High frequency circuit

Abstract

A high-frequency circuit comprises: a first dielectric layer; a circuit layer, which is arranged on the first dielectric layer and has a transmission path for high-frequency signals and a ground pattern arranged around the transmission path; a second dielectric layer, which is arranged so that the circuit layer is located between the second dielectric layer and the first dielectric layer; a first conductor layer, which is arranged so that the first dielectric layer is located between the first conductor layer and the circuit layer; a second conductor layer, which is arranged so that the second dielectric layer is located between the second conductor layer and the circuit layer; and an electromagnetic wave shielding member, which is arranged around the transmission path and is constituted by a grounding conductor on the inner surface of a plurality of holes penetrating the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer and the second conductor layer, wherein the plurality of holes are a plurality of long holes arranged at intervals in a direction surrounding the transmission path, and the length dimension of each of the plurality of long holes in the direction surrounding the transmission path is greater than the width dimension.

Description

Technical Field

[0001] The present disclosure relates to high frequency circuits.

[0002] This application claims the benefit of priority based on Japanese patent application No. 2020-084545 filed on May 13, 2020, and all the contents described in the aforementioned Japanese application are incorporated herein by reference. Background Art

[0003] Patent Document 1 discloses a structure including a plurality of shielded vias electrically connected to a front surface ground and a back surface ground of a dielectric substrate.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 8-274513 Summary of the invention

[0007] One aspect of the present disclosure is a high-frequency circuit. The high-frequency circuit of the present disclosure comprises: a first dielectric layer; a circuit layer, which is arranged on the first dielectric layer and has a transmission path for high-frequency signals and a ground pattern arranged around the transmission path; a second dielectric layer, which is arranged so that the circuit layer is located between it and the first dielectric layer; a first conductor layer, which is arranged so that the first dielectric layer is located between it and the circuit layer; a second conductor layer, which is arranged so that the second dielectric layer is located between it and the circuit layer; and an electromagnetic wave shielding member, which is arranged around the transmission path, and the electromagnetic wave shielding member is composed of a grounding conductor on the inner surface of a plurality of holes that penetrate the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer, wherein the plurality of holes are a plurality of long holes arranged at intervals in a direction surrounding the transmission path, and the length dimension of each of the plurality of long holes in the direction surrounding the transmission path is greater than the width dimension. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a top view of the high-frequency circuit according to the embodiment.

[0009] Figure 2 yes Figure 1 BB cross-section diagram.

[0010] Figure 3 It is an exploded perspective view of the first conductive layer, the circuit layer, and the second conductive layer.

[0011] Figure 4 It is a diagram showing the first half of the manufacturing process of the high-frequency circuit according to the embodiment.

[0012] Figure 5It is a diagram showing the second half of the manufacturing process of the high-frequency circuit according to the embodiment.

[0013] Figure 6 It is a plan view showing a modification of the high-frequency circuit.

[0014] Figure 7 It is a top view of a high-frequency circuit according to a comparative example. DETAILED DESCRIPTION

[0015] [Technical Problems to be Solved by the Present Disclosure]

[0016] The shielding via is formed by forming a plurality of circular through holes in a dielectric substrate in a thickness direction of the dielectric substrate when viewed from above, and placing a conductor such as copper in the through holes. The shielding via is used as an electromagnetic wave shield to prevent leakage of electromagnetic waves in the dielectric substrate.

[0017] Figure 7 The present invention shows an example of a structure in which a plurality of shield vias 102 are formed in a high-frequency circuit 100 having a signal transmission path 101 so as to surround the signal transmission path 101. Unnecessary electromagnetic waves are radiated from the high-frequency signal transmission path 101. The electromagnetic waves become noise to the surrounding circuits, degrading the characteristics of the surrounding circuits.

[0018] When a plurality of shielding vias 102 are provided around the signal transmission path 101 , the plurality of shielding vias 102 function as an electromagnetic wave shield. The electromagnetic wave shield can shield electromagnetic waves leaking from the signal transmission path 101 .

[0019] Among them, it is possible that electromagnetic waves may leak from each other between the shielding vias 102. In order to more reliably prevent the leakage of electromagnetic waves, as Figure 7 As shown, it is considered that multiple columns of shielding vias 102 are arranged in parallel around the signal transmission path 101. In this case, there is a problem that the number of shielding vias 102 becomes very large. When the number of shielding vias 102 increases, a large number of holes for shielding vias 102 need to be formed, which reduces the manufacturing efficiency of the circuit.

[0020] On the other hand, if the number of shielded vias 102 is reduced from the viewpoint of circuit manufacturing efficiency, electromagnetic waves are likely to leak from between the shielded vias 102 , thereby impairing electromagnetic wave shielding properties.

[0021] Therefore, it is desired to effectively prevent the leakage of electromagnetic waves.

[0022] [Effects of the present disclosure]

[0023] According to the present disclosure, leakage of electromagnetic waves can be effectively prevented.

[0024] [1. Description of embodiments of the present disclosure]

[0025] (1) A high-frequency circuit according to an embodiment includes: a first dielectric layer; a circuit layer provided on the first dielectric layer and including a transmission path for a high-frequency signal and a ground pattern arranged around the transmission path; a second dielectric layer provided so that the circuit layer is located between the second dielectric layer and the first dielectric layer; a first conductor layer provided so that the first dielectric layer is located between the first conductor layer and the circuit layer; a second conductor layer provided so that the second dielectric layer is located between the second conductor layer and the circuit layer; and an electromagnetic wave shield provided around the transmission path. Since the circuit layer is sandwiched between the first conductor layer and the second conductor layer, leakage of electromagnetic waves from the transmission path to the thickness direction of the high-frequency circuit can be prevented. The electromagnetic wave shield is formed by providing a ground conductor on the inner surface of a plurality of holes penetrating the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer. The plurality of holes are a plurality of long holes provided at intervals in a direction surrounding the transmission path, and the length dimension of each of the plurality of long holes in the direction surrounding the transmission path is greater than the width dimension. Since the hole in which the electromagnetic wave shield is formed is formed longer in the direction surrounding the transmission path, compared with the case of providing a circular shield via hole, it is possible to effectively prevent leakage of electromagnetic waves even if the number of holes is reduced.

[0026] (2) The length dimension is preferably greater than 5 times the width dimension. By making the length dimension of the hole greater than 5 times the width dimension of the hole, the hole becomes sufficiently long, and leakage of electromagnetic waves can be effectively prevented.

[0027] (3) The length dimension is preferably larger than the interval. By making the length dimension of the hole larger than the interval between the holes, leakage of electromagnetic waves can be effectively prevented.

[0028] (4) It is preferable that the length dimension is greater than 5 times the interval. By making the length dimension of the hole greater than 5 times the interval between the holes, leakage of electromagnetic waves can be effectively prevented.

[0029] (5) It is preferred that the plurality of holes each continuously penetrate the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer. The holes that continuously penetrate the first dielectric layer can more reliably prevent leakage of electromagnetic waves.

[0030] (6) It is preferred that the electromagnetic wave shielding member at least comprises a first shielding member provided around the transmission path and a second shielding member provided on the outer peripheral side of the first shielding member, wherein the first shielding member is formed by providing the ground conductor on the inner surface of a plurality of first holes penetrating the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer, wherein the plurality of first holes are a plurality of first long holes spaced apart in a direction surrounding the transmission path, wherein the length dimension of each of the plurality of first long holes in the direction surrounding the transmission path is greater than the width dimension, and the second shielding member is formed by providing the ground conductor on the inner surface of a plurality of second holes penetrating the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer on the outer peripheral side of the plurality of first holes, wherein the plurality of second holes are a plurality of second long holes spaced apart in a direction surrounding the transmission path, wherein the length dimension of each of the plurality of second long holes in the direction surrounding the transmission path is greater than the width dimension, and wherein the second shielding member is configured to shield leakage electromagnetic waves from between the plurality of first long holes. In this case, leakage of electromagnetic waves can be more effectively prevented.

[0031] (7) Preferably, the high-frequency circuit further includes a cover film attached to a surface of at least one of the first conductive layer and the second conductive layer. In this case, the cover film can ensure the strength of the high-frequency circuit having the long hole formed therein.

[0032] [2. Details of the embodiments of the present disclosure]

[0033] Hereinafter, the same reference numerals in the drawings represent the same objects.

[0034] Figures 1 to 6 The high-frequency circuit 10 according to the embodiment is shown. The high-frequency circuit 10 according to the embodiment is configured as a flexible printed circuit (FPC) for high-frequency signal transmission. The FPC has a structure in which a conductor such as copper foil is attached to a thin and soft insulating base film. It should be noted that the high-frequency circuit 10 is not limited to the FPC, and may also be a circuit formed on a rigid substrate.

[0035] like Figure 2 As shown, the high-frequency circuit 10 involved in the embodiment includes a first dielectric layer 11, a circuit layer 21, a second dielectric layer 12, a first conductive layer 31, a second conductive layer 32 and an electromagnetic wave shielding member 150. The high-frequency circuit 10 involved in the embodiment has a multilayer structure, and the multilayer structure has three conductive layers. It should be noted that the number of conductive layers is not particularly limited, and can also be two, four, five or more layers. Figure 2In the embodiment, the conductor layer arranged in the middle of the three conductor layers is a circuit layer 21 having a high-frequency transmission path 21A. Figure 2 On the lower side of the circuit layer 21, a first conductive layer 31 is disposed as one of the three conductive layers. Figure 2 On the upper side of the 3D image layer, a second conductive layer 32 is arranged as the remaining layer of the three conductive layers.

[0036] like Figure 3 As shown, the circuit layer 21 has a transmission path 21A and a ground pattern 21B located around the transmission path 21A. The space between the transmission path 21A and the ground pattern 21B is removed by etching, and the transmission path 21A and the ground pattern 21B are insulated. Figure 3 In the embodiment, the transmission path 21A is formed in a straight line, but may be formed in a curved shape. A hole 21C is formed around the transmission path 21A to be a part of a hole 151 for an electromagnetic shielding member 150 described later.

[0037] like Figure 2 As shown, the first dielectric layer 11 is provided between the circuit layer 21 and the first conductive layer 31. That is, the circuit layer 21 is provided on the first dielectric layer 11. In other words, the circuit layer 21 is provided above the first conductive layer 31 via the first dielectric layer 11. It should be noted that the circuit layer 21 and the first dielectric layer 11 are bonded via a bonding agent 60. Figure 3 As shown, the first conductor layer 31 is composed of a ground pattern 31B on almost the entire surface except for a hole 31C which is a part of a hole 151 used in an electromagnetic shielding material 150 described later. That is, the first conductor layer 31 is a ground layer.

[0038] The adhesive 60 is preferably an adhesive having excellent flexibility and heat resistance. The adhesive 60 is, for example, an adhesive of various resins such as modified polyphenylene ether, styrene resin, epoxy resin, butyral resin, and acrylic resin.

[0039] The main component of the adhesive 60 is preferably a thermosetting resin. The lower limit of the curing temperature of the thermosetting resin as the main component of the adhesive 60 is preferably 120°C, and more preferably 150°C. The upper limit of the curing temperature of the thermosetting resin as the main component of the adhesive 60 is preferably 250°C, more preferably 230°C, and further preferably 200°C. When the curing temperature of the thermosetting resin as the main component of the adhesive 60 is greater than the above lower limit, the handling of the adhesive 60 is easy. When the curing temperature of the thermosetting resin as the main component of the adhesive 60 is less than the above upper limit, when the adhesive 60 is cured, thermal deformation of the layers bonded by the adhesive 60 can be suppressed. By suppressing the above thermal deformation, the reduction in dimensional accuracy of the high-frequency circuit 10 can be suppressed.

[0040] The lower limit of the relative dielectric constant of the bonding agent 60 is preferably as small as possible, but in order to meet other conditions such as insulation and mechanical strength, 1.5 is considered to be the limit in reality. The upper limit of the relative dielectric constant of the bonding agent 60 is, for example, 3, preferably 2.8, and more preferably 2.6. In addition, when the relative dielectric constant of the bonding agent 60 is less than the above upper limit, the dielectric loss can be suppressed when a high-frequency signal is transmitted through the high-frequency circuit 10.

[0041] like Figure 2 As shown in FIG. 1 , the second dielectric layer 12 is provided between the circuit layer 21 and the second conductor layer 32. That is, the second dielectric layer 12 is provided so that the circuit layer 21 is located between the second dielectric layer 12 and the first dielectric layer 11. Figure 3 As shown, the second conductor layer 32 is composed of a ground pattern 32B over almost the entire surface except for a transmission path 32A for high-frequency signals and a hole 32C that is a part of the hole 151 for the electromagnetic shield 150. That is, the second conductor layer 32 is a ground layer.

[0042] like Figure 2 As shown, on the upper and lower sides of the circuit layer 21, that is, Figure 2 The first conductive layer 31 and the second conductive layer 32 functioning as ground layers are provided on both sides of the high frequency circuit 10 in the Z direction. Figure 2 The electromagnetic waves radiated from both sides of the Z direction are shielded by the first conductive layer 31 and the second conductive layer 32 .

[0043] Among the electromagnetic waves radiated from the transmission path 21A, there are Figure 2Electromagnetic waves radiated in a direction parallel to the XY plane. Electromagnetic waves radiated in a direction parallel to the XY plane cannot be shielded by the first conductive layer 31 and the second conductive layer 32, and may leak out of the high-frequency circuit 10 through the first dielectric layer 11 and the second dielectric layer 12. In view of this, the high-frequency circuit 10 of the embodiment has an electromagnetic wave shielding member 150 for shielding electromagnetic waves radiated in a direction parallel to the XY plane. It should be noted that the XY plane is a plane perpendicular to the thickness direction of the high-frequency circuit 10. The Z direction is the thickness direction of the high-frequency circuit 10, which is equivalent to the stacking direction in the multilayer structure of the above-mentioned conductive layer.

[0044] In the high-frequency circuit 10 according to the embodiment, the electromagnetic waves radiated in the Z direction are shielded by the first conductive layer 31 and the second conductive layer 32. The electromagnetic waves radiated in the direction parallel to the XY plane are shielded by the electromagnetic wave shield 150. Therefore, it is possible to effectively prevent the electromagnetic waves radiated from the transmission path 21A from leaking outside the high-frequency circuit 10. As a result, it is possible to suppress the influence of the leakage electromagnetic waves on other peripheral circuits.

[0045] The electromagnetic wave shielding member 150 is configured to function as a shielding wall around the transmission path 21A to shield electromagnetic waves passing through the first dielectric layer 11 and the second dielectric layer 12. Figure 1 As shown, the electromagnetic shield 150 is formed so as to surround the transmission path 21A in a plan view. In the embodiment, a plurality of electromagnetic shields 150 are provided at intervals D in a direction surrounding the transmission path 21A.

[0046] like Figure 2 As shown, the electromagnetic wave shielding member 150 is constituted by having a grounding conductor 152 on the inner surface of a hole 151 penetrating the first dielectric layer 11, the ground pattern 21B of the circuit layer 21, the second dielectric layer 12, the first conductive layer 31, and the second conductive layer 32. In the first conductive layer 31 and the second conductive layer 32, a grounding conductor 152 is provided on the inner surface of the hole 151 formed in the ground pattern 31B and 32B. The grounding conductor 152 exists in a manner of surrounding the transmission path 21A, so that it can shield the electromagnetic waves passing through the first dielectric layer 11 and the second dielectric layer 12. It should be noted that in Figure 1 On the lower side, the transmission path 21A is not surrounded by the electromagnetic wave shielding member 150. This is simply because, when drawing, Figure 1 The transmission path 21A is omitted from the lower side, and the electromagnetic wave shielding member 150 is also omitted. Therefore, in fact, the electromagnetic wave shielding member 150 can also surround the lower side of the transmission path 21A.

[0047] like Figure 7As shown in FIG. 1 , the conventional shielding via 102 is generally circular in a top view. Therefore, in order to shield the leakage electromagnetic wave, it is necessary to densely arrange a plurality of shielding vias 102 in a manner of surrounding the signal transmission path 101. Figure 1 In the illustrated embodiment, the electromagnetic wave shielding members 150 are elongated in the direction surrounding the transmission path 21A. That is, the length dimension L of each electromagnetic wave shielding member 150 in the direction surrounding the transmission path 21A is greater than the width dimension W. Therefore, compared with the circular shielding via 102, the leakage electromagnetic wave can be effectively shielded by a smaller number of electromagnetic wave shielding members 150.

[0048] Figure 4 and Figure 5 A method for manufacturing the high-frequency circuit 10 according to the embodiment is shown. Figure 4 In step S11 shown, as an example of a substrate, a fluororesin substrate with copper on both sides is prepared. The fluororesin substrate with copper on both sides includes a fluororesin substrate constituting the second dielectric layer 12, copper constituting the circuit layer 21, and copper constituting the second conductor layer 32. It should be noted that the material of the substrate is not limited to fluororesin.

[0049] In step S12 , through holes 41 penetrating the circuit layer 21 , the second dielectric layer 12 , and the second conductor layer 32 are formed at the positions of the transmission paths 21A and 32A.

[0050] In step S13, the inside of the through hole 41 is filled with a conductor by plating. Thus, a via 40 is formed to electrically connect the transmission path 21A and the transmission path 32A. The transmission path 32A functions as an external connection terminal for the transmission path 21A, for example. It should be noted that the inner surface of the through hole 41 can also be covered by plating, and the remaining space is filled with synthetic resin.

[0051] In step S14 , the circuit layer 21 and the second conductor layer 32 of the double-sided copper-coated fluororesin substrate are etched to form the transmission path 21A of the circuit layer 21 and the transmission path 32A of the second conductor layer 32 .

[0052] In step S15, a single-sided fluororesin substrate is bonded to the circuit layer 21 side. The single-sided fluororesin substrate includes a fluororesin substrate constituting the first dielectric layer 11 and copper constituting the first conductor layer 31. In step S15, the first dielectric layer 11 and the circuit layer 21 are bonded to each other via a bonding agent 60. The bonding agent 60 is, for example, a bonding sheet. The bonding sheet is used for bonding between substrate layers. The bonding sheet has insulation and bonding properties.

[0053] In step S31 following step S15, in order to form the electromagnetic wave shielding member 150, a plurality of holes 151 are formed by punching and punching to continuously penetrate from the first conductive layer 31 to the second conductive layer 32. The method for forming the holes 151 is not limited to the punching and punching process, but when the punching and punching process is used, it is advantageous to simultaneously form a plurality of holes 151. It should be noted that the holes 151 may also be formed by laser processing.

[0054] The plurality of holes 151 are arranged at intervals D along the direction surrounding the transmission path 21A. The plurality of holes 151 respectively have a length dimension L along the direction surrounding the transmission path 21A and a width dimension W orthogonal to the direction of the length dimension L. The plurality of holes 151 are respectively long holes. That is, the length dimension L of each of the plurality of holes 151 is greater than the width dimension W. The length dimension L is preferably greater than 5 times the width dimension W, more preferably greater than 10 times the width dimension W, further preferably greater than 15 times the width dimension W, and further preferably greater than 20 times the width dimension W. By making the length dimension L sufficiently greater than the width dimension W, the number of holes 151 can be reduced. In addition, by making the width dimension W sufficiently smaller than the length dimension L, the area of ​​the region required to form the electromagnetic wave shielding member 150 around the transmission path 21A can be reduced.

[0055] The length dimension L is greater than the interval D. The length dimension L is preferably greater than 5 times the interval D, preferably greater than 10 times the interval D, preferably greater than 15 times the interval D, and further preferably greater than 20 times the interval D. In order to suppress the leakage of electromagnetic waves in the interval D, the interval D is preferably less than 1 / 4 of the wavelength λ of the high frequency transmitted through the transmission path 21A, more preferably less than 1 / 8 of the wavelength λ, and further preferably less than 1 / 16 of the wavelength λ. The smaller the interval D, the more it is possible to suppress the leakage of electromagnetic waves. By making the interval D less than 1 / 16 of the wavelength λ, the leakage of electromagnetic waves can be sufficiently reduced.

[0056] By providing the intervals D between the plurality of holes 151 , it is possible to suppress a reduction in the strength of the high-frequency circuit 10 compared to a case where a single hole 151 is continuously formed over a long period of time.

[0057] Since the electromagnetic shielding member 150 is thicker as the width W increases, the permissible interval D increases. That is, when the width W increases, even if the interval D between the gaps between the plurality of holes 151 is the same, leakage of electromagnetic waves can be reduced.

[0058] In step S32 , the conductor 152 is formed on the inner surface of the hole 151 by plating. Figure 2The conductor 152 is provided in contact with the entire inner surface of the hole 151, and the conductor 152 is formed into a cylindrical shape having an outer peripheral shape corresponding to the inner peripheral shape of the hole 151. The conductor 152 may be formed only on the surface of the inner surface of the hole 151, or may be formed so as to completely fill the inside of the hole 151. The inside of the conductor 152 may be filled with a dielectric such as a synthetic resin, or may be filled with a conductor such as a conductive paste.

[0059] The conductor 152 electrically connects the ground pattern 21B, the ground pattern 31B, and the ground pattern 32B. Therefore, the conductor 152 is a ground conductor 152. The ground conductor 152 is provided inside each of the plurality of holes 151 surrounding the periphery of the transmission path 21A. Therefore, the plurality of ground conductors 152 formed in the plurality of holes 151 function as an electromagnetic wave shield 150 surrounding the periphery of the transmission path 21A. The electromagnetic waves radiated by the first dielectric layer 11 and the second dielectric layer 12 can be shielded by the ground conductor 152.

[0060] That is, the conductor 152 electrically connects the ground pattern 21B of the circuit layer 21 and the ground pattern 31B of the first conductor layer 31. Therefore, the conductor 152 and the ground patterns 21B and 31B have the same potential, and thus serve as the ground conductor 152. Since the ground conductor 152 is provided in the hole 151 surrounding the periphery of the transmission path 21A, it functions as the electromagnetic wave shield 150 surrounding the periphery of the transmission path 21A. The ground conductor 152 located in the first dielectric layer 11 can shield the electromagnetic waves radiated through the first dielectric layer 11.

[0061] In addition, the conductor 152 electrically connects the ground pattern 21B of the circuit layer 21 and the ground pattern 32B of the second conductor layer 32. Therefore, the conductor 152 and the ground patterns 21B and 32B have the same potential, and thus serve as a ground conductor 152. Since the ground conductor 152 is provided in the hole 151 surrounding the periphery of the transmission path 21A, it functions as an electromagnetic wave shield 150 surrounding the periphery of the transmission path 21A. The ground conductor 152 located in the second dielectric layer 12 can shield electromagnetic waves radiated through the second dielectric layer 12.

[0062] In step S33, cover films 71 and 72 are attached to the surfaces of the first conductor layer 31 and the second conductor layer 32 via adhesives 81 and 82. The cover films 71 and 72 are made of, for example, polyimide, and protect the first conductor layer 31 and the second conductor layer 32. By attaching the cover films 71 and 72, the strength of the high-frequency circuit 10 in which the hole 151 is formed can be ensured.

[0063] Figure 1The plurality of electromagnetic wave shielding members 150 and holes 151 shown are formed in a row around the transmission path 21A, but Figure 6 As shown, it can also be formed to be surrounded by multiple columns. Figure 6 The case where a plurality of electromagnetic wave shielding members 150 and holes 151 are arranged in two rows inside and outside is shown.

[0064] Right now, Figure 6 The electromagnetic wave shield 150 shown includes a first shield 150A provided around the transmission path 21A and a second shield 150B provided on the outer peripheral side of the first shield 150A. Another shield may be provided on the outer peripheral side of the second shield 150B.

[0065] The first shielding member 150A is constituted by having a grounding conductor 152 on the inner surface of a plurality of first holes 151A that continuously penetrate from the first conductor layer 31 to the second conductor layer 32, similarly to the hole 151. The plurality of first holes 151A are long holes similarly to the hole 151, and are sometimes referred to as first long holes herein. The row composed of the plurality of first holes 151A constitutes a first row that is spaced apart in a direction surrounding the periphery of the transmission path 21A. The length dimension L of each of the plurality of first long holes 151A in the direction surrounding the transmission path 21A is greater than the width dimension W similarly to the hole 151.

[0066] The second shielding member 150B is similar to the hole 151, and is configured by having a grounding conductor 152 on the inner surface of a plurality of second holes 151B that continuously penetrate from the first conductor layer 31 to the second conductor layer 32. The plurality of second holes 151B are long holes similar to the hole 151, and are sometimes referred to as second long holes. The row composed of the plurality of second holes 151B constitutes a second row that is spaced apart on the outer peripheral side of the plurality of first long holes 151A in a direction surrounding the periphery of the transmission path 21A. The length dimension L of each of the plurality of second long holes 151B in the direction surrounding the transmission path 21A is greater than the width dimension W similar to the hole 151.

[0067] The second long hole 151B is configured to exist at a position corresponding to the first long hole 151A. That is, the second long hole 151B is configured to block the first long holes 151A from the outer peripheral side of the first long hole 151A. Therefore, the second shielding member 150B composed of the grounded conductor 152 in the second long hole 151B can shield the leakage electromagnetic wave from the first shielding member 150A. Figure 6In the embodiment, the row of the second shielding member 150B as the outer electromagnetic wave shielding member is configured to shield the leakage electromagnetic wave from the row of the first shielding member 150A as the inner electromagnetic wave shielding member. By providing a plurality of rows of electromagnetic wave shielding members 150, the leakage electromagnetic wave can be effectively shielded. In addition, since the first hole 151A and the second hole 151B are long holes, the leakage electromagnetic wave can be effectively shielded even with a small number of rows.

[0068] It should be noted that the embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the above meaning, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0069] Description of Reference Numerals

[0070] 10: high-frequency circuit; 11: first dielectric layer; 12: second dielectric layer; 21: circuit layer; 21A: transmission path; 21B: ground pattern; 21C: hole; 31: first conductor layer; 31C: hole; 31B: ground pattern; 32: second conductor layer; 32A: transmission path; 32B: ground pattern; 32C: hole; 40: via; 41: through hole; 60: adhesive; 71: covering film; 72: covering film; 81: adhesive; 82: adhesive; 100: high-frequency circuit; 101: signal transmission path; 102: shielded via; 150: electromagnetic wave shielding member; 150A: first shielding member; 150B: second shielding member; 151: hole; 151A: first hole, first long hole; 151B: second hole, second long hole; 152: conductor, grounding conductor; L: length dimension; W: width dimension; D: spacing.

Claims

1. A high frequency circuit having: a first dielectric layer; a circuit layer, provided on the first dielectric layer, comprising a first transmission path for high-frequency signals and a ground pattern arranged around the first transmission path; a second dielectric layer, arranged so that the circuit layer is located between the second dielectric layer and the first dielectric layer; a first conductor layer, arranged so that the first dielectric layer is located between the first conductor layer and the circuit layer; a second conductor layer, arranged so that the second dielectric layer is located between the second conductor layer and the circuit layer; as well as an electromagnetic wave shielding member, which is arranged around the first transmission path and surrounds four sides of the first transmission path, The second conductor layer has a second transmission path, The second transmission path is electrically connected to the first transmission path, and the second transmission path is an external connection terminal for the first transmission path. The electromagnetic wave shielding member is formed by providing a ground conductor on the inner surface of a plurality of holes that continuously penetrate the first dielectric layer, the ground pattern, the second dielectric layer, the first conductive layer, and the second conductive layer. The first conductive layer is entirely formed of a first ground pattern except for a first hole that is a part of the plurality of holes. The plurality of holes are a plurality of long holes arranged at intervals in a direction surrounding the first transport path, The length dimension of each of the plurality of long holes in a direction surrounding the first transport path is greater than the width dimension.

2. The high frequency circuit according to claim 1, wherein: The length dimension is greater than 5 times the width dimension.

3. The high frequency circuit according to claim 1 or 2, wherein: The length dimension is greater than the spacing.

4. The high frequency circuit according to claim 3, wherein: The length dimension is greater than 5 times the spacing.

5. The high frequency circuit according to claim 1 or 2, wherein: The ground conductor is formed in a cylindrical shape having an outer peripheral shape corresponding to the inner peripheral shape of the long hole, and at least a portion of the inside of the ground conductor is filled with a dielectric or a conductor.

6. The high frequency circuit according to claim 1 or 2, wherein: The electromagnetic wave shielding member includes at least a first shielding member provided around the first transmission path and a second shielding member provided on the outer peripheral side of the first shielding member. The first shield is formed by providing the ground conductor on the inner surface of a plurality of second holes penetrating the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer. The plurality of second holes are a plurality of first long holes arranged at intervals in a direction surrounding the first transport path. The length dimension of each of the plurality of first long holes along the direction surrounding the first transmission path is greater than the width dimension, The second shield is formed by providing the ground conductor on the inner surface of a plurality of third holes penetrating the first dielectric layer, the ground pattern, the second dielectric layer, the first conductor layer, and the second conductor layer on the outer peripheral side of the plurality of second holes, The plurality of third holes are a plurality of second long holes arranged at intervals in a direction surrounding the first transport path. The length dimension of each of the plurality of second long holes along the direction surrounding the first transmission path is greater than the width dimension, The second shielding member is configured to shield leakage electromagnetic waves from between the plurality of first long holes.

7. The high frequency circuit according to claim 1 or 2, wherein: The high frequency circuit further comprises: The cover film is attached to a surface of at least one of the first conductive layer and the second conductive layer.

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