structure

Abstract

To miniaturize an electromagnetic band gap (EBG) structure.SOLUTION: A structure includes: a first conductive layer provided onto a first surface of a dielectric layer; and a second conductive layer provided to a second surface that is a surface opposite to the first surface of the dielectric layer. The first conductive layer includes: a first wiring part that is a wiring formed in a single cell, and coupling a plurality of points of an outer periphery of the single cell; and a second wiring part that is a wiring extended from the first wiring part so as to be branched. The second wiring part includes: a first branch having two end parts of which one is connected to the first wiring part, and the other is a first open end; and a second branch having two end parts of which one is connected to the first wiring part, and the other is a second open end.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates to structures. [Background technology]

[0002] In digital devices, analog circuits such as RF (Radio frequency) circuits and digital circuits are densely packed together. In densely packed circuits, the operation of the circuits is affected by electromagnetic interference (EMI) caused by unwanted radiation from the digital circuits and noise generated by high-speed switching of transistors in the circuits. As a measure against electromagnetic interference and / or noise in the circuits, the provision of a structure called an electromagnetic band gap (EBG) structure on the circuit board is being considered.

[0003] For example, Patent Document 1 describes a multilayer printed wiring board having a structure in which a first conductor layer and a second conductor layer are provided to sandwich an insulating layer made of an insulator, in which one or more unit cells consisting of floating island-like patch sections and bridge sections connecting these patch sections, or unit cells consisting of only bridge sections, are periodically arranged one or two-dimensionally on the first conductor layer or the second conductor layer, thereby forming an electromagnetic bandgap structure having a stopband in which electromagnetic wave propagation is suppressed in a specific frequency band, and the multilayer printed wiring board is configured so that the stopband can be controlled by the bridge section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-58585 A [Patent Document 2] Patent No. 5516407 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the size of the circuit board is limited, there is room for consideration on miniaturizing the EBG structure.

[0006] Non-limiting embodiments of the present disclosure facilitate providing structures that can be miniaturized. [Means for solving the problem]

[0007] A structure according to one embodiment of the present disclosure has a first conductor layer provided on a first surface of a dielectric layer, and a second conductor layer provided on a second surface of the dielectric layer opposite the first surface, the first conductor layer being formed within a unit cell and having a first wiring portion which is wiring connecting multiple points on the outer periphery of the unit cell, and a second wiring portion which is wiring branching off and extending from the first wiring portion, the second wiring portion having a first branch having two ends, one of which is connected to the first wiring portion and the other of which is a first open end, and a second branch having two ends, one of which is connected to the first wiring portion and the other of which is a second open end.

[0008] In addition, these comprehensive or specific aspects may be realized by a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0009] According to an embodiment of the present disclosure, the structure of the EBG structure can be miniaturized.

[0010] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings, in which such advantages and / or benefits are provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of which are provided to obtain one or more identical features. [Brief description of the drawings]

[0011] [Figure 1A] FIG. 1 is a diagram showing an example of a structure 1 according to an embodiment. [Figure 1B] A cross-sectional view taken along line A-A' of FIG. 1A. [Diagram 2] A diagram showing an example of propagation characteristics and an equivalent circuit [Diagram 3] A diagram showing an example of an equivalent circuit of a unit cell of an EBG structure. [Figure 4] A diagram showing an example of the propagation characteristics of a structure [Diagram 5] FIG. 1 is a diagram showing an example of a structure according to a first variation of an embodiment; [Figure 6] FIG. 1 is a diagram showing an example of a structure according to a second variation of an embodiment; [Figure 7] FIG. 13 is a diagram showing an example of a structure according to a third variation of an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functions are denoted by the same reference numerals, and redundant description will be omitted.

[0013] (One embodiment) An EBG structure has the characteristic of blocking electromagnetic wave propagation of a specific frequency by periodically arranging patterns called "unit cells" on the power layer or ground layer of a multilayer printed circuit board (PCB). Here, the specific frequency at which the EBG structure blocks electromagnetic wave propagation is called the propagation stop band. The bandwidth of the propagation stop band is also called the stop band width.

[0014] Since EBG structures are mounted on circuit boards that have size limitations, it is desirable to miniaturize the EBG structure. However, if the EBG structure is simply made smaller, the frequency at which it operates as a propagation stop band becomes higher and the stop band width becomes narrower.

[0015] For example, Patent Document 1 describes a multilayer printed wiring board having a structure in which a first conductor layer and a second conductor layer are provided to sandwich an insulating layer made of an insulator, in which one or more unit cells consisting of floating island-like patch sections and bridge sections connecting the patch sections, or unit cells consisting of only bridge sections, are periodically arranged one-dimensionally or two-dimensionally on the first conductor layer or the second conductor layer, thereby forming an electromagnetic bandgap structure having a stopband in which electromagnetic wave propagation is suppressed in a specific frequency band, and the multilayer printed wiring board is characterized in that it is configured so that the stopband can be controlled by the bridge section.

[0016] However, in the configuration of Patent Document 1, the patch area, that is, the floating island-like patch portion, requires space, making it difficult to reduce the size.

[0017] For example, Patent Document 2 describes a structure comprising a first conductor, a second conductor having at least a portion facing the first conductor, a plurality of first openings provided in the first conductor, and a plurality of wirings provided in the plurality of first openings and having one end connected to the first conductor, in which unit cells including the first openings and the wirings are repeatedly arranged.

[0018] However, the configuration of Patent Document 2 requires space for the opening, making it difficult to reduce the size.

[0019] In this embodiment, a structure capable of avoiding narrowing of the stopband width and realizing miniaturization will be described.

[0020] Fig. 1A is a diagram showing an example of a structure 1 according to the present embodiment. Fig. 1B is a cross-sectional view taken along line A-A' in Fig. 1A. The structure 1 shown in Figs. 1A and 1B is a unit cell structure of an EBG structure. The outer frame of the structure 1 corresponds to the outer frame of the unit cell.

[0021] The structure 1 has a dielectric layer 11, a first conductor layer 12 formed on one surface of the dielectric layer 11, and a second conductor layer 13 formed on the other surface of the dielectric layer 11. For example, the first conductor layer 12 and the second conductor layer 13 are each a copper foil layer.

[0022] As shown in Fig. 1A, wiring of a copper foil pattern is densely formed on the first conductor layer 12. Note that the wiring shown in Fig. 1A is uniformly formed of the same material (e.g., copper foil), but the display mode of the wiring is changed for convenience of illustration. Also, in Fig. 1A, points P1 to P8 are added to the structure 1 for convenience of illustration.

[0023] The width of the wiring formed in the first conductor layer 12 may be constant, and the distance between adjacent wirings may be constant. For example, when the size of the unit cell is 3 mm×3 mm, the width of the wiring is 0.1 mm, and the distance between adjacent wirings is 0.1 mm.

[0024] The first conductor layer 12 has a first wiring portion 121 and a second wiring portion 122 .

[0025] The first wiring portion 121 is included in the first conductor layer 12, and is a wiring that connects points P1 to P4 that contact the outer frame of the structure 1. The first wiring portion 121 may be called a bridge line portion.

[0026] The second wiring portion 122 is a wiring branched off from point P5 of the first wiring portion 121. The second wiring portion 122 may be referred to as an open stub portion. One end of the second wiring portion 122 is in contact with point P5. The other ends of the second wiring portion 122 are point P6, which is an open end, and point P7, which is also an open end. Point P6 and point P7, which are open ends, may be referred to as open end P6 and open end P7, respectively.

[0027] The second wiring portion 122 has a common portion 123 , a first branch portion 124 , and a second branch portion 125 .

[0028] The common part 123 is the wiring between the point P5 and the point P8.

[0029] The first branch portion 124 is a wiring between the point P8 and the open end P6. The second branch portion 125 is a wiring between the point P8 and the open end P7. An opening 126 may be provided in the area surrounded by the first branch portion 124. The length of the first branch portion 124 may be the same as that of the second branch portion 125.

[0030] A wiring pattern including the common portion 123 and the first branch portion 124 is referred to as a first branch. The first branch corresponds to a wiring that extends from the point P5, passes through the point P8, and reaches the open end P6.

[0031] A wiring pattern including common portion 123 and second branch portion 125 is referred to as a second branch. The second branch corresponds to a wiring extending from point P5, passing through point P8, to open end P7.

[0032] In other words, the second wiring portion 122 has a parallel structure of a first branch and a second branch. When the length of the first branch portion 124 is the same as that of the second branch portion 125, the length of the first branch is the same as that of the second branch.

[0033] In the above-described configuration, the structure 1 can be made compact by connecting the first branch and the second branch to the first wiring portion 121. In addition, the first branch and the second branch are connected to the first wiring portion 121, which makes it possible to prevent the stop bandwidth from becoming narrow.

[0034] 1A and 1B show an example in which the first branch and the second branch have a common portion 123, but the present disclosure is not limited thereto. For example, the first branch and the second branch do not need to have a common portion. In this case, the point at which the first wiring portion 121 and the first branch contact each other may be different from the point at which the first wiring portion 121 and the second branch contact each other.

[0035] Hereinafter, the reason why the structure 1 shown in FIGS. 1A and 1B can be miniaturized will be described.

[0036] Fig. 2 is a diagram showing an example of propagation characteristics and an equivalent circuit. Fig. 2 shows propagation characteristics in which the transmission characteristics are attenuated in a part of a band. The horizontal axis of the propagation characteristics in Fig. 2 indicates frequency, and the vertical axis indicates the amount of attenuation.

[0037] The propagation characteristics in Fig. 2 are divided into three regions A, B, and C, with region B corresponding to the propagation stop band. Fig. 2 also shows an equivalent circuit consisting of a series section and a parallel section for realizing the characteristics of each region.

[0038] As shown by the change from the inductor labeled "1" to the capacitor labeled "2" in Figure 2, the series part switches from inductive to capacitive when switching from region A to region B. Also, as shown by the change from the capacitor labeled "5" to the inductor labeled "6" in Figure 2, the parallel part switches from capacitive to inductive when switching from region B to region C. By shifting the point where the series part switches from inductive to capacitive to a lower frequency and the point where the parallel part switches from capacitive to inductive to a higher frequency, the propagation stop band can be widened.

[0039] Fig. 3 is a diagram showing an example of an equivalent circuit of a unit cell of an EBG structure, which has a parallel part, a series part corresponding to an LC parallel resonant circuit, and an open stub resonant circuit.

[0040] The LC parallel resonant circuit in the series section has a resonant frequency of f r At lower frequencies, the resonant circuit exhibits inductive characteristics at the resonant frequency f r At higher frequencies, it exhibits capacitive characteristics. When it exhibits inductive characteristics, it corresponds to the characteristics of the inductor marked "1" in the series part of the equivalent circuit in Figure 2. When it exhibits capacitive characteristics, it corresponds to the characteristics of the capacitors marked "2" and "3" in the series part of the equivalent circuit in Figure 2.

[0041] In the parallel open stub resonant circuit, the guide wavelength is λ g Then, the open stub length l op is λ g When the open stub length is less than l / 4, the capacitance characteristic is shown. op is λ g When the capacitance is 1 / 4 or more, it shows inductive characteristics. The capacitive characteristics correspond to the capacitors marked with "4" and "5" in the parallel part of the equivalent circuit in Figure 2. The inductive characteristics correspond to the inductor marked with "6" in the parallel part of the equivalent circuit in Figure 2. op When it is set to < (resonant wavelength of the LC parallel resonant circuit / 4), the condition is satisfied.

[0042] Next, in order to lower and widen the propagation stopband, it is desirable to shift the point where region A switches to region B in Figure 2 to a lower frequency, and to shift the point where region B switches to region C in Figure 2 to a higher frequency.

[0043] In FIG. 3, the point at which the region A in FIG. 2 switches to the region B is shifted to a lower frequency by lowering the resonant frequency of the LC parallel resonant circuit. In other words, the inductance of the inductor of the LC parallel resonant circuit is changed to L b and the capacitance of the capacitor is C s Then, the resonant frequency is f r =1 / (2π(L b C s ) 1 / 2 ) so L b and C. s By increasing the value of , the point where the frequency changes from region A to region B in Figure 2 is shifted to a lower frequency.

[0044] In addition, in Fig. 3, the open stub resonant circuit l op By shortening, the point where the transition from region B to region C in Figure 2 is made higher.

[0045] However, when the open stub resonant circuit behaves as a capacitive, the l opBy shortening the length, the capacitance component becomes smaller, so the resonant frequency that is the cutoff frequency in region A does not become lower. Therefore, it becomes difficult to lower the propagation stop band.

[0046] Therefore, in this embodiment, the parallel section has a capacitor component, and the op As a structure for shortening the length, the open stub resonant circuits are arranged in parallel to increase the combined capacitance. For example, as shown in Fig. 1A and Fig. 1B, the second wiring section 122 corresponding to the open stub resonant circuit has a parallel structure of a first branch including a common section 123 and a first branch section 124, and a second branch including the common section 123 and a second branch section 125, thereby increasing the combined capacitance. This structure can lower the propagation stop band and reduce the size.

[0047] Next, the propagation blocking characteristics of the structure according to this embodiment will be described.

[0048] Fig. 4 is a diagram showing an example of the propagation characteristics of the structure 1. The horizontal axis of Fig. 4 indicates the frequency axis, and the vertical axis indicates the amount of attenuation. The greater the amount of attenuation, the more the propagation of the electromagnetic wave is blocked. Note that the propagation characteristics in Fig. 4 show an example of the results of actual measurements on a substrate on which structures 1 are arranged two-dimensionally.

[0049] As shown in Fig. 4, in the case with the structure 1 (with EBG structure in Fig. 4), a propagation stop band is formed between about 1.8 GHz and 2.7 GHz. In addition, in the 2.4 GHz band, there is an attenuation of 20 dB or more compared to the case without the EBG structure (without EBG structure in Fig. 4).

[0050] As described above, the structure 1 according to the present embodiment includes the first conductor layer 12 provided on the first surface of the dielectric layer 11, and the second conductor layer 13 provided on the second surface of the dielectric layer 11, which is the surface opposite to the first surface. The first conductor layer 12 is formed in the unit cell and includes the first wiring portion 121 which is a wiring that connects between a plurality of points (points P1 to P4) on the periphery of the unit cell, and the second wiring portion 122 which is a wiring that branches and extends from the first wiring portion 121. The second wiring portion 122 includes a first branch having two ends, one of which (for example, point P5) is connected to the first wiring portion 121 and the other of which is a first open end (for example, point P6), and a second branch having two ends, one of which (for example, point P5) is connected to the first wiring portion 121 and the other of which is a second open end (for example, point P7). With this configuration, the second wiring section 122 corresponding to the open stub resonant circuit has a parallel structure of the first branch and the second branch, thereby increasing the combined capacitance, thereby preventing the rejection bandwidth from narrowing and achieving miniaturization.

[0051] Variations of the structure in this embodiment will be described below.

[0052] Fig. 5 is a diagram showing an example of a structure 2 according to Variation 1 of the present embodiment. The structure 2 shown in Fig. 5 is a unit cell structure of an EBG structure. The outer frame of the structure 2 corresponds to the outer frame of the unit cell. The structure 2 shown in Fig. 5 has narrower wiring widths and spaces between adjacent wirings than the structure 1 shown in Figs. 1A and 1B.

[0053] Structure 2 has a first conductor layer 22 and a dielectric layer 21 on which first conductor layer 22 is provided. Although omitted in Fig. 5, a second conductor layer is provided on the surface of dielectric layer 21 facing first conductor layer 22, similar to structure 1 shown in Fig. 1A and Fig. 1B. For example, first conductor layer 22 and second conductor layer are each a copper foil layer.

[0054] As shown in Fig. 5, wiring of a copper foil pattern is densely formed on the first conductor layer 22. Note that the wiring shown in Fig. 5 is uniformly formed of the same material (e.g., copper foil), but the display mode of the wiring is changed for convenience of illustration. Also, in Fig. 5, points P1 to P8 are added to the structure 2 for convenience of illustration.

[0055] The width of the wiring formed in the first conductor layer 22 may be constant, and the distance between adjacent wirings may be constant. For example, when the size of the unit cell is 3 mm×3 mm, the width of the wiring is 0.05 mm, and the distance between adjacent wirings is 0.05 mm.

[0056] The first conductor layer 22 has a first wiring portion 221 and a second wiring portion 222 .

[0057] The first wiring portion 221 is included in the first conductor layer 22, and is a wiring that connects points P1 to P4 that contact the outer frame of the structure 2. The first wiring portion 221 may be called a bridge line portion.

[0058] The second wiring portion 222 is a wiring branched off from point P5 of the first wiring portion 221. The second wiring portion 222 may be referred to as an open stub portion. One end of the second wiring portion 222 is in contact with point P5. The other ends of the second wiring portion 222 are open ends P6 and P7.

[0059] The second wiring portion 222 has a common portion 223 , a first branch portion 224 , and a second branch portion 225 .

[0060] The common part 223 is the wiring between the point P5 and the point P8.

[0061] The first branch portion 224 is a wiring between the point P8 and the open end P6. The second branch portion 225 is a wiring between the point P8 and the open end P7. An opening 226 may be provided in the area surrounded by the first branch portion 224. The length of the first branch portion 224 may be the same as that of the second branch portion 225.

[0062] A wiring pattern including the common portion 223 and the first branch portion 224 is referred to as a first branch. The first branch corresponds to a wiring that extends from the point P5, passes through the point P8, and reaches the open end P6.

[0063] A wiring pattern including common portion 223 and second branch portion 225 is referred to as a second branch. The second branch corresponds to a wiring extending from point P5, passing through point P8, to open end P7.

[0064] In other words, the second wiring portion 222 has a parallel structure of a first branch and a second branch. When the length of the first branch portion 224 is the same as that of the second branch portion 225, the length of the first branch is the same as that of the second branch.

[0065] In the above-described configuration, the structure 2 can be made smaller by connecting the first branch and the second branch to the first wiring portion 221. In addition, the first branch and the second branch are connected to the first wiring portion 221, which makes it possible to prevent the stop bandwidth from becoming narrow.

[0066] Fig. 6 is a diagram showing an example of a structure 3 according to Variation 2 of the present embodiment. The structure 3 shown in Fig. 6 is a unit cell structure of an EBG structure. The outer frame of the structure 3 corresponds to the outer frame of the unit cell.

[0067] Structure 3 has a first conductor layer 32 and a dielectric layer 31 on which the first conductor layer 32 is provided. Although omitted in Fig. 6, a second conductor layer is provided on the surface of dielectric layer 31 facing first conductor layer 32, similarly to structure 1. For example, first conductor layer 32 and second conductor layer are each a copper foil layer.

[0068] As shown in Fig. 6, wiring of a copper foil pattern is densely formed on the first conductor layer 32. Note that the wiring shown in Fig. 6 is uniformly formed of the same material (e.g., copper foil), but the display mode of the wiring is changed for convenience of illustration. Also, in Fig. 6, points P1 to P8 are added to the structure 3 for convenience of illustration.

[0069] The first conductor layer 32 has a first wiring portion 321 and a second wiring portion 322 .

[0070] The first wiring portion 321 is included in the first conductor layer 32, and is a wiring that connects points P1 to P4 that contact the outer frame of the structure 3. The first wiring portion 221 may be called a bridge line portion.

[0071] The second wiring portion 322 is a wiring branched off from point P5 of the first wiring portion 321. The second wiring portion 322 may be referred to as an open stub portion. One end of the second wiring portion 322 contacts point P5. The other ends of the second wiring portion 322 are open ends P6 and P7.

[0072] The second wiring portion 322 has a common portion 323 , a first branch portion 324 , and a second branch portion 325 .

[0073] The common part 323 is the wiring between the point P5 and the point P8.

[0074] The first branch 324 is a wiring between the point P8 and the open end P6. The second branch 325 is a wiring between the point P8 and the open end P7. The length of the first branch 324 may be the same as that of the second branch 325.

[0075] A wiring pattern including common portion 323 and first branch portion 324 is referred to as a first branch. The first branch corresponds to a wiring extending from point P5, passing through point P8, to open end P6.

[0076] A wiring pattern including common portion 323 and second branch portion 325 is referred to as a second branch. The second branch corresponds to a wiring extending from point P5, passing through point P8, to open end P7.

[0077] In other words, the second wiring portion 322 has a parallel structure of a first branch and a second branch. When the length of the first branch portion 324 is the same as that of the second branch portion 325, the length of the first branch is the same as that of the second branch.

[0078] In the above-described configuration, the structure 3 can be made smaller by connecting the first branch and the second branch to the first wiring portion 321. In addition, the structure 3 can be made smaller by connecting the first branch and the second branch to the first wiring portion 321.

[0079] FIG. 7 is a diagram showing an example of a structure 4 according to Variation 3 of this embodiment. The structure 4 shown in FIG. 7 is a unit cell structure of an EBG structure. The outer frame of the structure 4 corresponds to the outer frame of the unit cell. The width of the wiring and the distance between adjacent wirings in the structure 4 shown in FIG. 7 may be similar to those of the structure 1 shown in FIG. 1A and FIG. 1B. The direction in which the wiring in the structure 4 shown in FIG. 7 extends, the positions at which it bends, the positions at which it branches, etc. are different from those of the structure 1.

[0080] The structure 4 has a first conductor layer 42 and a dielectric layer 41 on which the first conductor layer 42 is provided. Although omitted in Fig. 7, a second conductor layer is provided on the surface of the dielectric layer 41 facing the first conductor layer 42, similar to the structure 1 shown in Figs. 1A and 1B. For example, the first conductor layer 42 and the second conductor layer are each a copper foil layer.

[0081] As shown in Fig. 7, wiring of a copper foil pattern is densely formed in the first conductor layer 42. Note that the wiring shown in Fig. 7 is formed uniformly from the same material (e.g., copper foil), but the display mode of the wiring is changed for convenience of illustration. Also, in Fig. 7, points P1 to P8 are added to the structure 4 for convenience of illustration.

[0082] The width of the wiring formed in the first conductor layer 42 may be constant, and the distance between adjacent wirings may be constant. For example, when the size of the unit cell is 3 mm×3 mm, the width of the wiring is 0.1 mm, and the distance between adjacent wirings is 0.1 mm.

[0083] The first conductor layer 42 has a first wiring portion 421 and a second wiring portion 422 .

[0084] The first wiring portion 421 is included in the first conductor layer 42, and is a wiring that connects points P1 to P4 that contact the outer frame of the structure 4. The first wiring portion 421 may be called a bridge line portion.

[0085] The second wiring portion 422 is a wiring branched off from point P5 of the first wiring portion 421. The second wiring portion 422 may be referred to as an open stub portion. One end of the second wiring portion 422 contacts point P5. The other ends of the second wiring portion 422 are open ends P6 and P7.

[0086] The second wiring portion 422 has a common portion 423 , a first branch portion 424 , and a second branch portion 425 .

[0087] The common part 423 is the wiring between the point P5 and the point P8.

[0088] The first branch portion 424 is a wiring between the point P8 and the open end P6. The second branch portion 425 is a wiring between the point P8 and the open end P7. An opening 426 may be provided in the area surrounded by the first branch portion 424. The length of the first branch portion 424 may be the same as that of the second branch portion 425.

[0089] A wiring pattern including common portion 423 and first branch portion 424 is referred to as a first branch. The first branch corresponds to a wiring extending from point P5, passing through point P8, to open end P6.

[0090] A wiring pattern including common portion 423 and second branch portion 425 is referred to as a second branch. The second branch corresponds to a wiring extending from point P5, passing through point P8, to open end P7.

[0091] In other words, the second wiring portion 422 has a parallel structure of a first branch and a second branch. When the length of the first branch portion 424 is the same as that of the second branch portion 425, the length of the first branch is the same as that of the second branch.

[0092] In the above-described configuration, the structure 4 can be made smaller by connecting the first branch and the second branch to the first wiring portion 421. In addition, the structure 4 can be made smaller by connecting the first branch and the second branch to the first wiring portion 421. This makes it possible to prevent the stop bandwidth from becoming narrow.

[0093] In addition, the size of the structure, the length of the wiring, the width of the wiring, etc. in the structure according to the above-mentioned embodiment and each variation are merely examples, and the present disclosure is not limited thereto. For example, the size of the structure, the length of the wiring, the width of the wiring, etc. may be designed according to a desired propagation stop band.

[0094] For example, the length of each branch may be increased by increasing the length of a common portion included in the structure according to the above-described embodiment and each variation.

[0095] In addition, in the structures according to the above-described embodiment and each variation, an example has been shown in which the second wiring portion corresponding to the open stub portion has a parallel structure of two branches, but the present disclosure is not limited to this. The second wiring portion corresponding to the open stub portion may have a parallel structure of three or more branches.

[0096] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or amended examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure. In addition, the components in the above-mentioned embodiments may be arbitrarily combined within the scope of the disclosure.

[0097] Although specific examples of the present disclosure have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. [Industrial Applicability]

[0098] The present disclosure is suitable for the structure of a circuit board. [Explanation of symbols]

[0099] 1, 2, 3, 4 structure 11, 21, 31, 41 Dielectric layers 12, 22, 32, 42 First conductor layer 13 Second conductor layer 121, 221, 321, 421 First wiring section 122, 222, 322, 422 Second wiring section 123, 223, 323, 423 Common section 124, 224, 324, 424 First branch 125, 225, 325, 425 Second branch 126, 226, 426 openings

Claims

1. a first conductor layer provided on a first surface of the dielectric layer; a second conductor layer provided on a second surface of the dielectric layer opposite to the first surface; having The first conductor layer is a first wiring portion formed in the unit cell and connecting a plurality of points on the periphery of the unit cell; a second wiring portion which is a wiring branched and extending from the first wiring portion; having The second wiring portion includes: a first branch having two ends, one of which is connected to the first wiring portion and the other of which is a first open end; a second branch having two ends, one of which is connected to the first wiring portion and the other of which is a second open end; having structure.

2. The second wiring portion includes: a common portion included in both the first branch and the second branch and extending from a first point connected to the first wiring portion to a second point; Have The structure of claim 1 .

3. the first branch is a wiring extending from the first point through the second point to the first open end, the second branch is a wiring extending from the first point through the second point to the second open end. The structure of claim 2.

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