HIGH-FREQUENCY TRANSMISSION LINE

Abstract

High-frequency transmission line (10, 10b, 10c, 10d) which has: a multilayered substrate (2, 2b, 2c, 2d) containing several dielectric layers (L1 to L3) stacked on top of each other; several conductor sections (30) arranged side by side in a direction that differs from a transmission direction (x) that is predetermined, each of the conductor sections (30) containing a signal line (3, 4) formed along the transmission direction (x) on one of two outer surfaces of the multilayer substrate (2, 2b, 2c, 2d); several signal contact holes (5), wherein one signal contact hole (5) from the signal contact holes (5) is arranged in each of the line sections (30) and connects the respective signal lines (3, 4) which are formed on the two outer surfaces; a grounding plane (6) contained in the multilayer substrate (2, 2b, 2c, 2d), arranged between the dielectric layers (L1 to L3) and covering peripheries of several transmission areas (61), which are areas whose centers are the respective signal contact holes (5); and several metal sections (80) which, when a high-frequency signal transmitted through the respective line sections (30) is transmitted through the transmission area (61) corresponding to the respective line sections (30), restrict the high-frequency signal to the transmission area (61), wherein the metal sections (80) extend in a layering direction through at least one dielectric layer (L1 to L3), are electrically continuous to the grounding plane (6), extend along the transmission direction (x), wherein each individual metal section (80) of the metal sections (80) is arranged between two signal contact holes (5) of the signal contact holes (5), such that the signal contact holes (5) are arranged in a direction that differs from the transmission direction (x) between the respective metal sections (80), Each of the metal sections (80) contains several grounding contact holes (7, 8) arranged side by side along the transmission direction (x), no earth contact hole (7, 8) surrounding a signal contact hole (5) of the signal contact holes (5) overlaps with any of the line sections (30) on the same line along the transmission direction (x); the grounding contact holes (7, 8) contain several types of grounding contact holes (7, 8) whose diameters differ from one another; and a section of the earthing contact holes (7, 8) contained in the respective two metal sections (80) and between which a single signal contact hole (5) is arranged, is arranged on a circle (C1) whose center is the signal contact hole (5) and a radius of the circle (C1) whose center is the signal contact hole (5) is equal to or less than an interval (R) between centers of adjacent signal contact holes (5) from the signal contact holes (5), wherein the interval (R) is equal to or less than half a wavelength of the radio frequency signal.

Description

[0001] The present invention relates to a technology for transmitting a high-frequency signal in a layering direction of a multilayer substrate. State of the art

[0002] JP 2015-50680A describes a technology in which a high-frequency transmission line is formed by arranging signal line patterns, formed on both surfaces of a multilayer wiring substrate and connected by a signal contact hole and a ground contact hole (which has a ground potential), along a circle whose center is the signal contact hole. When the high-frequency transmission line formed in this way is used, the high-frequency signal can be transmitted with low loss in the layering direction of the wiring substrate.

[0003] US 2013 / 0 235 542 A1, US 2002 / 0 139 579 A1, JP 2015-56 719 A and US 2006 / 0 158 280 A1 each disclose a high-frequency transmission line comprising: a multilayer substrate containing multiple dielectric layers stacked on top of each other; multiple line sections arranged side by side in a direction different from a transmission direction predetermined, each line section containing a signal line formed along the transmission direction on one of two outer surfaces of the multilayer substrate; multiple signal contact holes, each signal contact hole being arranged in a respective line section and connecting the respective signal lines formed on the two outer surfaces;a grounding plane contained in the multilayer substrate, arranged between the dielectric layers and covering the peripheries of several transmission areas, which are areas whose centers contain the respective signal contact holes;and several metal sections which, when a high-frequency signal transmitted through the respective conductor sections is transmitted through the transmission area corresponding to the respective conductor sections, confine the high-frequency signal to the transmission area, wherein the metal sections extend in a layering direction through at least one dielectric layer, are electrically continuous to the ground plane, are formed along the transmission direction and are arranged in an alternating manner with respect to the respective signal contact holes, such that the signal contact holes are arranged between them in a direction different from the transmission direction, and wherein each of the metal sections contains several ground contact holes arranged side by side along the transmission direction.

[0004] US Patent 2006 / 0255876A1 discloses a through-conductor transmission line for a multilayer printed circuit board. The transmission line has a center conductor forming an inner conductor layer boundary, which forms a signal through-hole, and a plurality of through-holes arranged around the center conductor forming an outer conductor layer boundary.

[0005] US Patent 8 212 154 B2 discloses a printed circuit board comprising: ground planes stacked over insulating planes in multiple layers; a through-hole; a gap serving as an anti-contact point and provided in an area between the through-hole and the ground planes; and signal wiring running from the through-hole through the gap between predetermined ground planes.

[0006] WO 2015 / 198 912 A1 discloses a semiconductor device in which an input / output wiring and the grounding wiring are provided with through holes to form a stripline structure, and a metal film is formed on the front and back sides. Summary of the invention

[0007] When the high-frequency transmission line described in JP 2015-50680A is used to supply power to an antenna having multiple antenna elements, particularly a wide-angle antenna, in order to prevent grid lobes, the interval between signal lines supplying power to the antenna elements is preferably equal to or less than half a wavelength. However, as a result of detailed studies carried out by the inventors, it was found that when multiple high-frequency transmission lines are arranged side by side, the ground contact holes of adjacent high-frequency transmission lines overlap if the distance between the signal lines is sufficiently reduced. Therefore, the interval between the signal lines cannot be reduced sufficiently.As a result of detailed studies by the inventors, it was found that even when several of the above-described high-frequency power lines are arranged side by side, it is difficult to use the high-frequency transmission lines for the power supply of an antenna that has multiple antenna elements, because the interval between the signal lines cannot be reduced sufficiently.

[0008] The object of the present invention is to provide a high-frequency transmission line that can be used to supply power to an antenna comprising multiple antenna elements. This object is achieved by a high-frequency transmission line having the features of claim 1. The dependent claims are directed to advantageous embodiments of the invention.

[0009] A high-frequency transmission line according to one aspect of the present invention comprises a multilayer substrate, several conductor sections, several signal contact holes, a ground plane, and several metal sections. The multilayer substrate contains several dielectric layers stacked on top of each other. The conductor sections are arranged side by side in a direction that differs from a transmission direction that is predetermined. Each conductor section contains a signal line formed along the transmission direction on the respective two outer surfaces of the multilayer substrate. Each signal contact hole is arranged in the respective conductor section and connects the signal lines formed on the respective two outer surfaces. The ground plane is contained within the multilayer substrate, arranged between the dielectric layers, and covers the surrounding environment.Peripheries of several transmission areas or transmission surfaces, which are surfaces whose centers lie at the respective signal contact holes.

[0010] The metal sections are arranged such that when a high-frequency signal transmitted through the respective conductor sections is transmitted through the transmission surface corresponding to the respective conductor sections, the high-frequency signal is confined within or to the transmission surface. The metal sections extend in a layering direction through at least a single dielectric layer, are electrically continuous with respect to the ground plane, are formed along the transmission direction, and are arranged in an alternating manner with respect to the respective signal contact holes, such that the respective signal contact holes are arranged between them in a direction that differs from the transmission direction.

[0011] In the high-frequency transmission line according to one aspect of the present invention, the metal sections are configured along the transmission direction in a manner similar to the signal line connected to the respective signal contact holes. Furthermore, the metal sections are arranged alternately with or towards the signal through-holes, such that the respective signal through-holes between them are arranged in a direction different from the transmission direction. Therefore, the signal contact holes adjacent to each other with the intervening metal section can divide the metal section located between them and form a quasi-coaxial conductor structure.

[0012] As a result, compared to a case where the metal section is arranged along a circle for each signal contact hole, the interval between multiple conductor sections can be sufficiently reduced. Furthermore, the metal section is positioned between adjacent signal contact holes. Therefore, a reduction in transmission loss and high isolation between adjacent signal contact holes can be achieved. Consequently, the high-frequency transmission line according to one aspect of the present invention can be used for powering an antenna comprising multiple antenna elements.

[0013] The reference numerals in parentheses in the claims indicate correspondences to specific devices described according to an embodiment which is described below as an aspect of the present invention, and do not limit the technical scope of the present invention. Brief description of the drawings Fig. 1 is a top view of a high-frequency transmission line according to a first embodiment of the invention; Fig. 2 is a cross-sectional view along line II-II of the Fig. 1; Fig. Figure 3 is a graph of transmission loss with respect to frequency, which was determined by simulation; Fig. Figure 4 is a graph of isolation or isolation with respect to frequency, which was determined by simulation; Fig. 5 is a top view of a high-frequency transmission line according to a second embodiment not according to the invention; Fig. 6 is a top view of a high-frequency transmission line according to a third embodiment according to the invention; Fig. 7 is a top view of a high-frequency transmission line according to a fourth embodiment according to the invention; Fig. 8 is a cross-sectional view along line VIII-VIII of the Fig. 7; Fig. 9 is a top view of a high-frequency transmission line according to a fifth embodiment according to the invention; Fig. Figure 10 is a cross-sectional view along line XX of the Fig. 9; and Fig. Figure 11 is a top view of a high-frequency transmission line according to a sixth embodiment not in accordance with the invention. Description of the embodiments

[0014] The following describes embodiments for carrying out the present invention with reference to the drawings. 1. First embodiment according to the invention 1-1. Configuration

[0015] It is now assumed that a high-frequency transmission line 10 according to the present embodiment is used for supplying power to each antenna element of a wide-angle antenna having two antenna elements. It is further assumed here that the high-frequency transmission line 10 is used for transmitting high-frequency signals with a frequency equal to or greater than 50 GHz.

[0016] First, a configuration of the high-frequency transmission line 10 is described with reference to Fig. 1 and Fig. The high-frequency transmission line 10 is described in Figure 2. It comprises a multilayer substrate 2, two conductor sections 30, two signal contact holes or signal contact passages 5, and three grounding contact passage sections or grounding contact hole sections 80. Directions parallel to a plane of the multilayer substrate 2 are designated as the x-direction and the y-direction. A direction perpendicular to the plane of the multilayer substrate 2 is designated as the z-direction. The x-direction and the y-direction are mutually perpendicular. Furthermore, the x-direction is a transmission direction of the high-frequency signal on the plane of the multilayer substrate 2.

[0017] The multilayer substrate 2 contains two dielectric layers L1 and L2 and three pattern layers P1 to P3, between which the respective dielectric layers L1 and L2 are arranged. Hereinafter, among the pattern layers P1 to P3, those P1 and P3, which are arranged on the outer surfaces of the multilayer substrate 2, are referred to as the outer layers. The pattern layer P2, which is arranged between the dielectric layers L1 and L2, is referred to as the intermediate layer.

[0018] Each of the two transmission line sections 30 contains a signal line 3 and a signal line 4, which serve as waveguides for transmitting the high-frequency signal. Signal line 3 is a conductor pattern formed on the outer layer P1 along the transmission direction. Signal line 4 is a conductor pattern formed on the outer layer P3 along the transmission direction. For example, a copper foil formed by etching or similar processes is used for signal lines 3 and 4. The two signal lines 3 are arranged side by side in the y-direction on the outer layer P1. The interval between adjacent signal lines 3 is a distance R. Similarly, the two signal lines 4 are arranged side by side in the y-direction on the outer layer P3. The interval between the centers of adjacent signal layers 4 is the distance R.Furthermore, the ends of the signal lines 3 and 4, which are contained in a single signal section 30, are arranged at opposite positions, with the dielectric layers L1 and L2 being arranged between the ends of the signal lines 3 and 4.

[0019] Each of the two signal contact holes 5 is a metal conductor. The two signal contact holes 5 are arranged in the respective two conductor sections 30. The signal contact hole 5 connects the ends of signal conductor 3 and signal conductor 4, which are opposite each other. The two signal contact holes 5 are arranged in a row in the y-direction. The interval between the centers of adjacent signal contact holes 5 is the distance R. Furthermore, the diameter of each signal contact hole 5 is smaller than the distance R and larger than the conductor width of signal conductors 3 and 4.

[0020] An earthing plane 6 is a conductor pattern formed on the intermediate layer P2 using a copper foil or similar material. The earthing plane 6 is connected to a ground potential. The earthing plane 6 covers the peripheries of the two transmission surfaces or areas 61 below the planes with which the two dielectric layers L1 and L2 are in contact. That is, the earthing plane 6 is configured such that it covers the entire area excluding the two transmission surfaces 61. The two transmission surfaces 61 are surfaces whose centers are the two signal contact holes 5. According to the present embodiment, the two transmission surfaces 61 are circular surfaces whose centers are the two signal contact holes 5.

[0021] Each of the two conductor sections 30 and the transmission area 61 corresponding to each conductor section 30 serve as a power supply line to the two antenna elements. That is, the power supply lines of the antenna elements are arranged side by side in the y-direction with an interval equal to the distance R. The distance R is a distance equal to or less than half the wavelength of the radio frequency signal transmitted via the radio frequency transmission line 10. According to the present embodiment, the radio frequency transmission line 10 transmits a radio frequency signal of 77 GHz. Furthermore, the wavelength here refers to an effective wavelength.

[0022] Each of the three grounding contact hole sections 80 is formed along the x-direction. Furthermore, each of the three grounding contact hole sections 80 is arranged alternately in the y-direction with respect to the two signal contact holes 5, such that the two signal contact holes 5 are located between them. Each of the three grounding contact hole sections 80 is a metal element that confines the high-frequency signal to the transmission area when the high-frequency signal, transmitted through a respective conductor section 30, is transmitted through the transmission area 61 in the periphery of the signal contact hole 5 corresponding to a respective conductor section 30. That is, the three grounding contact hole sections 80 are metal elements for forming a quasi-coaxial conductor structure through the signal contact hole 5 and the two grounding contact hole sections 80 between which the signal contact hole 5 is located.

[0023] Each of the three grounding contact hole sections 80 contains a single small grounding contact hole 7 and two large grounding contact holes 8, the diameter of which is larger than that of the small grounding contact hole 7. The small grounding contact hole 7 and the large grounding contact holes 8 extend through the multilayered substrate 2 in the layering direction and are electrically continuous to the grounding plane 6. According to the present embodiment, the diameter of the signal contact hole 5 is larger than the diameter of the small grounding contact hole 7 and smaller than the diameter of the large grounding contact hole 8. Furthermore, according to the present embodiment, the grounding contact hole section 80 corresponds to a metal section.

[0024] The single small grounding contact hole 7 and the two large grounding contact holes 8, which are contained in the same grounding contact hole section 80, are arranged in the x-direction such that the two large grounding contact holes 8 accommodate the small grounding contact hole 7 between them. Furthermore, the center of the small grounding contact hole 7 and the centers of the two large grounding contact holes 8 are arranged on the same line.

[0025] Furthermore, in a row in which the two signal contact holes 5 are arranged, three small grounding contact holes 7 are arranged in the three grounding contact hole sections 80 such that the respective two signal contact holes 5 are positioned between them. In other words, the centers of the three small grounding contact holes 7 and the centers of the two signal contact holes 5 are arranged on the same line.

[0026] Furthermore, the two grounding contact hole sections 80, between which a respective signal contact hole 5 is arranged, are linearly symmetrical with respect to the signal lines 3 and 4, which are connected to the signal contact hole 5 located between them. Here, the two signal contact holes 5 are a first signal contact hole and a second signal contact hole. The grounding contact hole section 80 between the first signal contact hole and the second signal contact hole is referred to as the second grounding contact hole section. The grounding contact hole section 80 that, together with the second grounding contact hole section, accommodates the first signal contact hole between itself is referred to as the first grounding contact hole section. The remaining grounding contact hole section 80 is referred to as the third grounding contact hole section.The second grounding contact hole section is linearly symmetrical to the first grounding contact hole section with respect to signal lines 3 and 4, which are connected to the first signal contact hole. Furthermore, the second grounding contact hole section is linearly symmetrical to the third grounding contact hole section with respect to signal lines 3 and 4, which are connected to the second signal contact hole.

[0027] Furthermore, the two small grounding contact holes 7 and the four large grounding contact holes 8, contained within the two grounding contact hole sections 80, between which a signal contact hole 5 is arranged, are arranged on a circle C1 whose center is the signal contact hole 5 located between them. That is, the first grounding contact hole section and the second grounding contact hole section are arranged on circle C1 whose center is the first signal contact hole. The second grounding contact hole section and the third grounding contact hole section are arranged on circle C1 whose center is the second signal contact hole. The second grounding contact hole section is arranged both on circle C1 whose center is the first signal contact hole and on circle C1 whose center is the second signal contact hole. Therefore, the second grounding contact hole section is shared by the adjacent first and second signal contact holes.

[0028] In particular, each small earthing contact hole 7 and each large earthing contact hole 8 are arranged such that a section of a connection surface of the small earthing contact hole 7 and a section of a connection surface of the large earthing contact hole 8 are arranged on the circle C1, the center of which is the signal contact hole 5.

[0029] When the high-frequency transmission line 10, which is designed in this way, is used to supply power to an antenna, when the high-frequency signal is supplied from the respective two signal lines 4, each of the supplied high-frequency signals is transmitted from the signal line 4 via the transmission area or transmission range 61 to the signal line 3 and supplied to a respective antenna element. 1-2. Effects

[0030] According to the first embodiment described above, the following effects are achieved. (1) The three earthing contact hole sections 80 are configured along the transmission direction in a manner similar to the two conductor sections 30. Furthermore, each of the three earthing contact hole sections 80 is arranged alternately with respect to the respective two signal contact holes 5 in a direction different from the transmission direction, such that the respective two signal contact holes 5 are accommodated between them. Therefore, the signal contact holes 5 adjacent to each other with respect to the intervening earthing contact hole section 80 can share the earthing contact hole section 80 that is arranged between them. As a result, the interval between two conductor sections 30 can be sufficiently reduced compared to a case in which the earthing contact hole section 80 is fixed along a circle for each signal contact hole 5. In addition, the earthing contact hole section 80 is arranged between adjacent signal contact holes 5.Therefore, a reduction in transmission loss and high isolation between adjacent signal contact holes 5 can be achieved. Consequently, current can be supplied to an antenna comprising multiple antenna elements. (2) The two adjacent signal contact holes 5 may share the single small earthing contact hole 7 and the two large earthing contact holes 8 which are arranged between the two adjacent signal contact holes 5 and are arranged side by side along the direction of transmission. (3) Each grounding contact hole section 80 contains the small grounding contact hole 7 and the large grounding contact holes 8, which have different diameters. Therefore, the small grounding contact hole 7 and the large grounding contact holes 8 can be arranged side by side in one direction along the transmission direction and on a circle whose center is the signal contact hole 5. Consequently, the effects of the quasi-coaxial conductor structure formed by the signal contact holes 5, the small grounding contact holes 7, and the large grounding contact holes 8 can be enhanced. (4) The three small earthing contact holes 7 are arranged in the same row as the two signal contact holes 5. Consequently, the interval between two signal contact holes 5 and also the interval between two conductor sections 30 can be reduced. (5) The two grounding contact hole sections, between which the signal contact hole 5 is arranged, are linearly symmetrical with respect to the signal lines 3 and 4 which are connected to the signal contact hole. Consequently, the transmission performance with respect to high-frequency signals can be improved. (6) Even when a high-frequency signal is transmitted at a high frequency equal to or greater than 50 GHz, the intervals between two signal contact holes 5 and two line sections 30 can be sufficiently reduced. (7) The intervals between two signal contact holes 5 and two conductor sections 30 can be set to a distance equal to or less than half the wavelength of the radio frequency signal. If the radio frequency transmission line 10 is used to supply power to an antenna having two antenna elements, the occurrence of grid lobes can be suppressed. Furthermore, the radio frequency transmission line 10 can be suitable for supplying power to a wide-angle antenna. 1-3. Simulation

[0031] Fig. Figure 3 shows a graph of the results of a transmission loss in the high-frequency transmission line 10, which was determined by simulation. For comparison, properties of a reference example are also shown, in which several grounding contact holes are arranged along a circle, the center of which is the signal contact hole. The transmission loss here includes a loss that occurs during transmission via signal lines 3 and 4 and the transmission area 61. Fig. Figure 3 shows that the difference between the present embodiment, in which the grounding contact holes are arranged along the x-direction, and the comparison example, in which the grounding contact holes are arranged along a circle whose center is the signal contact hole 5, is only about 0.1 dB. Therefore, it is evident that the present embodiment achieves a transmission performance similar to that of the comparison example.

[0032] Furthermore, it shows Fig. 4 a graph of the electrical power of the high-frequency signal leaking to another line section 30 when the high-frequency signal is applied to one of the two line sections 30. From Fig. As shown in Figure 4, leakage of the high-frequency signal to the adjacent line section 30 is sufficiently suppressed. That is, it is evident that if the high-frequency transmission line 10 is used for the power supply to two antenna elements, sufficient isolation between the two antenna elements can be achieved. Second embodiment not according to the invention 2-1. Differences from the first embodiment

[0033] A basic configuration according to a second embodiment is similar to that of the first embodiment. Therefore, the description of the common configurations is omitted. The focus is primarily on the differences. Here, the same reference numerals as in the first embodiment above denote the same configurations, and reference is made to the preceding description.

[0034] In the high-frequency transmission line 10 according to the first embodiment described above, the grounding contact hole section 80, which contains the single small grounding contact hole 7 and the two large grounding contact holes 8, is formed in the multilayer substrate 2. In this respect, a high-frequency transmission line 10a according to the second embodiment differs from that according to the first embodiment in that a grounding contact hole section 80a, which contains three small grounding contact holes 7, is formed in a multilayer substrate 2a. That is, in the grounding contact hole section 80a, the small grounding contact holes 7 are arranged at the same positions as the large grounding contact holes 8 in the grounding contact hole section 80.

[0035] Therefore, in the high-frequency transmission line 10a, the six small grounding contact holes contained in the two grounding contact hole sections 80a, between which the signal contact hole 5 is arranged, are not located on the circle C1, the center of which is the signal contact hole 5. Therefore, the high-frequency transmission line 10a does not achieve the same reduction in transmission loss as the high-frequency transmission line 10. However, since the respective three grounding contact hole sections 80a are arranged such that the respective two signal contact holes 5 are located between them, the reduction in transmission loss is achieved to a certain extent. 2-2. Effects

[0036] According to the second embodiment described above, the effects described above (1) and (2) as well as (4) to (7) are achieved according to the first embodiment. 3. Third embodiment according to the invention 3-1. Differences from the first embodiment

[0037] A basic configuration according to a third embodiment is similar to that of the first embodiment. Therefore, the description of the common configurations is omitted. The focus is primarily on the differences. Here, the same reference numerals as in the first embodiment denote the same configurations, and reference is made to the preceding description in this regard.

[0038] A high-frequency transmission line 10b according to the third embodiment differs from that according to the first embodiment in that small grounding contact holes 7 are added in addition to the high-frequency transmission line 10 described above according to the first embodiment. As described in Fig. As shown in Figure 6, in addition to the three grounding contact hole sections 80, eight small grounding contact holes 7 are formed in the multilayer substrate 2b of the high frequency transmission line 10b.

[0039] Among the three grounding contact hole sections 80, the grounding contact hole section 80 located in the center of the two signal contact holes 5 is an intermediate grounding contact hole section. The remaining two grounding contact hole sections 80 are external grounding contact hole sections. Among the eight added small grounding contact holes 7, four are arranged on each side of the two external grounding contact hole sections in the x-direction, with one on each side of each external grounding contact hole section. Furthermore, the remaining four small grounding contact holes 7 are arranged on each side of the intermediate grounding contact hole section in the x-direction, i.e., two on each side. The eight small grounding contact holes 7 are also arranged such that they are linearly symmetrical with respect to a center line LL.The center line LL is a line passing through the centers of the single small grounding contact hole 7 and the two large grounding contact holes 8 contained in the intermediate grounding contact hole section. That is, in the high-frequency transmission line 10b, four small grounding contact holes 7 are added for each signal contact hole 5, compared to the high-frequency transmission line 10. 3-2. Effects

[0040] According to the third embodiment described above, the effects (1) to (7) described above are achieved in accordance with the first embodiment. Furthermore, as a result of the higher number of small grounding contact holes 7 compared to the first embodiment, the transmission loss can be reduced. 4. Fourth embodiment according to the invention 4-1. Differences from the first embodiment

[0041] A basic configuration according to a fourth embodiment is similar to that of the first embodiment. Therefore, the description of the common configurations is omitted. The focus is primarily on the differences. Here, the same reference numerals as in the first embodiment denote the same configurations, and reference is made to the preceding description in this regard.

[0042] As it is in Fig. As shown in Figure 7, a high-frequency transmission line 10c according to the fourth embodiment differs from that according to the first embodiment in that an intermediate layer contact hole 9 is added. Fig. Figure 7 shows a section of the high-frequency transmission line 10c omitted, and a single signal contact hole 5 and the two grounding contact hole sections 80, between which the signal contact hole 5 is arranged, are shown. In fact, the high-frequency transmission line 10c, like the high-frequency transmission line 10, contains the two signal contact holes 5, the two line sections 30, and the three grounding contact hole sections 80.

[0043] As it is in Fig. 7 and Fig. As shown in Figure 8, the multilayer substrate 2c of the high-frequency transmission line 10c contains three dielectric layers L1 to L3 and four pattern layers P1 to P4, between which the respective dielectric layers L1 to L3 are arranged. Hereinafter, among the pattern layers P1 to P4, those P1 and P4, which are arranged on the outer surfaces of the multilayer substrate 2, are referred to as the outer layers. The other pattern layers P2 and P3 are referred to as the intermediate layers.

[0044] The two conductor sections 30 are formed in the outer layers P1 and P4. Furthermore, the grounding plane 6 is formed in each of the intermediate layers P2 and P3. Additionally, two intermediate layer contact holes 9 are formed in the multilayer substrate 2c for each conductor section 30. Each of the intermediate layer contact holes 9 is configured such that it passes through the dielectric layer L2 and provides electrical continuity between the two grounding planes 6 formed in the intermediate layers P2 and P3.

[0045] Furthermore, the two interlayer contact holes 9, each formed for a respective conductor segment 30, are arranged at positions that overlap with the signal lines 3 and 4 on an xy plane. One of the two interlayer contact holes 9 is located at a position that overlaps with signal line 3, and the other is located at a position that overlaps with signal line 4. That is, the interlayer contact holes 9 are formed at positions where they do not extend completely through the multilayer substrate 2, since the conductor segments 30 are formed in the outer layers P1 and P4. 4-2. Effects

[0046] According to the fourth embodiment described above, the effects (1) to (7) described above are achieved in accordance with the first embodiment. Furthermore, as a result of the addition of the interlayer contact holes 9, the transmission loss can be further reduced compared to the first embodiment. 5. Fifth embodiment according to the invention 5-1. Differences from the fourth embodiment

[0047] A basic configuration according to a fifth embodiment is similar to that according to the fourth embodiment. Therefore, the description of the common configurations is omitted. The focus is primarily on the differences. Here, the same reference numerals as in the first embodiment denote the same configurations, and reference is made to the preceding description in this regard.

[0048] In a high-frequency transmission line 10d according to the fifth embodiment, two interlayer contact holes 9 are also formed for each line section 30. However, the high-frequency transmission line 10d according to the fifth embodiment differs from that according to the fourth embodiment in that each interlayer contact hole 9 is exposed to one of the two outer surfaces of the multilayer substrate 2d.

[0049] As in Fig. 9 and Fig. As shown in Figure 10, two interlayer contact holes 9 are formed in the multilayer substrate 2d for each conductor section 30. One of the two interlayer contact holes 9 is arranged at a position that overlaps with the signal line 3 on an xy plane, and the other is arranged at a position that overlaps with the signal line 4.

[0050] The interlayer contact hole 9, located at the position overlapping with signal line 3, passes through dielectric layer L2, grounding plane 6 formed in interlayer P3, and dielectric layer L3, creating electrical continuity between the two grounding planes formed in interlayers P2 and P3. The interlayer contact hole 9, located at the position overlapping with signal line 4, passes through dielectric layer L1, grounding plane 6 formed in interlayer P2, and dielectric layer L2, creating electrical continuity between the two grounding planes formed in interlayers P2 and P3. That is, the two interlayer contact holes 9 are each configured such that they are exposed on the outer surface on sides opposite the respective overlapping signal lines 3 or 4. 5-2. Effects

[0051] According to the fifth embodiment described above, the effects (1) to (7) described above are achieved in accordance with the first embodiment. Furthermore, as a result of the addition of the interlayer contact holes 9, the transmission loss can be further reduced compared to the first embodiment. 6. Sixth embodiment not according to the invention 6-1. Differences from the first embodiment

[0052] A basic configuration according to a sixth embodiment is similar to that of the first embodiment. Therefore, the description of the common configurations is omitted. The focus is primarily on the differences. Here, the same reference numerals as in the first embodiment denote the same configurations, and reference is made to the preceding description in this regard.

[0053] In the high-frequency transmission line 10 described above according to the first embodiment, the three grounding contact hole sections 80 are configured such that the respective two signal contact holes 5 are arranged between them. In this respect, a high-frequency transmission line 10e according to the sixth embodiment differs in that three grooves 70 are formed, between which the respective two signal contact holes 5 are arranged.

[0054] As it is in Fig.As shown in Figure 11, the three grooves 70 in the multilayer substrate 2e are configured such that their longitudinal direction is the x-direction. Each of the three grooves 70 has a metal wall surface extending through the multilayer substrate 2e and is formed in a rectangular cylindrical shape with a rectangular xy cross-section. The grooves 70 extend in the x-direction from positions opposite to each other with respect to a signal contact hole 5 as the center. According to the present embodiment, the groove 70 corresponds to a metal section. 6-2. Effects

[0055] According to the sixth embodiment described above, the effects described above (1) and (5) to (7) are achieved according to the first embodiment. Other embodiments

[0056] The present invention can be implemented according to various modifications. (a) According to the embodiments described above, high-frequency transmission lines 10 and 10a to 10e have been described, which contain the two signal contact holes 5 and the two conductor sections 30. However, the high-frequency transmission lines 10 and 10a to 10e according to the embodiments can contain three or more signal contact holes 5 and three or more conductor sections 30. If the high-frequency transmission lines 10 and 10a to 10e according to the embodiments contain three or more signal contact holes 5 and three or more conductor sections 30, the high-frequency transmission lines 10 and 10a to 10e can also be used for supplying power to an antenna having three or more antenna elements. In this case, the signal contact holes 5, the conductor sections 30, the grounding contact hole sections 80 or 80a, or the slots 70 can be arranged side by side at equal intervals in the y-direction. (b) According to the embodiments described above, multilayer substrates 2 and 2a to 2e containing two or three dielectric layers have been described. However, a multilayer substrate in which even more dielectric layers are stacked on top of each other can also be used. In this case, the configuration is similar to that described above, except for an increase in the number of intermediate layers in which the grounding layer 6 is formed. (c) According to the fourth and fifth embodiments described above, the interlayer contact holes 9 are arranged only in positions that overlap with the signal lines 3 and 4. However, the interlayer contact holes 9 can also be arranged in other positions. Reference symbol list 2, 2a, 2b, 2c, 2d, 2e substrate 3 Signal line 4 Signal line 5 signal contact holes 6 Earthing level 7 small grounding contact holes 8 large grounding contact holes 9, 9a Interlayer contact hole 10, 10a, 10b, 10c, 10d, 10e High-frequency transmission line 30 Line section 61 Transmission area, transmission range 70 Nut 80, 80a Earthing contact hole section, metal section C1 Circle L1, L2, L3 dielectric layer LL center line P1, P4 Pattern layer, Outer layer P2, P3 Pattern layer, Intermediate layer R distance, interval x Transmission direction

Claims

[1] High-frequency transmission line (10, 10b, 10c, 10d) which has: a multilayered substrate (2, 2b, 2c, 2d) containing several dielectric layers (L1 to L3) stacked on top of each other; several conductor sections (30) arranged side by side in a direction that differs from a transmission direction (x) that is predetermined, each of the conductor sections (30) containing a signal line (3, 4) formed along the transmission direction (x) on one of two outer surfaces of the multilayer substrate (2, 2b, 2c, 2d); several signal contact holes (5), wherein one signal contact hole (5) from the signal contact holes (5) is arranged in each of the line sections (30) and connects the respective signal lines (3, 4) which are formed on the two outer surfaces; a grounding plane (6) contained in the multilayer substrate (2, 2b, 2c, 2d), arranged between the dielectric layers (L1 to L3) and covering peripheries of several transmission areas (61), which are areas whose centers are the respective signal contact holes (5); and several metal sections (80) which, when a high-frequency signal transmitted through the respective line sections (30) is transmitted through the transmission area (61) corresponding to the respective line sections (30), restrict the high-frequency signal to the transmission area (61), wherein the metal sections (80) extend in a layering direction through at least one dielectric layer (L1 to L3), are electrically continuous to the grounding plane (6), extend along the transmission direction (x), wherein each individual metal section (80) of the metal sections (80) is arranged between two signal contact holes (5) of the signal contact holes (5), such that the signal contact holes (5) are arranged in a direction that differs from the transmission direction (x) between the respective metal sections (80), Each of the metal sections (80) contains several grounding contact holes (7, 8) arranged side by side along the transmission direction (x), no earth contact hole (7, 8) surrounding a signal contact hole (5) of the signal contact holes (5) overlaps with any of the line sections (30) on the same line along the transmission direction (x); the grounding contact holes (7, 8) contain several types of grounding contact holes (7, 8) whose diameters differ from one another; and a section of the earthing contact holes (7, 8) contained in the respective two metal sections (80) and between which a single signal contact hole (5) is arranged, is arranged on a circle (C1) whose center is the signal contact hole (5) and a radius of the circle (C1) whose center is the signal contact hole (5) is equal to or less than an interval (R) between centers of adjacent signal contact holes (5) from the signal contact holes (5), wherein the interval (R) is equal to or less than half a wavelength of the radio frequency signal. [2] High-frequency transmission line (10, 10b, 10c, 10d) according to claim 1, wherein the types of earthing contact holes (7, 8) include a small earthing contact hole (7) and a large earthing contact hole (8) whose diameter is larger than that of the small earthing contact hole (7); the signal contact holes (5) are arranged in a row; and the small earthing contact holes (7) contained in the metal sections (80) are arranged such that the respective signal contact holes (5) are arranged between them in the row in which the signal contact holes (5) are arranged. [3] High-frequency transmission line (10, 10b, 10c, 10d) according to claim 1 or 2, wherein the two metal sections (80) between which a single signal contact hole (5) is arranged are linearly symmetrical to the signal line (3, 4) which is connected to the signal contact hole (5). [4] High-frequency transmission line (10, 10b, 10c, 10d) according to any one of claims 1 to 3, wherein a frequency of the high-frequency signal is equal to or greater than 50 GHz.

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