Laminate

Abstract

To provide a laminate that suppresses the decrease in radio wave transmittance.SOLUTION: A laminate according to an embodiment of the present invention includes a base layer having a first surface on one side in a thickness direction, through which radio waves are incident, and a second surface on the other side in the thickness direction, through which radio waves are emitted, and a conductor layer having a plurality of conductor patterns disposed at positions spaced apart from each other on the first surface, and the thickness d of the base layer satisfies the formula (1). [(0.2639×λ) / (ε)1 / 2]≤d≤[(0.4873×λ) / (ε)1 / 2] (1).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate. [Background technology]

[0002] Patent Document 1 discloses a laminate for suppressing a decrease in the reception strength of radio waves at a receiving device in a mobile communication system. The laminate disclosed in Patent Document 1 includes a substrate and a plurality of array elements each having a conductor patch formed on the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5177708 Summary of the Invention [Problem to be solved by the invention]

[0004] Recent mobile communication systems use radio waves with shorter wavelengths than conventional systems. As a result, in a base layer such as a substrate, the optical path difference between a first reflected wave from a first surface where the radio waves are incident and a second reflected wave from a second surface on the opposite side of the thickness direction from the first surface may correspond to the optical length of one wavelength of the radio waves. In this case, the first reflected wave and the second reflected wave reinforce each other, which may result in a decrease in the transmittance of the radio waves to the second surface.

[0005] An object of the present invention is to provide a laminate that suppresses a decrease in transmittance of radio waves. [Means for solving the problem]

[0006] A laminate according to one embodiment of the present invention comprises a base layer on one side in a thickness direction, the base layer having a first surface on which radio waves are incident and a second surface on the other side in the thickness direction, the second surface from which radio waves are emitted, and conductor layers each having a plurality of conductor patterns arranged at positions spaced apart from each other on the first surface, wherein the thickness d of the base layer satisfies formula (1), where λ is the wavelength of the radio waves, d is the thickness of the base layer, and ε is the dielectric constant of the base layer. [(0.2639×λ) / (ε) 1 / 2 ]≦d≦[(0.4873×λ) / (ε) 1 / 2 ] ···(1) [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a laminate that suppresses a decrease in transmittance of radio waves. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic plan view of a laminate according to an embodiment. [Figure 2] 2 is a cross-sectional view showing a schematic cross section of the laminate according to the embodiment, taken along line II-II in FIG. 1. FIG. [Figure 3] 10A and 10B are schematic plan views for explaining modified examples of conductor patterns in conductor layers included in the laminate according to the embodiment. [Figure 4] 10A and 10B are schematic plan views for explaining other modified examples of conductor patterns in conductor layers included in the laminate according to the embodiment. [Figure 5] 10 is a graph showing an example of the transmission characteristics of a laminate when the distance between two adjacent conductor patterns is changed. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same components are given the same reference numerals, and duplicated descriptions will be omitted as appropriate.

[0010] The embodiments shown below are examples of laminates for embodying the technical concept of the present invention, and the present invention is not limited to the embodiments shown below. The dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustration purposes only, and are not intended to limit the scope of the present invention unless otherwise specified. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated for clarity of explanation.

[0011] In the drawings shown below, directions may be indicated by the mutually orthogonal X-axis, Y-axis, and Z-axis. The X-axis direction corresponds to the width direction of the laminate according to the embodiment. The Y-axis direction corresponds to the depth direction of the laminate according to the embodiment. The Z-axis direction corresponds to the thickness direction of the laminate according to the embodiment. A direction parallel to the XY plane including the X-axis direction and the Y-axis direction may be referred to as an in-plane direction. The Z-axis direction may also be referred to as a thickness direction.

[0012] The direction in which the arrow points along the X-axis is referred to as the +X direction or +X side, and the direction opposite to the +X direction is referred to as the -X direction or -X side. The direction in which the arrow points along the Y-axis is referred to as the +Y direction or +Y side, and the direction opposite to the +Y direction is referred to as the -Y direction or -Y side. The direction in which the arrow points along the Z-axis is referred to as the +Z direction or +Z side, and the direction opposite to the +Z direction is referred to as the -Z direction or -Z side.

[0013] [Embodiment] An example of the configuration of a laminate 1 according to an embodiment will be described with reference to Fig. 1 to Fig. 5. Fig. 1 is a schematic plan view of the laminate 1. Fig. 2 is a cross-sectional view showing a schematic cross section of the laminate 1 taken along line II-II in Fig. 1. Fig. 3 is a schematic plan view illustrating a modified example of the conductor pattern 21 in the conductor layer 20 included in the laminate 1. Fig. 4 is a schematic plan view illustrating another modified example of the conductor pattern 21 in the conductor layer 20 included in the laminate 1. Fig. 5 is a graph showing an example of the transmission characteristics of the laminate 1 when the inter-pattern distance PD between two adjacent conductor patterns 21 is changed.

[0014] The laminate 1 is a structure that transmits, for example, radio waves 2RW having a frequency of about 3 GHz or more and about 30 GHz or less, called microwaves, and radio waves 2RW having a frequency of about 30 GHz or more and about 300 GHz or less, called millimeter waves. However, the laminate 1 may also be a structure that transmits radio waves 2RW having a frequency below 3 GHz. The laminate 1 may also transmit radio waves 2RW having a frequency above 300 GHz.

[0015] 1 and 2, the laminate 1 includes a base layer 10 and a conductor layer 20. The laminate 1 may further include other components such as a support layer 30 that supports the conductor layer 20 and an adhesive layer 40 that bonds the support layer 30 to the base layer 10. The components included in the laminate 1 will be described in detail below.

[0016] <Base material layer 10> An example of the configuration of the base layer 10 will be described. As shown in Figs. 1 and 2, the base layer 10 is a plate-like member having a first surface 11a on one side in the thickness direction and a second surface 11b on the other side in the thickness direction. In the example shown in Fig. 1, the base layer 10 has a substantially rectangular shape in plan view. However, the base layer 10 may have other shapes in plan view, such as a substantially circular shape, a substantially elliptical shape, or a substantially polygonal shape other than a rectangle.

[0017] In the example shown in Figures 1 and 2, the first surface 11a is on the +Z side of the base layer 10. The first surface 11a corresponds to the incident surface onto which the radio waves 2RW are incident. The second surface 11b is on the -Z side of the base layer 10. The second surface 11b corresponds to the exit surface from which the radio waves 2RW that have passed through the base layer 10 are emitted. The first surface 11a and the second surface 11b face each other in the thickness direction. Note that the radio waves 2RW shown in Figure 2 are incident on the first surface 11a along the Z-axis direction. That is, the radio waves 2RW shown in Figure 2 are incident on the first surface 11a at an incident angle of 0°. However, the incident angle of the radio waves 2RW is not limited to 0°.

[0018] Examples of materials constituting the substrate layer 10 include glass, resin, and ceramics, as well as composites containing two or more of these, all of which are transparent to radio waves 2RW. Examples of glass include soda glass, borosilicate glass, and quartz glass. Examples of resins include homopolymers and copolymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polypropylene (PP), polyethylene, polycycloolefin, polyurethane, acrylic (PMMA), and ABS. Examples of ceramics include aluminum nitride, aluminum oxide, and silicon carbide.

[0019] The relative dielectric constant ε of the base layer 10 is arbitrary, but is preferably, for example, 4.0 or more from the viewpoint of improving the transmission function at the frequency of the radio waves 2RW. However, the relative dielectric constant ε of the base layer 10 is not limited to this. Hereinafter, the relative dielectric constant ε of the base layer 10 will be simply referred to as "dielectric constant ε."

[0020] In the base material layer 10, the length d along the thickness direction between the first surface 11a and the second surface 11b is arbitrary. Hereinafter, in the base material layer 10, the length d along the thickness direction between the first surface 11a and the second surface 11b will be referred to as the "thickness d". Examples of the thickness d of the base material layer 10 include 1 mm or more and 20 mm or less. Furthermore, the thickness d of the base material layer 10 may be 5 mm or more and 20 mm or less. Furthermore, the thickness d of the base material layer 10 may be 10 mm or more and 20 mm or less. However, the thickness d of the base material layer 10 is not limited to these.

[0021] The thickness d satisfies the relationship of formula (1) between the wavelength λ of the radio wave 2RW and the dielectric constant ε of the base layer 10. [(0.2639×λ) / (ε) 1 / 2 ]≦d≦[(0.4873×λ) / (ε) 1 / 2 ] ···(1) Here, the wavelength λ of the radio wave 2RW is the wavelength in the atmosphere. The wavelength λ of the radio wave 2RW may be considered to be the wavelength in a vacuum. The effects when the relationship of formula (1) is satisfied will be explained separately.

[0022] <Conductor layer 20> An example of the configuration of the conductor layer 20 will be described. As shown in FIGS. 1 and 2, the conductor layer 20 has a plurality of conductor patterns 21. The plurality of conductor patterns 21 are arranged at positions spaced apart from each other on the first surface 11a of the base layer 10. For example, the plurality of conductor patterns 21 are periodically arranged along each of the X-axis direction and the Y-axis direction. However, the arrangement direction of the plurality of conductor patterns 21 may be a direction different from the X-axis direction and the Y-axis direction. In the example shown in FIGS. 1 and 2, no conductor layer 20 is arranged in the space between adjacent conductor patterns 21.

[0023] The size of each of the plurality of conductor patterns 21 is arbitrary. Furthermore, of the plurality of conductor patterns 21, two adjacent conductor patterns 21 are arranged with a pattern distance PD between them. Here, the pattern distance PD is the shortest distance between adjacent conductor patterns 21, as shown in FIG. 1 . The pattern distance PD is arbitrary. Examples of the pattern distance PD include a range of 0.0001 mm to 10 mm. The pattern distance PD may also be 0.0001 mm to 5 mm. Furthermore, the pattern distance PD may also be 0.0001 mm to 1 mm. Furthermore, the pattern distance PD may also be 0.0001 mm to 0.5 mm. However, the pattern distance PD is not limited to these.

[0024] An example of the thickness of each of the multiple conductor patterns 21 is 1 nm or more and 30 μm or less. However, the thickness of each of the multiple conductor patterns 21 is not limited to this. The thickness of each of the multiple conductor patterns 21 is smaller than the thickness d of the base layer 10 by, for example, about two orders of magnitude. Therefore, the thickness d of the base layer 10 accounts for most of the overall thickness of the laminate 1, while the thickness of the conductor patterns 21 can be ignored. Furthermore, the size of each of the multiple conductor patterns 21 in the in-plane direction is also arbitrary.

[0025] Examples of materials that may be used to form each of the plurality of conductive patterns 21 include metals such as titanium, silicon, niobium, indium, zinc, tin, gold, silver, copper, aluminum, cobalt, chromium, nickel, lead, iron, palladium, platinum, tungsten, zirconium, tantalum, and hafnium; conductive metal oxides such as ITO (oxide of indium and tin), zinc oxide, and tin oxide; and materials containing two or more of these metals or metal oxides, or alloys containing these metals as the main component.

[0026] In the example shown in FIG. 1, each of the multiple conductor patterns 21 has a substantially circular shape in plan view. However, each of the multiple conductor patterns 21 may have other shapes in plan view, such as a substantially oval shape, or a substantially polygonal shape including a substantially rectangular shape. The conductor pattern 21 shown in FIG. 1 may be referred to as a "single-core type." The diameter (size in the in-plane direction) of the single-core conductor pattern 21 is arbitrary. An example of the diameter of the single-core conductor pattern 21 is 1 mm or more and 10 mm or less. However, the diameter of the single-core conductor pattern 21 is not limited to this.

[0027] 3, each of the plurality of conductor patterns 21 may have a configuration in which a first rectangular pattern 21b1 extending in the X-axis direction intersects with a second rectangular pattern 21b2 extending in the Y-axis direction. As shown in FIG. 3, the first rectangular pattern 21b1 and the second rectangular pattern 21b2 are orthogonal to each other. The conductor pattern 21 shown in FIG. 3 may be referred to as a "cross-dipole type." When each of the plurality of conductor patterns 21 is a cross-dipole type, the inter-pattern distance PD corresponds to the distance between the opposing ends of the first rectangular patterns 21b1 (second rectangular patterns 21b2) of each of two adjacent conductor patterns 21.

[0028] 4, each of the plurality of conductor patterns 21 may have a comb-like pattern arranged on its periphery. Specifically, each of the plurality of conductor patterns 21 shown in FIG. 4 has a square base portion 21c and a rectangular peripheral portion 21d that is joined perpendicularly to each of the four sides of the basic portion 21c. In FIG. 4, three peripheral portions 21d are joined to each side of the basic portion 21c. However, the number of peripheral portions 21d is not limited to this. The conductor pattern 21 shown in FIG. 4 may be referred to as a "comb-like" pattern. When each of the plurality of conductor patterns 21 is a comb-like pattern, the inter-pattern distance PD corresponds to the distance between one side of the basic portion 21c of one of two adjacent conductor patterns 21 and the end of the peripheral portion 21d of the other conductor pattern 21 that faces the side of the basic portion 21c.

[0029] Next, with reference to FIG. 5, the transmission characteristics of the laminate 1 when the inter-pattern distance PD between two adjacent conductor patterns 21 is changed will be described. In the example shown in FIG. 5, a mono-core conductor pattern 21 is used. FIG. 5 is a graph showing an example of the transmittance T [dB] of each of a plurality of laminates 1 having different inter-pattern distances PD. Here, when the incident intensity of the radio wave 2RW incident from the first surface 11a side of the base material layer 10 after passing through the conductor layer 20 is I0 and the outgoing intensity of the radio wave 2RW emitted from the second surface 11b side of the base material layer 10 is T0, the "transmittance T" in this specification is expressed as "T = T0 / I0". Note that when the unit [dB] is written together with "transmittance T" or the like, that is, when written as "transmittance T [dB]", the value obtained by multiplying the common logarithm of the transmittance T by the number "20" (20 × log 10 T).

[0030] The horizontal axis of Fig. 5 corresponds to the frequency of the radio wave 2RW incident from the first surface 11a side of the base layer 10. The vertical axis of Fig. 5 corresponds to the transmittance T [dB]. On the vertical axis of Fig. 5, a larger value indicates a higher transmittance T [dB] of the radio wave 2RW. On the other hand, on the vertical axis of Fig. 5, a smaller value indicates a lower transmittance T [dB] of the radio wave 2RW.

[0031] The solid line L1 in FIG. 5 indicates the transmission characteristics of the laminate 1 having a pattern distance PD of 0.5 mm. The laminate 1 in this case is sometimes referred to as "Sample 1." The dashed-dotted line L2 in FIG. 5 indicates the transmission characteristics of the laminate 1 having a pattern distance PD of 0.001 mm. The laminate 1 in this case is sometimes referred to as "Sample 2." In contrast, the dashed-two-dotted line L3 in FIG. 5 indicates the transmission characteristics of the base layer 10 alone. The base layer 10 alone in this case is sometimes referred to as "Reference 1."

[0032] 5, the transmittance T increases and decreases periodically in each of Sample 1, Sample 2, and Reference 1. That is, the transmittance T of each of Sample 1, Sample 2, and Reference 1 increases and decreases in a wave-like manner according to the frequency of the radio wave 2RW.

[0033] At frequencies corresponding to the multiple peaks on each of the lines L1, L2, and L3, the first reflected wave reflected by the first surface 11a of the base layer 10 and the second reflected wave reflected by the second surface 11b of the base layer 10 of the radio wave 2RW act to weaken each other. Therefore, at frequencies corresponding to the multiple peaks on each of the lines L1, L2, and L3, the reflection loss is reduced and the transmittance T is increased.

[0034] In contrast, at frequencies corresponding to the multiple valleys in each of the lines L1, L2, and L3, the first reflected wave reflected by the first surface 11a of the base layer 10 and the second reflected wave reflected by the second surface 11b of the base layer 10 of the radio wave 2RW act to reinforce each other. Therefore, at frequencies corresponding to the multiple valleys in each of the lines L1, L2, and L3, the reflection loss increases and the transmittance T decreases.

[0035] Of the multiple peaks where the transmittance T is high, the peak corresponding to the lowest frequency will be referred to as the "first peak" hereinafter. Furthermore, the peaks that appear sequentially as the frequency increases will be referred to as the "second peak," "third peak," ..., and "nth peak," respectively. Each of the "first peak," "second peak," "third peak," ..., and "nth peak" is an example of a "peak of transmittance T."

[0036] As shown in Fig. 5, the first peaks in Sample 1 and Sample 2, which have conductive patterns 21, are shifted to lower frequencies compared to the first peak in Reference 1, which is the base layer 10 alone. Furthermore, when comparing Sample 1 and Sample 2, which both have conductive patterns 21, the first peak in Sample 2, which has a relatively short inter-pattern distance PD, is shifted to lower frequencies compared to the first peak in Sample 1. In other words, the shorter the inter-pattern distance PD, the more the first peak shifts to lower frequencies. This transmission characteristic holds true whether the conductive pattern 21 is a dipole type or a comb-tooth type.

[0037] Furthermore, the transmittance T at the first peak of Sample 1 is higher than the transmittance T of Reference 1 at the frequency corresponding to the first peak of Sample 1. Accordingly, in the frequency region near the first peak of Sample 1, the transmittance T of Sample 1 is higher than the transmittance T of Reference 1. The same is true for Sample 2. This means that by changing the inter-pattern distance PD between two adjacent conductor patterns 21 based on the frequency of the radio wave 2RW, the transmittance T of the laminate 1 can be made higher than the transmittance T of Reference 1.

[0038] In the laminate 1, from the viewpoint of increasing the transmittance T at the frequency of the radio wave 2RW, the inter-pattern distance PD between adjacent conductor patterns 21 is preferably 0.0001 mm or more. The inter-pattern distance PD is preferably 10.00 mm or less. The inter-pattern distance PD is preferably 1.00 mm or less. The inter-pattern distance PD is preferably 0.50 mm or less. The inter-pattern distance PD is preferably 0.0001 mm or more and 10.00 mm or less, more preferably 0.0001 mm or more and 1.00 mm or less, and even more preferably 0.0001 mm or more and 0.50 mm or less.

[0039] If the inter-pattern distance PD is less than 0.0001 mm, there is a concern that the processing precision will be insufficient and that short circuits will occur between adjacent conductor patterns 21. Furthermore, if the inter-pattern distance PD is more than 10.00 mm, there is a concern that the transmittance T may not be improved sufficiently. However, the range of the inter-pattern distance PD is not limited to these.

[0040] From the viewpoint of increasing the transmittance T at the frequency of the radio wave 2RW, it is preferable that the difference between the frequency of the first peak in the laminate 1 and the frequency of the first peak of the base layer 10 alone (Reference 1) is, for example, 0.3 GHz or more. By making the difference between the frequency of the first peak in the laminate 1 and the frequency of the first peak of the base layer 10 alone 0.3 GHz or more, it is possible to more effectively increase the transmittance T at the frequency of the radio wave 2RW. The difference between the frequency of the first peak in the laminate 1 and the frequency of the first peak of the base layer 10 alone is hereinafter referred to as the "shift amount." In this case, it is preferable that the dielectric constant ε of the base layer 10 in the laminate 1 is 4.0 or more.

[0041] <Support layer 30> A description will be given of an example of the configuration of the support layer 30. The support layer 30 supports the conductor layer 20. As shown in Fig. 2, the support layer 30 is disposed between the base material layer 10 and the conductor layer 20 in the thickness direction.

[0042] Examples of materials constituting the support layer 30 include glass, resin, and ceramics, which transmit radio waves 2RW, as well as composites containing two or more of these. When the support layer 30 is glass, it may be the same as the glass exemplified for the base layer 10. When the support layer 30 is resin, it may be the same as the resin exemplified for the base layer 10. When the support layer 30 is ceramic, it may be the same as the ceramic exemplified for the base layer 10.

[0043] The dielectric constant of the support layer 30 is preferably, for example, not less than 2.0 and not more than 4.0. By setting the dielectric constant of the support layer 30 within this range, the transmittance T at the frequency of the radio wave 2RW can be further increased. However, the dielectric constant of the support layer 30 is not limited to this.

[0044] The thickness of the support layer 30 is preferably, for example, 400 μm or less. The thickness of the support layer 30 is also preferably, for example, 50 μm or more. The thickness of the support layer 30 is preferably, for example, 50 μm or more and 400 μm or less. On the other hand, if the thickness of the support layer 30 is less than 50 μm, there is a concern that the support layer 30 will deform, leading to destruction of the conductor layer 20. If the thickness of the support layer 30 is more than 400 μm, there is a concern that the transmittance T will be affected. However, the thickness of the support layer 30 is not limited to these. The thickness of the support layer 30 is smaller than the thickness of the base layer 10 by, for example, one to two orders of magnitude. Therefore, the thickness d of the base layer 10 accounts for most of the overall thickness of the laminate 1, while the thickness of the support layer 30 is negligible.

[0045] The support layer 30 supporting the conductor layer 20 can be attached, for example, to the window glass of already constructed buildings such as residential and commercial buildings, and mobile bodies such as automobiles and trains, via an adhesive layer 40 (described separately). In this case, the window glass corresponds to the substrate layer 10. By subsequently attaching the support layer 30 supporting the conductor layer 20 to the window glass of a building or mobile body, there is no need to replace the window glass, which can reduce costs.

[0046] <Adhesive layer 40> An example of the configuration of the adhesive layer 40 will be described. The adhesive layer 40 bonds the support layer 30 to the base material layer 10. As shown in Fig. 2, the adhesive layer 40 is disposed between the base material layer 10 and the support layer 30 in the thickness direction.

[0047] An example of the adhesive layer 40 is a material that transmits radio waves 2RW and contains, for example, an adhesive resin as a main component. An example of an adhesive resin is a (meth)acrylic polymer. However, the material constituting the adhesive layer 40 is not limited to this. The thickness of the adhesive layer 40 is thinner than the support layer 30. Therefore, the thickness d of the base layer 10 accounts for most of the overall thickness of the laminate 1, while the thickness of the adhesive layer 40 is negligible. The dielectric constant of the adhesive resin constituting the adhesive layer 40 is preferably 3.0 or more and 5.0 or less. If the dielectric constant is too low, it may affect the adhesiveness, and if it is too high, it may affect the transmittance T. The dielectric loss tangent of the adhesive resin is preferably 0.02 or less. If it is too high, it may affect the transmittance T. [Example]

[0048] Next, the present invention will be described in more detail using examples and comparative examples. However, the present invention is not limited to the examples shown below. Simulations for the examples and comparative examples were performed using Dassault Systèmes' CST Studio Suite, a three-dimensional electromagnetic field simulation software. A base layer 10, a conductor layer 20, etc. were constructed within a three-dimensional model corresponding to the examples and comparative examples. The conductor layer 20 has a periodic structure corresponding to the conductor pattern 21, but only the periodic structure was defined as a three-dimensional model. In addition, the arrangement of the periodic structure was reproduced by setting the boundary conditions to periodic boundary conditions.

[0049] <Simulation result 1 when the thickness d of the base layer 10 is changed> Simulation results 1 regarding the transmittance T of the laminate 1 when the thickness d of the base layer 10 is changed will be described. Table 1 shows the configurations of Examples 1 to 12, and Comparative Examples 1 and 2. Each of Examples 1 to 12, and Comparative Examples 1 and 2 includes a mono-core conductor pattern 21.

[0050] [Table 1]

[0051] In Table 1, the "lower limit of the range" is the value of [(0.2639 × λ) / (ε) 1 / 2 ]. The "upper limit value of the range" is a parameter calculated by [(0.4873 × λ) / (ε) 1 / 2 ] is a parameter calculated by the following equation. The wavelength λ of the radio wave 2RW can also be calculated from [λ = C0 / f]. Here, C0 is the speed of light in the atmosphere. The speed of light in the atmosphere may be considered the speed of light in a vacuum. Also, f is the frequency of the radio wave 2RW. In Table 1, f is 3.5 GHz. An example is one in which the thickness d of the base layer 10 is between the lower limit and the upper limit of the range. On the other hand, a comparative example is one in which the thickness d of the base layer 10 is outside the lower limit and the upper limit of the range.

[0052] In Examples 1 to 12 and Comparative Examples 1 and 2, the dielectric constant ε of the base layer 10 is 7.4. An example of a material having a dielectric constant ε of 7.4 is glass. The frequency of the radio wave 2RW incident on each of the Examples and Comparative Examples is 3.5 GHz.

[0053] Table 2 shows the simulation results for Examples 1 to 12 and Comparative Examples 1 and 2.

[0054] [Table 2]

[0055] In Table 2, "Transmittance [dB] of base layer alone" refers to the transmittance T [dB] of the base layer 10 alone having the same thickness d as that of each example and comparative example. "Difference in transmittance [dB]" refers to the difference [dB] between the transmittance T [dB] of the example or the transmittance T [dB] of the comparative example and the transmittance T [dB] of the base layer alone. Note that transmittance T is the transmittance at the frequency of radio waves 2RW. The same applies to other examples, comparative examples, and base layer 10 alone. The units for "frequency of first peak of base layer alone," "frequency of first peak," and "shift amount" are each in GHz. The same applies to other tables.

[0056] As shown in Table 2, in all of Examples 1 to 12 in which the thickness d of the base layer 10 was between the lower limit and the upper limit of the range, the transmittance T [dB] at the frequency of the radio wave 2RW exceeded the transmittance T [dB] of the base layer 10 alone at the frequency of the radio wave 2RW. Furthermore, in Examples 1 to 11 in which the thickness d of the base layer 10 was the same, the difference [dB] in the transmittance T [dB] increased as the inter-pattern distance PD became shorter.

[0057] Furthermore, in the examples in which the shift amount was 0.3 GHz or more, the difference [dB] in transmittance T [dB] exceeded 0.5 dB. That is, the transmittance T [dB] for these examples was significantly increased compared to the base layer 10 alone. This indicates that the decrease in transmittance T [dB] is significantly suppressed in the laminate 1 in which the thickness d of the base layer 10 is between the lower limit and the upper limit of the range and the shift amount is 0.3 GHz or more.

[0058] In contrast, in Comparative Examples 1 and 2, where the thickness d of the base layer 10 was outside the range from the lower limit to the upper limit, the transmittance T [dB] was lower than the transmittance T [dB] of the base layer 10 alone.

[0059] <Simulation result 2 when the thickness d of the base layer 10 is changed> Simulation result 2 regarding the transmittance T of the laminate 1 when the thickness d of the base layer 10 is changed will be described. Table 3 shows the configurations of Examples 13 to 19, and Comparative Examples 3 and 4. Each of Examples 13 to 19, and Comparative Examples 3 and 4 includes a comb-tooth shaped conductor pattern 21.

[0060] [Table 3]

[0061] In Examples 13 to 19 and Comparative Examples 3 and 4, the dielectric constant ε of the base layer 10 is 7.4. The frequency of the radio wave 2RW incident on each of the Examples and Comparative Examples is 3.5 GHz. These conditions are the same as those of the Examples and Comparative Examples shown in Table 1.

[0062] Table 4 shows the simulation results for Examples 13 to 19 and Comparative Examples 3 and 4.

[0063] [Table 4]

[0064] As shown in Table 4, in Examples 13 to 19 in which the thickness d of the base layer 10 was between the lower limit and the upper limit of the range, similarly to the Examples having the single-core conductor pattern 21, the transmittance T [dB] exceeded the transmittance T [dB] of the base layer 10 alone. Furthermore, in Examples 13 to 19, the difference [dB] in the transmittance T [dB] increased as the inter-pattern distance PD became shorter.

[0065] Furthermore, when the thickness d of the base layer 10 has a value between the lower limit value and the upper limit value of the range and the shift amount is 0.3 GHz or more, the reduction in transmittance T [dB] is significantly suppressed, as in the example having a single-core conductor pattern 21.

[0066] In contrast, in Comparative Examples 3 and 4, in which the thickness d of the base layer 10 was outside the range from the lower limit value to the upper limit value, similar to the comparative examples having a single-core conductor pattern 21, the transmittance T [dB] was lower than the transmittance T [dB] of the base layer 10 alone.

[0067] <Simulation Results When the Inter-Pattern Distance PD is Varying in an Example Including a Cross-Dipole Type Conductor Pattern 21> A description will be given of the simulation results when the inter-pattern distance PD is changed in an example having a cross-dipole type conductor pattern 21. Table 5 shows the configurations of Examples 20 to 24.

[0068] [Table 5]

[0069] In Examples 20 to 24, the dielectric constant ε of the base layer 10 is 7.4. The frequency of the radio wave 2RW incident on each Example is 3.5 GHz. These conditions are the same as those of the Examples and Comparative Examples shown in Tables 1 and 3. The thickness d of the base layer 10 in each Example is 12 mm.

[0070] The simulation results for Examples 20 to 24 are shown in Table 6.

[0071] [Table 6]

[0072] As shown in Table 6, in all of Examples 20 to 24, the transmittance T [dB] exceeded the transmittance T [dB] of the base layer 10 alone. Furthermore, the shorter the inter-pattern distance PD, the greater the difference [dB] in transmittance T [dB]. Furthermore, similar to the examples including the mono-core conductor pattern 21 and the examples including the cross-dipole conductor pattern 21, when the thickness d of the base layer 10 was between the lower limit and the upper limit of the range and the shift amount was 0.3 GHz or more, the decrease in transmittance T [dB] was significantly suppressed.

[0073] <Simulation results when the radio wave 2RW frequency is 28GHz> The following describes the simulation results for the transmittance T of the laminate 1 when the frequency of the radio wave 2RW is 28 GHz. Table 7 shows the configurations of Example 25, Comparative Example 5, and Comparative Example 6. Each of Example 25, Comparative Example 5, and Comparative Example 6 includes a mono-core conductor pattern 21.

[0074] [Table 7]

[0075] In Example 25 and Comparative Examples 5 and 6, the dielectric constant ε of the base material layer 10 is 7.4. This condition is the same as that of the Examples and Comparative Examples shown in Tables 1, 3, and 5.

[0076] The simulation results for Example 25 and Comparative Examples 5 and 6 are shown in Table 8.

[0077] [Table 8]

[0078] As shown in Table 8, in Example 25, where the thickness d of the base layer 10 was between the lower limit and the upper limit of the range, the transmittance T [dB] exceeded the transmittance T [dB] of the base layer 10 alone. In contrast, in Comparative Examples 5 and 6, where the thickness d of the base layer 10 was outside the range from the lower limit to the upper limit of the range, the transmittance T [dB] was lower than the transmittance T [dB] of the base layer 10 alone. In other words, even when the frequency of the radio wave 2RW was changed, the results were similar to those of the above-mentioned Examples and Comparative Examples.

[0079] <Simulation Results When the Dielectric Constant ε of the Base Layer 10 is Relatively Low> The following describes the simulation results for the transmittance T of the laminate 1 when the dielectric constant ε of the base layer 10 is relatively low. Table 9 shows the configurations of Examples 26 to 28 and Comparative Example 7. Each of Examples 26 to 28 and Comparative Example 7 includes a mono-core conductor pattern 21.

[0080] [Table 9]

[0081] The dielectric constant ε of the base material layer 10 is 3.7 in Examples 26 to 28 and Comparative Example 7. An example of a substance having a dielectric constant ε of 3.7 is a resin.

[0082] The simulation results for Examples 26 to 28 and Comparative Example 7 are shown in Table 10.

[0083] [Table 10]

[0084] As shown in Table 10, even when the dielectric constant ε of the base material layer 10 was 3.7, in Examples 26 to 28 in which the thickness d of the base material layer 10 was between the lower limit and the upper limit of the range, the transmittance T [dB] exceeded the transmittance T [dB] of the base material layer 10 alone. In contrast, in Comparative Example 7 in which the thickness d of the base material layer 10 was outside the range from the lower limit to the upper limit of the range, the transmittance T [dB] was lower than the transmittance T [dB] of the base material layer 10 alone. In other words, even when the dielectric constant ε of the base material layer 10 was relatively low, the results were similar to those of the above-mentioned Examples and Comparative Examples.

[0085] <Simulation Results When the Dielectric Constant ε of the Base Layer 10 is Relatively High> The following describes the simulation results for the transmittance T of the laminate 1 when the dielectric constant ε of the base layer 10 is relatively low. Table 11 shows the configurations of Example 29 and Comparative Examples 8 to 10. Each of Example 29 and Comparative Examples 8 to 10 includes a mono-core conductor pattern 21.

[0086] [Table 11]

[0087] In Example 29 and Comparative Examples 8 to 10, the dielectric constant ε of the base layer 10 is 10. An example of a material having a dielectric constant ε of 10 is ceramics.

[0088] Table 12 shows the simulation results for Example 29 and Comparative Examples 8 to 10.

[0089] [Table 12]

[0090] As shown in Table 12, even when the dielectric constant ε of the base material layer 10 was 10, in Example 29, in which the thickness d of the base material layer 10 was between the lower limit and the upper limit of the range, the transmittance T [dB] exceeded the transmittance T [dB] of the base material layer 10 alone. In contrast, in Comparative Examples 8 to 10, in which the thickness d of the base material layer 10 was outside the range from the lower limit to the upper limit of the range, the transmittance T [dB] was lower than the transmittance T [dB] of the base material layer 10 alone. In other words, even when the dielectric constant ε of the base material layer 10 was relatively high, the results were similar to those of the above-mentioned Examples and Comparative Examples.

[0091] The aspects of the present invention are as follows, for example. <1> a base layer having a first surface on one side in the thickness direction, to which radio waves are incident, and a second surface on the other side in the thickness direction, from which radio waves are emitted; a conductor layer having a plurality of conductor patterns disposed at positions spaced apart from each other on the first surface; Equipped with When the wavelength of the radio wave is λ, the thickness of the base material layer is d, and the dielectric constant of the base material layer is ε, A laminate, wherein the thickness d of the base layer satisfies formula (1). [(0.2639×λ) / (ε) 1 / 2 ]≦d≦[(0.4873×λ) / (ε) 1 / 2 ] ···(1) <2> the transmittance of the radio waves that are incident on the first surface side and exit from the second surface side, wherein the transmittance at a frequency of the radio waves is higher than the transmittance when radio waves having the same frequency as the frequency of the radio waves are incident on the base material layer alone; The aforementioned <1> The laminate according to claim 1. <3> In the conductor layer, the distance between two adjacent conductor patterns is 0.0001 mm or more and 0.50 mm or less. The aforementioned <1> or the above <2> The laminate according to claim 1. <4> the laminate and the base material layer alone each have a plurality of transmittance peaks according to the frequency of the radio wave, When the peak on the lowest frequency side of the plurality of peaks in the transmittance is defined as a first peak, the first peak of the laminate is shifted to a lower frequency side than the first peak of the base material layer alone, a difference in frequency between the first peaks of the laminate and the base material layer alone is 0.3 GHz or more, and the dielectric constant ε of the base material layer included in the laminate is 4.0 or more; The aforementioned <2> or the above <3> The laminate according to claim 1. <5> a support layer disposed between the base layer and the conductor layer in the thickness direction and supporting the conductor layer; an adhesive layer disposed between the base layer and the support layer in the thickness direction and adhering the support layer to the base layer; The said further comprises <1> From the above <4> 10. The laminate according to claim 9, wherein the first and second layers are laminates. [Explanation of symbols]

[0092] 1. Laminate 10 Base material layer 11a 1st page 11b Side 2 20 Conductor layer 21 Conductor pattern 30 Support layer 40 Adhesive layer

Claims

1. a base layer having a first surface on one side in a thickness direction, to which radio waves are incident, and a second surface on the other side in the thickness direction, from which radio waves are emitted; a conductor layer having a plurality of conductor patterns disposed at positions spaced apart from each other on the first surface; Equipped with When the wavelength of the radio wave is λ, the thickness of the base material layer is d, and the dielectric constant of the base material layer is ε, A laminate, wherein the thickness d of the base material layer satisfies formula (1). [(0.2639×λ) / (e) １／２ ]≦T≦[(0.4873×λ) / (M) １／２ ]・・・(1)

2. the transmittance of the radio waves that are incident on the first surface side and exit from the second surface side, wherein the transmittance at a frequency of the radio waves is higher than the transmittance when radio waves having the same frequency as the frequency of the radio waves are incident on the base material layer alone; The laminate according to claim 1 .

3. In the conductor layer, the distance between two adjacent conductor patterns is 0.0001 mm or more and 0.50 mm or less. The laminate according to claim 1 or claim 2.

4. the laminate and the base material layer alone each have a plurality of transmittance peaks according to the frequency of the radio wave, When the peak on the lowest frequency side of the plurality of peaks in the transmittance is defined as a first peak, the first peak of the laminate is shifted to a lower frequency side than the first peak of the base material layer alone, a difference in frequency between the first peaks of the laminate and the base material layer alone is 0.3 GHz or more, and the dielectric constant ε of the base material layer included in the laminate is 4.0 or more; The laminate according to claim 2 .

5. a support layer disposed between the base layer and the conductor layer in the thickness direction and supporting the conductor layer; an adhesive layer disposed between the base layer and the support layer in the thickness direction and adhering the support layer to the base layer; The laminate according to claim 1 or claim 2, further comprising:

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