Multilayer substrate

Abstract

When viewed in the negative direction of the Z-axis, a ground conductor layer non-formation region in which the one or more first ground conductor layers are not provided exists in a radiation conductor layer region in which the radiation conductor layer is provided. The signal conductor layer has an overlapping portion that overlaps the ground conductor layer non-forming region when viewed in the negative direction of the Z-axis. In the ground conductor layer non-forming region, there is no conductor covering the entire ground conductor layer non-forming region except the radiation conductor layer at a position closer to the front side of the Z axis than the signal conductor layer. The first branch conductor layer and the second branch conductor layer are provided on the laminate, and are electrically connected to the signal conductor layer. When viewed along the negative direction of the Z-axis, there is a virtual line that passes through the overlapping portion and makes the first branch conductor layer and the second branch conductor layer linearly symmetrical.

Description

Technical Field

[0001] The present invention relates to multi-layer substrates. Background Art

[0002] As a conventional invention related to a multilayer substrate, for example, a microstrip antenna described in Patent Document 1 is known. The microstrip antenna includes a ground conductor, a center conductor, and a radiating conductor. The center conductor is located below the ground conductor. The radiating conductor is located above the ground conductor. A slit is provided in the ground conductor. When viewed from the bottom, the slit overlaps with the radiating conductor and the center conductor. As a result, the radiating conductor and the ground conductor are electromagnetically coupled.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2000-261235 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, in the microstrip antenna described in Patent Document 1, there is a desire to easily adjust the input impedance of the antenna. Therefore, it is considered to add a matching circuit to the microstrip antenna. However, when adding a matching circuit to the microstrip antenna, it is sometimes difficult to maintain the symmetry of the radiation characteristics and reception characteristics of the microstrip antenna.

[0008] Therefore, an object of the present invention is to provide a multilayer substrate capable of easily adjusting input impedance to a radiating conductor layer and suppressing a decrease in the symmetry of radiation characteristics and reception characteristics of the radiating conductor layer.

[0009] Technical solutions to solve problems

[0010] A multilayer substrate according to one embodiment of the present invention includes a laminate, a radiation conductor layer, one or more first ground conductor layers, a signal conductor layer, a first branch conductor layer, and a second branch conductor layer.

[0011] The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis.

[0012] The radiation conductor layer is provided in the laminated body,

[0013] The one or more first ground conductor layers are provided in the laminate, overlap the radiation conductor layer when viewed in the negative direction of the Z axis, and are located on the negative side of the Z axis than the radiation conductor layer.

[0014] The signal conductor layer is provided in the laminate and overlaps with the radiation conductor layer and the one or more first ground conductor layers when viewed in the negative direction of the Z axis, and is located on the negative side of the Z axis than the radiation conductor layer and the one or more first ground conductor layers, and is not electrically connected to the radiation conductor layer.

[0015] When viewed in the negative direction of the Z axis, a ground conductor layer non-formed region where the one or more first ground conductor layers are not provided exists in the radiation conductor layer region where the radiation conductor layer is provided.

[0016] When viewed along the negative direction of the Z axis, the signal conductor layer has an overlapping portion overlapping the ground conductor layer non-formed region.

[0017] In the ground conductor layer non-formed region, at a position closer to the positive side of the Z axis than the signal conductor layer, no conductor other than the radiation conductor layer covers the entire ground conductor layer non-formed region.

[0018] The first branch conductor layer and the second branch conductor layer are provided in the laminate and are electrically connected to the signal conductor layer.

[0019] When viewed in the negative direction of the Z-axis, there is an imaginary line that passes through the overlapping portion and makes the first branch conductor layer and the second branch conductor layer line-symmetrical.

[0020] Effects of the Invention

[0021] According to the multilayer substrate of the present invention, the input impedance to the radiating conductor layer in the frequency band of the high-frequency signal transmitted and received by the radiating conductor layer can be easily adjusted, and the symmetry of the radiation characteristic and the reception characteristic of the radiating conductor layer can be suppressed from being reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an exploded perspective view of the multi-layer substrate 10 .

[0023] Figure 2 is a top view of the multi-layer substrate 10 .

[0024] Figure 3 is a cross-sectional view of the multi-layer substrate 10 .

[0025] Figure 4 It is an exploded perspective view of the multi-layer substrate 10a.

[0026] Figure 5 It is an exploded perspective view of the multi-layer substrate 10b.

[0027] Figure 6 is a cross-sectional view of the multi-layer substrate 10c.

[0028] Figure 7 It is an exploded perspective view of the multi-layer substrate 10d. DETAILED DESCRIPTION

[0029] (Implementation Method)

[0030] [Multilayer substrate structure]

[0031] Hereinafter, the structure of the multilayer substrate 10 according to the embodiment of the present invention will be described with reference to the drawings. Figure 1 It is an exploded perspective view of the multi-layer substrate 10 . Figure 2 is a top view of the multi-layer substrate 10 . Figure 3 is a cross-sectional view of the multi-layer substrate 10 . Figure 3 yes Figure 2 Cross-sectional view at AA.

[0032] In this specification, directions are defined as follows. The direction in which the insulating layers 16a to 16f are arranged in sequence is defined as a downward direction. The downward direction coincides with the negative direction of the Z axis. When viewed in the downward direction, two sides of the stack 15 extend along the front-back axis. The front-back axis coincides with the Y axis. The remaining two sides of the stack 15 extend along the left-right axis. The left-right axis coincides with the X axis. The up-down axis (Z axis), the front-back axis (Y axis), and the left-right axis (X axis) are orthogonal to each other. It should be noted that the up-down axis, the front-back axis, and the left-right axis in this embodiment may not be consistent with the up-down axis, the front-back axis, and the left-right axis when the multilayer substrate 10 is in use.

[0033] First, refer to Figures 1 to 3 The structure of the multilayer substrate 10 is described. The multilayer substrate 10 is an antenna module built into an electronic device such as a wireless communication terminal. Figure 1 As shown, the multilayer substrate 10 includes a laminate 15 , a radiation conductor layer 17 , a signal conductor layer 18 , a first ground conductor layer 20 , a second ground conductor layer 22 , an external electrode 28 , a ring-shaped ground conductor layer 30 , and interlayer connection conductors v1 to v3 .

[0034] The laminate 15 has a plate shape. The laminate 15 has a rectangular shape when viewed from the bottom. The laminate 15 has a structure in which insulating layers 16a to 16f are stacked along the up-down axis (Z axis). The insulating layers 16a to 16f are arranged in sequence in the bottom direction. The insulating layers 16a to 16f are melted between adjacent layers. The material of the insulating layers 16a to 16f is a thermoplastic resin. The thermoplastic resin is, for example, a liquid crystal polymer.

[0035] The radiation conductor layer 17 is provided on the laminate 15. In the present embodiment, the radiation conductor layer 17 is located on the upper main surface of the laminate 15. Therefore, the radiation conductor layer 17 is located on the upper main surface of the insulating layer 16a. The radiation conductor layer 17 has a rectangular shape when viewed from the bottom. It should be noted that the radiation conductor layer 17 may also have a square shape when viewed from the bottom. When viewed from the bottom, two sides of the radiation conductor layer 17 extend along the front-back axis. The remaining two sides of the radiation conductor layer 17 extend along the left-right axis.

[0036] The first ground conductor layer 20 is provided in the laminate 15. In the present embodiment, the first ground conductor layer 20 is located on the upper main surface of the insulating layer 16d. Thus, the first ground conductor layer 20 is located below (on the negative side of the Z axis) the radiation conductor layer 17. The first ground conductor layer 20 covers most of the upper main surface of the insulating layer 16d. Thus, the first ground conductor layer 20 overlaps with the radiation conductor layer 17 when viewed from the bottom. The first ground conductor layer 20 as described above is connected to the ground potential.

[0037] The signal conductor layer 18 is provided in the laminate 15. In the present embodiment, the signal conductor layer 18 is located on the upper main surface of the insulating layer 16e. Therefore, the signal conductor layer 18 is located below (on the negative side of the Z axis) the radiation conductor layer 17 and the first ground conductor layer 20. In addition, when viewed in the downward direction (the negative direction of the Z axis), the signal conductor layer 18 overlaps with the radiation conductor layer 17 and the first ground conductor layer 20. However, the signal conductor layer 18 is not electrically connected to the radiation conductor layer 17 and the first ground conductor layer 20. The signal conductor layer 18 has a linear shape extending along the left-right axis (X axis). Therefore, the signal conductor layer 18 has a left end (first end) and a right end. A high-frequency signal is transmitted in the signal conductor layer 18 as described above.

[0038] The second ground conductor layer 22 is provided in the laminate 15. In the present embodiment, the second ground conductor layer 22 is located on the lower main surface of the insulating layer 16f. Thus, the second ground conductor layer 22 is located below (on the negative side of the Z axis) the signal conductor layer 18. The second ground conductor layer 22 covers most of the lower main surface of the insulating layer 16f. Thus, the second ground conductor layer 22 overlaps the radiation conductor layer 17 and the signal conductor layer 18 when viewed from the bottom. The second ground conductor layer 22 as described above is connected to the ground potential.

[0039] The signal conductor layer 18 , the first ground conductor layer 20 , and the second ground conductor layer 22 as described above have a stripline structure.

[0040] The external electrode 28 is provided on the laminate 15. In the present embodiment, the external electrode 28 is located on the lower main surface of the insulator layer 16f. However, the external electrode 28 is not in contact with the second ground conductor layer 22. The external electrode 28 has a rectangular shape when viewed from the bottom. The external electrode 28 overlaps with the right end of the signal conductor layer 18 when viewed from the bottom. The external electrode 28 is connected to the electrode of the circuit board by solder.

[0041] The annular ground conductor layer 30 is provided in the laminate 15. In the present embodiment, the annular ground conductor layer 30 is located on the upper main surface of the insulating layer 16e. The annular ground conductor layer 30 has a rectangular ring shape when viewed from the bottom. The signal conductor layer 18 is located in the area surrounded by the annular ground conductor layer 30 when viewed from the bottom. The annular ground conductor layer 30 is connected to the ground potential.

[0042] The interlayer connection conductor v1 electrically connects the signal conductor layer 18 and the external electrode 28. The interlayer connection conductor v1 penetrates the insulating layers 16e and 16f along the vertical axis. The upper end of the interlayer connection conductor v1 contacts the right end of the signal conductor layer 18. The lower end of the interlayer connection conductor v1 contacts the external electrode 28.

[0043] The interlayer connection conductors v2 and v3 electrically connect the first ground conductor layer 20, the second ground conductor layer 22, and the annular ground conductor layer 30. The interlayer connection conductors v2 and v3 penetrate the insulating layers 16d to 16f along the vertical axis. The upper ends of the interlayer connection conductors v2 and v3 are in contact with the first ground conductor layer 20. The lower ends of the interlayer connection conductors v2 and v3 are in contact with the second ground conductor layer 22. The middle portions of the interlayer connection conductors v2 and v3 are in contact with the annular ground conductor layer 30.

[0044] In addition, if Figure 2 As shown in FIG. 1 , the region where the radiation conductor layer 17 is provided when viewed in the downward direction (negative direction of the Z axis) is defined as the radiation conductor layer region A1. When viewed in the downward direction (negative direction of the Z axis), there is a ground conductor layer non-formation region A0 in which the first ground conductor layer 20 is not provided in the radiation conductor layer region A1. When viewed in the downward direction (negative direction of the Z axis), the ground conductor layer non-formation region A0 is surrounded by the first ground conductor layer 20. Specifically, the ground conductor layer non-formation region A0 has a rectangular shape when viewed in the downward direction. The two long sides of the ground conductor layer non-formation region A0 extend in the front-to-back direction. The two short sides of the ground conductor layer non-formation region A0 extend in the left-to-right direction. The length of the ground conductor layer non-formation region A0 in the direction along the front-to-back axis (Y axis) is less than 1 / 4 of the wavelength of the high-frequency signal transmitted in the signal conductor layer 18. As a result, in the ground conductor layer non-formation region A0, the generation of unnecessary resonance is suppressed, and the generation of noise is suppressed.

[0045] When viewed in the downward direction, the ground conductor layer non-formation area A0 intersects with the signal conductor layer 18. In the present embodiment, when viewed in the downward direction, the ground conductor layer non-formation area A0 is orthogonal to the signal conductor layer 18. Thus, when viewed in the downward direction (negative direction of the Z axis), the signal conductor layer 18 overlaps with the ground conductor layer non-formation area A0. That is, when viewed in the downward direction (negative direction of the Z axis), the signal conductor layer 18 has an overlapping portion P that overlaps with the ground conductor layer non-formation area A0. Moreover, when viewed in the downward direction (negative direction of the Z axis), the length L1 of the signal conductor layer 18 between the left end (first end) of the signal conductor layer 18 and the overlapping portion P is less than 1 / 4 of the wavelength of the high-frequency signal transmitted in the signal conductor layer 18. Thus, in the signal conductor layer 18 between the left end of the signal conductor layer 18 and the overlapping portion P, the generation of unnecessary resonance is suppressed, and the generation of noise is suppressed.

[0046] When viewed in the downward direction (negative direction of the Z axis), in the ground conductor layer non-formed region A0, the signal conductor layer 18 overlaps with the radiation conductor layer 17. That is, when viewed in the downward direction, the overlapping portion P overlaps with the radiation conductor layer 17. Figure 3 As shown in FIG. 1 , in the ground conductor layer non-formed region A0, at a position above the signal conductor layer 18 (on the positive side of the Z axis), there is no conductor covering the entire ground conductor layer non-formed region A0 except for the radiation conductor layer 17. As a result, the signal conductor layer 18 and the radiation conductor layer 17 are electromagnetically coupled. In the present embodiment, the signal conductor layer 18 and the radiation conductor layer 17 are mainly magnetically coupled. As a result, the high-frequency signal transmitted in the signal conductor layer 18 is transmitted to the radiation conductor layer 17 through the ground conductor layer non-formed region A0 by the electromagnetic field. In addition, a standing wave of the high-frequency signal is generated in the radiation conductor layer 17. The radiation conductor layer 17 radiates the electromagnetic wave of the high-frequency signal in the upward direction. It should be noted that the radiation conductor layer 17 receives the electromagnetic wave of the high-frequency signal based on the same principle.

[0047] In addition, the multilayer substrate 10 further includes a first branch conductor layer 24 and a second branch conductor layer 26. The first branch conductor layer 24 and the second branch conductor layer 26 are provided in the laminate 15. In the present embodiment, the first branch conductor layer 24 and the second branch conductor layer 26 are located on the upper main surface of the insulating layer 16e. The first branch conductor layer 24 and the second branch conductor layer 26 have an L-shaped shape when viewed from the lower direction. More specifically, the first branch conductor layer 24 includes a first portion 24a and a second portion 24b. The first portion 24a extends in the front-to-back direction. The rear end of the first portion 24a is connected to the connection portion P0 of the signal conductor layer 18. The connection portion P0 is located between the left end and the right end of the signal conductor layer 18. In the present embodiment, the length L2 of the transmission path of the high-frequency signal from the overlapping portion P to the connection portion P0 is shorter than half the wavelength of the high-frequency signal. That is, the length L2 of the transmission path of the high-frequency signal from the overlapping portion P to the first branch conductor layer 24 is shorter than half the wavelength of the high-frequency signal. The second portion 24b extends in the left-right direction. The right end of the second portion 24b is connected to the front end of the first portion 24a. Thus, the first branch conductor layer 24 is electrically connected to the signal conductor layer 18. Moreover, the length of the first branch conductor layer 24 is less than half the wavelength of the high-frequency signal transmitted in the signal conductor layer 18. The first branch conductor layer 24 as described above functions as an open short stub.

[0048] The second branch conductor layer 26 includes a first portion 26a and a second portion 26b. The first portion 26a extends in the front-to-back direction. The front end of the first portion 26a is connected to the connection portion P0 of the signal conductor layer 18. In the present embodiment, the length L2 of the transmission path of the high-frequency signal from the overlapping portion P to the connection portion P0 is shorter than half of the wavelength of the high-frequency signal. That is, the length L2 of the transmission path of the high-frequency signal from the overlapping portion P to the second branch conductor layer 26 is shorter than half of the wavelength of the high-frequency signal. The second portion 26b extends in the left-right direction. The right end of the second portion 26b is connected to the rear end of the first portion 26a. Thus, the second branch conductor layer 26 is electrically connected to the signal conductor layer 18. Moreover, the length of the second branch conductor layer 26 is less than half of the wavelength of the high-frequency signal transmitted in the signal conductor layer 18. The second branch conductor layer 26 as described above functions as an open short stub.

[0049] Here, the length of the first portion 24a is equal to the length of the first portion 26a. The length of the second portion 24b is equal to the length of the second portion 26b. Thus, when viewed in the downward direction (negative direction of the Z axis), there is an imaginary line L that passes through the overlapping portion P and makes the first branch conductor layer 24 and the second branch conductor layer 26 line symmetrical. In the present embodiment, the imaginary line L extends along the left-right axis. Therefore, when viewed in the downward direction, the signal conductor layer 18 overlaps the imaginary line L over its entire length. Moreover, when viewed in the downward direction, the signal conductor layer 18 has a shape that is line symmetrical about the imaginary line L.

[0050] In addition, when viewed in the downward direction (negative direction of the Z axis), the radiation conductor layer 17 has a shape that is line-symmetrical about the imaginary line L. Furthermore, when viewed in the downward direction (negative direction of the Z axis), the ground conductor layer non-formation region A0 extends along the front-rear axis. Thus, when viewed in the downward direction (negative direction of the Z axis), the ground conductor layer non-formation region A0 extends along an axis that is orthogonal to the imaginary line L. Furthermore, the ground conductor layer non-formation region A0 has a structure that is line-symmetrical about the imaginary line L.

[0051] The radiation conductor layer 17, the signal conductor layer 18, the first ground conductor layer 20, the second ground conductor layer 22, the first branch conductor layer 24, the second branch conductor layer 26, the external electrode 28, and the annular ground conductor layer 30 are formed by patterning a metal foil attached to the upper main surface or the lower main surface of the insulating layers 16a, 16d to 16f. The metal foil is, for example, a copper foil.

[0052] The interlayer connection conductors v1 to v3 are formed by filling a conductive paste into through holes penetrating the insulating layers 16 d to 16 f along the vertical axis and curing the conductive paste by heat treatment and pressure treatment.

[0053] [Effect]

[0054] According to the multilayer substrate 10, the input impedance to the radiation conductor layer 17 can be easily adjusted. More specifically, in the multilayer substrate 10, the first branch conductor layer 24 and the second branch conductor layer 26 are electrically connected to the signal conductor layer 18. Thus, by adjusting the shapes of the first branch conductor layer 24 and the second branch conductor layer 26, the first branch conductor layer 24 and the second branch conductor layer 26 can function as a matching circuit. As a result, the input impedance to the radiation conductor layer 17 can be easily adjusted.

[0055] According to the multilayer substrate 10, it is possible to suppress the symmetry of the radiation characteristic of the radiation conductor layer 17 from being reduced. More specifically, when the first branch conductor layer 24 and the second branch conductor layer 26 are provided in the multilayer substrate 10, the radiation characteristic of the radiation conductor layer 17 is affected by the first branch conductor layer 24 and the second branch conductor layer 26. Therefore, when viewed from the bottom direction, there is an imaginary line L that passes through the overlap portion P and makes the first branch conductor layer 24 and the second branch conductor layer 26 linearly symmetrical. That is, the first branch conductor layer 24 and the second branch conductor layer 26 are in a linearly symmetrical relationship. As a result, the influence of the first branch conductor layer 24 on the first half of the radiation pattern of the radiation conductor layer 17 is close to the influence of the second branch conductor layer 26 on the second half of the radiation pattern of the radiation conductor layer 17. As a result, according to the multilayer substrate 10, it is possible to suppress the symmetry of the radiation characteristic of the radiation conductor layer 17 from being reduced. It should be noted that, for the same reason, according to the multilayer substrate 10, it is possible to suppress the symmetry of the reception characteristic of the radiation conductor layer 17 from being reduced.

[0056] (First Modification)

[0057] Hereinafter, a multilayer substrate 10a according to a first modification will be described with reference to the drawings. Figure 4 It is an exploded perspective view of the multi-layer substrate 10a.

[0058] The multilayer substrate 10a is different from the multilayer substrate 10 in that the signal conductor layer 18 and the first branch conductor layer 24 and the second branch conductor layer 26 are located on different insulating layers. More specifically, the signal conductor layer 18 is located on the upper main surface of the insulating layer 16e. The first branch conductor layer 24 and the second branch conductor layer 26 are located on the upper main surface of the insulating layer 16g. The insulating layer 16g is located between the insulating layer 16e and the insulating layer 16f. As a result, the first branch conductor layer 24 and the second branch conductor layer 26 are located below the signal conductor layer 18 (on the negative side of the Z axis).

[0059] The interlayer connection conductor v1 electrically connects the signal conductor layer 18, the first branch conductor layer 24, the second branch conductor layer 26, and the external electrode 28. The interlayer connection conductor v1 penetrates the insulating layers 16e, 16g, and 16f along the vertical axis. The upper end of the interlayer connection conductor v1 contacts the right end of the signal conductor layer 18. The lower end of the interlayer connection conductor v1 contacts the external electrode 28. The middle portion of the interlayer connection conductor v1 contacts the first branch conductor layer 24 and the second branch conductor layer 26. The other structures of the multilayer substrate 10a are the same as those of the multilayer substrate 10, so the description is omitted. The multilayer substrate 10a can achieve the same effect as the multilayer substrate 10.

[0060] In the multilayer substrate 10a, the first branch conductor layer 24 and the second branch conductor layer 26 are located below (on the negative side of the Z axis) the signal conductor layer 18. Thus, the first branch conductor layer 24 and the second branch conductor layer 26 are separated from the radiation conductor layer 17. As a result, the radiation characteristics of the radiation conductor layer 17 are less likely to be affected by the first branch conductor layer 24 and the second branch conductor layer 26.

[0061] (Second Modification)

[0062] Hereinafter, a multilayer substrate 10b according to a second modification will be described with reference to the drawings. Figure 5 It is an exploded perspective view of the multi-layer substrate 10b.

[0063] The multilayer substrate 10b is different from the multilayer substrate 10 in that it further includes annular ground conductor layers 32, 34, and 36. The annular ground conductor layers 32, 34, and 36 are provided on the laminate 15. In the present embodiment, the annular ground conductor layer 32 is located on the upper main surface of the insulating layer 16a. The annular ground conductor layer 34 is located on the upper main surface of the insulating layer 16b. The annular ground conductor layer 36 is located on the upper main surface of the insulating layer 16c. The annular ground conductor layers 32, 34, and 36 have a rectangular ring shape when viewed from the bottom. The radiation conductor layer 17, the signal conductor layer 18, the first branch conductor layer 24, and the second branch conductor layer 26 are located in the area surrounded by the annular ground conductor layers 32, 34, and 36 when viewed from the bottom.

[0064] The interlayer connection conductors v2 and v3 electrically connect the first ground conductor layer 20, the second ground conductor layer 22, and the annular ground conductor layers 30, 32, 34, and 36. Thus, the annular ground conductor layers 32, 34, and 36 are connected to the ground potential. The other structures of the multilayer substrate 10b are the same as those of the multilayer substrate 10, and thus the description thereof is omitted. The multilayer substrate 10b can achieve the same effects as those of the multilayer substrate 10.

[0065] In the multilayer substrate 10b, the radiation conductor layer 17, the signal conductor layer 18, the first branch conductor layer 24, and the second branch conductor layer 26 are located in the area surrounded by the annular ground conductor layers 32, 34, and 36 when viewed from the bottom. As a result, the intrusion of noise into the multilayer substrate 10b is suppressed, and the radiation of noise from the multilayer substrate 10b in the front direction, the rear direction, the left direction, and the right direction is suppressed. In addition, the radiation conductor layer 17, the signal conductor layer 18, the first branch conductor layer 24, and the second branch conductor layer 26 are suppressed from forming capacitance with the conductors around the multilayer substrate 10b. In addition, the electromagnetic field radiated from the ground conductor layer non-formation area A0 is suppressed from spreading in the left-right direction, so that power is efficiently input to the radiation conductor layer 17.

[0066] (Third Modification)

[0067] Hereinafter, a multilayer substrate 10c according to a third modified example will be described with reference to the drawings. Figure 6 is a cross-sectional view of the multi-layer substrate 10c.

[0068] The multilayer substrate 10c is different from the multilayer substrate 10 in that the laminate 15 is curved. More specifically, the laminate 15 includes a first section A11 in which the radiation conductor layer 17 is provided when viewed in the downward direction (negative direction of the Z axis), and second sections A12a and A12b in which the radiation conductor layer 17 is not provided when viewed in the downward direction (negative direction of the Z axis). The thickness of a portion of the second section A12b in the vertical direction is smaller than the thickness of the first section A11 in the vertical direction. Furthermore, the second section A12b of the laminate 15 has a curved portion when viewed in the front direction (direction orthogonal to the Z axis). The other structures of the multilayer substrate 10c are the same as those of the multilayer substrate 10, and thus description thereof is omitted. The multilayer substrate 10c can achieve the same effects as the multilayer substrate 10.

[0069] In addition, in the multilayer substrate 10c, the thickness of a portion of the second section A12b in the vertical direction is smaller than the thickness of the first section A11 in the vertical direction. As a result, when viewed in the front direction (direction orthogonal to the Z axis), the second section A12b of the laminate 15 is easily bent. In addition, the first section A11 and the second section A12b include the insulating layers 16d to 16f. As a result, no connection portion of the signal conductor layer 18 is generated between the first section A11 and the second section A12b. As a result, the loss generated in the signal conductor layer 18 is suppressed.

[0070] (Fourth Modification)

[0071] Hereinafter, a multilayer substrate 10d according to a fourth modification will be described with reference to the drawings. Figure 7 It is an exploded perspective view of the multi-layer substrate 10d.

[0072] The multilayer substrate 10d is different from the multilayer substrate 10 in that the material of the insulator layers 16a to 16c is different from the material of the insulator layers 16d to 16f. The dielectric constant of the insulator layers 16a to 16c is higher than the dielectric constant of the insulator layers 16d to 16f. The other structures of the multilayer substrate 10d are the same as those of the multilayer substrate 10, so the description is omitted. The multilayer substrate 10d can achieve the same effect as the multilayer substrate 10.

[0073] In the multilayer substrate 10d, the dielectric constants of the insulating layers 16a to 16c are higher than the dielectric constants of the insulating layers 16d to 16f. This produces a wavelength shortening effect in the radiating conductor layer 17. As a result, the radiating conductor layer 17 can be miniaturized.

[0074] (Other Embodiments)

[0075] The multilayer substrate according to the present invention is not limited to the multilayer substrates 10 and 10a to 10d, and can be modified within the scope of the gist thereof. It should be noted that the structures of the multilayer substrates 10 and 10a to 10d can be arbitrarily combined.

[0076] It should be noted that the number of first grounding conductor layers is not limited to one. The number of first grounding conductor layers can be one or more. When the number of first grounding conductor layers is two, a grounding conductor layer non-forming area A0 is formed between the two first grounding conductor layers. In this case, the grounding conductor layer non-forming area A0 is not surrounded by the first grounding conductor layer. For example, when viewed from the downward direction, there is no first grounding conductor layer in front of and behind the grounding conductor layer non-forming area A0.

[0077] It should be noted that the dielectric constant of the insulating layers 16a to 16c may be less than the dielectric constant of the insulating layers 16d to 16f. In this case, the capacitance between the radiation conductor layer 17 and the first ground conductor layer 20 is reduced. As a result, the gain of the multilayer substrate is improved.

[0078] It should be noted that the second ground conductor layer 22 , the external electrode 28 , and the annular ground conductor layers 30 , 32 , 34 , and 36 are not essential components.

[0079] The dielectric constant of the insulating layers 16a to 16c may be lower than that of the insulating layers 16d to 16f. In this case, the distance between the radiation conductor layer 17 and the first ground conductor layer 20 is shortened, so the thickness of the multilayer substrate 10 in the vertical direction is reduced.

[0080] It should be noted that the first branch conductor layer 24 and the second branch conductor layer 26 may be located above the signal conductor layer 18 .

[0081] It should be noted that the first branch conductor layer 24 and the second branch conductor layer 26 may be located to the left of the ground conductor layer non-formed area A0. That is, the connection point P0 may be located between the left end of the signal conductor layer 18 and the overlapping portion P.

[0082] It should be noted that the first branch conductor layer 24 and the second branch conductor layer 26 may be short-circuited stubs instead of open-circuited stubs. In this case, the first branch conductor layer 24 and the second branch conductor layer 26 are connected to the annular ground conductor layer 32, for example.

[0083] It should be noted that the length L2 of the high-frequency signal transmission path from the overlapping portion P to the first branch conductor layer 24 and the second branch conductor layer 26 may be longer than half the wavelength of the high-frequency signal.

[0084] It should be noted that the radiation conductor layer 17 may not have a shape that is line-symmetrical with respect to the imaginary line L when viewed from the downward direction.

[0085] It should be noted that the signal conductor layer 18 may not have a shape that is line-symmetrical with respect to the imaginary line L when viewed from the downward direction.

[0086] It should be noted that the ground conductor layer non-formed region A0 may not extend along the axis perpendicular to the virtual line L when viewed from the downward direction.

[0087] Note that, when viewed from below, the length L1 of the signal conductor layer 18 between the left end of the signal conductor layer 18 and the overlapping portion P may be longer than half the wavelength of the high-frequency signal transmitted through the signal conductor layer 18 .

[0088] It should be noted that the length of the ground conductor layer non-formed region A0 along the front-rear axis may be longer than half the wavelength of the high-frequency signal transmitted through the signal conductor layer 18 .

[0089] It should be noted that the multilayer substrate 10, 10a to 10d may also include one or more branch conductor layers. When viewed from the bottom, the one or more branch conductor layers may not have a shape that is line-symmetrical about the imaginary line L. However, the length of the transmission path from the first branch conductor layer 24 to the overlapping portion P and the length of the transmission path from the second branch conductor layer 26 to the overlapping portion P are shorter than the length of the transmission path from the one or more branch conductor layers to the overlapping portion P.

[0090] It should be noted that each of the first branch conductor layer 24 and the second branch conductor layer 26 may have a straight line shape or a curved shape when viewed from the bottom.

[0091] In addition, the multilayer substrates 10 and 10a to 10d may further include a third branch conductor layer and a fourth branch conductor layer having a line-symmetric relationship with respect to the virtual line L.

[0092] It should be noted that the first branch conductor layer 24 and the second branch conductor layer 26 may not overlap with the radiating conductor layer 17 when viewed from the bottom. Therefore, the entire first branch conductor layer 24 and the entire second branch conductor layer 26 may overlap with the radiating conductor layer 17 when viewed from the bottom, or a portion of the first branch conductor layer 24 and a portion of the second branch conductor layer 26 may overlap with the radiating conductor layer 17 when viewed from the bottom.

[0093] The present invention has the following structures. (1)

[0095] A multilayer substrate comprises a laminate, a radiation conductor layer, one or more first ground conductor layers, a signal conductor layer, a first branch conductor layer, and a second branch conductor layer.

[0096] The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis.

[0097] The radiation conductor layer is provided in the laminated body,

[0098] The one or more first ground conductor layers are provided in the laminate, overlap the radiation conductor layer when viewed in the negative direction of the Z axis, and are located on the negative side of the Z axis than the radiation conductor layer.

[0099] The signal conductor layer is provided in the laminate and overlaps with the radiation conductor layer and the one or more first ground conductor layers when viewed in the negative direction of the Z axis, and is located on the negative side of the Z axis than the radiation conductor layer and the one or more first ground conductor layers, and is not electrically connected to the radiation conductor layer.

[0100] When viewed in the negative direction of the Z axis, a ground conductor layer non-formed region where the one or more first ground conductor layers are not provided exists in the radiation conductor layer region where the radiation conductor layer is provided.

[0101] When viewed along the negative direction of the Z axis, the signal conductor layer has an overlapping portion overlapping the ground conductor layer non-formed region.

[0102] In the ground conductor layer non-formed region, at a position closer to the positive side of the Z axis than the signal conductor layer, no conductor other than the radiation conductor layer covers the entire ground conductor layer non-formed region.

[0103] The first branch conductor layer and the second branch conductor layer are provided in the laminate and are electrically connected to the signal conductor layer.

[0104] When viewed in the negative direction of the Z-axis, there is an imaginary line that passes through the overlapping portion and makes the first branch conductor layer and the second branch conductor layer line-symmetrical. (2)

[0106] The multilayer substrate according to (1), wherein:

[0107] The first branch conductor layer and the second branch conductor layer are located on the negative side of the Z axis with respect to the signal conductor layer. (3)

[0109] The multilayer substrate according to (1) or (2), wherein:

[0110] A length of a transmission path of a high-frequency signal from the overlapping portion to the first branch conductor layer and the second branch conductor layer is shorter than half a wavelength of the high-frequency signal. (4)

[0112] The multilayer substrate according to any one of (1) to (3), wherein:

[0113] The radiation conductor layer has a shape that is line-symmetrical about the imaginary line when viewed in the negative direction of the Z axis. (5)

[0115] The multilayer substrate according to any one of (1) to (4), wherein:

[0116] The ground conductor layer non-formed region extends along an axis that is orthogonal to the imaginary line when viewed in the negative direction of the Z axis. (6)

[0118] The multilayer substrate according to any one of (1) to (5), wherein:

[0119] The signal conductor layer has a first end,

[0120] When viewed in the negative direction of the Z-axis, the length of the signal conductor layer between the first end and the overlapping portion is less than or equal to half the wavelength of a high-frequency signal transmitted through the signal conductor layer. (7)

[0122] The multilayer substrate according to any one of (1) to (6), wherein:

[0123] The multilayer substrate further comprises a second ground conductor layer.

[0124] The second ground conductor layer is provided in the laminate, overlaps with the radiation conductor layer when viewed in the negative direction of the Z axis, and is located on the negative side of the Z axis relative to the signal conductor layer. (8)

[0126] The multilayer substrate according to any one of (1) to (7), wherein:

[0127] The laminate has a first section where the radiating conductor layer is provided when viewed in the negative direction of the Z axis, and a second section where the radiating conductor layer is not provided when viewed in the negative direction of the Z axis.

[0128] The second section of the stacked body has a curved portion when viewed in a direction perpendicular to the Z axis. (9)

[0130] The multilayer substrate according to any one of (1) to (8), wherein:

[0131] The signal conductor layer extends along the X-axis,

[0132] The Y axis is orthogonal to the X axis and the Z axis,

[0133] The length of the ground conductor layer non-formed region along the Y-axis is equal to or less than half the wavelength of a high-frequency signal transmitted through the signal conductor layer. (10)

[0135] The multilayer substrate according to any one of (1) to (9), wherein:

[0136] The signal conductor layer extends along the X-axis,

[0137] The Y axis is orthogonal to the X axis and the Z axis,

[0138] The ground conductor layer non-formation region is surrounded by the first ground conductor layer when viewed in the negative direction of the Z-axis.

[0139] Description of Reference Numerals

[0140] 10, 10a~10d: multi-layer substrate;

[0141] 15: laminate;

[0142] 16a~16g: insulator layer;

[0143] 17: Radiating conductor layer;

[0144] 18: signal conductor layer;

[0145] 20: first ground conductor layer;

[0146] 22: second ground conductor layer;

[0147] 24: first branch conductor layer;

[0148] 24a, 26a: Part I;

[0149] 24b, 26b: Part II;

[0150] 26: second branch conductor layer;

[0151] 28: external electrode;

[0152] 30, 32, 34, 36: annular ground conductor layer;

[0153] A0: ground conductor layer non-formed area;

[0154] A1: radiating conductor layer area;

[0155] A11: first interval;

[0156] A12a, A12b: second interval;

[0157] L: imaginary line;

[0158] P: overlapping part;

[0159] P0: connection site;

[0160] v1~v3: interlayer connecting conductors.

Claims

1. A multilayer substrate comprising a laminate, a radiation conductor layer, one or more first ground conductor layers, a signal conductor layer, a first branch conductor layer, and a second branch conductor layer, The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis. The radiation conductor layer is provided in the laminated body, The one or more first ground conductor layers are provided in the laminate, overlap the radiation conductor layer when viewed in the negative direction of the Z axis, and are located on the negative side of the Z axis than the radiation conductor layer. The signal conductor layer is provided in the laminate and overlaps with the radiation conductor layer and the one or more first ground conductor layers when viewed in the negative direction of the Z axis, and is located on the negative side of the Z axis than the radiation conductor layer and the one or more first ground conductor layers, and is not electrically connected to the radiation conductor layer. When viewed in the negative direction of the Z axis, a ground conductor layer non-formed region where the one or more first ground conductor layers are not provided exists in the radiation conductor layer region where the radiation conductor layer is provided. When viewed along the negative direction of the Z axis, the signal conductor layer has an overlapping portion overlapping the ground conductor layer non-formed region. In the ground conductor layer non-formed region, at a position closer to the positive side of the Z axis than the signal conductor layer, no conductor other than the radiation conductor layer covers the entire ground conductor layer non-formed region. The first branch conductor layer and the second branch conductor layer are provided in the laminate and are electrically connected to the signal conductor layer. When viewed in the negative direction of the Z-axis, there is an imaginary line that passes through the overlapping portion and makes the first branch conductor layer and the second branch conductor layer line-symmetrical.

2. The multi-layer substrate according to claim 1, wherein The first branch conductor layer and the second branch conductor layer are located on the negative side of the Z axis with respect to the signal conductor layer.

3. The multi-layer substrate according to claim 1 or 2, wherein: A length of a transmission path of a high-frequency signal from the overlapping portion to the first branch conductor layer and the second branch conductor layer is shorter than half a wavelength of the high-frequency signal.

4. The multilayer substrate according to any one of claims 1 to 3, wherein The radiation conductor layer has a shape that is line-symmetrical about the imaginary line when viewed in the negative direction of the Z axis.

5. The multilayer substrate according to any one of claims 1 to 4, wherein The ground conductor layer non-formed region extends along an axis that is orthogonal to the imaginary line when viewed in the negative direction of the Z axis.

6. The multilayer substrate according to any one of claims 1 to 5, wherein: The signal conductor layer has a first end, When viewed in the negative direction of the Z-axis, the length of the signal conductor layer between the first end and the overlapping portion is less than or equal to half the wavelength of a high-frequency signal transmitted through the signal conductor layer.

7. The multilayer substrate according to any one of claims 1 to 6, wherein The multilayer substrate further comprises a second ground conductor layer. The second ground conductor layer is provided in the laminate, overlaps with the radiation conductor layer when viewed in the negative direction of the Z axis, and is located on the negative side of the Z axis relative to the signal conductor layer.

8. The multilayer substrate according to any one of claims 1 to 7, wherein The laminate has a first section where the radiating conductor layer is provided when viewed in the negative direction of the Z axis, and a second section where the radiating conductor layer is not provided when viewed in the negative direction of the Z axis. The second section of the stacked body has a curved portion when viewed in a direction perpendicular to the Z axis.

9. The multilayer substrate according to any one of claims 1 to 8, wherein: The signal conductor layer extends along the X-axis, The Y axis is orthogonal to the X axis and the Z axis, The length of the ground conductor layer non-formed region along the Y-axis is equal to or less than half the wavelength of a high-frequency signal transmitted through the signal conductor layer.

10. The multilayer substrate according to any one of claims 1 to 9, wherein The signal conductor layer extends along the X-axis, The Y axis is orthogonal to the X axis and the Z axis, The ground conductor layer non-formation region is surrounded by the first ground conductor layer when viewed in the negative direction of the Z-axis.

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