Wiring boards and mounting structures

Abstract

To provide a wiring board that efficiently transmits signals regardless of the signal frequency band. [Solution] The wiring board according to this disclosure has an insulating board comprising a first surface and a second surface located opposite the first surface, wherein a plurality of insulating layers and a plurality of conductor layers are alternately laminated. Among the conductor layers, the conductor layer constituting the first surface includes a first ground conductor and an antenna conductor. The antenna conductor includes a feed point, an antenna line connected to the feed point, and an antenna element connected to the antenna line, and extends in a first direction which is the extending direction of the antenna line. The first ground conductor includes an opening having a wide region and a narrow region in which the width of the opening in a second direction perpendicular to the first direction is narrower than that of the wide region. A part of the antenna line and the feed point are located in the narrow region, and the remainder of the antenna line and the antenna element are located in the wide region.

Description

Technical Field

[0001] The present invention relates to a wiring board and a mounting structure using the same.

Background Art

[0002] Conventionally, in communication devices using a wireless network, an antenna structure as described in Patent Document 1, for example, has been adopted for transmission and reception of electrical signals.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] In a conventional antenna structure, transmission loss increases as the frequency increases. Therefore, there is a problem that high-frequency signals are not transmitted as efficiently.

[0005] An object of the present disclosure is to provide a wiring board on which signals are efficiently transmitted regardless of the frequency band of the signals.

Means for Solving the Problems

[0006] The wiring board according to this disclosure has an insulating board comprising a first surface and a second surface located opposite the first surface, wherein a plurality of insulating layers and a plurality of conductor layers are alternately laminated. Among the conductor layers, the conductor layer constituting the first surface includes a first ground conductor and an antenna conductor. The antenna conductor extends in a first direction, which is the direction in which the antenna line extends, and includes a feed point, an antenna line connected to the feed point, and an antenna element connected to the antenna line. The first ground conductor includes an opening having a wide region and a narrow region in which the width of the opening in a second direction perpendicular to the first direction is narrower than that of the wide region. A part of the antenna line and the feed point are located in the narrow region, and the remainder of the antenna line and the antenna element are located in the wide region.

[0007] The implementation structure relating to this disclosure includes the above-mentioned wiring board and electronic components connected to the wiring board. [Effects of the Invention]

[0008] The wiring board relating to this disclosure has the configuration described in the section on means for solving the problem, thereby enabling efficient signal transmission regardless of the signal frequency band. [Brief explanation of the drawing]

[0009] [Figure 1] This is an enlarged diagram illustrating a wiring board according to one embodiment of the present disclosure. [Figure 2] This is an explanatory diagram illustrating an example of a key component viewed from the direction of arrow A shown in Figure 1 (excluding the solder mask). [Figure 3A] This is an explanatory diagram illustrating a modified example of a wide area in an opening. [Figure 3B] This is an explanatory diagram illustrating a modified example of a wide area in an opening. [Figure 4A] This is an explanatory diagram illustrating a modified example of a wide area in an opening. [Figure 4B] This is an explanatory diagram illustrating a modified example of a wide area in an opening. [Figure 5A]This is an explanatory diagram illustrating a modified example of a wide area in an opening. [Figure 5B] This is an explanatory diagram illustrating a modified example of a wide area in an opening. [Figure 6] This is an explanatory diagram illustrating another example of the main components as viewed from the direction of arrow A shown in Figure 1 (excluding the solder mask). [Figure 7] This is an explanatory diagram illustrating yet another example of the main components as viewed from the direction of arrow A shown in Figure 1 (excluding the solder mask). [Modes for carrying out the invention]

[0010] A wiring board according to one embodiment of the present disclosure will be described with reference to Figures 1 to 7. Figure 1 is an enlarged explanatory diagram for illustrating a wiring board 10 according to one embodiment of the present disclosure. Specifically, Figure 1 shows the main parts of the wiring board 10. The wiring board 10 according to one embodiment includes an insulating substrate and a solder resist 4 having a structure in which insulating layers 1 and conductive layers 2 are alternately laminated. In this specification, "insulating substrate" means a laminate in which insulating layers 1 and conductive layers 2 are alternately laminated.

[0011] As shown in Figure 1, in a wiring board 10 according to one embodiment, the insulating substrate includes a core layer and a build-up layer. The core layer includes a core insulating layer 11 and a core conductor layer 21. The build-up layer includes a build-up insulating layer 12 and a build-up conductor layer 22.

[0012] The core insulating layer 11 is located approximately in the center of the insulating substrate in the thickness direction and is an insulating layer 1 with a relatively large thickness. The core insulating layer 11 is not particularly limited as long as it is made of an insulating material. Examples of insulating materials include epoxy resin, bismaleimide-triazine resin, polyimide resin, polyphenylene ether resin, and glass. Only one of these insulating materials may be used, or two or more may be used in combination. The thickness of the core insulating layer 11 is not particularly limited and may be, for example, 100 μm or more and 1000 μm or less.

[0013] The insulating layer 11 for the core may contain a reinforcing material. Examples of the reinforcing material include insulating fabric materials such as glass fiber, glass non-woven fabric, aramid non-woven fabric, aramid fiber, and polyester fiber. Only one type of reinforcing material may be used, or two or more types may be used in combination. Furthermore, the insulating layer 11 for the core may contain inorganic insulating fillers such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide. Only one type of inorganic insulating filler may be used, or two or more types may be used in combination.

[0014] On both sides of the insulating layer 11 for the core, a conductor layer 21 for the core is located. The conductor layer 21 for the core is a part of the conductor layer 2. The conductor layer 21 for the core is not particularly limited as long as it is a material having conductivity. Examples of the material having conductivity include metals such as copper. The thickness of the conductor layer 21 for the core is not limited, and may be, for example, 20 μm or more and 50 μm or less.

[0015] As shown in FIG. 1, in the insulating layer 11 for the core, a through-hole conductor 2T is located in order to electrically connect the upper and lower surfaces of the insulating layer 11 for the core. The through-hole conductor 2T is located in a through-hole that penetrates from the upper surface to the lower surface of the insulating layer 11 for the core. The through-hole conductor 2T is formed of, for example, a metal such as copper. The through-hole conductor 2T is also a part of the conductor layer 2.

[0016] The through-hole conductor 2T is connected to the conductor layer 21 for the core located on both sides of the insulating layer 11 for the core. The through-hole conductor 2T may be integral with the conductor layer 21 for the core. The through-hole conductor 2T may be located only on the inner wall surface of the through-hole, or may be filled in the through-hole.

[0017] Although the insulating substrate shown in FIG. 1 includes a core layer, the core layer is not an essential member. For example, there is also an insulating substrate that does not include a core layer, such as a so-called coreless substrate.

[0018] As shown in FIG. 1, build-up layers are located on both sides of the core layer. The build-up layer has a structure in which build-up insulating layers 12 and build-up conductor layers 22 are alternately laminated. As described above, in the case of an insulating substrate that does not include a core layer, the insulating substrate includes only the build-up layer.

[0019] The build-up insulating layer 12 is an insulating layer 1 other than the core insulating layer 11. The build-up insulating layer 12 is not particularly limited as long as it is a material having insulating properties. Examples of materials having insulating properties include resins such as epoxy resin, bismaleimide-triazine resin, polyimide resin, and polyphenylene ether resin. These resins may be used alone or in combination of two or more.

[0020] The build-up insulating layers 12 may be the same resin or different resins. The build-up insulating layer 12 and the core insulating layer 11 may be the same resin or different resins. The thickness of the build-up insulating layer 12 is not particularly limited, and may be, for example, 30 μm or more and 100 μm or less. The build-up insulating layers 12 may have the same thickness or different thicknesses.

[0021] The build-up insulating layer 12 may contain a reinforcing material. Examples of the reinforcing material include insulating cloth materials such as glass fiber, glass non-woven fabric, aramid non-woven fabric, aramid fiber, and polyester fiber. The reinforcing material may be used alone or in combination of two or more. Further, the build-up insulating layer 12 may contain inorganic insulating fillers such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide. The inorganic insulating fillers may be used alone or in combination of two or more.

[0022] A build-up conductor layer 22 is located on the surface of the build-up insulating layer 12. The build-up conductor layer 22 is not particularly limited as long as it is made of a conductive material. Examples of conductive materials include metals such as copper. The thickness of the build-up conductor layer 22 is not limited and may be, for example, 10 μm or more and 40 μm or less.

[0023] The build-up conductor layers 22 may be made of the same metal or different metals. The build-up conductor layers 22 and the core conductor layer 21 may be made of the same metal or different metals. The build-up conductor layers 22 may have the same thickness or different thicknesses.

[0024] The build-up insulating layer 12 has via-hole conductors 2V for electrically connecting the upper and lower surfaces of the build-up insulating layer 12. The via-hole conductors 2V are located within via holes that penetrate from the upper surface to the lower surface of the build-up insulating layer 12. The via-hole conductors 2V are not particularly limited as long as they are made of a conductive material. Examples of conductive materials include metals such as copper. The via-hole conductors 2V may be filled inside the via holes, or they may be located only on the inner wall surface of the via holes. The via-hole conductors 2V are part of the build-up conductor layer 22.

[0025] As shown in Figure 1, solder resist 4 may be located on the first surface 1a and the second surface 1b of the insulating substrate. The solder resist 4 is made of resin, and examples of the resin include acrylic-modified epoxy resin.

[0026] Of the build-up conductor layers 22, the build-up conductor layer 22 constituting the first surface 1a of the insulating substrate includes a first ground conductor 22G and an antenna conductor 3. As shown in Figure 2, the first ground conductor 22G has an opening 5. Figure 2 is an explanatory diagram illustrating an example of the main parts as viewed from the direction of arrow A shown in Figure 1 (excluding the solder resist 4).

[0027] The antenna conductor 3 includes a feed point 31, an antenna line 32, and an antenna element 33. The feed point 31 is connected to a via-hole conductor 2V and is located at the base of the antenna conductor 3. The antenna line 32 is connected to the feed point 31 and extends in a first direction. In this specification, "first direction" means the direction in which the antenna line 32 extends. The antenna element 33 is connected to the antenna line 32 and has the function of transmitting and receiving signals. In Figure 2, four antenna elements 33 are connected to the antenna line 32, but it is sufficient for at least one antenna element 33 to be connected to the antenna line 32.

[0028] The antenna conductor 3 is located in the opening 5 of the first ground conductor 22G. As shown in Figure 2, the opening 5 includes a wide region 51 and a narrow region 52. Specifically, the narrow region 52 is the region in which the width of the opening in the second direction perpendicular to the first direction is narrower than that of the wide region 51. A portion of the antenna line 32 and the feed point 31 of the antenna conductor 3 are located in the narrow region 52. On the other hand, the remaining portion of the antenna line 32 and the antenna element 33 of the antenna conductor 3 are located in the wide region 51.

[0029] In the wiring board 10, signals are efficiently transmitted regardless of the signal frequency band, because a portion of the antenna line 32 and the feed point 31 of the antenna conductor 3 are located in the narrow region 52 of the opening 5 of the first ground conductor 22G, and the remaining portion of the antenna line 32 and the antenna element 33 are located in the wide region 51 of the opening 5. If the entire antenna line 32 is located in the narrow region 52, multiple reflections caused by changes in impedance will affect the antenna element 33. This can lead to a decrease in antenna gain. Furthermore, if the entire antenna line 32 is located in the wide region 51, the impedance will change abruptly. This can also lead to a decrease in antenna gain. In this disclosure, a portion of the antenna line 32 is located in the narrow region 52, and the remainder is located in the wide region 51. As a result, the problem of decreased antenna gain can be reduced, and signals are transmitted efficiently.

[0030] The shape of the opening 5 is not limited as long as it includes a wide region 51 and a narrow region 52. As shown in Figures 3A and 3B, when the opening 5 is viewed from above, the wide region 51 may have at least one of the following shapes: one in which the length in the second direction gradually increases along the first direction, and another in which the length gradually decreases. Figures 3A and 3B are explanatory diagrams illustrating variations of the wide region 51 in the opening 5. Having such a shape in the opening 5 allows for variations in the strength of the electric field. As a result, the signal is more easily directed in the direction of the wider opening 5, allowing the signal to be transmitted in any direction.

[0031] The wide region 51 may have a shape in which the length in the second direction gradually increases or decreases along the first direction, as well as shapes as shown in Figures 4A and 4B. That is, as shown in Figures 4A and 4B, when the opening 5 is viewed from above, the wide region 51 may have a shape in which the length in the second direction increases or decreases towards the center in the first direction. Figures 4A and 4B are explanatory diagrams for illustrating modified examples of the wide region 51 in the opening 5. In Figures 4A and 4B, the length increases or decreases towards the center in the first direction, but the form is not limited to this. For example, the opening edge of the opening 5 may be wavy, and the lengths may be irregular.

[0032] If the width (length in the second direction) of the wide area 51 is not constant, as shown in Figures 3A, 3B, 4A, and 4B, the length of the longest part of the width (length in the second direction) of the wide area 51 may be, for example, 1.1 times or more and 1.6 times or less of the length of the shortest part.

[0033] As shown in Figures 5A and 5B, when the opening 5 is viewed from above, the end 511 opposite the narrow area 52 in the wide area 51 may be curved. Figures 5A and 5B are explanatory diagrams illustrating modified examples of the wide area 51 in the opening 5. By having such a shape in the opening 5, signal distortion is reduced. As a result, signals are transmitted more efficiently.

[0034] When the end portion 511 is curved, the entire end portion 511 may be curved as shown in Figure 5A, or only the corners of the end portion 511 may be curved as shown in Figure 5B. In the case where the entire end portion 511 is curved as shown in Figure 5A, the signal is transmitted more efficiently due to power concentration. When the end portion 511 is curved, a larger radius of curvature is preferable, for example, it may be 1 / 5 or more of the width W1 of the wide area 51, or 1 / 2 or less of the width W1 of the wide area 51.

[0035] Even if the width (length in the second direction) of the wide area 51 is not constant as shown in Figures 3A, 3B, 4A, and 4B, the portion corresponding to the end 511 may be curved, as shown in Figures 5A and 5B. Furthermore, in the opening 5 located on the wiring board 10, all wide areas 51 may have the same shape, or some wide areas 51 may have different shapes.

[0036] The length L1 (length in the first direction) and width W1 (length in the second direction) of the wide area 51 are not limited and are set appropriately according to the length of the antenna line 32 and the size of the antenna element 33. The length L1 of the wide area 51 may be, for example, 5 mm or more and 20 mm or less. The width W1 of the wide area 51 may be, for example, 1.0 mm or more and 3.0 mm or less.

[0037] The length L2 (length in the first direction) of the narrow region 52 is not limited, but is usually shorter than the length L1 of the wide region 51. The length L2 of the narrow region 52 may be, for example, 0.5 mm or more and 2.0 mm or less. The width W2 (length in the second direction) of the narrow region 52 is not limited as long as it is narrower than the width W1 of the wide region 51. If the width W1 of the wide region 51 is not a constant width as shown in Figures 3A, 3B, 4A, and 4B, the maximum and minimum widths of the wide region 51 should be within the above ranges.

[0038] The statement that the width W2 of a narrow region 52 is narrower than the width W1 of a wide region 51 means that the width W2 of adjacent narrow regions 52 is narrower (shorter) than the width W1 of a wide region 51.

[0039] In the wiring board 10, among the antenna elements 33 included in the antenna conductor 3, the antenna element 33 located at the end opposite to the feed point 31 is the first antenna element 331. The distance D in the first direction between the first ground conductor 22G and the first antenna element 331 may be twice or more the width W of the first antenna element 331 in the first direction. When the distance D between the first ground conductor 22G and the first antenna element 331 is twice or more the width W of the first antenna element 331, the decrease in resonant frequency due to the increase in capacitance is reduced. As a result, the signal is transmitted more efficiently. Although the distance D is not limited to twice or more the width W, considering the size of the antenna conductor 3 and the size of the aperture 5, the distance D may be 5.0 times or less the width W. Furthermore, the distance in the second direction between the first ground conductor 22G and the antenna element 33 may be λ / 4 or more of the frequency used, and is not limited thereto. The positional relationship between the antenna conductor 3 and the aperture 5 should be appropriately optimized depending on the frequency used and the size of the antenna element 33. The distance between the antenna conductors 3 may be less than or equal to λ / 2 of the wavelength used, and the optimal distance can be set as appropriate depending on the frequency used.

[0040] The size of the antenna element 33 is not limited and can be set appropriately according to the application of the wiring board 10. Typically, the width of the antenna element 33 in the first direction may be 300 μm or more and 6 mm or less, and is particularly effective when it is 300 μm or more and 600 μm or less. The width of the antenna element 33 in the second direction may be 300 μm or more and 12 mm or less, and is particularly effective when it is 300 μm or more and 1200 μm or less. The antenna elements 33, including the first antenna element 331, may have the same shape, different shapes, the same size, or different sizes.

[0041] In the wiring board 10, the length of the remaining portion of the antenna line 32 located in the wide region 51 in the first direction may be longer than the length of a portion of the antenna line 32 located in the narrow region 52 in the first direction. This configuration makes it less likely for multiple reflections caused by changes in impedance to affect the antenna element 33.

[0042] As shown in Figure 6, when viewed from above, the ground via hole conductor 2VG may be located on the periphery of the opening 5. Figure 6 is an explanatory diagram illustrating another example of the main part as seen from the direction of arrow A shown in Figure 1 (excluding the solder resist 4). The ground via hole conductor 2VG is not limited as long as it is located on the periphery of the opening 5.

[0043] For example, as shown in Figure 6, when viewed from a planar perspective, at least two rows of ground via hole conductors 2VG may be arranged in a staggered pattern around the periphery of the opening 5. When at least two rows of ground via hole conductors 2VG are arranged in a staggered pattern around the periphery of the opening 5, electric field leakage is reduced. As a result, signals are transmitted more efficiently.

[0044] The gap between adjacent ground via hole conductors 2VG may be less than or equal to 1 / 4 of the wavelength of the signal flowing through the antenna conductor 3. In this case, the gap refers to the distance between the via walls. This configuration reduces electric field leakage and allows for more efficient signal transmission.

[0045] As shown in Figure 7, the wiring board 10 may further include at least one branch antenna conductor 3B, which includes a branch antenna line 32B and a branch antenna element 33B connected to the branch antenna line 32B. Figure 7 is an explanatory diagram illustrating yet another example of the main part as seen from the direction of arrow A shown in Figure 1 (excluding the solder resist 4). Having two sets of antenna conductors 3 enables beamforming by sending phase-shifted signals to each antenna conductor 3.

[0046] The branch antenna conductor 3B branches off from the remaining portion of the antenna line 32 and is located along the antenna conductor 3. Figure 7 shows one branch antenna conductor 3B, but is not limited to at least one. The number of branch antenna conductors 3B is set appropriately depending on the application of the wiring board 10.

[0047] The wiring board 10 can be formed, for example, as follows: First, through-holes are formed in the core insulating layer 11 by drilling or laser. Then, a semi-additive method is applied to the core insulating layer 11 to form a core conductor layer 21 on the upper and lower surfaces of the core insulating layer 11, and a through-hole conductor 2T is formed in the through-holes.

[0048] Next, a build-up insulating layer 12 is laminated onto the upper and lower surfaces of the core insulating layer 11 on which the core conductor layer 21 is formed. The build-up insulating layer 12 is formed by adhering a build-up insulating layer film to the core insulating layer 11 under reduced pressure and then heat-curing it.

[0049] Next, a laser is irradiated onto the build-up insulating layer 12 to form via holes with a portion of the core conductor layer 21 as the bottom. Then, a semi-additive method is applied to the surface of the build-up insulating layer 12 and inside the via holes to form the build-up conductor layer 22 on the surface of the build-up insulating layer 12 and the via hole conductor 2V inside the via holes.

[0050] The desired number of layers can be formed by repeatedly forming the build-up insulating layer 12 and the build-up conductor layer 22. The first ground conductor 22G and the antenna conductor 3 can be formed by processing the build-up conductor layer 22 formed on the uppermost surface into a desired pattern.

[0051] As described above, the first ground conductor 22G and the antenna conductor 3 are part of the build-up conductor layer 22 that constitutes the first surface 1a of the insulating substrate. Subsequently, if necessary, a solder resist film may be applied to the uppermost and lowermost build-up insulating layers 12 under reduced pressure and heat-cured to form a solder resist 4.

[0052] Next, the mounting structure according to this disclosure will be described with reference to Figure 1. The mounting structure according to one embodiment includes a wiring board 10 according to one embodiment and an electronic component E located in the mounting area of ​​the wiring board 10.

[0053] Figure 1 shows a state in which the wiring board 10 and the electronic component E are not connected. By connecting the electronic component connection pad P (part of the build-up conductor layer 22 that constitutes the second surface 1b of the insulating substrate), which is exposed through an opening in the solder resist 4 located on one surface of the wiring board 10, to the electrodes of the electronic component E via solder S, a mounting structure according to one embodiment can be obtained. Examples of electronic components E include semiconductor integrated circuit elements and optoelectronic elements.

[0054] In one embodiment of the mounting structure, electronic components E may also be connected via solder S to other pads (part of the build-up conductor layer 22 constituting the first surface 1a of the insulating substrate) that are exposed through openings in the solder resist 4 located on other surfaces of the wiring board 10. Alternatively, a motherboard or the like may be connected via solder S to other pads of the wiring board 10.

[0055] The embodiments of this disclosure have been described above. However, the inventions relating to this disclosure are not limited to the embodiments described above, and various modifications and improvements are possible within the scope of this disclosure as shown in (1) to (9) below.

[0056] (1) The wiring board according to the present disclosure has an insulating board having a first surface and a second surface located opposite the first surface, wherein a plurality of insulating layers and a plurality of conductor layers are alternately laminated. Among the conductor layers, the conductor layer constituting the first surface includes a first ground conductor and an antenna conductor. The antenna conductor extends in a first direction, which is the direction in which the antenna line extends, and includes a feed point, an antenna line connected to the feed point, and an antenna element connected to the antenna line. The first ground conductor includes an opening having a wide region and a narrow region in which the width of the opening in a second direction perpendicular to the first direction is narrower than that of the wide region. A part of the antenna line and the feed point are located in the narrow region, and the remainder of the antenna line and the antenna element are located in the wide region. (2) In the wiring board described in (1) above, the distance in the first direction between the first ground conductor and the first antenna element located at the end opposite to the feed point is at least twice the width of the first antenna element in the first direction. (3) In the wiring board described in (1) or (2) above, the length in the first direction of the remaining portion of the antenna line located in the wide region is longer than the length in the first direction of a portion of the antenna line located in the narrow region. (4) In the wiring board described in any of (1) to (3) above, when the opening is viewed from above, the wide region has at least one of the following shapes: a shape in which the length in the second direction gradually increases along the first direction, and a shape in which the length gradually decreases. (5) In the wiring board described in any of (1) to (4) above, when the opening is viewed from above, the end opposite to the narrow area in the wide area is curved. (6) In the wiring board described in any of (1) to (5) above, when viewed from above, at least two rows of ground via hole conductors are arranged in a staggered pattern around the periphery of the opening. (7) In the wiring board described in (6) above, the gap between adjacent ground via hole conductors is less than or equal to 1 / 4 of the wavelength of the signal flowing through the antenna conductor. (8) The wiring board described in any of (1) to (7) above further includes a branch antenna line and at least one branch antenna conductor including a branch antenna element connected to the branch antenna line. The branch antenna conductor branches off from the remainder of the antenna line and is located along the antenna conductor. (9) The implementation structure relating to this disclosure includes a wiring board as described in any of (1) to (8) above, and an electronic component connected to the wiring board. [Explanation of symbols]

[0057] 1. Insulating layer 11. Insulating layer for core 12. Insulating layer for build-up 1a 1st page 1b 2nd side 2 Conductor layers 21 Conductor layer for core 22. Build-up conductor layer 22G First Ground Conductor 2T Through-hole conductor 2V via hole conductor 2VG Ground via hole conductor 3 Antenna conductors 31 Power supply section 32 Antenna lines 33 Antenna elements 331 First Antenna Element 3B Conductor for Branch Antenna 32B Branch Antenna Line 33B Branching antenna element 4 Solder Resist 5 Openings 51 Wide area 511 End 52 Narrow area E Electronic parts S Handa 10 Wiring board

Claims

1. The insulating substrate has multiple insulating layers and multiple conductive layers stacked alternately, and includes a first surface and a second surface located opposite the first surface. Of the aforementioned conductor layers, the conductor layer constituting the first surface includes an antenna conductor and a first ground conductor. The antenna conductor includes a feed point, an antenna line connected to the feed point, and an antenna element connected to the antenna line, and extends in a first direction which is the direction in which the antenna line extends. The first ground conductor includes an opening having a wide region and a narrow region in which the width of the opening in a second direction perpendicular to the first direction is narrower than that of the wide region. The narrow region contains a portion of the antenna line and the power supply section, while the wide region contains the remaining portion of the antenna line and the antenna element. Wiring board.

2. The wiring board according to claim 1, wherein the distance in the first direction between the first ground conductor and the first antenna element located at the end opposite to the power supply portion is at least twice the width of the first antenna element in the first direction.

3. The wiring board according to claim 1, wherein the length in the first direction of the remaining portion of the antenna line located in the wide region is longer than the length in the first direction of a portion of the antenna line located in the narrow region.

4. The wiring board according to claim 1, wherein, when the opening is viewed from above, the wide region has at least one of a shape in which the length in the second direction gradually increases along the first direction, and a shape in which the length gradually decreases.

5. The wiring board according to claim 1, wherein, when viewed from above, the end of the wide region opposite to the narrow region is curved.

6. The wiring board according to claim 1, wherein, when viewed from above, at least two rows of ground via hole conductors are arranged in a staggered pattern around the periphery of the opening.

7. The wiring board according to claim 6, wherein the gap between adjacent ground via hole conductors is less than or equal to one-quarter of the wavelength of the signal flowing through the antenna conductor.

8. The branch antenna further includes at least one branch antenna line and a branch antenna element connected to the branch antenna line, The aforementioned branch antenna conductor branches off from the remaining portion of the antenna line and is located along the antenna conductor. The wiring board according to claim 1.

9. A mounting structure comprising a wiring board according to any one of claims 1 to 8 and an electronic component connected to the wiring board.

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