm is transmitted. Transmission and reception of the radio wave are performed with nothing set in the sample holder (11), and the state where the transmission attenuation is 0 dB (the radio wave is transmitted in its entirety) is used as the standard for measuring the transmission attenuation of the incident wave perpendicular to the plane direction of each sample. Next, after setting a sample in the sample holder (11), as shown in FIG. 7, the receiver is installed at angles of 0°, 15°, 30°, 45°, 60°, and 75° respectively with respect to the direction from the transmitter (9) to the receiver (10), which is perpendicular to the plane direction of each sample, and transmission and reception of the radio wave are performed, and the transmission attenuation at 76.5 GHz is measured. In addition, if the structure of the wave scatterer is a convex shape, the measurement is taken in a state where the longitudinal direction of the convex shape formed on the first surface is perpendicular to the amplitude direction of the electric field of the incident wave. Based on the measured values ​​of the transmission attenuation amount at each angle of 0°, 15°, 30°, 45°, 60°, and 75°, each P from the above equation (1) i Calculate / P0 (receive / transmit power ratio), and each calculated P iBased on / P0 (received / transmitted power ratio), scattering rate I and scattering rate II are calculated by the following equations (2.1) and (2.2).

[0044] (Laying rate I) = (P at 15°, 30°, 45°, 60°, 75°) i / Sum of P0 (receive / transmit power ratio) / (P at 0° i / P0(receive / transmit power ratio)) × 100 … (2.1)

[0045] (Laying rate II) = (P at 15°, 30°, 45°, 60°, 75°) i / Sum of P0 (receive / transmit power ratio) / (P at 0°, 15°, 30°, 45°, 60°, 75°) i / Sum of P0 (receive / transmit power ratio)) × 100 … (2.2)

[0046] Here, if the spawning rate I is d1 and the spawning rate II is d2, it can be converted to the following equation (2.3).

[0047] d2 = (100d1 / (100 + 100d1)) × 100... (2.3)

[0048] In addition, in the above method for measuring the scattering rate, the interval of the reception angle of the transmitted wave is set to 5° intervals, and the scattering rate III is calculated by the following equation (2.4).

[0049] (Laying rate III) = (P at 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° i / Sum of P0 (receive / transmit power ratio) / (P at 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° i / Sum of P0 (receive / transmit power ratio) × 100 … (2.4)

[0050] Since the scattering rate II of the flat members of Comparative Examples 1 to 5 described below, which are examples of members in which a structural part (5) that causes scattering of radio waves is not formed on the first main body (2), was 0.1% to 0.2%, as described above, "transmitted radio waves are emitted in a scattered state" means that the scattering rate III is 1.0% or higher.

[0051] In addition, the scattering rate should ideally be based on the ratio of the total power of the radio waves scattered three-dimensionally in other angle directions to the power of the radio waves in the 0° direction, but since it is technically difficult to measure this at present, the scattering rate was defined as in the above equations (2.1), (2.2), and (2.4). Also, based on the scattering rate defined in this way, the statement that "the transmitted radio waves are emitted in a scattered state" as described above means that the scattering rate III is 1.0% or higher.

[0052] Since the sample related to Comparative Example 1 does not have a convex portion formed, the scattering rate, which is the ratio of the total amount of power received by installing the receiver at 15, 30, 45, 60, and 75° to the power received by installing it at 0°, is 0.06%, indicating that most of the transmitted radio waves are not scattered. In contrast, the scattering ratio of the radio waves in Example 3, which is described later and has a convex portion formed, is 385.38%, indicating that the transmitted radio waves are in a scattered state.

[0053] Regarding the mechanism by which transmitted radio waves can be emitted in a scattered state by forming a convex portion, it is thought that multiple mechanisms are involved, but one main mechanism is that the convex portion acts as a diffraction grating.

[0054] Therefore, taking the case where the cross-section of the convex portion is rectangular as an example, it is examined using diffraction theory. FIG. 8 is a diagram showing the relationship between the transmission attenuation amount of the samples of Examples 4, 4.1, 4.2, 4.3, and 4.4 described below, calculated by the above measurement method, and the height of the convex portion. From FIG. 8, it was confirmed that the transmission attenuation amount is greatest when the height of the convex portion is 3 mm, and as the height of the convex portion moves away from 3 mm, the transmission attenuation amount tends to decrease.

[0055] In the case of light diffraction, for a diffraction grating with a rectangular cross-section, the zero-order light transmittance is I0, and the real part of the permittivity is ε r It is known that if the height of the convexity is h and the wavelength is λ, the following relationship holds (scalar diffraction theory).

[0056]

[0057] When λ is fixed at a wavelength of 3.92 mm at 76.5 GHz, I0 is ε r It becomes a function of and h, and ε is the same as in the example. r When ε is set to 2.6, the relationship between the height of the convex portion and I0 is as shown in Fig. 9. As can be seen from Fig. 9, the lowest I0 is observed when the height of the convex portion is 3 mm, and as the height moves away from 3 mm, a tendency for I0 to increase is confirmed. Here, the zero-order light transmittance I0 represents the ratio of the intensity of straight-line transmitted light to the total transmitted light, and can be considered to correspond to the transmission attenuation amount of the straight-line transmitted wave in the present invention. Therefore, given that the behavior of Fig. 8 obtained by actual measurement and the theory based on Fig. 9 exhibit generally similar behavior, it is inferred that the radio wave scatterer in the present invention is related to the scalar diffraction theory of light. Accordingly, the real part of the permittivity ε r By controlling the height h of the convex portion, a suitable radio wave scatterer can be obtained for the frequency of the target radio wave.

[0058] Furthermore, according to Bragg's law, the direction (angle) of the scattered waves caused by diffraction is determined by the period (length of the width and the interval) of the convex section. The diffracted waves transmitted between the convex sections form interference fringes where they reinforce each other and weaken each other. At this time, the portions that reinforce each other are observed as scattered waves. The angles at which the transmitted waves reinforce each other or weaken each other are expressed by the following equations (4) and (5) (d: period, m: integer).

[0059] When they reinforce each other: dsinθ = mλ … (4)

[0060] Case where they weaken each other: dsinθ = (m + 1 / 2)λ … (5)

[0061] When λ is fixed, the only variables are the mutual reinforcement intensity θ and the period d, so the angle of the scattered wave changes according to the period. Table 1 shows the change in the angle of mutual reinforcement of the diffracted waves, that is, the angle of the scattered wave, when the period d is varied.

[0062] [Table 1]

[0063]

[0064] In this regard, Table 2 corresponds to Example 3 described below, and shows the results of measuring transmission attenuation by manufacturing a sample with a length (P) of 150 mm and a width (Q) of 150 mm and installing receivers at angles of 0°, 15°, 30°, 45°, 60°, and 75° using a device used to measure scattering rate.

[0065] [Table 2]

[0066]

[0067] From Table 2, the angle at which the transmission attenuation is smallest, that is, the angle at which the scattered wave is observed, is considered to be 30°. Since the width of the convex portion of the sample in Example 3 is 4 mm and the spacing is also 4 mm, the period d is 8, which can be confirmed to roughly correspond to the direction of the scattered wave at d = 8 in Table 1, which is 29°. Therefore, it is inferred that the radio wave scatterer of the present invention is also related to Bragg's law. Accordingly, the spacing of the convex portions can be appropriately arranged based on equations (4) and (5).

[0068] From the above considerations, it is inferred that the convex portion of the wave scatterer acts as a diffraction grating; therefore, it is thought that by configuring it as follows, strong waves can be suppressed in a specific direction. As described above, according to Bragg's law, when a single width and interval (period) are repeated, diffracted waves reinforce each other in a specific direction. Therefore, it is thought that by mixing different widths within the repeated width and interval structure, mutual reinforcement in a specific direction can be suppressed, thereby promoting uniformity of transmission attenuation in a direction and suppressing the emission of strong waves in a specific direction.

[0069] In these reviews, the theory of light diffraction was referenced, but it is not easy to apply this to millimeter waves. This is because it is necessary to consider that radio waves, especially millimeter waves and quasi-millimeter waves, have wavelengths that are three orders of magnitude larger than visible light. For example, millimeter waves have lower straightness than visible light (making them prone to diffraction) and are more likely to penetrate objects such as plastic walls or paper compared to visible light, so a design that takes these characteristics into account is required.

[0070] For example, let us compare the radio wave scatterer of Example 14 described below, which has a shape of repeating units of convex shapes with widths of 2 mm, 4 mm, and 8 mm arranged in sequence at intervals of 4 mm as shown in FIG. 10, with the radio wave scatterer of Example 3, which has a shape of convex shapes with a width of 4 mm arranged at intervals of 4 mm. Table 3 and FIG. 11 show the results of measuring the transmission attenuation amount by installing receivers at angles of 0°, 15°, 30°, 45°, 60°, and 75° for the sample of Example 14 and the sample of Example 3 using the above measurements.

[0071] [Table 3]

[0072]

[0073] In the wave scatterer of Example 3, the diffracted waves reinforce each other at around 30° in accordance with Bragg's law, whereas in the case where convex shapes of different widths are mixed as in the wave scatterer of Example 14, no reinforcement in a specific direction is observed, and it was confirmed that a uniform amount of transmission attenuation is obtained with respect to the direction.

[0074] Accordingly, in the radio wave scatterer of the present invention, when diffraction acts as a major factor, by configuring it to mix different widths or spacings, the amount of transmission attenuation is made uniform with respect to direction, and the emission of strong radio waves in a specific direction can be suppressed.

[0075] In the above embodiment, the convex portion (6) is formed in a shape that is convex and has a rectangular cross-section that crosses the length direction, but the shape of the convex portion (6) is not limited to this and can be any other suitable shape. For example, as shown in FIG. 12, the cross-sectional shape may be triangular, and as shown in FIG. 13, the cross-sectional shape may be circular. When the cross-sectional shape is a shape other than a rectangle (e.g., a triangle or a circle), scattering due to refraction is added to the scattering due to diffraction described above, and it is thought that the degree of scattering becomes greater.

[0076] In addition, in the above embodiment, the convex portion (6) was a continuous convex shape in the longitudinal direction, but it may be an intermittent convex shape in the longitudinal direction. Furthermore, the convex portion (6) may be formed in a dot shape. FIG. 14 is a plan view of an example of a radio wave scatterer in which the shape of the convex portion (6) is a square pyramid (cross-sectional shape is an isosceles triangle) and the spacing (S) is 0 and arranged in a matrix. FIG. 15 is a plan view of an example of a radio wave scatterer in which the shape of the convex portion (6) is a hemisphere (cross-sectional shape is a semicircle) and the spacing (S) is 0 and arranged in a matrix. In these examples, the convex portion (6) is arranged in a matrix, but the arrangement of the convex portion (6) is not limited to this, and can be any other suitable arrangement, such as a zigzag arrangement.

[0077] In addition, the convex portion (6) may be in the shape of a dot and arranged in a matrix or in a zigzag pattern. FIG. 16 is a plan view of an example of a radio wave scatterer in which the shape of the convex portion (6) is a square prism (the cross-sectional shape is a rectangle) and arranged in a matrix at a predetermined interval (S). FIG. 17 is a plan view of an example of a radio wave scatterer in which the shape of the convex portion (6) is a square prism (the cross-sectional shape is a rectangle) and arranged in a zigzag pattern at a predetermined interval (S). FIG. 18 is a plan view of an example of a radio wave scatterer in which the shape of the convex portion (6) is a regular hexagonal prism (the cross-sectional shape is a rectangle) and arranged in a honeycomb pattern at a predetermined interval (S).

[0078] When the convex portion (6) is a convex shape, the radio waves are scattered mainly in a direction perpendicular to the length direction of the convex shape due to the properties similar to a diffraction grating, and are hardly scattered in the length direction of the convex shape. In contrast, when the convex portion (6) is a dot shape, especially when it has a point-symmetric shape when viewed from a plane, the waves are scattered in all directions when viewed from a plane, so the radio waves can be scattered more uniformly compared to when the convex portion (6) is a convex shape. Also, when the convex portion (6) is a dot shape, the scattering direction of the radio waves can be manipulated by its arrangement. The scattering direction of the radio waves in the shape and arrangement of the convex portion (6) as described above is illustrated in FIGS. 16, FIGS. 17, and FIGS. 18. The right-hand side of each figure is a figure showing the result of an electromagnetic field simulation by the finite element method of the transmitted wave in the shape and arrangement of the convex portion (6) of the left-hand side of each figure. In the case of an aligned arrangement, the waves are scattered in four directions of the adjacent convex portion (6), whereas by changing the arrangement method to a honeycomb arrangement or a zigzag arrangement, the direction of diffusion of the waves can be increased. As the scattering direction of the waves increases, the wave density per unit area decreases, so the emission of strong waves in a specific direction can be further suppressed.

[0079] In addition, in the above embodiment, the convex portion (6) is formed as convex sections that are parallel to each other, but the convex sections do not necessarily have to be formed parallel to each other. For example, the convex sections may be formed to be arranged in a zigzag pattern, as in the radio wave scatterer of Example 84 described later shown in FIG. 19, or the convex sections may be formed to be arranged radially, as in the radio wave scatterer of Example 85 described later shown in FIG. 20. However, it is preferable that the convex sections be formed parallel to each other because it makes the design easier.

[0080] Also, in the above embodiment, the convex portion (6) is formed as a straight convex shape, but the shape of the convex shape is not limited to this and can be formed in any other suitable shape. For example, as shown in FIG. 21, it may be formed in a zigzag bent shape, or as shown in FIG. 22, it may be formed in a wave shape.

[0081] In addition, when forming a convex structure in a place where mud or contaminants are likely to adhere, it is desirable to install the length of the convex structure in a direction perpendicular to the ground so that contaminants do not accumulate easily.

[0082] In addition, in the above embodiment, the structural part was composed of a convex part, but the structural part may be composed of a hole part, or may be composed of both a convex part and a hole part. Here, the "hole part" is a concept that includes both a concave part, i.e., a hole with a bottom, and a through hole.

[0083] If a convex portion is formed as in the above embodiment, the amount of material used to manufacture the radio wave scatterer increases by the amount of the convex portion, and the weight of the radio wave scatterer increases. Therefore, by forming a hole portion in the support portion, the increase in weight of the radio wave scatterer can be suppressed. FIG. 23 is a plan view and a cross-sectional view XX of an example configuration in which a hole portion is formed in the support portion of the radio wave scatterer. Similar to the radio wave scatterer in the above embodiment, the radio wave scatterer (1) has a support portion (4) having a first main surface (2) and a second main surface (3), and a structural portion (5) that generates scattering of radio waves is formed on the first main surface (2). The structural portion (5) is composed of a plurality of convex portions (6). In this embodiment, the convex portions (6) are convex, all extend in the same direction, and are formed parallel to each other. In addition to this, a cylindrical hole portion (7) is formed between adjacent convex portions (6). The hole portion (7) has a width (diameter) of V and a depth of D, and is arranged in a matrix with a spacing of U between adjacent hole portions (7). The hole portion (7) has a bottom portion with a thickness of T3. According to this configuration, as described above, not only can the increase in weight of the radio wave scatterer be suppressed, but the remaining portion of the support portion (4) adjacent to the hole portion (7) is also thought to contribute to the scattering of incident radio waves in addition to the convex portion (6). Also, in FIG. 23, the shape of the hole portion is cylindrical, but it does not necessarily have to be circular, and can be any other suitable shape such as a triangular prism or a square prism.

[0084] In addition, the hole portion (7) may be a through hole, but for example, when applying the radio wave scatterer of this embodiment to a cover member placed inside a bumper of a vehicle as described in the above "Background Technology" section, it is preferable to make it a hole with a bottom rather than a through hole so as not to reduce the anti-fouling function (prevention of contamination of the radar surface by mud, etc.) which is a function of the cover member.

[0085] In addition, in the above embodiment, the structural part that generates scattering of radio waves formed in the radio wave scatterer was formed on the first main surface, i.e., the incident surface of the radio waves; however, since the structural part can generate a scattering state of radio waves even if formed on the second main surface, i.e., the exit surface of the radio waves, it may be formed on the exit surface of the radio waves, or it may be formed on both the incident surface of the radio waves and the exit surface of the radio waves. When convex parts are formed on both the incident surface of the radio waves and the exit surface of the radio waves, the sum of the heights of the convex parts on both sides should be within the suitable range described above. When convex parts and / or holes are formed on both the incident surface of the radio waves and the exit surface of the radio waves, it is easier to obtain a better amount of transmission attenuation by forming the convex parts and / or holes on the exit surface of the radio waves at a position opposite to the convex parts and / or holes formed on the incident surface of the radio waves. FIG. 24 is a cross-sectional view of an example of a radio wave scatterer having a structure as shown in FIG. 5, wherein a convex portion is formed at a position opposite to the convex portion formed on the incident surface of the radio wave on the emitting surface of the radio wave, and the sum of the heights of both convex portions is H, which is the same as the convex portion (6) of FIG. 5.

[0086] In addition, the shape of the convex portion may be stepped. FIG. 25 is a cross-sectional view of an example of a radio wave scatterer in which the shape of the convex portion is stepped in two stages. With such a configuration, it is thought that in addition to the lower portion, the upper portion also contributes to the scattering of incident radio waves.

[0087] As described above, when the wavelength of the incident wave is λ, it is preferable that the height of the convex portion is 0.26λ or more, the width of the convex portion is 0.26 or more, and the spacing of the convex portion is 5.1λ or less. Considering that the height, width, and spacing of the convex portion correspond to the depth, spacing, and width of the hole portion, respectively, when the wavelength of the incident wave is λ, it is preferable that the height of the convex portion is 0.26λ or more, the width of the convex portion is 0.26 or more, and the spacing of the convex portion is 5.1λ or less, and / or, the depth of the hole portion is 0.26λ or more, the spacing of the hole portion is 0.26λ or more, and the width of the hole portion is 5.1λ or less.

[0088] In addition, the height of the convex portion and the depth of the hole portion are more preferably designed to be in a range of 0.51λ or more, and even more preferably designed to be in a range of 0.77λ or more.

[0089] In addition, the width of the portion rising from the first main surface of the convex portion and the spacing of the portion descending from the adjacent first main surface of the hole portion are more preferably designed to be in a range of 0.26λ or more, and even more preferably designed to be in a range of 0.51λ or more.

[0090] In addition, it is more preferable that the spacing between adjacent convex parts and the width of the hole part be designed to be in the range of 3.10λ or less, and even more preferable that they be designed to be in the range of 2.04λ or less. Also, as described above, the spacing between adjacent convex parts is a value measured between the parts where opposing convex parts rise from the first main surface, and the width of the hole part is a value measured between the parts where opposing hole parts descend from the first main surface.

[0091] In addition, the volume ratio of the convex portion described below is preferably designed to be in a range of 3% or more, more preferably in a range of 3.8% or more, even more preferably in a range of 15% or more, even more preferably in a range of 16.7% or more, and even more preferably in a range of 25% or more. In addition, the volume ratio of the convex portion is more preferably designed to be in a range of 90% or less, more preferably in a range of 85.2% or less, even more preferably in a range of 65% or less, even more preferably in a range of 60.9% or less, even more preferably in a range of 55% or less, and even more preferably in a range of 50.0% or less.

[0092] Here, the volume ratio of the convex portion is the ratio of the volume of the convex portion within the unit structure to the volume of the unit structure space of the structural portion. The unit structure is a structure corresponding to a single convex portion in the structural portion. The unit structure space is a space enclosed by the bottom surface, the top surface, and the side surface, with the bottom surface of the unit structure as the bottom surface, the top surface being a plane parallel to the bottom surface located at a distance equal to the maximum height of the convex portion within the unit structure from the bottom surface, and the side surface being a plane perpendicular to the bottom surface of the unit structure passing through the boundary line of the bottom surface of the unit structure. For example, in the case of a radio wave scatterer (1) in which the support part (4) as shown in the plan view and FF cross-section of FIG. 26 is flat in shape, the convex part (6) is dot-shaped, and the bottom surface has the shape of a square pyramid with a side length of W, and is arranged in a matrix at interval S, the unit structure (8) is the part shown as a halftone in FIG. 26, and the unit structure space (81) is a rectangular space in which the bottom surface (83) of the unit structure (8) (a square with a side length of (W + S)) is the bottom surface and the height (H) of the convex part (6) is the height.

[0093] The performance of the electromagnetic scatterer with respect to the height, width, and spacing of the convex portion, and the depth, spacing, and width of the hole portion, and the volumetric ratio of the convex portion, may be verified by manufacturing and evaluating a sample in the manner described in the examples, or by electromagnetic field analysis simulation.

[0094] In addition, although the above embodiment describes the case where the incident radio wave is incident perpendicularly to the main surface of the radio wave scatterer, scattering can also occur in the emitted radio wave even when the incident radio wave is incident obliquely to the main surface of the radio wave scatterer. Table 4 shows an example of the change in transmission attenuation when the incident angle is changed, which is measured by a device used to measure the scattering rate, by manufacturing a sample corresponding to Example 2 with a length (P) of 150 mm and a width (Q) of 150 mm.

[0095] [Table 4]

[0096]

[0097] From Table 4, it can be seen that even when the incident radio wave is incident obliquely on the main surface of the radio wave scatterer, it can cause scattering in the emitted radio wave.

[0098] In addition, in the above embodiment, the support member was a flat plate, but the support member may be curved.

[0099] In addition, in the above embodiment, millimeter wave radio waves were used as an example of incident radio waves, but the wavelength of the incident radio waves is not limited to millimeter waves and can be any other suitable wavelength.

[0100] [Component for attenuating radio waves]

[0101] The member for attenuating the radio waves of the present invention comprises the radio wave scatterer described above.

[0102] FIG. 27 is a perspective view of an embodiment in which the member for attenuating radio waves according to the present invention is the cover member (31) in the example shown in FIG. 1 in the [Background Art] section.

[0103] The cover member (31), which is a component for attenuating radio waves, is a molded body made of a resin composition identical to that of the radio wave scatterer (1), and its basic configuration is identical to that of the radio wave scatterer (1). Therefore, the same symbol is assigned to points with the same configuration as the radio wave scatterer (1), and the description thereof is omitted.

[0104] As shown in FIG. 27, the cover member (31) has a first opening (32) on its upper surface (39) and a second opening (33) on its lower surface (40), and is formed as a hollow pyramidal object. Additionally, a plurality of convex protrusions (6) extending in the vertical direction are formed on the inner surface (35) of the side wall (34). Furthermore, the cover member (31) is typically mounted so that its upper surface (39) contacts the mounting object.

[0105] As shown in FIG. 28a, the YY cross-sectional view in FIG. 28b, and the ZZ cross-sectional view in FIG. 28c, the height (L) of the cover member (31) is typically formed to be 0.5 to 25 cm, more preferably 1 to 20 cm, and even more preferably 2 to 15 cm, although this may vary depending on the size of the mounting target and the radar (36). Also, the length (M) and depth (N) are both typically formed to be 1 to 50 cm, more preferably 1.5 to 40 cm, and even more preferably 3 to 30 cm.

[0106] The cover member (31) has a plurality of convex protrusions (6) formed on the inner surface (35) of the side wall (34), and these are all extended in the vertical direction (the direction connecting the upper surface (39) and the lower surface (40)) and formed to be parallel to each other. The width of the convex protrusions (6) decreases as they move away from the inner surface (35), so the angle of elevation (θ) of the convex protrusions (6) relative to the inner surface (35) of the side wall (34) is formed as an acute angle.

[0107] According to the above configuration, since a plurality of convex protrusions (6) are formed in a special shape on the inner surface (35) of the side wall (34) of the cover member (31), sufficient electromagnetic wave absorption capability can be achieved even without stacking multiple layers using multiple materials with different dielectric constants. Therefore, after forming a member of a specific shape, there is no need to stack layers made of metal or the like, and it can be provided as a molded body. In addition, the angle of elevation (θ) of the convex protrusions (6) with respect to the inner surface (35) of the side wall (34) is formed as an acute angle, and since the convex protrusions (6) are extended in the vertical direction, ejection from the mold is easy, and production efficiency is increased.

[0108] In addition, in the above embodiment, the entire cover member (31) is formed as a pyramidal shape, but the overall shape is not limited to this, and, for example, as shown in FIG. 29a and FIG. 29b, it may be a cone shape. However, in the case where the entire shape is formed as a pyramidal shape, or in the case where it is formed as a cone shape, the shape and arrangement of the plurality of convex parts (6) formed on the inner surface (35) need to be designed with consideration for ease of ejection from the mold.

[0109] In addition, in the above embodiment, the entire cover member (31) is formed as a pyramidal shape (square pyramidal shape), but it may also be an n-sided (where n is a positive integer) pyramidal shape. Also, the shape of the cover member (31) is not limited to a pyramidal shape, and can be flexibly adapted to the shape of the mounting target or radar (36), and can be any suitable shape, such as a plate shape or a pyramidal shape that expands in the opposite direction to the direction of radar wave emission.

[0110] In addition, in the above embodiment, a plurality of convex sections (6) formed on the inner surface (35) of the side wall (34) are formed as one continuous line in the vertical direction (the direction connecting the upper surface (39) and the lower surface (40)) on the inner surface (35) of the side wall (34), as shown in FIG. 30a, but the plurality of convex sections (6) may each be formed intermittently. However, if the plurality of convex sections (6) are formed as one continuous line, there is a tendency for ejection from the mold to be easier.

[0111] In addition, in the above embodiment, a plurality of convex protrusions (6) formed on the inner surface (35) of the side wall (34) are formed as shown in FIG. 30b, rising from the boundary between the upper surface (39) and the side wall (34) and connected as one (continuously) toward the lower surface (40). However, as shown in FIG. 30c, the plurality of convex protrusions (6) may rise gently from the periphery edge of the upper surface (39), and the rising may be done gradually in a curved manner so that the upper surface (39) and the upper surface of the convex protrusions (6) are continuously connected. In this way, if the plurality of convex protrusions (6) are formed so that the upper surface (39) and the upper surface of the convex protrusions (6) are continuously connected, it tends to be easier to eject from the mold.

[0112] In addition, in the above embodiment, a plurality of convex shapes (6) formed on the inner surface (35) of the side wall (34) are formed parallel to each other on the same face of the truncated pyramid as shown in FIG. 30a, but the plurality of convex shapes (6) do not necessarily have to be formed parallel to each other. For example, on each face of the side wall (34), a plurality of convex shapes (6) may be arranged such that they widen toward the ends from the upper surface (39) toward the lower surface (40), as in the arrangement of FIG. 20, and when viewed inward from the lower surface (40) of the cover member (31), the plurality of convex shapes (6) may be formed to extend radially from the upper surface (39). Also, a plurality of convex shapes (6) may be formed such that they are arranged in a zigzag pattern, as in the arrangement of FIG. 19. However, in order to facilitate ejection from the mold, as shown in FIG. 30a, it is preferable that a plurality of convex segments (6) be formed parallel to each other on the same plane of the truncated pyramid.

[0113] In addition, in the above embodiment, the upper surface (39) has a first opening (32) and the lower surface (40) has a second opening (33), but the upper surface (39) does not necessarily have to have the first opening (32). If the upper surface (39) does not have the first opening (32), the radar (36) can be placed inside the upper surface (39). If the radar (36) is placed inside the cover member (31), the radar (36) and the cover member (31) can be installed simultaneously on the mounting target, which is an advantage.

[0114] In the above embodiment, the radio wave scatterer was integrally molded with the cover member to form a member for attenuating radio waves, but a radio wave scatterer separate from the cover member may be mounted on the cover member to form a member for attenuating radio waves.

[0115] In addition, in the above embodiment, a radar cover member was described as an example of a member for attenuating radio waves, but the member for attenuating radio waves is not limited to this and can be any other suitable member.

[0116] [Radar Assembly]

[0117] The radar assembly of the present invention is such that the radar is mounted on the cover member of the radar described above.

[0118] FIG. 31 is a perspective view of one embodiment of a radar assembly according to the present invention. The basic configuration of the radar assembly (10) is the same as the cover member (31) and radar (36) of the radar described above. Points with the same configuration as the cover member (31) and radar (36) are given the same reference numerals and their descriptions are omitted. As shown in FIG. 31, the radar (36) is mounted on the upper surface (39) of the cover member (31) to form the radar assembly (10).

[0119] [bumper]

[0120] The bumper of the present invention includes a member for attenuating the radio waves described above. FIG. 32 is a drawing showing an overview of one embodiment of the bumper according to the present invention. In the [Background] section, the same reference numerals are assigned to points with the same configuration as the collision prevention system shown in FIG. 1 and the radar assembly shown in FIG. 31, and their descriptions are omitted. As shown in FIG. 32, a radar assembly (10) is disposed on the chassis (not shown) inside the bumper (38) of a vehicle (11), and a radio wave attenuation plate (91), which is a member for attenuating radio waves, is disposed on the side of the radar assembly (10). In addition, a radio wave attenuation area (92), which is a radio wave scatterer, is formed on the bumper (38). If a radio wave scatterer is formed on the cover member, the radio wave attenuation plate (91) and the radio wave attenuation area (92) may be omitted. In addition, if a radio wave scatterer is not formed in the cover member, a radio wave attenuation plate (91) and / or a radio wave attenuation area (92) may be provided. The radar assembly (10) may be mounted on the bumper (38).

[0121] [vehicle]

[0122] The vehicle of the present invention comprises a member for attenuating the radio waves described above, a radar assembly, and / or a bumper.

[0123] FIG. 33 is a diagram showing an overview of one embodiment of a vehicle according to the present invention. The basic configuration of the radar assembly (10) is the same as the radar cover member (31) and radar (36) described above. Points with the same configuration as the cover member (31) and radar (36) are given the same reference numerals and their descriptions are omitted. As shown in FIG. 33, a radar assembly (10) including a radar cover member, which is a member for attenuating radio waves, is disposed within the bumper (38) of the vehicle (11). The radar assembly, which is a member for attenuating radio waves, can be disposed at any appropriate location in any combination.

[0124] <Resin Composition>

[0125] The resin composition has resin as the main component. "Main component" means that, with respect to the total weight of the resin composition, the lower limit is 50 weight% or more, or 60 weight% or more, or 70 weight% or more, and the upper limit is 99 weight% or less, or 90 weight% or less, or 80 weight% or less.

[0126] The resin that is the main component of the resin composition is not particularly limited, but is preferably a thermoplastic resin. Examples include polyethylene, polypropylene, polyvinyl alcohol, polyethylene terephthalate, polybutylene terephthalate, ethylene-vinyl acetate copolymer resin, polystyrene, acrylonitrile styrene resin, acrylonitrile-butadiene-styrene copolymer synthetic resin, acrylic resin such as ASA resin, AES resin, PMMA, MS resin, MBS resin, cycloolefin resin, polyacetal resin, polyamide resin, polyester resin, polycarbonate resin, polyurethane resin, liquid crystal polymer, EPDM, PPS, PEEK, PPE, polysulfone-based resin, polyimide-based resin, fluorine-based resin, thermoplastic elastomer, acrylic elastomer, etc. Among these, polypropylene, polyethylene, and polyamide resins are preferably used. Photocurable resins such as epoxy resin or acrylic resin, and thermosetting resins such as silicone resin, can also be used, although a curing process is required.

[0127] The resin constituting the resin composition can be used alone or in combination of multiple types. That is, when used alone, the mechanical properties of the radio wave scatterer made of the resin composition are excellent, and when multiple types of resins are used in combination, the balance of strength and toughness is excellent. When multiple types of resins are used in combination, for example, polypropylene and EPDM (ethylene propylene diene rubber) can be used in combination.

[0128] Fillers may be mixed into the resin composition. Examples of fillers to be mixed include carbon black for coloring, inorganic materials such as talc, glass fiber, and minerals for improving strength, and softeners for improving flexibility.

[0129] For the talc for strength enhancement mentioned above, from the perspective of reinforcement and moldability (injection molding, etc.), the particle size D50 is preferably small, and the range is 0.8 to 50 μm, preferably 2 to 30 μm, and more preferably 5 to 20 μm.

[0130] For the above-mentioned strength enhancement, it is preferable for the glass fibers to be long, but since they fold during processing, a length of 1 to 5 mm is sufficient. To further increase strength, there is a method of inducing the roving of glass fibers into an impregnation die, uniformly impregnating the filaments with molten thermoplastic resin, and then cutting them to the required length (typically 5 to 20 mm). In addition, the shape of the glass fibers is generally cylindrical, but to reduce deformation during molding, glass fibers with a flat cross-sectional shape may also be used.

[0131] Minerals for improving the strength mentioned above include calcium carbonate, silica, clay, mica, silica balloon, aluminum hydroxide, magnesium hydroxide, titanium oxide, etc., but from the perspective of cost, calcium carbonate or silica is preferred.

[0132] The carbon black for coloring above has a DBP absorption amount of 100 ml / 100 g or less, as measured in accordance with, for example, JIS K 6217 or JIS K 6221. Also, from the perspective of coloring power, it is preferable to have a small particle size and a large specific surface area, but a general-purpose carbon black with a low cost can also be used.

[0133] The above-mentioned softeners include paraffin-based oils, naphthenic oils, and aroma oils, but it is preferable to select one that has good compatibility with the resin being used.

[0134] In addition, particularly preferred combinations of resin and filler constituting the resin composition used in the present invention include using polypropylene or polyethylene as the resin and using talc as the reinforcing filler, or using polyamide resin as the resin and glass fiber as the reinforcing filler.

[0135] The resin composition used in the present invention may contain additives other than resin, reinforcing agent, and softening agent. Examples of such additives include flame retardants, impact resistance improvers, reinforcing agents, compatibilizers, weather resistance improvers, antioxidants, pigments, dyes, etc.

[0136] The resin composition mixed with the above filler can be obtained by mixing (kneading) it in a predetermined formulation using, for example, a single-axis or multi-axis kneader, a batch mixer such as a laboplastomil, or a roll kneader, or by mixing it while dissolved or suspended using a solvent. In terms of productivity, the method of mixing using a kneader or a batch mixer is particularly preferred.

[0137] Methods for molding a cover member placed inside a bumper of a vehicle using the above resin composition include injection molding, press molding, blow molding, vacuum molding, machining, molding using a photocurable resin, and molding using a 3D printer.

[0138] Among the above molding methods, injection molding, which has excellent productivity, is preferred. For the resin composition used in injection molding, materials are generally mixed using a two-axis mixer, and the mixed resin is molded into pellets. These resin pellets are fed into an injection molding machine, melted, injected into a mold having a predetermined shape, and then removed after cooling and solidification to obtain a molded body.

[0139] The resin composition may transmit at least 20% of electromagnetic waves incident perpendicularly to a 3 mm thick plate made of the resin composition.

[0140] The resin composition has a complex relative permittivity, and at any frequency from 10 to 300 GHz, it is preferable that the imaginary part ε' of the relative permittivity be 0.1 or less, more preferable that it be designed to be 0.07 or less, and even more preferable that it be 0.05 or less. When the imaginary part ε' of the relative permittivity is such a value, the resin composition does not need to include dielectric loss materials or magnetic loss materials, making it possible to produce lightweight or at low cost. In addition, it is generally known that when the imaginary part ε' of the relative permittivity is such a value, the resin composition does not absorb radio waves of the corresponding frequency.

[0141] In the resin composition, at any frequency of 10 to 300 GHz, the real part ε' of the relative permittivity is preferably 2 or more and 4 or less, more preferably 2.1 or more and 3.5 or less, and even more preferably 2.2 or more and 3.0 or less.

[0142] Examples

[0143] The radio wave scatterer of the present invention will be further explained using the following examples. Furthermore, the radio wave scatterer of the present invention is not limited to these examples.

[0144] [Example 1]

[0145] Pellet of acrylic elastomer (manufactured by Kuraray, LA2330) was press-molded using a 50 t vacuum press (manufactured by Meisho Press, MS-VPF-50) under conditions of a hot plate temperature of 160°C and a pressurization time of 20 seconds to form a flat plate with a thickness of 3.0 mm. The obtained flat resin molded product was cut to produce a flat support with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, the same process was repeated to obtain a flat acrylic elastomer with a thickness of 2.0 mm, and this was cut to produce a predetermined number of rectangular bodies as convex parts (convex sections), with a cross-sectional shape perpendicular to the longitudinal direction being rectangular, a height (H) of 2.0 mm, a width (W) of 4.0 mm, and a length of 50 mm. These were laminated onto the surface of one side of the support using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections was 4.0 mm, thereby manufacturing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0146] [Example 2]

[0147] A radio wave scatterer was prepared in the same manner as in Example 1, except that the height (H) of the convex shape was set to 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0148] [Example 3]

[0149] A radio wave scatterer was prepared in the same manner as in Example 2, except that a polypropylene plate (real part of dielectric constant 2.3, imaginary part 0.0) was used as the resin composition. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0150] [Example 4]

[0151] 100 parts by weight of polypropylene (manufactured by Japan Polypro Co., Ltd., EA9HD) and 7.3 parts by weight of carbon black for coloring (manufactured by Asahi Carbon Co., Ltd., #50 (iodine adsorption amount 23 mg / g DBP absorption amount 63 ml / 100 g)) were introduced from the inlet in the order of polypropylene and carbon black, and a resin composition was prepared by melt-kneading at 200°C using a labo-plastomil (manufactured by Toyo Seiki Co., Ltd.).

[0152] A resin composition was extracted from a labo-plastomill and press-molded using a 50 t vacuum press (manufactured by Meisho Press, MS-VPF-50) under conditions of a hot plate temperature of 200 ℃ and a pressurization time of 20 seconds to process it into a flat plate with a thickness of 3 mm. The processed resin composition was cut to have a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm to produce a support member.

[0153] In the same manner, a resin composition processed into a flat plate with a thickness of 2.0 mm was obtained, and this was cut to produce a predetermined number of rectangular bodies as convex parts (convex sections), wherein the cross-sectional shape in the direction perpendicular to the longitudinal direction is rectangular, and the height (H) is 3.0 mm, the width (W) is 4.0 mm, and the length is 50 mm. These were laminated onto the surface of one side of a support using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections is 4.0 mm, thereby producing a radio wave scattering body. The characteristics of the obtained radio wave scattering body are shown in Table 5-1.

[0154] [Example 4.1]

[0155] A radio wave scatterer was prepared in the same manner as in Example 4, except that the height (H) of the convex shape was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0156] [Example 4.2]

[0157] A radio wave scatterer was prepared in the same manner as in Example 4, except that the height (H) of the convex shape was set to 2.5 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0158] [Example 4.3]

[0159] A radio wave scatterer was prepared in the same manner as in Example 4, except that the height (H) of the convex shape was set to 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0160] [Example 4.4]

[0161] A radio wave scatterer was prepared in the same manner as in Example 4, except that the height (H) of the convex shape was set to 6.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0162] [Example 5]

[0163] A resin composition prepared in the same manner as in Example 4 was press-molded using a 50 t vacuum press (manufactured by Meisho Press, MS-VPF-50) under conditions of a hot plate temperature of 200°C and a pressurization time of 20 seconds to process it into a flat plate with a thickness of 3 mm. The processed resin composition was cut to have a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3 mm to produce a support member.

[0164] Similarly, a resin composition prepared in the same manner as in Example 4 was press-molded using a 50-t vacuum press (manufactured by Meisho Press, MS-VPF-50) under conditions of a hot plate temperature of 200°C and a pressurization time of 20 seconds to be processed into a flat plate with a thickness of 5.0 mm. As a convex part (convex section), two sheets of the resin composition processed into a flat plate with a thickness of 5.0 mm were laminated and cut to produce square pyramids with a height (H) of 9.0 mm and a base side (W) of 9.0 mm arranged in a matrix such that the spacing (S) between adjacent square pyramids is 0.0 mm. This was laminated to one surface of a support using double-sided tape (manufactured by Nitto Electric Company, No. 5000NS) to produce a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0165] [Example 6]

[0166] A radio wave scatterer was prepared in the same manner as in Example 1, except that the height (H) of the convex shape was set to 1.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0167] [Example 7]

[0168] A radio wave scatterer was prepared in the same manner as in Example 1, except that the height (H) of the convex rays was 3.0 mm, the width (W) of the convex rays was 1.0 mm, and the spacing (S) between adjacent convex rays was 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-1.

[0169] [Example 8]

[0170] A radio wave scatterer was prepared in the same manner as in Example 1, except that the height (H) of the convex rays was 3.0 mm, the width (W) of the convex rays was 16 mm, and the spacing (S) between adjacent convex rays was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0171] [Example 9]

[0172] A radio wave scatterer was prepared in the same manner as in Example 1, except that the height (H) of the convex rays was 3.0 mm and the spacing (S) of adjacent convex rays was 20 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0173] [Example 10]

[0174] As a convex portion, a polypropylene sphere with a diameter of Φ12.7 mm (1-6602-06, sold by As One Co., Ltd.) was cut in half to produce a hemisphere with an arc cross-section, a height of 6.4 mm, and a width of 12.7 mm. This was arranged on one surface of a flat polypropylene support plate manufactured in Example 3, which has a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm, so that the hemispheres are arranged in a matrix such that the spacing (S) between adjacent hemispheres is 0.0 mm, and then laminated using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) to produce a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0175] [Example 11]

[0176] This embodiment corresponds to the embodiment of FIG. 23. A flat polypropylene plate with a thickness of 2.4 mm (real part of dielectric constant 2.3, imaginary part 0.0) was cut into a short sheet shape to produce a flat support with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (D) of 2.4 mm. Through holes of Φ8 were drilled in the support in a matrix pattern over the entire surface of the support using a drilling machine at intervals (U) of 3.0 mm. Next, a polypropylene plate with a thickness of 2.0 mm (real part of dielectric constant 2.3, imaginary part 0.0) was cut to produce a predetermined number of rectangular bodies with a cross-sectional shape perpendicular to the longitudinal direction that is rectangular, a height (H) of 2.0 mm, a width (W) of 2.0 mm, and a length of 50 mm. These were laminated to one surface of the support using double-sided tape (manufactured by Nitto Denko, No. 5000NS) so that the spacing (S) between adjacent convex sections is 9.0 mm and the convex sections and through holes do not overlap. In addition, a polypropylene plate (real part of dielectric constant 2.3, imaginary part 0.0) was cut to produce a flat member with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T3) of 1.0 mm, and a radio wave scatterer was manufactured by laminating it to the other surface of the support using double-sided tape (manufactured by Nitto Denko, No. 5000NS). The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0177] [Example 12]

[0178] A plate-shaped nylon 6 with a thickness of 1.0 mm (real part of dielectric constant 3.5, imaginary part 0.065) was cut into a flat shape to produce a flat support with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 1.0 mm. Next, as a convex part (convex shape), a plate-shaped nylon 6 with a thickness of 1.0 mm (real part of dielectric constant 3.5, imaginary part 0.0) was cut to produce a predetermined number of rectangular bodies with a cross-sectional shape perpendicular to the longitudinal direction that is rectangular, a height (H) of 1.0 mm, a width (W) of 4.0 mm, and a length of 50 mm. These were laminated onto the surface of one side of the support using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections was 4.0 mm, thereby manufacturing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0179] [Example 13]

[0180] A radio wave scatterer was prepared in the same manner as in Example 12, except that the height (H) of the convex shape was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0181] [Example 14]

[0182] In the same manner as in Example 2, a flat support member was manufactured having a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, as a convex part (convex shape), a polypropylene plate with a thickness of 4.0 mm (real part of dielectric constant 2.3, imaginary part 0.0) was cut to manufacture a predetermined number of rectangular bodies with a cross-sectional shape perpendicular to the longitudinal direction, a height (H) of 4.0 mm, a width (W) of 2.0 mm, and a length of 50 mm, a rectangular body with a height (H) of 4.0 mm, a width (W) of 4.0 mm, and a length of 50 mm, and a rectangular body with a height (H) of 4.0 mm, a width (W) of 8.0 mm, and a length of 50 mm. A radio wave scatterer was manufactured by laminating these onto one surface of a support using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that units of convex shapes with widths of 2.0 mm, 4.0 mm, and 8.0 mm arranged in sequence at a spacing of 4.0 mm were repeated. The characteristics of the obtained radio wave scatterer are shown in Table 5-2.

[0183] [Example 15]

[0184] A radio wave scatterer was prepared in the same manner as in Example 3, except that the width (W) of the convex shape was 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0185] [Example 16]

[0186] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex shape was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0187] [Example 17]

[0188] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex shape was set to 3.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0189] [Example 18]

[0190] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex shape was set to 5.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0191] [Example 19]

[0192] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex shape was set to 7.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0193] [Example 20]

[0194] A radio wave scatterer was prepared in the same manner as in Example 12, except that the height (H) of the convex shape was set to 3.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0195] [Example 21]

[0196] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex shape was set to 9.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0197] [Example 22]

[0198] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex shape was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0199] [Example 23]

[0200] A radio wave scatterer was prepared in the same manner as in Example 3, except that the width (W) of the convex shape was 1.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0201] [Example 24]

[0202] A radio wave scatterer was prepared in the same manner as in Example 2, except that the height (H) of the convex ray was 3.0 mm and the width (W) of the convex ray was 16 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0203] [Example 25]

[0204] A radio wave scatterer was prepared in the same manner as in Example 3, except that the width (W) of the convex shape was 16 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-1.

[0205] [Example 26]

[0206] A radio wave scatterer was prepared in the same manner as in Example 4, except that the spacing (S) of adjacent convex rays was set to 20 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0207] [Example 27]

[0208] A radio wave scatterer was prepared in the same manner as in Example 3, except that the spacing (S) of adjacent convex rays was set to 20 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0209] [Example 28]

[0210] A radio wave scatterer was prepared in the same manner as in Example 12, except that the height (H) of the convex portion was 2.0 mm, the width (W) of the convex portion was 1.0 mm, and the spacing (S) of adjacent convex portions was 1.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0211] [Example 29]

[0212] A radio wave scatterer was prepared in the same manner as in Example 28, except that the spacing (S) of adjacent convex rays was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0213] [Example 30]

[0214] A radio wave scatterer was prepared in the same manner as in Example 28, except that the width (W) of the convex shape was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0215] [Example 31]

[0216] A radio wave scatterer was prepared in the same manner as in Example 28, except that the width (W) of the convex section was 12 mm and the spacing (S) of adjacent convex sections was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0217] [Example 32]

[0218] A radio wave scatterer was prepared in the same manner as in Example 3, except that the height (H) of the convex portion was 6.0 mm, the width (W) of the convex portion was 1.0 mm, and the spacing (S) of adjacent convex portions was 1.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0219] [Example 33]

[0220] A radio wave scatterer was prepared in the same manner as in Example 32, except that the spacing (S) of adjacent convex rays was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0221] [Example 34]

[0222] A radio wave scatterer was prepared in the same manner as in Example 32, except that the width (W) of the convex shape was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0223] [Example 35]

[0224] A radio wave scatterer was prepared in the same manner as in Example 32, except that the width (W) of the convex section was 12 mm and the spacing (S) of adjacent convex sections was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-2.

[0225] [Example 36]

[0226] In the same manner as in Example 12, a flat support was manufactured having a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, a plate-shaped nylon 6 with a thickness of 2.0 mm (real part of dielectric constant 3.5, imaginary part 0.065) was cut to manufacture a square prism with a height (H) of 2.0 mm and a bottom side length (W) of 1.0 mm. This was arranged on one surface of the support so that the spacing (S) between adjacent square prisms was 1.0 mm, and the prisms were laminated using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) to manufacture a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0227] [Example 37]

[0228] A radio wave scatterer was prepared in the same manner as in Example 36, except that the spacing (S) between adjacent square prisms was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0229] [Example 38]

[0230] A radio wave scatterer was prepared in the same manner as in Example 36, except that the width (W) of the square prism was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0231] [Example 39]

[0232] A radio wave scatterer was prepared in the same manner as in Example 36, except that the width (W) of the square prism was 12 mm and the spacing (S) between adjacent square prisms was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0233] [Example 40]

[0234] A radio wave scatterer was manufactured in the same manner as in Example 36, except that as a support member, a flat polypropylene plate (real part of dielectric constant 2.3, imaginary part 0.0) with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm, identical to that of Example 3, was used, and in the manufacture of a square prism, a polypropylene plate (real part of dielectric constant 2.3, imaginary part 0.0) with a thickness of 6.0 mm was used, and the height (H) of the square prism was set to 6.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0235] [Example 41]

[0236] A radio wave scatterer was prepared in the same manner as in Example 40, except that the spacing (S) between adjacent square prisms was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0237] [Example 42]

[0238] A radio wave scatterer was prepared in the same manner as in Example 40, except that the width (W) of the square prism was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0239] [Example 43]

[0240] A radio wave scatterer was prepared in the same manner as in Example 40, except that the width (W) of the square prism was 12 mm and the spacing (S) between adjacent square prisms was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-3.

[0241] [Example 44]

[0242] A flat support member was manufactured in the same manner as in Example 12, with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, a plate-shaped nylon 6 (dielectric constant real part 3.5, imaginary part 0.065) with a thickness of 2.0 mm was cut to produce a predetermined number of triangular prisms as convex parts (convex sections), wherein the cross-sectional shape perpendicular to the longitudinal direction is an isosceles triangle, the height (H) is 2.0 mm, the length (width) (W) of the base of the isosceles triangle cross-section is 1.0 mm, and the length is 50 mm. These were laminated onto one surface of the support member using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections is 1.0 mm, thereby manufacturing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0243] [Example 45]

[0244] A radio wave scatterer was prepared in the same manner as in Example 44, except that the spacing (S) of adjacent convex rays was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0245] [Example 46]

[0246] A radio wave scatterer was prepared in the same manner as in Example 44, except that the width (W) of the convex shape was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0247] [Example 47]

[0248] A radio wave scatterer was prepared in the same manner as in Example 44, except that the width (W) of the convex section was 12 mm and the spacing (S) of adjacent convex sections was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0249] [Example 48]

[0250] A radio wave scatterer was manufactured in the same manner as in Example 44, except that as a support member, a flat polypropylene plate (real part of dielectric constant 2.3, imaginary part 0.0) with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm, identical to that of Example 3, was used, and in the manufacture of the triangular prism, a polypropylene plate (real part of dielectric constant 2.3, imaginary part 0.0) with a thickness of 6.0 mm was used, and the height (H) of the convex part was set to 6.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0251] [Example 49]

[0252] A radio wave scatterer was prepared in the same manner as in Example 48, except that the spacing (S) of adjacent convex sections was set to 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0253] [Example 50]

[0254] A radio wave scatterer was prepared in the same manner as in Example 48, except that the width (W) of the convex shape was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0255] [Example 51]

[0256] A radio wave scatterer was prepared in the same manner as in Example 48, except that the width (W) of the convex section was 12 mm and the spacing (S) of adjacent convex sections was 12 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-4.

[0257] [Example 52]

[0258] A radio wave scatterer was prepared in the same manner as in Example 28, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0259] [Example 53]

[0260] A radio wave scatterer was prepared in the same manner as in Example 19, except that the spacing (S) of adjacent convex rays was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0261] [Example 54]

[0262] A radio wave scatterer was prepared in the same manner as in Example 30, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0263] [Example 53]

[0264] A radio wave scatterer was prepared in the same manner as in Example 31, except that the spacing (S) of adjacent convex rays was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0265] [Example 56]

[0266] A radio wave scatterer was prepared in the same manner as in Example 32, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0267] [Example 57]

[0268] A radio wave scatterer was prepared in the same manner as in Example 34, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0269] [Example 58]

[0270] A radio wave scatterer was prepared in the same manner as in Example 35, except that the spacing (S) of adjacent convex rays was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0271] [Example 59]

[0272] A radio wave scatterer was prepared in the same manner as in Example 36, except that the width (W) of the square prism was 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0273] [Example 60]

[0274] A radio wave scatterer was prepared in the same manner as in Example 37, except that the width (W) of the square prism was 2.0 and the spacing (S) between adjacent square prisms was 10 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0275] [Example 61]

[0276] A radio wave scatterer was prepared in the same manner as in Example 39, except that the spacing (S) between adjacent square prisms was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0277] [Example 62]

[0278] A radio wave scatterer was prepared in the same manner as in Example 40, except that the width (W) of the square prism was 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0279] [Example 63]

[0280] A radio wave scatterer was prepared in the same manner as in Example 41, except that the width (W) of the square prism was 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0281] [Example 64]

[0282] A radio wave scatterer was prepared in the same manner as in Example 43, except that the spacing (S) between adjacent square prisms was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-5.

[0283] [Example 65]

[0284] A radio wave scatterer was prepared in the same manner as in Example 44, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0285] [Example 66]

[0286] A radio wave scatterer was prepared in the same manner as in Example 45, except that the spacing (S) of adjacent convex rays was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0287] [Example 67]

[0288] A radio wave scatterer was prepared in the same manner as in Example 48, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0289] [Example 68]

[0290] A radio wave scatterer was prepared in the same manner as in Example 51, except that the spacing (S) of adjacent convex rays was set to 11 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0291] [Example 69]

[0292] A radio wave scatterer was prepared in the same manner as in Example 40, except that the height (H) of the convex portion was 4.0 mm, the width (W) of the square prism was 4.0 mm, and the spacing (S) of adjacent square prisms was 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0293] [Example 70]

[0294] A radio wave scatterer was prepared in the same manner as in Example 69, except that the arrangement of each square prism was a zigzag arrangement in which the side edges of adjacent square prisms in the inclined direction touch each other, and the spacing (S) between adjacent square prisms in the vertical and horizontal directions is 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0295] [Example 71]

[0296] A radio wave scatterer was prepared in the same manner as in Example 48, except that the height (H) of the convex portion was 4.0 mm and the width (W) of the convex portion was 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0297] [Example 72]

[0298] A radio wave scatterer was prepared in the same manner as in Example 48, except that the height (H) of the convex portion was 4.0 mm, the width (W) of the convex portion was 4.0 mm, and the spacing (S) of adjacent convex portions was 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0299] [Example 73]

[0300] A radio wave scatterer was prepared in the same manner as in Example 48, except that the height (H) of the convex portion was 4.0 mm, the width (W) of the convex portion was 4.0 mm, and the spacing (S) of adjacent convex portions was 3.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0301] [Example 74]

[0302] A radio wave scatterer was prepared in the same manner as in Example 48, except that the height (H) of the convex portion was 4.0 mm, the width (W) of the convex portion was 4.0 mm, and the spacing (S) of adjacent convex portions was 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0303] [Example 75]

[0304] A support member was manufactured by molding a UV-curable acrylic resin (real part of dielectric constant 2.5, imaginary part 0.050) into a flat member with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm using a 3D printer (Agilista, manufactured by Keyence). Similarly, a UV-curable acrylic resin was molded into a square pyramid with a height (H) of 4.0 mm and a bottom side length (W) of 4.0 mm using a 3D printer (Agilista, manufactured by Keyence). This was laminated to one surface of the support member using double-sided tape (No. 5000NS, manufactured by Nitto Electric Co., Ltd.) such that the spacing (S) between adjacent square pyramids was 2.0 mm, thereby manufacturing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0305] [Example 76]

[0306] A radio wave scatterer was prepared in the same manner as in Example 75, except that the spacing (S) of adjacent square pyramids was set to 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-6.

[0307] [Example 77]

[0308] A flat support member was manufactured in the same manner as in Example 3, with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, a polypropylene cylinder with a diameter of Φ8.0 mm and a length of 50 mm (real part of dielectric constant 2.3, imaginary part 0.0) was cut in half to produce a predetermined number of semi-cylinders as convex parts (convex sections), wherein the cross-sectional shape perpendicular to the longitudinal direction is a semicircle, the height (H) is 4.0 mm, the diameter (width) (W) of the cross-section semicircle is 8.0 mm, and the length is 50 mm. These were laminated onto one surface of the support member using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections is 1.0 mm, thereby manufacturing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-7.

[0309] [Example 78]

[0310] A radio wave scatterer was prepared in the same manner as in Example 77, except that the spacing (S) of adjacent convex rays was set to 2.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-7.

[0311] [Example 79]

[0312] A radio wave scatterer was prepared in the same manner as in Example 77, except that the spacing (S) of adjacent convex rays was set to 3.0 mm. The characteristics of the obtained radio wave scatterer are shown in Tables 6-7.

[0313] [Example 80]

[0314] A radio wave scatterer was prepared in the same manner as in Example 77, except that the spacing (S) of adjacent convex rays was set to 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-7.

[0315] [Example 81]

[0316] A radio wave scatterer was manufactured in the same manner as in Example 10, except that a Φ12.7 mm polypropylene sphere (1-6602-05, sold by As One Co., Ltd.) was used for manufacturing the hemispheres, and the arrangement of each hemisphere was in the most crowded arrangement with a spacing (S) of 2.0 mm from all six surrounding hemispheres. The characteristics of the obtained radio wave scatterer are shown in Tables 6-7.

[0317] [Example 82]

[0318] A radio wave scatterer was prepared in the same manner as in Example 81, except that the spacing (S) between adjacent hemispheres was set to 4.0 mm. The characteristics of the obtained radio wave scatterer are shown in Tables 6-7.

[0319] [Example 83]

[0320] A flat support was manufactured in the same manner as in Example 75, with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, a regular hexagonal prism with a height (H) of 5.0 mm and a bottom side length of 2.0 mm (width (W) of 4.0 mm) was manufactured using a 3D printer (Keyence, Agilista) with UV-curable acrylic resin (real part of dielectric constant 2.5, imaginary part 0.050). This was arranged on one surface of the support in a honeycomb pattern such that the spacing (S) between the six surrounding hexagonal prisms was 2.0 mm, and the prisms were laminated using double-sided tape (Nitto Electric, No. 5000NS) to manufacture a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-7.

[0321] [Example 84]

[0322] This embodiment corresponds to the embodiment of FIG. 19. A radio wave scatterer was manufactured except that the width (W) of the convex portion (6) was 2.0 mm and the arrangement of the convex portions was in a zigzag shape as shown in FIG. 19. The specific arrangement of the convex portions is as follows. The height (H) of each convex portion was 4.0 mm, the width (W) was 2.0 mm, and the length was 50 mm. Eight convex portions were arranged so that one end of the convex portion arranged on the far left side roughly coincided with the corner of the support portion, and the distance between the ends of adjacent convex portions (a value measured between the parts where the opposing convex portions (6) rise from the first main surface (2)) was 8 mm, and the other end of the adjacent convex portions was arranged to be in contact. In this arrangement, the spacing between adjacent convex rays was 4 mm with respect to the position of the longitudinal midpoint of the convex rays. The characteristics of the obtained radio wave scatterer are shown in Table 6-8.

[0323] [Example 85]

[0324] This embodiment corresponds to the embodiment of FIG. 20. A radio wave scatterer was manufactured except that the width (W) of the convex portion (6) is 2.0 mm and the arrangement of the convex portions is radial as shown in FIG. 20. The specific arrangement of the convex portions is as follows. The height (H) of each convex portion is 4.0 mm, the width (W) is 2.0 mm, and the length is 50 mm. One convex portion was arranged on a straight line connecting the midpoints of the upper and lower sides of the support portion. Next, convex portions were arranged on both sides of this convex portion such that the upper portions of adjacent convex portions are in contact with each other and the distance between the lower portions of adjacent convex portions is 8 mm. Additionally, convex portions were arranged on the outer side of each of these convex portions such that the upper portions of adjacent convex portions are in contact with each other and the distance between the lower portions of adjacent convex portions is 8 mm. The characteristics of the obtained radio wave scatterer are shown in Table 6-8.

[0325] [Example 86]

[0326] This embodiment corresponds to the embodiment of FIG. 25. In the same manner as in Example 3, a flat support member was manufactured having a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, a polypropylene plate with a thickness of 2.0 mm was cut to produce a predetermined number of rectangular bodies as convex parts (convex sections), wherein the cross-sectional shape in the direction perpendicular to the length direction is rectangular, and the height is 2.0 mm, the width is 4.0 mm, and the length is 50 mm. These were laminated to one surface of the support member using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections is 4.0 mm. Next, a polypropylene plate with a thickness of 2.0 mm was cut to produce a predetermined number of rectangular bodies as convex parts (convex sections), each having a rectangular cross-sectional shape perpendicular to the length direction, a height of 2.0 mm, a width of 2.0 mm, and a length of 50 mm. Each of these was then laminated to the respective surface of the convex section with a width of 4.0 mm using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the centers in the width direction coincided with each other, thereby producing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-8.

[0327] [Example 87]

[0328] This embodiment corresponds to the embodiment of FIG. 24. A radio wave scatterer was manufactured in the same manner as in Example 16, except that a convex shape with a height (H) of 2.0 mm was laminated to the other surface of the support member at a position opposite to the convex shape laminated to one surface of the support member. The characteristics of the obtained radio wave scatterer are shown in Table 6-8.

[0329] [Example 88]

[0330] In the same manner as in Example 3, a flat support member was manufactured having a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. Next, a polypropylene plate with a thickness of 4.0 mm was cut to produce a predetermined number of rectangular bodies, each having a rectangular cross-sectional shape perpendicular to the longitudinal direction, a height (H) of 4.0 mm, a width (W) of 12 mm, and a length of 50 mm. Then, three of the obtained rectangular bodies were laminated together using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) to produce a predetermined number of rectangular bodies as convex parts (convex parts), each having a height (H) of 12 mm, a width (W) of 12 mm, and a length of 50 mm. These were laminated onto one surface of a support using double-sided tape (manufactured by Nitto Electric Co., Ltd., No. 5000NS) so that the spacing (S) between adjacent convex sections was 12 mm, thereby manufacturing a radio wave scatterer. The characteristics of the obtained radio wave scatterer are shown in Table 6-8.

[0331] [Comparative Example 1]

[0332] A polypropylene plate with a thickness of 3.0 mm (real part of dielectric constant 2.3, imaginary part 0.0) was cut to produce a flat member with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. The characteristics of the obtained flat member are shown in Table 5-2.

[0333] [Comparative Example 2]

[0334] A resin composition prepared in the same manner as in Example 4 was press-molded using a 50 t vacuum press (manufactured by Meisho Press, MS-VPF-50) under conditions of a hot plate temperature of 200 ℃ and a pressurization time of 20 seconds to process it into a flat plate with a thickness of 3.0 mm. The processed resin composition was cut to have a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm to produce a flat plate member. The characteristics of the obtained flat plate member are shown in Table 5-2.

[0335] [Comparative Example 3]

[0336] A planar member was prepared in the same manner as Comparative Example 1, except that an acrylic elastomer (manufactured by Kuraray, LA2330) was used as the resin composition. The characteristics of the obtained planar member are shown in Table 5-2.

[0337] [Comparative Example 4]

[0338] A polypropylene plate with a thickness of 3.0 mm (real part of dielectric constant 3.5, imaginary part 0.065) was cut to produce a flat member with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm. The characteristics of the obtained flat member are shown in Table 5-2.

[0339] [Comparative Example 5]

[0340] UV-curable acrylic resin (real part of dielectric constant 2.5, imaginary part 0.050) was molded into a flat member with a width (Q) of 50 mm, a length (P) of 50 mm, and a thickness (T1) of 3.0 mm using a 3D printer (Agilista, manufactured by Keyence). The characteristics of the obtained flat member are shown in Table 6-8.

[0341] [Table 5-1]

[0342]

[0343] [Table 5-2]

[0344]

[0345] [Table 6-1]

[0346]

[0347] [Table 6-2]

[0348]

[0349] [Table 6-3]

[0350]

[0351] [Table 6-4]

[0352]

[0353] [Table 6-5]

[0354]

[0355] [Table 6-6]

[0356]

[0357] [Table 6-7]

[0358]

[0359] [Table 6-8]

[0360]

[0361] [evaluation]

[0362] (Measurement of dimensions)

[0363] The dimensions of the radio wave scatterer, the height, width, and length of the bulges formed on the radio wave scatterer, and the spacing between adjacent bulges were measured using a vernier caliper.

[0364] (Measurement of egg-laying rate)

[0365] The scattering rate was measured using the same measurement method as described in the [Radio Wave Scattering] section above. The transmission attenuation was measured at 60 to 90 GHz using a radio transceiver (EAS03, manufactured by Kicom Co., Ltd.) in accordance with the following sequence, with reference to JIS R 1679. The transmission attenuation is expressed as the absolute value of the value calculated by the following equation (1).

[0366] 10Log|P i / P0|… (1) (P i : Received power, P0: Transmitted power)

[0367] As shown in the schematic of FIG. 6, a sample holder (11), a millimeter wave lens (12), a transmitter (9), and a receiver (10) are arranged. From the transmitter (9), a radio wave with a diameter of 150 mm is transmitted. The transmitter (9) and the receiver (10) are arranged, and transmission and reception of the radio wave are performed with nothing set in the sample holder (11), and the state in which the transmission attenuation is 0 dB (the radio wave is transmitted in its entirety) is used as the standard for measuring the transmission attenuation of the incident wave perpendicular to the plane direction of each radio wave scatterer. Next, after setting the radio wave scatterer in the sample holder (11), the receiver was installed at angles of 0°, 15°, 30°, 45°, 60°, and 75° respectively with respect to the direction from the transmitter (9) to the receiver (10), which is perpendicular to the plane direction of each sample, and transmission and reception of radio waves were performed, and the amount of transmission attenuation at 76.5 GHz was measured. In addition, if the structure of the radio wave scatterer is a convex shape, the measurement was taken in a state where the length direction of the convex shape formed on the first main surface is perpendicular to the amplitude direction of the electric field of the incident wave. Based on the measured values ​​of the amount of transmission attenuation at each angle of 0°, 15°, 30°, 45°, 60°, and 75°, each P from the above equation (1) i Calculate / P0 (receive / transmit power ratio), and each calculated P i Based on / P0 (received / transmitted power ratio), scattering rate I and scattering rate II were calculated by the following equations (2.1) and (2.2).

[0368] (Laying rate I) = (P at 15°, 30°, 45°, 60°, 75°) i / Sum of P0 (receive / transmit power ratio) / (P at 0° i / P0(receive / transmit power ratio)) × 100 … (2.1)

[0369] (Laying rate II) = (P at 15°, 30°, 45°, 60°, 75°) i / Sum of P0 (receive / transmit power ratio) / (P at 0°, 15°, 30°, 45°, 60°, 75°) i / Sum of P0 (receive / transmit power ratio)) × 100 … (2.2)

[0370] Here, if the spawning rate I is d1 and the spawning rate II is d2, it can be converted to the following equation (2.3).

[0371] d2 = (100d1 / (100 + 100d1)) × 100... (2.3)

[0372] In addition, in the above method for measuring the scattering rate, the interval of the reception angle of the transmitted wave was set to 5° intervals, and the scattering rate III was calculated by the following equation (2.4).

[0373] (Laying rate III) = (P at 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° i / Sum of P0 (receive / transmit power ratio) / (P at 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° i / Sum of P0 (receive / transmit power ratio) × 100 … (2.4)

[0374] (Measurement of specific permittivity and transmittance)

[0375] FIG. 34 is a diagram illustrating a schematic method for measuring reflection attenuation. First, for the planar members of Comparative Examples 1 to 4, the reflection attenuation was measured at 70 to 90 GHz using a radio wave transceiver (EAS02, manufactured by Kicom Co., Ltd.) in accordance with the following sequence, referring to JIS R 1679. As shown in the schematic in FIG. 34, a sample holder (11) and a transceiver (13) were arranged, and a reference metal was set on the sample holder (11) to perform transmission and reception of radio waves. For the reference metal, a stainless steel plate with a size of Φ150 mm and a thickness of 2 mm was used. At this time, the reflection attenuation was set to a level of 0 dB (total reflection of radio waves) and used as the standard for measuring the reflection attenuation of incidence perpendicular to the plane direction of each planar member. Then, instead of the above reference metal, each flat plate member was set in the sample holder (11) to transmit and receive radio waves, and the amount of reflection attenuation was measured.

[0376] Next, the amount of transmission attenuation was measured for the flat members of Comparative Examples 1 to 4 using the same measurement method as described in the section (Measurement of amount of transmission attenuation) below.

[0377] Next, using the values ​​of the reflection attenuation of the planar members and the transmission attenuation of the straight-line transmitted wave measured in Comparative Examples 1 to 4, the transmittance was calculated as follows.

[0378] Let Z0 be the impedance of air and μ be the relative permeability. r (= μ r ' - jμ r "), relative permittivity ε r (= ε r ' - jε r "), if the wavelength is λ, the material impedance Z and propagation constant γ are expressed by the following equations (6) and (7).

[0379]

[0380] When the thickness of the object is d, from the above Z and γ, the reflection attenuation and transmission attenuation are expressed by the following equations (8) and (9) according to transmission line theory.

[0381] Transmission attenuation (dB) = 20log{2 / (A + B / Z0+ CZ0+ D)} … (8)

[0382] Reflection attenuation (dB) = 20log{(A + B / Z0- CZ0- D) / (A + B / Z0+ CZ0+ D)} … (9)

[0383] Here, A = cosh (γd), B = Zsinh (γd), C = (1 / Z)sinh (γd), D = cosh (γd).

[0384] At this time, μ r , and expected predetermined ε r Substitute into equations (6) and (7), and based on the obtained Z, γ and the measured thickness d, the reflection attenuation and transmission attenuation at 70 to 90 GHz are calculated from equations (8) and (9), respectively.

[0385] For the curve of reflection attenuation calculated from the actual values ​​and the curve of reflection attenuation calculated from the above equations (6), (7), and (9), and for the curve of transmission attenuation calculated from the actual values ​​and the curve of transmission attenuation calculated from the above equations (6) to (8), curve fitting by the least squares method is performed, and a plausible ε r Derive and set this as the relative permittivity of each planar member. FIGS. 35a and 35b are drawings illustrating an example of this curve fitting. The expected predetermined ε r 을 ε r ' : 3.50, ε r When " : 0.20, as shown in Fig. 35a, the two curves diverge, but ε r By performing curve fitting using the least squares method by varying , the ε at which the error between the two curves is minimized r This εr ' : 2.73, ε r " : 0.06 is obtained, and at this time, both curves are fitted as shown in Fig. 35b.

[0386] Induced ε r Based on Z and γ obtained by using and substituting them back into equations (6) and (7), the transmittance (%) when the thickness d is 3 mm is calculated by the following equation (10).

[0387] Transmittance (%) = 2 / (A + B / Z0 + CZ0 + D) × 100 … (10)

[0388] (Calculation of transmission attenuation)

[0389] Except for differences in the measuring device, the device of the measurement frequency, the diameter of the transmitted wave, and the fact that only the direct transmission wave was measured as transmission attenuation, the transmission attenuation was measured using the same measurement method as described in the above (measurement of scattering rate) section. The transmission attenuation was measured at 70 to 90 GHz using a radio transceiver (EAS02, manufactured by Kicom Co., Ltd.) in accordance with the order shown below, with reference to JIS R 1679. The transmission attenuation is expressed as the absolute value of the value calculated by the following equation (1).

[0390] 10Log|P i / P0|… (1) (P i : Received power, P0: Transmitted power)

[0391] As shown in the schematic of FIG. 6, a sample holder (11), a millimeter wave lens (12), a transmitter (9), and a receiver (10) were arranged. From the transmitter (9), a radio wave with a diameter of 30 mm was transmitted. After arranging the transmitter (9) and the receiver (10), transmission and reception of the radio wave were performed with nothing set in the sample holder (11), and the state where the transmission attenuation was 0 dB (the radio wave was transmitted in its entirety) was used as the standard for measuring the transmission attenuation of the incident wave perpendicular to the plane direction of each radio wave scatterer. Next, each sample was set in the sample holder (11) and transmission and reception of the radio wave were performed, and the transmission attenuation at 76.5 GHz was measured. In addition, regarding the electromagnetic wave scatterer of the example, the sample was formed by applying a designated convex portion to a support having a width (Q) of 50 mm and a length (P) of 50 mm, and in the case of a convex shape, the measurement was performed in a state where the length direction of the convex shape formed on the main surface was perpendicular to the amplitude direction of the electric field of the incident wave. In addition, regarding the measurement positions, a total of 5 points were measured at the center of the sample, offset by 5 mm to the left and 10 mm to the right, and the average value was evaluated.

[0392] (evaluation)

[0393] From Tables 5-1 to 5-2 and Tables 6-1 to 6-8, the following points could be observed. While the transmission attenuation of the straight-line transmitted wave was 0 to 2 dB in each comparative example, in each embodiment it was 2.9 dB or higher, exceeding each comparative example. That is, the wave scatterer of each embodiment was able to effectively attenuate the straight-line transmitted wave.

[0394] In addition, the following points could be found from Tables 5-1 to 5-2 and Tables 6-1 to 6-8. In each comparative example, the transmission attenuation amount of the straight transmitted wave was 0 to 2 dB, whereas in each comparative example, the height (H), width (W), and spacing (S) of the convex portion (6) are set to 0.51λ or more and 1.5λ or less, 0.26λ or more and 3.1λ or less, and 0.51λ or more and 2.6λ or less when the wavelength of the incident wave is λ, in Examples 1 to 4.4, 8, 9, 11, 13, 14, 16 to 19, 21, 54, 57, 60, 61, 63, 69, 70, 72 to 76, 78 to 82 (in the case where the convex portion (6) is convex, 0.51λ or more and 1.5λ or less, 0.26λ or more and 3.1λ or less, and Examples 1 to 4.4, 7, 8, 9, 11, 13, 14, 16 to 19, 21, 23, 33, 37, 38, 42, 46, 47, 49, 50, 52 to 58, 65 to 68, 78 to 80, where the convex portion (6) is a dot shape, 0.51λ to 1.5λ, 0.51λ to 3.1λ, and 0.51λ to 2.6λ (Examples 37, 42, 59 to 64, 69, 70, 72 to 76, 81, 82) have a value of 4.0 dB or higher, which is higher than each comparative example. That is, in the wave scatterer of each embodiment, the straight-line transmitted wave could be attenuated more effectively.

[0395] In addition, from Tables 5-1 to 5-2 and Tables 6-1 to 6-8, the following points could be observed. While the transmission attenuation of the straight-line transmitted wave was 0 to 2 dB in each comparative example where the convex volume ratio was 0%, there were cases where 5.0 dB or more could be achieved when the convex volume ratio was 3% or more and 90% or less, cases where 10.0 dB or more could be achieved when the convex volume ratio was 15% or more and 65% or less, and cases where 15.0 dB or more could be achieved when the convex volume ratio was 25% or more and 55% or less. That is, it was found that in a radio wave scatterer having the above convex volume ratio, the straight-line transmitted wave can be effectively attenuated.

[0396] In addition, Example 11 showed good transmission attenuation. Therefore, it can be seen that a configuration in which a hole is formed in the support portion of the radio wave scatterer can achieve good attenuation of straight-line transmitted waves while suppressing an increase in the weight of the radio wave scatterer.

[0397] Table 3 and Figure 10 show the transmission attenuation amounts at each reception angle of Example 3 and Example 14. From Table 3 and Figure 10, the following points could be observed. In Example 3, the transmission attenuation amount increases at a reception angle of 30° in a specific direction, whereas in Example 14, the transmission attenuation amount is uniform in each direction of the reception angle, so strong radio waves are not emitted in a specific direction, and thus the emission of strong radio waves can be effectively suppressed. Therefore, it is believed that by mixing different widths in a repeating structure of width and spacing, mutual reinforcement in a specific direction is suppressed, and thus the emission of strong radio waves can be effectively suppressed in any emission direction.

[0398] Although the present invention has been described above with reference to the drawings for specific embodiments, numerous modifications are possible in addition to the configurations shown and described. Accordingly, the present invention is not limited to the configurations shown and described, and its scope should be determined only by the appended claims and their equivalents. Explanation of the symbols

[0399] 1 : Radio wave scatterer 2 : 1st week 3 : The second week 4 : Support 5 : Structural part 6: Convex part 7: Hole part 8 : Unit structure 81 : Unit structural space 83: Floor surface of the unit structure 10: Radar Assembly 11 : Vehicle 31: Cover part H: Height of the convex part W: Width of the convex portion S: Spacing of the convex parts D: Depth of the hole U: Spacing of the hole V: Width of the hole

Claims

Claim 1 A radio wave scatterer composed of a resin composition having a resin as the main component, configured such that at least a portion of the incident radio waves are transmitted and the transmitted radio waves are emitted in a scattered state, wherein the radio wave scatterer has at least two surfaces, one of which constitutes a radio wave incident surface and the other constitutes an emission surface, and a structural part that generates scattering of radio waves is formed on at least one of the two surfaces, wherein the structural part is composed of at least one convex part and / or a hole part, and when the wavelength of the incident radio wave is λ, the height of the convex part is 0.26λ or more, the width of the convex part is 0.26λ or more, and the spacing of the convex part is 5.1λ or less, and / or, the depth of the hole part is 0.26λ or more, the width of the hole part is 5.1λ or less, and the spacing of the hole part is 0.26λ or more, and wherein the resin composition has a complex relative permittivity and at any frequency of 10 to 300 GHz A radio wave scatterer in which the imaginary part ε" of the relative permittivity is 0.1 or less. Claim 2 In claim 1, the resin composition is a radio wave scatterer that transmits at least 50% of radio waves incident perpendicularly to a 3 mm thick plate made of the resin composition. Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 In claim 1, the resin composition is a radio wave scatterer in which the real part ε' of the relative permittivity is 2 or more and 4 or less at any frequency of 10 to 300 GHz. Claim 8 A member for attenuating radio waves having a radio wave scatterer as described in claim 1. Claim 9 In claim 8, the member for attenuating the above-mentioned radio waves is a molded body, and the radio wave scattering body is formed in at least a part thereof. Claim 10 In claim 8, the member for attenuating the above-mentioned radio waves is a member that is a cover member of the radar. Claim 11 A radar assembly in which a radar is mounted on a cover member of the radar described in claim 10. Claim 12 A bumper comprising a member for attenuating the radio waves described in claim 8. Claim 13 A vehicle having a member described in any one of claims 8 to 10, a radar assembly described in claim 11, and / or a bumper described in claim 12.

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