JP7750263B2 - multilayer board - Google Patents

Description

The present invention relates to a multilayer substrate having a radiating conductor layer.

A known example of a conventional invention related to a multilayer substrate is the antenna module described in Patent Document 1. The antenna module includes an antenna package and a connecting member. The connecting member is a flexible, strip-shaped substrate. The connecting member includes a power feed line. The antenna package is fixed onto the connecting member. The antenna package includes a patch antenna. The patch antenna is electrically connected to the power feed line.

US Patent Application Publication No. 2020/0194893

However, in the antenna module described in Patent Document 1, mismatches in characteristic impedance may occur in the section between the patch antenna and the feeder line.

The object of the present invention is to provide a multilayer substrate that can prevent mismatches in characteristic impedance in the section between the signal conductor layer and the radiation conductor layer.

A multilayer substrate according to one embodiment of the present invention comprises:
a laminate having a structure in which a plurality of insulator layers including an intermediate insulator layer and a negative-side adjacent insulator layer are stacked so as to be aligned in the Z-axis direction, each of the plurality of insulator layers having a positive main surface and a negative main surface located on the negative side of the Z-axis from the positive main surface, and the negative-side adjacent insulator layer is located on the negative side of the Z-axis of the intermediate insulator layer and is in contact with the intermediate insulator layer;
a radiation conductor layer provided on the laminate and positioned on the positive side of the Z axis relative to the intermediate insulator layer;
a signal conductor layer provided on the laminate and positioned on the negative side of the Z axis relative to the intermediate insulator layer;
a connecting conductor layer provided in the laminate, located on the negative principal surface of the intermediate insulator layer, and including a first connecting section, a second connecting section, a line section, a first intermediate section, and a second intermediate section, wherein the first intermediate section is adjacent to the first connecting section, the second intermediate section is adjacent to the second connecting section, and the line section is adjacent to the first intermediate section and the second intermediate section;
a first ground conductor layer provided on the laminate, positioned on the negative side of the Z-axis relative to the connection conductor layer and the signal conductor layer, and overlapping at least a portion of the connection conductor layer and at least a portion of the signal conductor layer when viewed in the Z-axis direction;
a first interlayer connection conductor in contact with the first connection section;
a second interlayer connection conductor in contact with the second connection section;
It is equipped with
one of the first interlayer connection conductor and the second interlayer connection conductor penetrates the intermediate insulator layer in the Z-axis direction and electrically connects the radiation conductor layer and the connection conductor layer;
the other of the first interlayer connection conductor and the second interlayer connection conductor penetrates the negative-side adjacent insulator layer in the Z-axis direction and electrically connects the signal conductor layer and the connection conductor layer,
The direction in which the connecting conductor layer extends is defined as an extension direction,
A direction perpendicular to the stretching direction and the Z-axis direction is defined as a line width direction,
the first connection section is located at a first end of the connection conductor layer in the extension direction, the second connection section is located at a second end of the connection conductor layer in the extension direction, and the second end of the connection conductor layer is located on the opposite side of the first end of the connection conductor layer in the extension direction;
In the extension direction, both ends of the first connection section are positioned at equal distances from the center of the first interlayer connection conductor as viewed in the Z-axis direction,
In the extension direction, both ends of the second connection section are positioned at equal distances from the center of the second interlayer connection conductor as viewed in the Z-axis direction,
a maximum width of the second connection section in the line width direction is smaller than a maximum width of the first connection section in the line width direction;
the first intermediate section includes a first thick line section having a width in the line width direction that is larger than a width of the line section in the line width direction,
the second intermediate section includes a second thick line section having a width in the line width direction that is larger than a width of the line section in the line width direction,
The first thick line section and the second thick line section are adjacent to the rail section.

The multilayer board according to the present invention can prevent mismatches in characteristic impedance in the section between the signal conductor layer and the radiation conductor layer.

FIG. 1 is an exploded perspective view of a multilayer substrate 10. FIG. FIG. 2 is a cross-sectional view of the multilayer substrate 10 taken along line AA in FIG. FIG. 3 is a top view of the connecting conductor layer 24. As shown in FIG. FIG. 4 is a Smith chart. FIG. 5 is a top view of the connecting conductor layer 24a. FIG. 6 is a top view of the connecting conductor layer 24b. FIG. 7 is a top view of the connecting conductor layer 24c. FIG. 8 is a Smith chart. FIG. 9 is a top view of the connecting conductor layer 24d. FIG. 10 is a cross-sectional view of the multilayer substrate 10a. FIG. 11 is a cross-sectional view of the multilayer substrate 10b. FIG. 12 is a top view of the connecting conductor layer 24 provided on the multilayer substrate 10b.

(First embodiment)
[Structure of multilayer substrate 10]
The structure of a multilayer substrate 10 according to a first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is an exploded perspective view of the multilayer substrate 10. Fig. 2 is a cross-sectional view of the multilayer substrate 10 taken along line A-A in Fig. 1. Fig. 3 is a top view of a connecting conductor layer 24.

In the following, the stacking direction of the laminate 12 of the multilayer substrate 10 is defined as the up-down direction. The up-down direction coincides with the Z-axis direction. The up direction is the positive direction of the Z-axis. The down direction is the negative direction of the Z-axis. When viewing the multilayer substrate 10 in the up-down direction, the two directions in which the edges of the multilayer substrate 10 extend are defined as the left-right direction and the front-back direction. The left-right direction coincides with the X-axis direction. The front-back direction coincides with the Y-axis direction. The left-right direction is perpendicular to the up-down direction. The front-back direction is perpendicular to both the up-down direction and the left-right direction. Note that the definitions of directions in this specification are merely examples. Therefore, the directions in actual use of the multilayer substrate 10 do not necessarily have to coincide with the directions in this specification. Furthermore, the up-down direction may be reversed in each drawing. Similarly, the left-right direction may be reversed in each drawing. The front-back direction may be reversed in each drawing.

In the following, X is a component or member of the multilayer substrate 10. In this specification, unless otherwise specified, each part of X is defined as follows: The front part of X means the front half of X. The rear part of X means the rear half of X. The left part of X means the left half of X. The right part of X means the right half of X. The upper part of X means the upper half of X. The lower part of X means the lower half of X. The front end of X means the front end of X. The rear end of X means the rear end of X. The left end of X means the left end of X. The right end of X means the right end of X. The upper end of X means the upper end of X. The lower end of X means the lower end of X. The front end of X means the front end of X and its vicinity. The rear end of X means the rear end of X and its vicinity. The left end of X means the left end of X and its vicinity. The right end of X means the right end of X and its vicinity. The upper end of X means the upper end of X and its vicinity. The lower end of X means the lower end of X and its vicinity.

The multilayer substrate 10 is used, for example, in electronic devices such as mobile phones. As shown in FIG. 1, the multilayer substrate 10 includes a laminate 12, a second ground conductor layer 18, a radiation conductor layer 20, connection conductor layers 22a, 22b, and 24, a signal conductor layer 26, a first ground conductor layer 28, and interlayer connection conductors v1 to v4.

The laminate 12 has a plate shape. The laminate 12 has a structure in which insulator layers 14a-14g and protective layers 15a-15c are stacked in the Z-axis direction. Insulator layers 14a-14d and protective layer 15a have a rectangular shape when viewed in the vertical direction. Insulator layers 14e-14g and protective layers 15b and 15c have a strip shape extending in the left-right direction when viewed in the vertical direction. Protective layer 15a, insulator layers 14a-14f, and protective layer 15b are arranged in this order from top to bottom. Insulator layers 14e and 14f and protective layer 15b extend to the right from insulator layers 14a-14d when viewed in the vertical direction.

Insulator layer 14g is layered on insulator layer 14e. Insulator layer 14g is located to the right of insulator layer 14d. However, insulator layer 14g is not in contact with insulator layer 14d. Protective layer 15c is layered on insulator layer 14g.

Each of the insulator layers 14a-14g and protective layers 15a-15c described above has an upper main surface (positive main surface) and a lower main surface (negative main surface) located below the upper main surface (positive main surface) (on the negative side of the Z axis). Furthermore, the insulator layers 14a-14g include the insulator layer 14d, which is an intermediate insulator layer, and the insulator layer 14e, which is a negative-side adjacent insulator layer. The insulator layer 14e, which is a negative-side adjacent insulator layer, is located below the insulator layer 14d, which is an intermediate insulator layer, (on the negative side of the Z axis) and is in contact with the insulator layer 14d, which is an intermediate insulator layer.

The insulating layers 14a to 14g are made of a thermoplastic resin such as polyimide or liquid crystal polymer. The protective layers 15a to 15c are insulating films applied to the upper or lower principal surfaces of the insulating layers. Each of the protective layers 15a to 15c protects the radiation conductor layer 20, the first ground conductor layer 28, and the second ground conductor layer 18. The laminate 12 described above is flexible.

As shown in FIG. 2, the laminate 12 has a first section A1, a second section A2, and a third section A3 arranged in this order in the left-right direction (the X-axis direction perpendicular to the Z-axis direction). The first section A1, the second section A2, and the third section A3 are arranged in this order from left to right. The thickness of the first section A1 in the up-down direction (Z-axis direction) is greater than the thickness of the second section A2 in the up-down direction (Z-axis direction). The thickness of the third section A3 in the up-down direction (Z-axis direction) is greater than the thickness of the second section A2 in the up-down direction (Z-axis direction). The thickness of the third section A3 in the up-down direction (Z-axis direction) is smaller than the thickness of the first section A1 in the up-down direction (Z-axis direction).

As shown in FIG. 2, the laminate 12 includes a first laminate portion 12a and a second laminate portion 12b. The first laminate portion 12a includes insulator layers 14a-14c located above (on the positive side of the Z axis) intermediate insulator layer 14d, intermediate insulator layer 14d, and protective layer 15a. The second laminate portion 12b includes insulator layers 14e and 14f located below (on the negative side of the Z axis) intermediate insulator layer 14d. The second laminate portion 12b further includes insulator layer 14g and protective layers 15b and 15c. The laminate 12 is fabricated by thermocompression bonding the first laminate portion 12a, thermocompression bonding the second laminate portion 12b, and then thermocompression bonding the first laminate portion 12a and the second laminate portion 12b together.

The radiating conductor layer 20 functions as a patch antenna. The radiating conductor layer 20 emits and/or receives high-frequency signals. As shown in FIG. 1, the radiating conductor layer 20 is provided on the laminate 12. The radiating conductor layer 20 is located above (on the positive side of the Z axis) the insulator layer 14d, which is an intermediate insulator layer. More specifically, the radiating conductor layer 20 is located on the upper main surface of the insulator layer 14a. When viewed in the vertical direction, the radiating conductor layer 20 has a diamond shape with diagonals extending in the left-right and front-to-back directions.

High-frequency signals are transmitted through the signal conductor layer 26. As shown in FIG. 1, the signal conductor layer 26 is provided in the laminate 12. The signal conductor layer 26 is located below (on the negative side of the Z axis) the insulator layer 14d, which is an intermediate insulator layer. More specifically, the signal conductor layer 26 is located on the lower main surface of the insulator layer 14e. When viewed in the vertical direction, the signal conductor layer 26 has a linear shape that extends in the horizontal direction. As shown in FIG. 2, the signal conductor layer 26 is located in the first section A1, second section A2, and third section A3.

High-frequency signals are transmitted to the connecting conductor layer 24. The connecting conductor layer 24 is provided in the laminate 12. The connecting conductor layer 24 is located on the lower main surface (negative main surface) of the insulator layer 14d, which is an intermediate insulator layer. More specifically, the connecting conductor layer 24 is located on the lower main surface of the insulator layer 14d. When viewed in the vertical direction, the connecting conductor layer 24 has a linear shape extending in the left-right direction. When viewed in the vertical direction, the right end of the connecting conductor layer 24 overlaps with the left end of the signal conductor layer 26. As shown in Figure 2, the connecting conductor layer 24 is located in the first section A1. The connecting conductor layer 24 is not located in the second section A2 or the third section A3.

The first ground conductor layer 28 is connected to a ground potential. The first ground conductor layer 28 is provided on the laminate 12. The first ground conductor layer 28 is located below the connection conductor layer 24 and the signal conductor layer 26 (on the negative side of the Z axis). The first ground conductor layer 28 is located on the lower main surface of the insulator layer 14f. The first ground conductor layer 28 covers almost the entire lower main surface of the insulator layer 14f. As a result, the first ground conductor layer 28 overlaps at least a portion of the connection conductor layer 24 and at least a portion of the signal conductor layer 26 when viewed in the vertical direction (Z axis direction). In this embodiment, the first ground conductor layer 28 overlaps the entire connection conductor layer 24 and the entire signal conductor layer 26 when viewed in the vertical direction. Furthermore, there is no conductor between the first ground conductor layer 28 and the connection conductor layer 24. There is no conductor between the first ground conductor layer 28 and the signal conductor layer 26. Furthermore, the first ground conductor layer 28 overlaps the radiation conductor layer 20 when viewed in the vertical direction (Z-axis direction). The first ground conductor layer 28 as described above is located in the first section A1, the second section A2, and the third section A3.

The second ground conductor layer 18 is connected to a ground potential. The second ground conductor layer 18 is provided on the laminate 12. The second ground conductor layer 18 is located above the signal conductor layer 26 (on the positive side of the Z axis). The second ground conductor layer 18 is located on the upper main surface of the insulator layer 14g. The second ground conductor layer 18 covers almost the entire upper main surface of the insulator layer 14g. As a result, the second ground conductor layer 18 overlaps at least a portion of the signal conductor layer 26 when viewed in the vertical direction (Z axis direction). In this embodiment, the second ground conductor layer 18 overlaps the entire signal conductor layer 26 when viewed in the vertical direction. Furthermore, no conductors other than the interlayer connection conductor v4 and the first ground conductor layer 28 exist between the second ground conductor layer 18 and the signal conductor layer 26. The second ground conductor layer 18 as described above is located in the third section A3. The second ground conductor layer 18 is not located in the first section A1 or the second section A2.

As described above, the signal conductor layer 26 forms a microstripline structure together with the first ground conductor layer 28 in the first section A1 and the second section A2. The signal conductor layer 26 forms a stripline structure together with the first ground conductor layer 28 and the second ground conductor layer 18 in the third section A3. As a result, the characteristic impedance generated in the signal conductor layer 26 is a predetermined characteristic impedance (50 Ω).

The connecting conductor layer 22a is located on the upper main surface of the insulator layer 14b. The connecting conductor layer 22a has a linear shape extending in the left-right direction. The left end of the connecting conductor layer 22a overlaps with the radiating conductor layer 20 when viewed in the up-down direction.

The connection conductor layer 22b is located on the upper main surface of the insulator layer 14c. The connection conductor layer 22b has a linear shape extending in the left-right direction. When viewed in the up-down direction, the left end of the connection conductor layer 22b overlaps with the left end of the connection conductor layer 24. When viewed in the up-down direction, the right end of the connection conductor layer 22b overlaps with the right end of the connection conductor layer 22a.

The interlayer connection conductor v1 passes through the insulator layer 14a in the vertical direction. The interlayer connection conductor v1 contacts the left end portions of the radiating conductor layer 20 and the connecting conductor layer 22a. As a result, the interlayer connection conductor v1 electrically connects the radiating conductor layer 20 and the connecting conductor layer 22a.

The interlayer connection conductor v2 penetrates the insulator layer 14b in the vertical direction. The interlayer connection conductor v2 contacts the right end of the connection conductor layer 22a and the right end of the connection conductor layer 22b. As a result, the interlayer connection conductor v2 electrically connects the connection conductor layer 22a and the connection conductor layer 22b.

The interlayer connection conductor v3 is an example of a second interlayer connection conductor. The interlayer connection conductor v3 penetrates the intermediate insulator layers 14d and 14c in the vertical direction (Z-axis direction). The interlayer connection conductor v3 contacts the left end of the connection conductor layer 22b and the left end of the connection conductor layer 24. As a result, the interlayer connection conductor v3 electrically connects the connection conductor layer 22b and the connection conductor layer 24. In this way, the interlayer connection conductor v3 is electrically connected to the radiating conductor layer 20.

The interlayer connection conductor v4 is an example of a first interlayer connection conductor. The interlayer connection conductor v4 penetrates the insulator layer 14e, which is the negative-side adjacent insulator layer, in the vertical direction (Z-axis direction). The interlayer connection conductor v4 contacts the right end of the connection conductor layer 24 and the left end of the signal conductor layer 26. As a result, the interlayer connection conductor v4 electrically connects the connection conductor layer 24 and the signal conductor layer 26. Therefore, the interlayer connection conductor v4 is electrically connected to the signal conductor layer 26.

Here, the length of the current path from the interlayer connection conductor v3 to the radiation conductor layer 20 is shorter than the length of the current path from the interlayer connection conductor v4 (described below) to the radiation conductor layer 20. The length of the current path from the interlayer connection conductor v4 to the signal conductor layer 26 is shorter than the length of the current path from the interlayer connection conductor v3 to the signal conductor layer 26.

The second ground conductor layer 18, radiation conductor layer 20, connection conductor layers 22a, 22b, and 24, signal conductor layer 26, and first ground conductor layer 28 are formed by patterning metal foil attached to the upper or lower principal surfaces of the insulator layers 14a to 14g. The metal foil is, for example, copper foil. The interlayer connection conductors v1 to v3 are formed, for example, by filling through-holes that vertically penetrate the insulator layers 14a to 14d with conductive paste and then heating the conductive paste to solidify it. The interlayer connection conductor v4 is formed by filling through-holes that vertically penetrate the insulator layer 14e with solder. In this way, the material of interlayer connection conductor v3, which is the second interlayer connection conductor, is different from the material of interlayer connection conductor v4, which is the first interlayer connection conductor.

The structure of the connecting conductor layer 24 will be described in detail below with reference to Figure 3. The direction in which the connecting conductor layer 24 extends is defined as the extension direction. The extension direction is the left-right direction. The direction perpendicular to the extension direction and the up-down direction (Z-axis direction) is defined as the line width direction. The line width direction is the front-to-back direction.

The connecting conductor layer 24 includes a first connecting section A11, a second connecting section A12, a line section A31, a first intermediate section A21, and a second intermediate section A22. The first connecting section A11, the first intermediate section A21, the line section A31, the second intermediate section A22, and the second connecting section A12 are arranged in this order from right to left. Therefore, the first intermediate section A21 is adjacent to the first connecting section A11. The second intermediate section A22 is adjacent to the second connecting section A12. The line section A31 is adjacent to the first intermediate section A21 and the second intermediate section A22. The first connecting section A11 is located at the right end (first end) of the connecting conductor layer 24 in the extension direction. The second connecting section A12 is located at the left end (second end) of the connecting conductor layer 24 in the extension direction. Therefore, the right end of the first connecting section A11 coincides with the right end of the connecting conductor layer 24. The left end of the second connection section A12 coincides with the left end of the connection conductor layer 24.

The interlayer connection conductor v4 (first interlayer connection conductor) is in contact with the first connection section A11. In the left-right direction, which is the extension direction, both ends of the first connection section A11 are located at equal distances from the center of the interlayer connection conductor v4 (first interlayer connection conductor) when viewed in the up-down direction (Z-axis direction). Therefore, the distance from the center of the interlayer connection conductor v4 to the left end of the first connection section A11 is equal to the distance from the center of the interlayer connection conductor v4 to the right end of the first connection section A11.

The interlayer connection conductor v3 (second interlayer connection conductor) is in contact with the second connection section A12. In the left-right direction, which is the extension direction, both ends of the second connection section A12 are located at equal distances from the center of the interlayer connection conductor v3 (second interlayer connection conductor) when viewed in the up-down direction (Z-axis direction). Therefore, the distance from the center of the interlayer connection conductor v3 to the left end of the second connection section A12 is equal to the distance from the center of the interlayer connection conductor v3 to the right end of the second connection section A12. The maximum width in the front-to-back direction (line width direction) of the second connection section A12 is smaller than the maximum width in the front-to-back direction (line width direction) of the first connection section A11. The first connection section A11 and the second connection section A12 have a circular shape. The diameter of the second connection section A12 is smaller than the diameter of the first connection section A11.

The first intermediate section A21 includes a first thin line section A21a and a first thick line section A21b. The first thin line section A21a has a width in the front-to-back direction (line width direction) that is smaller than the width of the second thick line section A22b in the front-to-back direction (line width direction). The first thick line section A21b is adjacent to the track section A31. The first thick line section A21b has a width in the front-to-back direction (line width direction) that is larger than the width of the track section A31 in the front-to-back direction (line width direction).

The second intermediate section A22 includes a second thin line section A22a and a second thick line section A22b. The second thin line section A22a has a width in the front-to-back direction (line width direction) that is smaller than the width of the second thick line section A22b in the front-to-back direction (line width direction). The second thick line section A22b is adjacent to the track section A31. The second thick line section A22b has a width in the front-to-back direction (line width direction) that is smaller than the width of the track section A31 in the front-to-back direction (line width direction).

[effect]
The multilayer substrate 10 can prevent mismatching of characteristic impedance in the section between the signal conductor layer 26 and the radiation conductor layer 20. The following description will be made with reference to the drawings. FIG. 4 is a Smith chart. Z0 is the characteristic impedance occurring in the line section A31. Z0 is 50 Ω. Z1 is the characteristic impedance occurring in the first connection section A11. Z1 is, for example, 20 Ω.

More specifically, in the multilayer substrate 10, the width in the line width direction of the first connection section A11 and the second connection section A12 of the connecting conductor layer 24 is greater than the width in the line width direction of the line section A31. Furthermore, the interlayer connection conductor v4 contacts the first connection section A11. The interlayer connection conductor v3 contacts the second connection section A12. Therefore, the characteristic impedance generated in the first connection section A11 and the second connection section A12 of the connecting conductor layer 24 tends to deviate from the desired specific impedance (50 Ω).

The connecting conductor layer 24 therefore includes a first intermediate section A21. The first intermediate section A21 includes a first thin line section A21a having a width in the line width direction smaller than the width in the line width direction of the second thick line section A22b. The first intermediate section A21 is adjacent to the first connecting section A11. As a result, the first thin line section A21a functions as an inductance. In other words, an inductor is connected in series to the line section A31. As a result, as shown by arrow X1 on the Smith chart in Figure 4, the first thin line section A21a rotates the impedance clockwise starting from Z1.

The first intermediate section A21 also includes a first thick line section A21b, which has a width in the line width direction greater than the width of the line section A31. The first thick line section A21b is adjacent to the line section A31. The first thick line section A21b also overlaps with the first ground conductor layer 28 when viewed in the top-bottom direction. As a result, capacitance is generated in the first thick line section A21b. In other words, capacitance is connected in parallel to the line section A31. As a result, as shown by arrow X2 on the Smith chart in Figure 4, the first thick line section A21b rotates the impedance clockwise from the tip of arrow X1.

As a result, the first intermediate section A21 matches the characteristic impedance occurring in the line section A31 with the characteristic impedance occurring in the first connection section A11. Using the same principle, the second intermediate section A22 matches the characteristic impedance occurring in the line section A31 with the characteristic impedance occurring in the second connection section A12, although this will not be explained further. As a result, the multilayer substrate 10 can prevent mismatches in characteristic impedance from occurring in the section between the signal conductor layer 26 and the radiating conductor layer 20. Furthermore, by preventing mismatches in characteristic impedance from occurring in the section between the signal conductor layer 26 and the radiating conductor layer 20, the bandwidth of the multilayer substrate 10 is broadened.

Furthermore, the multilayer substrate 10 more reliably connects the first connection section A11 and the interlayer connection conductor v4. More specifically, the laminate 12 is created by thermocompression bonding the first laminate portion 12a, thermocompression bonding the second laminate portion 12b, and then thermocompression bonding the first laminate portion 12a and the second laminate portion 12b together. The first connection section A11 and the interlayer connection conductor v4 are connected during the thermocompression bonding of the first laminate portion 12a and the second laminate portion 12b. Therefore, the maximum width in the line width direction of the first connection section A11 is greater than the maximum width in the line width direction of the second connection section A12. This more reliably connects the first connection section A11 and the interlayer connection conductor v4.

(First Modification)
The connecting conductor layer 24a according to the first modification will be described below with reference to the drawings. Fig. 5 is a top view of the connecting conductor layer 24a.

The connecting conductor layer 24a differs from the connecting conductor layer 24 in the following points.
The width w1 of the first thick line section A21b in the line width direction is larger than the width w2 of the second thick line section A22b in the line width direction.
The width w11 in the line width direction of the first thin line section A21a and the width w12 in the line width direction of the second thin line section A22a are smaller than the width w3 in the line width direction of the line section A31.

The rest of the structure of the connecting conductor layer 24a is the same as that of the connecting conductor layer 24, so a description thereof will be omitted. A multilayer substrate 10 including the connecting conductor layer 24a can achieve the same effects as a multilayer substrate 10 including the connecting conductor layer 24.

Furthermore, with a multilayer substrate 10 including the connecting conductor layer 24a, the first intermediate section A21 matches the characteristic impedance occurring in the line section A31 with the characteristic impedance occurring in the first connection section A11. The maximum width in the line width direction of the first connection section A11 is larger than the maximum width in the line width direction of the second connection section A12. Therefore, the characteristic impedance occurring in the first connection section A11 is smaller than the characteristic impedance occurring in the second connection section A12. In other words, the difference between the specified characteristic impedance (50 Ω) and the characteristic impedance occurring in the first connection section A11 becomes larger. Therefore, the width w1 in the line width direction of the first thick line section A21b is larger than the width w2 in the line width direction of the second thick line section A22b. This increases the capacitance value occurring in the first thick line section A21b. The width w11 of the first thin line section A21a in the line width direction and the width w12 of the second thin line section A22a in the line width direction are smaller than the width w3 of the line section A31 in the line width direction. This increases the inductance value generated in the first thin line section A21a. As a result, the first intermediate section A21 matches the characteristic impedance generated in the line section A31 with the characteristic impedance generated in the first connection section A11.

(Second Modification)
The connecting conductor layer 24b according to the second modification will be described below with reference to the drawings. Fig. 6 is a top view of the connecting conductor layer 24b.

The connecting conductor layer 24b differs from the connecting conductor layer 24a in the shape of the first thick line section A21b and the second thick line section A22b. The first thick line section A21b and the second thick line section A22b have a tapered shape. The width of the first thick line section A21b and the second thick line section A22b decreases as they approach the line section A31. This suppresses sudden changes in the characteristic impedance that occur in the first thick line section A21b and the second thick line section A22b. The rest of the structure of the connecting conductor layer 24b is the same as that of the connecting conductor layer 24a. A multilayer substrate 10 including the connecting conductor layer 24b can achieve the same effects as a multilayer substrate 10 including the connecting conductor layer 24a.

(Third Modification)
The connecting conductor layer 24c according to the third modification will be described below with reference to the drawings. Fig. 7 is a top view of the connecting conductor layer 24c.

The connecting conductor layer 24c differs from the connecting conductor layer 24 in that it does not have the first thin line section A21a or the second thin line section A22a. The first thick line section A21b is adjacent to the first connecting section A11. The second thick line section A22b is adjacent to the second connecting section A12. The rest of the structure of the connecting conductor layer 24c is the same as that of the connecting conductor layer 24, so a description will be omitted.

A multilayer substrate 10 including the connection conductor layer 24c can prevent mismatches in characteristic impedance in the section between the signal conductor layer 26 and the radiation conductor layer 20. The following explanation will be given with reference to the drawings. Figure 8 is a Smith chart. Z0 is the characteristic impedance occurring in the line section A31. Z0 is 50 Ω. Z1 is the characteristic impedance occurring in the first connection section A11. Z1 is, for example, 20 Ω.

More specifically, in the multilayer substrate 10, the width in the line width direction of the first connection section A11 and the second connection section A12 of the connection conductor layer 24c is greater than the width in the line width direction of the line section A31. Furthermore, the interlayer connection conductor v4 contacts the first connection section A11. The interlayer connection conductor v3 contacts the second connection section A12. Therefore, the characteristic impedance generated in the first connection section A11 and the second connection section A12 of the connection conductor layer 24c tends to deviate from the desired specific impedance (50 Ω).

The connecting conductor layer 24c includes the first intermediate section A21. The first thick line section A21b overlaps the first ground conductor layer 28 when viewed in the vertical direction. This allows the first thick line section A21b to function as a transmission line. The first intermediate section A21 includes the first thick line section A21b, which has a width in the line width direction greater than the width of the line section A31. Therefore, the characteristic impedance Z2 generated in the first thick line section A21b is smaller than the predetermined characteristic impedance (50 Ω). As a result, the impedance moves along a circle centered on the characteristic impedance Z2 generated in the first thick line section A21b and passing through Z0. Therefore, the characteristic impedance Z2 generated in the first thick line section A21b is set to an appropriate value, and the length of the first thick line section A21b is set to an appropriate length. As a result, the first intermediate section A21 matches the characteristic impedance occurring in the line section A31 with the characteristic impedance occurring in the first connection section A11. Using the same principle, the second intermediate section A22 matches the characteristic impedance occurring in the line section A31 with the characteristic impedance occurring in the second connection section A12, although this will not be explained further. As a result, the multilayer substrate 10 including the connection conductor layer 24c can prevent mismatches in characteristic impedance from occurring in the section between the signal conductor layer 26 and the radiating conductor layer 20.

(Fourth Modification)
The connecting conductor layer 24d according to the fourth modification will be described below with reference to the drawings. Fig. 9 is a top view of the connecting conductor layer 24d.

Connecting conductor layer 24d differs from connecting conductor layer 24 in that line section A31 is bent when viewed in the vertical direction. In this way, line section A31 does not have to have a straight shape. The rest of the structure of connecting conductor layer 24d is the same as that of connecting conductor layer 24, so a description thereof will be omitted. A multilayer substrate 10 including connecting conductor layer 24d can achieve the same effects as a multilayer substrate 10 including connecting conductor layer 24.

Second Embodiment
A multilayer substrate 10a according to a second embodiment will be described below with reference to the drawings. Fig. 10 is a cross-sectional view of the multilayer substrate 10a.

Multilayer substrate 10a differs from multilayer substrate 10 in that the primary insulating material of second laminate portion 12b is different from the primary insulating material of first laminate portion 12a. The Young's modulus of the primary insulating material of second laminate portion 12b is higher than the Young's modulus of the primary insulating material of first laminate portion 12a. The material of first laminate portion 12a is Teflon (registered trademark) or FR-4. The material of second laminate portion 12b is, for example, polyimide or liquid crystal polymer. The rest of the structure of multilayer substrate 10a is the same as that of multilayer substrate 10, so a description will be omitted. Multilayer substrate 10a can achieve the same effects as multilayer substrate 10.

In the multilayer substrate 10a, the Young's modulus of the primary insulating material of the second laminate portion 12b is higher than the Young's modulus of the primary insulating material of the first laminate portion 12a. This makes it possible to easily process the second laminate portion 12b into any desired shape.

(Third embodiment)
A multilayer substrate 10b according to a third embodiment will be described below with reference to the drawings. Fig. 11 is a cross-sectional view of the multilayer substrate 10b. Fig. 12 is a top view of a connecting conductor layer 24 provided on the multilayer substrate 10b.

The multilayer substrate 10b differs from the multilayer substrate 10 mainly in that the interlayer connection conductor v3 is located on the signal conductor layer 26 side, and the interlayer connection conductor v4 is located on the radiation conductor layer 20 side.

In the third embodiment, not only insulator layers 14e and 14f but also insulator layer 14d extend rightward from insulator layers 14a to 14c. Insulator layer 14g is stacked on insulator layer 14d. In the third embodiment, insulator layer 14c corresponds to the intermediate insulator layer, and insulator layer 14d corresponds to the negative-side adjacent insulator layer.

The first laminate portion 12a includes insulator layers 14a-14c and protective layer 15a. The second laminate portion 12b includes insulator layers 14d-14g and protective layers 15b and 15c. The laminate 12 is created by thermocompression bonding the first laminate portion 12a, thermocompression bonding the second laminate portion 12b, and then thermocompression bonding the first laminate portion 12a and the second laminate portion 12b together.

The connecting conductor layer 24 is located on the upper main surface of the insulator layer 14d. As shown in FIG. 12, the connecting conductor layer 24 is arranged so that the direction from the first connecting section A11 to the second connecting section A12 coincides with the rightward direction. In the third embodiment, the left end of the connecting conductor layer 24 corresponds to the first end of the connecting conductor layer 24, and the right end of the connecting conductor layer 24 corresponds to the second end of the connecting conductor layer 24.

The interlayer connection conductor v3 passes through the insulator layers 14d and 14e in the vertical direction. The interlayer connection conductor v3 contacts the right end of the connection conductor layer 24, i.e., the second connection section A12 of the connection conductor layer 24, and the left end of the signal conductor layer 26. As a result, the interlayer connection conductor v3 electrically connects the connection conductor layer 24 and the signal conductor layer 26. Therefore, the interlayer connection conductor v3 is electrically connected to the signal conductor layer 26.

The interlayer connection conductor v4 passes through the insulator layer 14c in the vertical direction. The interlayer connection conductor v4 contacts the left end of the connection conductor layer 22b and the left end of the connection conductor layer 24, i.e., the first connection section A11 of the connection conductor layer 24. As a result, the interlayer connection conductor v4 electrically connects the connection conductor layer 22b and the connection conductor layer 24. Therefore, the interlayer connection conductor v4 is electrically connected to the radiation conductor layer 20.

Here, the length of the current path from the interlayer connection conductor v4 to the radiation conductor layer 20 is shorter than the length of the current path from the interlayer connection conductor v3 to the radiation conductor layer 20. The length of the current path from the interlayer connection conductor v3 to the signal conductor layer 26 is shorter than the length of the current path from the interlayer connection conductor v4 to the signal conductor layer 26.

The rest of the structure of multilayer substrate 10b is the same as that of multilayer substrate 10, so a detailed description will be omitted. Multilayer substrate 10b can achieve the same effects as multilayer substrate 10.

(Other embodiments)
The multilayer substrate according to the present invention is not limited to the multilayer substrates 10, 10a, and 10b, and can be modified within the scope of the invention. Furthermore, the structures of the multilayer substrates 10, 10a, and 10b may be arbitrarily combined. Furthermore, the structures of the connecting conductor layers 24, 24a to 24d may be arbitrarily combined.

The width of the first thick line section A21b in the line width direction may be less than or equal to the width of the second thick line section A22b in the line width direction.

The width in the line width direction of the first thin line section A21a and the width in the line width direction of the second thin line section A22a may be equal to or greater than the width in the line width direction of the line section A31.

The multilayer substrates 10, 10a, and 10b may further include a ground conductor located above the signal conductor layer 26 and overlapping the signal conductor layer 26 when viewed in the vertical direction.

Note that the laminate 12 does not have to be flexible.

The material of the insulator layers 14a-14g may be a material other than thermoplastic resin.

The material of the second interlayer connection conductor, interlayer connection conductor v3, may be the same as the material of the first interlayer connection conductor, interlayer connection conductor v4.

The present invention has the following structure:

(1)
a laminate having a structure in which a plurality of insulator layers including an intermediate insulator layer and a negative-side adjacent insulator layer are stacked so as to be aligned in the Z-axis direction, each of the plurality of insulator layers having a positive main surface and a negative main surface located on the negative side of the Z-axis from the positive main surface, and the negative-side adjacent insulator layer is located on the negative side of the Z-axis of the intermediate insulator layer and is in contact with the intermediate insulator layer;
a radiation conductor layer provided on the laminate and positioned on the positive side of the Z axis relative to the intermediate insulator layer;
a signal conductor layer provided on the laminate and positioned on the negative side of the Z axis relative to the intermediate insulator layer;
a connecting conductor layer provided in the laminate, located on the negative principal surface of the intermediate insulator layer, and including a first connecting section, a second connecting section, a line section, a first intermediate section, and a second intermediate section, wherein the first intermediate section is adjacent to the first connecting section, the second intermediate section is adjacent to the second connecting section, and the line section is adjacent to the first intermediate section and the second intermediate section;
a first ground conductor layer provided on the laminate, positioned on the negative side of the Z-axis relative to the connection conductor layer and the signal conductor layer, and overlapping at least a portion of the connection conductor layer and at least a portion of the signal conductor layer when viewed in the Z-axis direction;
a first interlayer connection conductor in contact with the first connection section;
a second interlayer connection conductor in contact with the second connection section;
It is equipped with
one of the first interlayer connection conductor and the second interlayer connection conductor penetrates the intermediate insulator layer in the Z-axis direction and electrically connects the radiation conductor layer and the connection conductor layer;
the other of the first interlayer connection conductor and the second interlayer connection conductor penetrates the negative-side adjacent insulator layer in the Z-axis direction and electrically connects the signal conductor layer and the connection conductor layer,
The direction in which the connecting conductor layer extends is defined as an extension direction,
A direction perpendicular to the stretching direction and the Z-axis direction is defined as a line width direction,
the first connection section is located at a first end of the connection conductor layer in the extension direction, the second connection section is located at a second end of the connection conductor layer in the extension direction, and the second end of the connection conductor layer is located on the opposite side of the first end of the connection conductor layer in the extension direction;
In the extension direction, both ends of the first connection section are positioned at equal distances from the center of the first interlayer connection conductor as viewed in the Z-axis direction,
In the extension direction, both ends of the second connection section are positioned at equal distances from the center of the second interlayer connection conductor as viewed in the Z-axis direction,
a maximum width of the second connection section in the line width direction is smaller than a maximum width of the first connection section in the line width direction;
the first intermediate section includes a first thick line section having a width in the line width direction that is larger than a width of the line section in the line width direction,
the second intermediate section includes a second thick line section having a width in the line width direction that is larger than a width of the line section in the line width direction,
The first thick line section and the second thick line section are adjacent to the rail section.
Multilayer board.

(2)
The width of the first thick line section in the line width direction is larger than the width of the second thick line section in the line width direction.
The multilayer substrate according to (1).

(3)
the first intermediate section includes a first thin line section having a width in the line width direction smaller than a width in the line width direction of the first thick line section,
the second intermediate section includes a second thin line section having a width in the line width direction smaller than a width in the line width direction of the second thick line section,
the first thin line section is adjacent to the first connection section,
the second thin line section is adjacent to the second connection section;
A multilayer substrate according to either (1) or (2).

(4)
a width of the first thin line section in the line width direction and a width of the second thin line section in the line width direction are smaller than a width of the line section in the line width direction;
(3) The multilayer substrate according to (3).

(5)
the first ground conductor layer overlaps the radiation conductor layer when viewed in the Z-axis direction;
A multilayer substrate according to any one of (1) to (4).

(6)
the laminate has a first section and a second section aligned in an X-axis direction perpendicular to the Z-axis direction,
The thickness of the first section in the Z-axis direction is greater than the thickness of the second section in the Z-axis direction,
the connecting conductor layer is located in the first section,
the signal conductor layer is located in the first section and the second section;
A multilayer substrate according to any one of (1) to (5).

(7)
the laminate has a first section, a second section, and a third section arranged in this order in an X-axis direction perpendicular to the Z-axis direction,
The thickness of the first section in the Z-axis direction is greater than the thickness of the second section in the Z-axis direction,
The thickness of the third section in the Z-axis direction is greater than the thickness of the second section in the Z-axis direction,
The multilayer substrate comprises:
a second ground conductor layer located in the third section and not located in the first section or the second section;
It also has
the first ground conductor layer is located in the first section, the second section, and the third section;
the second ground conductor layer is located on the positive side of the Z-axis relative to the signal conductor layer and overlaps at least a portion of the signal conductor layer when viewed in the Z-axis direction;
the signal conductor layer forms a microstrip line structure together with the first ground conductor layer in the first section and the second section,
the signal conductor layer forms a stripline structure together with the first ground conductor layer and the second ground conductor layer in the third section;
A multilayer substrate according to any one of (1) to (6).

(8)
the laminate includes a first laminate portion and a second laminate portion,
the first stacked body portion includes one or more of the insulator layers and the intermediate insulator layer located on the positive side of the Z axis relative to the intermediate insulator layer,
the second stacked body portion includes one or more of the insulator layers located on the negative side of the Z axis relative to the intermediate insulator layer,
a main insulating material of the second laminate portion is different from a main insulating material of the first laminate portion;
A multilayer substrate according to any one of (1) to (7).

(9)
The Young's modulus of the main insulating material of the second laminate section is higher than the Young's modulus of the main insulating material of the first laminate section.
(8) The multilayer substrate according to (8).

(10)
the material of the second interlayer connection conductor is different from the material of the first interlayer connection conductor;
A multilayer substrate according to either (8) or (9).

(11)
The laminate has flexibility.
A multilayer substrate according to any one of (1) to (10).

(12)
the material of the plurality of insulating layers is a thermoplastic resin;
A multilayer substrate according to any one of (1) to (11).

10, 10a, 10b: Multilayer substrate 12: Laminate 12a: First laminate section 12b: Second laminate section 14a to 14g: Insulator layers 15a to 15c: Protective layer 18: Second ground conductor layer 20: Radiation conductor layers 22a, 22b, 24, 24a to 24d: Connection conductor layer 26: Signal conductor layer 28: First ground conductor layer A1: First section A11: First connection section A12: Second connection section A2: Second section A21: First intermediate section A21b: First thick line section A21a: First thin line section A22: Second intermediate section A22b: Second thick line section A22a: Second thin line section A3: Third section A31: Line sections v1 to v4: Interlayer connection conductors

Claims (12)

a laminate having a structure in which a plurality of insulator layers including an intermediate insulator layer and a negative-side adjacent insulator layer are stacked so as to be aligned in the Z-axis direction, each of the plurality of insulator layers having a positive main surface and a negative main surface located on the negative side of the Z-axis from the positive main surface, and the negative-side adjacent insulator layer is located on the negative side of the Z-axis of the intermediate insulator layer and is in contact with the intermediate insulator layer;
a radiation conductor layer provided on the laminate and positioned on the positive side of the Z axis relative to the intermediate insulator layer;
a signal conductor layer provided on the laminate and positioned on the negative side of the Z axis relative to the intermediate insulator layer;
a connecting conductor layer provided in the laminate, located on the negative principal surface of the intermediate insulator layer, and including a first connecting section, a second connecting section, a line section, a first intermediate section, and a second intermediate section, wherein the first intermediate section is adjacent to the first connecting section, the second intermediate section is adjacent to the second connecting section, and the line section is adjacent to the first intermediate section and the second intermediate section;
a first ground conductor layer provided on the laminate, positioned on the negative side of the Z-axis relative to the connection conductor layer and the signal conductor layer, and overlapping at least a portion of the connection conductor layer and at least a portion of the signal conductor layer when viewed in the Z-axis direction;
a first interlayer connection conductor in contact with the first connection section;
a second interlayer connection conductor in contact with the second connection section;
It is equipped with
one of the first interlayer connection conductor and the second interlayer connection conductor penetrates the intermediate insulator layer in the Z-axis direction and electrically connects the radiation conductor layer and the connection conductor layer;
the other of the first interlayer connection conductor and the second interlayer connection conductor penetrates the negative-side adjacent insulator layer in the Z-axis direction and electrically connects the signal conductor layer and the connection conductor layer,
The direction in which the connecting conductor layer extends is defined as an extension direction,
A direction perpendicular to the stretching direction and the Z-axis direction is defined as a line width direction,
the first connection section is located at a first end of the connection conductor layer in the extension direction, the second connection section is located at a second end of the connection conductor layer in the extension direction, and the second end of the connection conductor layer is located on the opposite side of the first end of the connection conductor layer in the extension direction;
In the extension direction, both ends of the first connection section are positioned at equal distances from the center of the first interlayer connection conductor as viewed in the Z-axis direction,
In the extension direction, both ends of the second connection section are positioned at equal distances from the center of the second interlayer connection conductor as viewed in the Z-axis direction,
a maximum width of the second connection section in the line width direction is smaller than a maximum width of the first connection section in the line width direction;
the first intermediate section includes a first thick line section having a width in the line width direction that is larger than a width of the line section in the line width direction,
the second intermediate section includes a second thick line section having a width in the line width direction that is larger than a width of the line section in the line width direction,
The first thick line section and the second thick line section are adjacent to the rail section.
Multilayer board. The width of the first thick line section in the line width direction is larger than the width of the second thick line section in the line width direction.
The multilayer substrate according to claim 1 . the first intermediate section includes a first thin line section having a width in the line width direction smaller than a width in the line width direction of the first thick line section,
the second intermediate section includes a second thin line section having a width in the line width direction smaller than a width in the line width direction of the second thick line section,
the first thin line section is adjacent to the first connection section,
the second thin line section is adjacent to the second connection section;
The multilayer substrate according to claim 1 or 2. a width of the first thin line section in the line width direction and a width of the second thin line section in the line width direction are smaller than a width of the line section in the line width direction;
The multilayer substrate according to claim 3 . the first ground conductor layer overlaps the radiation conductor layer when viewed in the Z-axis direction;
The multilayer substrate according to claim 1 or 2. the laminate has a first section and a second section aligned in an X-axis direction perpendicular to the Z-axis direction,
The thickness of the first section in the Z-axis direction is greater than the thickness of the second section in the Z-axis direction,
the connecting conductor layer is located in the first section,
the signal conductor layer is located in the first section and the second section;
The multilayer substrate according to claim 1 or 2. the laminate has a first section, a second section, and a third section arranged in this order in an X-axis direction perpendicular to the Z-axis direction,
The thickness of the first section in the Z-axis direction is greater than the thickness of the second section in the Z-axis direction,
The thickness of the third section in the Z-axis direction is greater than the thickness of the second section in the Z-axis direction,
The multilayer substrate comprises:
a second ground conductor layer located in the third section and not located in the first section or the second section;
It also has
the first ground conductor layer is located in the first section, the second section, and the third section;
the second ground conductor layer is located on the positive side of the Z-axis relative to the signal conductor layer and overlaps at least a portion of the signal conductor layer when viewed in the Z-axis direction;
the signal conductor layer forms a microstrip line structure together with the first ground conductor layer in the first section and the second section,
the signal conductor layer forms a stripline structure together with the first ground conductor layer and the second ground conductor layer in the third section;
The multilayer substrate according to claim 1 or 2. the laminate includes a first laminate portion and a second laminate portion,
the first stacked body portion includes one or more of the insulator layers and the intermediate insulator layer located on the positive side of the Z axis relative to the intermediate insulator layer,
the second stacked body portion includes one or more of the insulator layers located on the negative side of the Z axis relative to the intermediate insulator layer,
a main insulating material of the second laminate portion is different from a main insulating material of the first laminate portion;
The multilayer substrate according to claim 1 or 2. The Young's modulus of the main insulating material of the second laminate section is higher than the Young's modulus of the main insulating material of the first laminate section.
The multilayer substrate according to claim 8 . the material of the second interlayer connection conductor is different from the material of the first interlayer connection conductor;
The multilayer substrate according to claim 8 . The laminate has flexibility.
The multilayer substrate according to claim 1 or 2. the material of the plurality of insulating layers is a thermoplastic resin;
The multilayer substrate according to claim 1 or 2.