JP6211835B2 - High frequency transmission line - Google Patents

Description

  The present invention relates to a high-frequency transmission technique, and more particularly to a high-frequency transmission line for propagating an input high-frequency signal from the uppermost layer to the lowermost layer of a multilayer wiring board.

  In a high-frequency transmission line that propagates an input high-frequency signal vertically from the top layer to the bottom layer in a multilayer wiring board in which conductor layers and insulating layers are alternately stacked, the transmission loss and reflection loss of the high-frequency signal should be minimized. There is a need to reduce it.

Conventionally, as such a high-frequency transmission line, a technique has been proposed in which a high-frequency signal via is formed in a stepped manner from the uppermost layer to the lowermost layer of a multilayer wiring board and propagated (see, for example, Non-Patent Document 1).
16A and 16B are explanatory views showing the configuration of a conventional high-frequency transmission line, in which FIG. 16A is a top view, FIG. 16B is a cross-sectional view taken along line bb in FIG. 16A, and FIG. Is a bottom view, and FIG. 16D is a sectional view taken along the line dd of FIG.

  In the high-frequency transmission line 50, as shown in FIG. 16, a high-frequency signal via 52 is formed in a step shape on the multilayer wiring board 51, and the uppermost upper conductor pad 53 A and the lowermost layer are formed via the high-frequency signal via 52. The lower conductor pad 53B is connected.

In the uppermost layer, a linear high-frequency signal line 54A is connected to the upper conductor pad 53A, and the upper anti-pad region 55A is sandwiched between the upper conductor pad 53A and the upper high-frequency signal line 54A. A ground plane 56A is formed.
In the lowermost layer, a linear lower high-frequency signal line 54B is connected to the lower conductor pad 53B, and a lower antipad region 55B is sandwiched between the lower conductor pad 53B and the lower high-frequency signal line 54B. Thus, the lower ground plane 56B is formed.

Y. C. Lee, et al, "A Novel CPW-to-Stripline Vertical Via Transition Using a Stagger Via Structure and Embedded Air Cavities for V-band LTCC SiP Applications", APMC2005.

According to the above-described prior art, since the high-frequency signal via 52 is formed in a staircase pattern from the uppermost layer to the lowermost layer in the multilayer wiring board 51, the high-frequency signal line is bent vertically in a small region. However, it is easy to generate unnecessary radiation at the bent portion of such a high-frequency signal line, and it is possible to suppress a certain amount of radiation by increasing the effective bending radius at the bent portion. There is a problem that the radiation component of the signal cannot be completely removed, and the passage loss and reflection loss increase.
In addition, in order to form the high-frequency signal via 52 in a stepped manner from the uppermost layer to the lowermost layer of the multilayer wiring board 51, precise processing is required and also the volume of the multilayer wiring board is increased. There was a problem of causing it.

  The present invention is to solve such a problem, and provides a high-frequency transmission line capable of propagating a high-frequency signal with a small passage loss and reflection loss at a bent portion from the substrate plane direction to the vertical direction. It is an object.

In order to achieve such an object, a high-frequency transmission line according to the present invention includes a multilayer wiring board in which conductor layers and insulating layers are alternately stacked, and the inside of the multilayer wiring board vertically from the top layer to the bottom layer. A high-frequency signal via formed in a penetrating manner, formed in a substantially circular shape in plan view in the uppermost layer, and connected to an upper end of the high-frequency signal via, and formed in a linear shape in the uppermost layer An upper anti-pad region in which an upper high-frequency signal line whose tip is connected to the upper conductor pad and a conductor layer formed on the uppermost layer and connected to a ground potential is selectively removed. And an upper ground plane formed around the upper conductor pad and the upper high-frequency signal line, and formed in the multilayer wiring board, and in the upper ground plane and the multilayer wiring board. A plurality of ground vias for connecting the conductor layers, and the upper portion along the orthogonal direction perpendicular to the extending direction of the upper high-frequency signal line among the conductor layers forming the upper ground plane. The conductor layer located on the opposite side of the upper high-frequency signal line across the upper boundary line passing over the conductor pad is at least the width of the upper antipad region in the orthogonal direction and the orthogonal direction of the uppermost layer in the orthogonal direction Are selectively removed so as to be continuous with the upper antipad region up to the side end along the line .

In another configuration example of the high-frequency transmission line according to the present invention, the conductor layer to be removed is a conductor layer forming the upper ground plane, and the upper high-frequency transmission line sandwiching the upper boundary line. It consists of all the conductor layers located on the opposite side to the signal line .

  In another configuration example of the high-frequency transmission line according to the present invention, the width of the conductor layer to be removed gradually widens as the side end is approached.

  In another configuration example of the high-frequency transmission line according to the present invention, the upper ground plane is a boundary between a region along the upper high-frequency signal line and a region along the upper conductor pad in the upper antipad region. In the position, the end facing the upper high-frequency signal line has a convex portion protruding toward the upper high-frequency signal line.

  In addition, another configuration example of the high-frequency transmission line according to the present invention includes a lower conductor pad formed in a substantially circular shape in plan view on the lowermost layer and connected to a lower end of the high-frequency signal via, and the lowermost layer A lower high-frequency signal line whose tip is connected to the lower conductor pad, and a conductor layer formed in the lowermost layer and connected to the ground potential, the conductor layer selectively A lower ground plane formed around the lower conductor pad and the lower high-frequency signal line, with the removed lower antipad region interposed therebetween, and each ground via is connected to the lower ground plane. A lower boundary line passing over the lower conductor pad along an orthogonal direction orthogonal to the extending direction of the lower high-frequency signal line among the conductor layers forming the lower ground plane. Nde, wherein the lower high-frequency signal transmission line part of the conductor layer located on the opposite side or all, those which are selectively removed so as to continue with the lower anti-pad region.

  In addition, another configuration example of the high-frequency transmission line according to the present invention is formed in a substantially circular shape in a plan view in the lowermost layer instead of the upper conductor pad, and is connected to a lower end of the high-frequency signal via. In place of the lower conductor pad, the upper high-frequency signal line, instead of the upper high-frequency signal line, the lower high-frequency signal line that is formed in a linear shape in the lowermost layer and the tip is connected to the lower conductor pad, the upper ground plane, Formed around the lower conductor pad and the lower high-frequency signal line across the lower antipad region formed of the conductor layer connected to the ground potential and selectively removed from the lower antipad region. A lower ground plane, wherein each ground via is connected to the lower ground plane, and is connected to the lower ground plane. A part or all of the conductor layer located on the opposite side of the lower high-frequency signal line across the lower boundary line passing over the lower conductor pad along the orthogonal direction orthogonal to the extending direction of the lower high-frequency signal line, It is selectively removed so as to be continuous with the lower antipad region.

  In another configuration example of the high-frequency transmission line according to the present invention, the high-frequency signal via and the ground via have a pseudo coaxial line structure.

  According to the present invention, among the capacitance components generated between the upper conductor pad and the ground potential across the upper antipad region, the extension direction is compared with the extension capacitance component generated along the extension direction. The orthogonal capacitance component and the orthogonal capacitance component generated along the orthogonal direction orthogonal to Therefore, anisotropy is generated in the electric field density in the upper conductor pad, electric field lines in the orthogonal direction are concentrated as compared with the extending direction, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic field of the high-frequency signal propagating in the extending direction and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed. It is possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion.

It is a top view which shows the structure of the high frequency transmission line concerning 1st Embodiment. It is II-II sectional drawing of FIG. It is a bottom view which shows the structure of the high frequency transmission line concerning 1st Embodiment. FIG. 4 is a sectional view taken along the line IV-IV in FIGS. 1 and 3. It is VV sectional drawing of FIG. 2 and FIG. It is a top view which shows the structure of the high frequency transmission line concerning 2nd Embodiment. It is VII-VII sectional drawing of FIG. It is a bottom view which shows the structure of the high frequency transmission line concerning 2nd Embodiment. It is IX-IX sectional drawing of FIG. 6 and FIG. FIG. 10 is a cross-sectional view taken along the line X-X in FIGS. 7 and 9. It is a top view which shows the structure of the high frequency transmission line concerning 3rd Embodiment. It is XII-XII sectional drawing of FIG. It is a bottom view which shows the structure of the high frequency transmission line concerning 3rd Embodiment. It is XIV-XIV sectional drawing of FIG. 11 and FIG. It is XV-XV sectional drawing of FIG. 12 and FIG. It is explanatory drawing which shows the structure of the conventional high frequency transmission line.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, with reference to FIGS. 1-4, the high frequency transmission line 10 concerning the 1st Embodiment of this invention is demonstrated. FIG. 1 is a top view showing the configuration of the high-frequency transmission line according to the first embodiment. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a bottom view showing the configuration of the high-frequency transmission line according to the first embodiment. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIGS. 1 and 3. 5 is a cross-sectional view taken along the line V-V in FIGS. 2 and 4.

  The high-frequency transmission line 10 according to this embodiment is configured such that an input high-frequency signal is transmitted from the uppermost layer (the upper surface of the substrate) to the lowermost layer (the substrate) in the multilayer wiring substrate 11 in which the conductor layers 11M and the insulating layers 11P are alternately stacked. This is a high-frequency transmission line for propagating vertically to the bottom surface. The high-frequency transmission line 10 is suitable for an electronic device or an electronic component in which a high-speed electrical signal of 10 GHz to 100 GHz or less propagates through the multilayer wiring board 11, for example.

  As shown in FIGS. 1 to 5, the high-frequency transmission line 10 mainly includes a multilayer wiring board 11, a high-frequency signal via 12, an upper conductor pad 13A, an upper high-frequency signal line 14A, an upper ground plane 16A, a lower conductor pad 13B, It consists of a lower high-frequency signal line 14B, a lower ground plane 16B, and a ground via 17.

The high-frequency signal via 12 is made of a conductor such as metal, and is a via formed by vertically penetrating the insulating layer 11P in the multilayer wiring board 11 and the insulating region in the conductor layer 11M from the uppermost layer to the lowermost layer. is there.
The upper conductor pad 13 </ b> A is a conductor pad made of a conductor such as metal, formed in a substantially circular shape in plan view on the uppermost layer, and connected to the upper end of the high-frequency signal via 12.

The upper high-frequency signal line 14A is a high-frequency signal line that is made of a conductor such as metal, is formed in a linear shape on the uppermost layer, and has a tip connected to the upper conductor pad 13A.
The upper ground plane 16A is formed of a conductive layer such as a metal connected to the ground potential and formed on the uppermost layer, and the upper conductive pad 13A and the upper conductive pad 13A are sandwiched by sandwiching the upper antipad region 15A from which the conductive layer is selectively removed. This is a ground conductor formed around the upper high-frequency signal line 14A.

  The upper antipad region 15A includes an annular region formed by selectively removing the periphery of the conductor layer of the upper ground plane 16A around the upper conductor pad 13A in a substantially circular shape in plan view, and along the upper high-frequency signal line 14A. And a part of or all of the conductor layer located on the opposite side of the upper high-frequency signal line 14A across the upper boundary line SA to be described later. It includes areas that have been selectively removed.

The lower conductor pad 13 </ b> B is a conductor pad made of a conductor such as a metal, formed in a substantially circular shape in plan view in the lowermost layer, and connected to the lower end of the high-frequency signal via 12.
The lower high-frequency signal line 14B is a high-frequency signal line that is made of a conductor such as metal, is formed in a linear shape in the lowermost layer, and has a tip connected to the lower conductor pad 13B.
The lower ground plane 16B is formed of a conductive layer such as a metal connected to the ground potential and formed in the lowermost layer. The lower conductive pad 13B and the lower conductive pad 13B are sandwiched by sandwiching the lower antipad region 15B from which the conductive layer is selectively removed. This is a ground conductor formed around the lower high-frequency signal line 14B.

The lower antipad region 15B includes a region formed by selectively removing the periphery of the conductor layer of the lower ground plane 16B around the lower conductor pad 13B in a substantially circular shape in plan view, and along the lower high-frequency signal line 14B. It consists of a region that is selectively removed linearly with a gap of a certain width, and part or all of the conductor layer located on the side opposite to the lower high-frequency signal line 14B across the lower boundary line SB described later is selectively removed. It includes the area that is made.
The ground via 17 is made of a conductor such as metal, and is formed in the multilayer wiring board 11, and includes an upper ground plane 16A and a lower ground plane 16B, and each conductor layer 11M stacked between the ground planes 16A and 16B. Is a via.

  As shown in FIG. 2, the upper high-frequency signal line 14A formed in the extending direction X along the substrate plane is connected to the high-frequency signal via 12 formed in the vertical direction Z perpendicular to the substrate plane by the upper conductor pad 13A. In the high frequency transmission line, the propagation direction of the high frequency signal is bent from the extending direction X to the vertical direction Z. Therefore, unnecessary radiation of the high-frequency signal is generated at the bent portion of the high-frequency transmission line, and the passage loss and the reflection loss are increased.

According to the present invention, such unnecessary radiation can be suppressed by the anisotropy of the electric field density in the upper conductor pad 13A, whereby electromagnetic waves between a high-frequency signal propagating in the extending direction X and a high-frequency signal propagating in the vertical direction Z are obtained. The focus is on the efficient coupling of the fields.
As a specific method for generating such anisotropy of the electric field density, the upper portion along the orthogonal direction Y orthogonal to the extending direction X of the upper high-frequency signal line 14A among the conductor layers forming the upper ground plane 16A. A part of the conductor layer located on the opposite side of the upper high-frequency signal line 14A across the upper boundary line SA passing over the conductor pad 13A is selectively removed so as to be continuous with the upper antipad region 15A. is there. At this time, the upper boundary line SA may be at any position as long as it is on the upper conductor pad 13A.

  As a result, among the capacitance components generated between the upper conductor pad 13A and the ground potential (upper ground plane 16A) across the upper antipad region 15A, the extension capacitance component CXA generated along the extension direction X is changed. In comparison, the orthogonal capacitance component CA and the orthogonal capacitance component CB generated along the orthogonal direction Y orthogonal to the extending direction X are increased.

  Therefore, anisotropy occurs in the electric field density in the upper conductor pad 13A, electric field lines in the orthogonal direction Y are concentrated compared to the extending direction X, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic fields of the high-frequency signal propagating in the extending direction X and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed, and perpendicular to the substrate plane direction. It becomes possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion in the direction.

  In the present embodiment, the structure for giving the anisotropy of the electric field density in the upper conductor pad 13A is realized by adjusting the shape of the upper ground plane 16A. Therefore, the conductive layer is very simply etched. In addition, since it is not necessary to add a new process, cost reduction of the high-frequency transmission line can be realized.

  In the present embodiment, the conductor layer to be removed of the upper ground plane 16A has a constant width equal to the width W of the upper antipad region 15A in the orthogonal direction Y, and is the uppermost layer in the multilayer wiring board 11. Among them, since the side end 18A along the orthogonal direction Y is selectively removed, the orthogonal capacitance component CA and the orthogonal capacitance component CB are greatly effectively increased compared to the distracted capacitance component CXA. Therefore, unnecessary radiation at the bent portion of the high-frequency transmission line can be suppressed more efficiently.

  In the present embodiment, as shown in FIG. 1, on both sides of the upper high-frequency signal line 14A, the upper anti-pad region 15A is selectively removed in a line with a constant width along the upper high-frequency signal line 14A. An upper ground plane 16A is formed with the gap region formed therebetween, and has a coplanar line structure as a whole.

At this time, the upper high frequency signal line 14A and the upper ground plane 16A are located at the boundary between the gap region and the annular region of the upper antipad region 15A, which is located before the connection point between the upper high frequency signal line 14A and the upper conductor pad 13A. Therefore, the capacitance between the upper high-frequency signal line 14A and the upper ground plane 16A (ground potential) is rapidly reduced.
Usually, the characteristic impedance of the coplanar line is inversely proportional to the 0.5th power of the capacitance between the high-frequency signal line and the ground potential. For this reason, the characteristic impedance of the upper high-frequency signal line 14A rises rapidly in accordance with the decrease in the capacitance, causing a mismatch with the characteristic impedance of the high-frequency signal via 12 and causing loss.

In the present embodiment, as shown in FIG. 1, the upper high-frequency signal is provided at the end of the upper ground plane 16A facing the upper high-frequency signal line 14A at the boundary position between the gap region and the annular region of the upper antipad region 15A. A convex portion B projecting toward the line 14A is provided.
As a result, the gap width between the upper high-frequency signal line 14A and the upper ground plane 16A becomes narrow and the capacitance increases, so that an increase in the characteristic impedance of the upper high-frequency signal line 14A can be suppressed. Therefore, matching with the characteristic impedance of the high-frequency signal via 12 can be maintained, and the occurrence of loss can be suppressed.

Further, in the present embodiment, as shown in FIG. 5, a plurality of ground vias 17 are formed in a cylindrical shape so as to surround the high-frequency signal via 12, and each ground composed of the conductor layer 11 </ b> M in the multilayer wiring board 11 is formed. A pseudo coaxial line structure in which the high-frequency signal via 12 is shielded by a pseudo cylindrical conductor may be formed by removing the center of the plane in a circular shape to form an insulator.
In this pseudo coaxial line structure, a high frequency signal propagates to the high frequency signal via 12 and a skin current flows on the surface of the conductor, and a ground via 17 forming a pseudo cylindrical conductor and a conductor layer 11M in the multilayer wiring board 11 are formed. A return current flows through each ground plane.

  As a result, the electric field strength distribution in the pseudo coaxial line structure is circular with the high-frequency signal via 12 as the center in the plane of the substrate without causing distortion such as an ellipse, and the electric field distribution of the high-frequency signal propagating through the high-frequency signal via 12 It becomes almost equal to the strength. This means that only the fundamental mode of the pseudo coaxial line structure is excited and propagated, that is, it is well coupled with the fundamental mode.

  When the fundamental mode is not well coupled, the electric field strength distribution in the pseudo coaxial line structure is not circular, and the center of the high-frequency signal via 12 is shifted back and forth with respect to the extending direction X of the upper high-frequency signal line 14A. It propagates so as to meander in the vertical direction Z. At this time, if the electric field overlaps with the ground plane in the inner layer of the multilayer wiring substrate 11, the energy of the high-frequency signal is absorbed by the ground potential according to the amount of the overlap, so that stable propagation cannot be obtained.

  On the other hand, according to the present embodiment, as described above, since it is well coupled with the fundamental mode of the pseudo coaxial line structure, the line length of the pseudo coaxial line structure, that is, the upper conductor pad 13A and the lower conductor pad 13B. Regardless of the line length of the high-frequency signal via 12 connected to the high-frequency signal via, the high-frequency signal can be stably propagated with low loss and low reflection.

  In the present embodiment, since the power supply layer and the low-speed signal layer can be simultaneously formed by increasing the number of layers of the multilayer wiring board 11, a multi-functional multilayer wiring board is not dedicated to the high-frequency signal line. It can also be provided.

In the present embodiment, the bending portion located in the uppermost layer of the multilayer wiring board 11 among the bending portions of the high-frequency transmission line has been described. However, the same structure is applied to the bending portion located in the lowermost layer. Also good.
That is, as shown in FIG. 3, among the conductor layers forming the lower ground plane 16B, the lower boundary line SB passing on the lower conductor pad 13B along the orthogonal direction Y orthogonal to the extending direction X of the lower high-frequency signal line 14B. A part of the conductor layer located on the opposite side to the lower high-frequency signal line 14B is selectively removed so as to be continuous with the lower antipad region 15B. At this time, the lower boundary line SB may be at any position as long as it is on the lower conductor pad 13B.

  As a result, among the capacitance components generated between the lower conductor pad 13B and the ground potential (lower ground plane 16B) across the lower antipad region 15B, the extension capacitance component CXB generated along the extension direction X is changed. In comparison, the orthogonal capacitance component CC and the orthogonal capacitance component CD generated along the orthogonal direction Y orthogonal to the extending direction X are increased.

  Therefore, anisotropy occurs in the electric field density in the lower conductor pad 13B, electric field lines in the orthogonal direction Y are concentrated as compared with the extending direction X, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic fields of the high-frequency signal propagating in the extending direction X and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed, and perpendicular to the substrate plane direction. It becomes possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion in the direction.

  In the present embodiment, the structure for giving the electric field density anisotropy in the lower conductor pad 13B is realized by adjusting the shape of the lower ground plane 16B. In addition, since it is not necessary to add a new process, cost reduction of the high-frequency transmission line can be realized.

  Further, in the present embodiment, the conductor layer to be removed of the lower ground plane 16B has a constant width equal to the width W of the lower antipad region 15B in the orthogonal direction Y and is the lowermost layer in the multilayer wiring board 11. Among them, since the side end portion 18B along the orthogonal direction Y is selectively removed, the orthogonal capacitance component CC and the orthogonal capacitance component CD are greatly effectively increased compared to the distraction capacitance component CXB. Therefore, unnecessary radiation at the bent portion of the high-frequency transmission line can be suppressed more efficiently.

  Further, in the present embodiment, as shown in FIG. 3, on both sides of the lower high-frequency signal line 14B, selective removal is linearly performed with a constant width gap along the lower high-frequency signal line 14B in the lower antipad region 15B. A lower ground plane 16B is formed with the gap region formed therebetween, forming a coplanar line structure as a whole.

At this time, the lower high-frequency signal line 14B and the lower ground plane 16B are located at the boundary between the gap region and the annular region of the lower antipad region 15B, which is located before the connection point between the lower high-frequency signal line 14B and the lower conductor pad 13B. Therefore, the capacitance between the lower high-frequency signal line 14B and the lower ground plane 16B (ground potential) rapidly decreases.
Usually, the characteristic impedance of the coplanar line is inversely proportional to the 0.5th power of the capacitance between the high-frequency signal line and the ground potential. For this reason, the characteristic impedance of the lower high-frequency signal line 14B rises rapidly in accordance with the decrease in the capacitance, causing a mismatch with the characteristic impedance of the high-frequency signal via 12, causing loss.

In the present embodiment, as shown in FIG. 3, at the boundary position between the gap region and the annular region, the lower ground plane 16B protrudes toward the lower high-frequency signal line 14B at the end facing the lower high-frequency signal line 14B. Convex part B is provided.
As a result, the gap width between the lower high-frequency signal line 14B and the lower ground plane 16B becomes narrow and the capacitance increases, so that an increase in the characteristic impedance of the lower high-frequency signal line 14B can be suppressed. Therefore, matching with the characteristic impedance of the high-frequency signal via 12 can be maintained, and the occurrence of loss can be suppressed.

  In the present embodiment, as shown in FIG. 1 and FIG. 3, the present invention is applied to both bent portions located at the uppermost layer and the lowermost layer of the multilayer wiring board 11 among the bent portions of the high-frequency transmission line. Although the case where it is applied has been described as an example, the present invention may be applied to only one of the bent portion located in the uppermost layer or the bent portion located in the lowermost layer, and the same effect as described above can be obtained. Can be obtained.

[Second Embodiment]
Next, with reference to FIGS. 6-10, the high frequency transmission line 10 concerning the 2nd Embodiment of this invention is demonstrated. FIG. 6 is a top view showing the configuration of the high-frequency transmission line according to the second embodiment. 7 is a sectional view taken along line VII-VII in FIG. FIG. 8 is a bottom view showing the configuration of the high-frequency transmission line according to the second embodiment. 9 is a cross-sectional view taken along the line IX-IX in FIGS. 6 and 8. 10 is a cross-sectional view taken along the line XX of FIGS. 7 and 9.

  In the first embodiment, the conductor layer to be removed of the upper ground plane 16A has a constant width equal to the width W of the upper antipad region 15A in the orthogonal direction Y, and is the uppermost layer in the multilayer wiring board 11. The case of selectively removing up to the side end 18A has been described as an example, but the shape of the region to be removed is not limited to the above example.

  That is, in the present embodiment, as shown in FIG. 6, all of the conductor layers located on the side opposite to the upper high-frequency signal line 14A across the upper boundary line SA among the conductor layers forming the upper ground plane 16A. Specifically, the right half of the upper ground plane 16A toward the paper surface is selectively removed.

  Thereby, in the same way as in the first embodiment, among the electric capacity components generated between the upper conductor pad 13A and the ground potential (upper ground plane 16A) across the upper antipad region 15A, in the extending direction X. The orthogonal capacitance component CA and the orthogonal capacitance component CB generated along the orthogonal direction Y orthogonal to the extension direction X are larger than the extended capacitance component CXA generated along the extension direction X.

  Therefore, anisotropy occurs in the electric field density in the upper conductor pad 13A, electric field lines in the orthogonal direction Y are concentrated compared to the extending direction X, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic fields of the high-frequency signal propagating in the extending direction X and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed, and perpendicular to the substrate plane direction. It becomes possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion in the direction.

  In the present embodiment, the structure for giving the anisotropy of the electric field density in the upper conductor pad 13A is realized by adjusting the shape of the upper ground plane 16A. Therefore, the conductive layer is very simply etched. In addition, since it is not necessary to add a new process, cost reduction of the high-frequency transmission line can be realized.

  Similarly to the first embodiment, in this embodiment, as shown in FIG. 6, the upper high-frequency signal of the upper ground plane 16A is located at the boundary position between the gap region and the annular region of the upper antipad region 15A. You may provide the convex part B which protruded in the edge part which opposes the track | line 14A to the upper high frequency signal track | line 14A side. Thereby, an increase in the characteristic impedance of the upper high-frequency signal line 14A can be suppressed, matching with the characteristic impedance of the high-frequency signal via 12 can be maintained, and the occurrence of loss can be suppressed.

As in the first embodiment, in the present embodiment, a plurality of ground vias 17 are formed in a cylindrical shape so as to surround the high-frequency signal via 12, and from the conductor layer 11 </ b> M in the multilayer wiring board 11. By removing the center of each ground plane in a circular shape to form an insulator, a pseudo coaxial line structure in which the high-frequency signal via 12 is shielded by a pseudo cylindrical conductor may be formed.
Thereby, regardless of the line length of the pseudo coaxial line structure, that is, the line length of the high-frequency signal via 12 connected to the upper conductor pad 13A or the lower conductor pad 13B, the high-frequency signal is stably propagated with low loss and low reflection. be able to.

  In the present embodiment, since the power supply layer and the low-speed signal layer can be simultaneously formed by increasing the number of layers of the multilayer wiring board 11, a multi-functional multilayer wiring board is not dedicated to the high-frequency signal line. It can also be provided.

In the present embodiment, the bending portion located in the uppermost layer of the multilayer wiring board 11 among the bending portions of the high-frequency transmission line has been described. However, the same structure is applied to the bending portion located in the lowermost layer. Also good.
That is, as shown in FIG. 8, among the conductor layers forming the lower ground plane 16B, all of the conductor layers located on the opposite side of the lower high-frequency signal line 14B across the lower boundary line SB, specifically, In the lower ground plane 16B, the left half of the lower ground plane 16B is selectively removed.

  As a result, among the capacitance components generated between the lower conductor pad 13B and the ground potential (lower ground plane 16B) across the lower antipad region 15B, the extension capacitance component CXB generated along the extension direction X is changed. In comparison, the orthogonal capacitance component CC and the orthogonal capacitance component CD generated along the orthogonal direction Y orthogonal to the extending direction X are increased.

  Therefore, anisotropy occurs in the electric field density in the lower conductor pad 13B, electric field lines in the orthogonal direction Y are concentrated as compared with the extending direction X, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic fields of the high-frequency signal propagating in the extending direction X and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed, and perpendicular to the substrate plane direction. It becomes possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion in the direction.

  In the present embodiment, the structure for giving the electric field density anisotropy in the lower conductor pad 13B is realized by adjusting the shape of the lower ground plane 16B. In addition, since it is not necessary to add a new process, cost reduction of the high-frequency transmission line can be realized.

  As in the first embodiment, also in this embodiment, as shown in FIG. 8, the connection with the lower conductor pad 13B of the end portion of the lower ground plane 16B facing the lower high-frequency signal line 14B is provided. You may provide the convex part B which protruded in the position before the point to the lower high frequency signal track | line 14B side. As a result, an increase in the characteristic impedance of the lower high-frequency signal line 14B can be suppressed, matching with the characteristic impedance of the high-frequency signal via 12 can be maintained, and occurrence of loss can be suppressed.

  In the present embodiment, as shown in FIGS. 6 and 8, the present invention is applied to both the bent portions located at the uppermost layer and the lowermost layer of the multilayer wiring board 11 among the bent portions of the high-frequency transmission line. Although the case where it is applied has been described as an example, the present invention may be applied to only one of the bent portion located in the uppermost layer or the bent portion located in the lowermost layer, and the same effect as described above can be obtained. Can be obtained.

[Third Embodiment]
Next, with reference to FIGS. 11-15, the high frequency transmission line 10 concerning the 3rd Embodiment of this invention is demonstrated. FIG. 11 is a top view showing the configuration of the high-frequency transmission line according to the third embodiment. 12 is a cross-sectional view taken along the line XII-XII in FIG. FIG. 13 is a bottom view showing the configuration of the high-frequency transmission line according to the third embodiment. 14 is a cross-sectional view taken along the line XIV-XIV in FIGS. 11 and 13. 15 is a cross-sectional view taken along XV-XV in FIGS. 12 and 14.

  In the first embodiment, the conductor layer to be removed of the upper ground plane 16A has a constant width equal to the width W of the upper antipad region 15A in the orthogonal direction Y, and is the uppermost layer in the multilayer wiring board 11. The case of selectively removing up to the side end 18A has been described as an example, but the shape of the region to be removed is not limited to the above example.

  That is, in the present embodiment, as shown in FIG. 11, among the conductor layers forming the upper ground plane 16A, one of the conductor layers located on the opposite side of the upper high-frequency signal line 14A across the upper boundary line SA. The portion is selectively removed up to the side end portion 18A with a width that gradually expands toward the side end portion 18A of the uppermost layer.

  As a result, among the capacitance components generated between the upper conductor pad 13A and the ground potential (upper ground plane 16A) across the upper antipad region 15A, the extension capacitance component CXA generated along the extension direction X is changed. In comparison, the orthogonal capacitance component CA and the orthogonal capacitance component CB generated along the orthogonal direction Y orthogonal to the extending direction X are increased.

  Therefore, anisotropy occurs in the electric field density in the upper conductor pad 13A, electric field lines in the orthogonal direction Y are concentrated compared to the extending direction X, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic fields of the high-frequency signal propagating in the extending direction X and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed, and perpendicular to the substrate plane direction. It becomes possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion in the direction.

  In the present embodiment, the structure for giving the anisotropy of the electric field density in the upper conductor pad 13A is realized by adjusting the shape of the upper ground plane 16A. Therefore, the conductive layer is very simply etched. In addition, since it is not necessary to add a new process, cost reduction of the high-frequency transmission line can be realized.

  In the present embodiment, the width of the conductor layer to be removed in the upper ground plane 16A is gradually increased from the width W of the upper antipad region 15A in the orthogonal direction Y toward the side end 18A of the uppermost layer. For example, it is selectively removed to the side edge 18A along a straight line connecting the upper right corner and the lower right corner of the uppermost layer from the intersection of the upper boundary line SA and the outer periphery of the upper antipad region 15A. Therefore, compared with the first embodiment, the angle range in which the distracted capacitance component CXA can be reduced can be increased, and the efficiency can be improved even when the unnecessary radiation at the bent portion of the high-frequency transmission line has a certain extent. It can be well suppressed.

  Similarly to the first embodiment, in this embodiment, as shown in FIG. 11, the upper high-frequency signal of the upper ground plane 16A is located at the boundary position between the gap region and the annular region of the upper antipad region 15A. You may provide the convex part B which protruded in the edge part which opposes the track | line 14A to the upper high frequency signal track | line 14A side. Thereby, an increase in the characteristic impedance of the upper high-frequency signal line 14A can be suppressed, matching with the characteristic impedance of the high-frequency signal via 12 can be maintained, and the occurrence of loss can be suppressed.

As in the first embodiment, in the present embodiment, a plurality of ground vias 17 are formed in a cylindrical shape so as to surround the high-frequency signal via 12, and from the conductor layer 11 </ b> M in the multilayer wiring board 11. By removing the center of each ground plane in a circular shape to form an insulator, a pseudo coaxial line structure in which the high-frequency signal via 12 is shielded by a pseudo cylindrical conductor may be formed.
Thereby, regardless of the line length of the pseudo coaxial line structure, that is, the line length of the high-frequency signal via 12 connected to the upper conductor pad 13A or the lower conductor pad 13B, the high-frequency signal is stably propagated with low loss and low reflection. be able to.

  In the present embodiment, since the power supply layer and the low-speed signal layer can be simultaneously formed by increasing the number of layers of the multilayer wiring board 11, a multi-functional multilayer wiring board is not dedicated to the high-frequency signal line. It can also be provided.

In the present embodiment, the bending portion located in the uppermost layer of the multilayer wiring board 11 among the bending portions of the high-frequency transmission line has been described. However, the same structure is applied to the bending portion located in the lowermost layer. Also good.
That is, as shown in FIG. 13, among the conductor layers forming the lower ground plane 16B, a part of the conductor layer located on the opposite side of the lower high-frequency signal line 14B across the lower boundary line SB The width gradually expands as it approaches the side end 18B, and is selectively removed up to the side end 18B.

  As a result, among the capacitance components generated between the lower conductor pad 13B and the ground potential (lower ground plane 16B) across the lower antipad region 15B, the extension capacitance component CXB generated along the extension direction X is changed. In comparison, the orthogonal capacitance component CC and the orthogonal capacitance component CD generated along the orthogonal direction Y orthogonal to the extending direction X are increased.

  Therefore, anisotropy occurs in the electric field density in the lower conductor pad 13B, electric field lines in the orthogonal direction Y are concentrated as compared with the extending direction X, the electric field density is increased, and unnecessary radiation is suppressed. For this reason, it is possible to efficiently couple the electromagnetic fields of the high-frequency signal propagating in the extending direction X and the high-frequency signal propagating in the vertical direction Z in a state in which the generation of unnecessary radiation is suppressed, and perpendicular to the substrate plane direction. It becomes possible to propagate a high-frequency signal with a small passage loss and reflection loss at the bent portion in the direction.

  In the present embodiment, the structure for giving the electric field density anisotropy in the lower conductor pad 13B is realized by adjusting the shape of the lower ground plane 16B. Therefore, the cost of the high-frequency transmission line can be reduced.

  In the present embodiment, the width of the conductor layer to be removed in the lower ground plane 16B is gradually increased from the width W of the lower antipad region 15B in the orthogonal direction Y toward the lowermost side end 18B. For example, along the straight line connecting the two intersections of the lower boundary line SB and the outer periphery of the lower antipad region 15B with the upper left corner and the lower left corner of the lowermost layer, the side end portion 18B of the lowermost layer is formed. As compared with the first embodiment, the angle range in which the distracted capacitance component CXB is reduced can be increased, and unnecessary radiation at the bent portion of the high-frequency transmission line is reduced. Even if it has a certain extent, it can be efficiently suppressed.

  As in the first embodiment, also in this embodiment, as shown in FIG. 13, the connection with the lower conductor pad 13B of the end portion of the lower ground plane 16B facing the lower high-frequency signal line 14B is provided. You may provide the convex part B which protruded in the position before the point to the lower high frequency signal track | line 14B side. As a result, an increase in the characteristic impedance of the lower high-frequency signal line 14B can be suppressed, matching with the characteristic impedance of the high-frequency signal via 12 can be maintained, and occurrence of loss can be suppressed.

  In the present embodiment, as shown in FIG. 12 and FIG. 14, the present invention is applied to both the bent portions located at the uppermost layer and the lowermost layer of the multilayer wiring board 11 among the bent portions of the high-frequency transmission line. Although the case where it is applied has been described as an example, the present invention may be applied to only one of the bent portion located in the uppermost layer or the bent portion located in the lowermost layer, and the same effect as described above can be obtained. Can be obtained.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, each embodiment can be implemented in any combination within a consistent range.

  DESCRIPTION OF SYMBOLS 10 ... High frequency transmission line, 11 ... Multilayer wiring board, 11M ... Conductor layer, 11P ... Insulating layer, 12 ... High frequency signal via, 13A ... Upper conductor pad, 13B ... Lower conductor pad, 14A ... Upper high frequency signal line, 14B ... Lower High-frequency signal line, 15A: upper antipad region, 15B: lower antipad region, 16A ... upper ground plane, 16B ... lower ground plane, 17 ... ground via, 18A ... end (uppermost layer), 18B ... end (uppermost) Lower layer), B ... convex part, CA, CB, CC, CD ... orthogonal capacitance component, CXA, CXB ... distraction capacitance component.

Claims (7)

A multilayer wiring board in which conductor layers and insulating layers are alternately laminated;
A high-frequency signal via formed vertically through the multilayer wiring board from the uppermost layer to the lowermost layer;
An upper conductor pad formed in the uppermost layer in a substantially circular shape in plan view and connected to an upper end of the high-frequency signal via;
An upper high-frequency signal line formed linearly on the uppermost layer and having a tip connected to the upper conductor pad;
The uppermost layer is formed of a conductor layer connected to the ground potential, and the upper antipad region where the conductor layer is selectively removed is sandwiched between the upper conductor pad and the upper high-frequency signal line. The formed upper ground plane;
A plurality of ground vias formed in the multilayer wiring board and connecting the upper ground plane and the conductor layers stacked in the multilayer wiring board;
Of the conductor layer forming the upper ground plane, opposite to the upper high-frequency signal line across an upper boundary line passing over the upper conductor pad along a direction orthogonal to the extending direction of the upper high-frequency signal line The conductive layer located on the side is at least the width of the upper antipad region in the orthogonal direction and is selectively connected to the upper antipad region up to the side end portion in the orthogonal direction of the uppermost layer. A high-frequency transmission line characterized by being removed. In the high frequency transmission line according to claim 1,
The conductor layer to be removed is composed of all conductor layers located on the opposite side of the upper high-frequency signal line across the upper boundary line among the conductor layers forming the upper ground plane. A high-frequency transmission line. In the high frequency transmission line according to claim 1 ,
The high-frequency transmission line according to claim 1, wherein the width of the conductor layer to be removed gradually increases as the side end portion is approached. In the high frequency transmission line according to any one of claims 1 to 3,
The upper ground plane has an end facing the upper high-frequency signal line at a boundary position between a region along the upper high-frequency signal line and a region along the upper conductor pad in the upper anti-pad region. A high-frequency transmission line having a convex portion protruding toward the line side. In the high frequency transmission line according to any one of claims 1 to 4,
A lower conductor pad formed in a substantially circular shape in plan view on the lowermost layer and connected to a lower end of the high-frequency signal via;
A lower high-frequency signal line that is formed in a line shape in the lowermost layer and has a tip connected to the lower conductor pad,
The conductor layer is formed on the lowermost layer and is connected to the ground potential, and the lower conductor pad and the lower high-frequency signal line are surrounded by the lower antipad region where the conductor layer is selectively removed. A lower ground plane formed,
Each of the ground vias is connected to the lower ground plane,
Of the conductor layers forming the lower ground plane, opposite to the lower high-frequency signal line across a lower boundary line passing over the lower conductor pad along an orthogonal direction orthogonal to the extending direction of the lower high-frequency signal line A part or all of the conductor layer located on the side is selectively removed so as to be continuous with the lower antipad region. In the high frequency transmission line according to any one of claims 1 to 4,
Instead of the upper conductor pad, the lower conductor pad formed in a substantially circular shape in plan view on the lowermost layer, and connected to the lower end of the high-frequency signal via,
Instead of the upper high-frequency signal line, a lower high-frequency signal line that is formed in a line shape in the lowermost layer and has a tip connected to the lower conductor pad,
Instead of the upper ground plane, the lower conductor pad is formed on the lowermost layer and is composed of a conductor layer connected to a ground potential, and the lower conductor pad and the lower antipad region where the conductor layer is selectively removed are sandwiched. A lower ground plane formed around the lower high-frequency signal line,
Each of the ground vias is connected to the lower ground plane,
Of the conductor layers forming the lower ground plane, opposite to the lower high-frequency signal line across a lower boundary line passing over the lower conductor pad along an orthogonal direction orthogonal to the extending direction of the lower high-frequency signal line A part or all of the conductor layer located on the side is selectively removed so as to be continuous with the lower antipad region. In the high frequency transmission line according to any one of claims 1 to 6,
The high-frequency transmission line, wherein the high-frequency signal via and the ground via have a pseudo coaxial line structure.

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