Antenna module

Abstract

To provide an antenna module with a high electromagnetic wave shielding effect.SOLUTION: An antenna module 1 includes a multilayer wiring substrate 10 having a main surface 10a and a main surface 10b opposite to the main surface 10a, a transmitting antenna 21 and a receiving antenna 22 arranged on the main surface 10a, an RFIC 30 arranged on the main surface 10b, via wiring 41 that penetrates the multilayer wiring substrate 10 in the thickness direction and connects the transmitting antenna 21 and the RFIC 30, via wiring 42 that penetrates the multilayer wiring substrate 10 in the thickness direction and connects the receiving antenna 22 and the RFIC 30, and a plurality of electromagnetic wave absorbers 60 that penetrates at least part of the multilayer wiring substrate 10 in the thickness direction. The plurality of electromagnetic wave absorbers 60 is arranged in a lattice pattern between the via wiring 41 and the via wiring 42 in a plan view of the main surface 10a.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an antenna module.

Background Art

[0002] Patent Document 1 discloses a wireless communication package structure having an integrated antenna for millimeter-wave applications. In the structure disclosed in Patent Document 1, vertical conductive vias are provided in an interface layer disposed between an RFIC (Radio Frequency Integrated Circuit) chip and an antenna layer. The conductive vias are utilized as a shielding structure for high-frequency signals by being grounded.

[0003] Patent Document 2 discloses a circuit board including a millimeter-wave absorber provided inside a multilayer substrate. The millimeter-wave absorber is arranged in a plan view so as to sandwich a feeding line from both sides along the path of the feeding line.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the shielding structure described in Patent Document 1, electromagnetic waves radiated from a feeding line provided in an interface layer may be reflected by the conductive vias and included as noise in the signals transmitted and received by the antenna.

[0006] In addition, there is room for improvement in the arrangement of the millimeter-wave absorber described in Patent Document 2, and effective shielding performance has not been obtained.

[0007] Therefore, the present disclosure provides an antenna module with a high electromagnetic wave shielding effect.

Means for Solving the Problems

[0008] An antenna module according to an aspect of the present disclosure includes a multilayer wiring board having a first main surface and a second main surface on the opposite side of the first main surface, a first antenna and a second antenna disposed on the first main surface, a semiconductor element disposed on the second main surface, a first via wiring that penetrates the multilayer wiring board in the thickness direction and connects the first antenna and the semiconductor element, a second via wiring that penetrates the multilayer wiring board in the thickness direction and connects the second antenna and the semiconductor element, and a plurality of electromagnetic wave absorbers that penetrate at least a part of the multilayer wiring board in the thickness direction, and the plurality of electromagnetic wave absorbers are arranged in a lattice pattern between the first via wiring and the second via wiring in a plan view of the first main surface.

Advantages of the Invention

[0009] According to the present disclosure, an antenna module with a high electromagnetic wave shielding effect can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0011] (Summary of the present disclosure) The antenna module according to the first aspect of the present disclosure includes a multilayer wiring board having a first main surface and a second main surface on the opposite side of the first main surface, a first antenna and a second antenna disposed on the first main surface, a semiconductor element disposed on the second main surface, a first via wiring that penetrates the multilayer wiring board in the thickness direction and connects the first antenna and the semiconductor element, a second via wiring that penetrates the multilayer wiring board in the thickness direction and connects the second antenna and the semiconductor element, and a plurality of electromagnetic wave absorbers that penetrate at least a part of the multilayer wiring board in the thickness direction. The plurality of electromagnetic wave absorbers are arranged in a lattice pattern between the first via wiring and the second via wiring in a plan view of the first main surface.

[0012] Thereby, by resonating (resonating) the plurality of electromagnetic wave absorbers arranged in a lattice pattern electromagnetically, the electromagnetic field coupling between the first antenna and the second antenna can be efficiently suppressed. Therefore, an antenna module with a high electromagnetic wave shielding effect can be provided.

[0013] The antenna module according to the second aspect of the present disclosure is the antenna module according to the first aspect, wherein the electromagnetic wave absorber contains a magnetic material, and the magnetic material contains at least one selected from the group consisting of ε-iron oxide, strontium ferrite, and barium ferrite.

[0014] Thereby, electromagnetic waves in the millimeter wave band can be absorbed by magnetic loss. In this specification, electromagnetic waves in the millimeter wave band mean electromagnetic waves having a wavelength in the range of 1 mm or more and 10 mm or less, or a frequency in the range of 30 GHz or more and 300 GHz or less.

[0015] The antenna module according to the third aspect of the present disclosure is the antenna module according to the second aspect, wherein the electromagnetic wave absorber further includes a dielectric material, and the dielectric material includes at least one selected from the group consisting of titanium black oxide, barium titanate, conductive carbon, and carbon nanotubes.

[0016] Thereby, electromagnetic waves in the millimeter-wave band can be further absorbed by dielectric loss. The absorption efficiency of electromagnetic waves can be enhanced by the combination of magnetic loss and dielectric loss.

[0017] The antenna module according to the fourth aspect of the present disclosure is the antenna module according to any one of the first to third aspects, wherein the plurality of electromagnetic wave absorbers are two square lattices having the same lattice interval from each other, and are arranged at the vertices of each of the two square lattices such that one vertex is located at the center of the other square.

[0018] Thereby, a plurality of electromagnetic wave absorbers can be arranged at a high density and resonated electromagnetically, so that the absorption efficiency of electromagnetic waves can be further enhanced.

[0019] The antenna module according to the fifth aspect of the present disclosure is the antenna module according to any one of the first to fourth aspects, and includes a plurality of metal films provided corresponding to each of the plurality of electromagnetic wave absorbers, and the plurality of metal films include materials different from those of the plurality of electromagnetic wave absorbers.

[0020] Thereby, by reflecting electromagnetic waves by the metal films, leakage of electromagnetic waves can be suppressed, and the absorption efficiency of electromagnetic waves by the plurality of electromagnetic wave absorbers can be enhanced.

[0021] The antenna module according to the sixth aspect of the present disclosure is the antenna module according to the fifth aspect, wherein each of the plurality of metal films covers the corresponding electromagnetic wave absorber in a plan view of the first main surface.

[0022] Thus, by reflecting electromagnetic waves with the metal film, leakage of electromagnetic waves in the thickness direction of the substrate can be suppressed. Therefore, the absorption efficiency of electromagnetic waves by the plurality of electromagnetic wave absorbers can be further enhanced.

[0023] The antenna module according to the seventh aspect of the present disclosure is the antenna module according to the fifth aspect or the sixth aspect, wherein a structure including the metal film and the electromagnetic wave absorber corresponding to the metal film is laminated in two or more layers in the thickness direction of the multilayer wiring substrate.

[0024] Thus, by laminating a structure including a metal film and an electromagnetic wave absorber, the confinement effect of electromagnetic waves in the thickness direction can be enhanced, and the absorption efficiency of electromagnetic waves can be enhanced.

[0025] Hereinafter, embodiments will be specifically described with reference to the drawings.

[0026] Note that all of the embodiments described below show comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0027] Also, each figure is a schematic diagram and is not necessarily drawn precisely. Therefore, for example, the scales in each figure do not necessarily match. Also, in each figure, substantially the same configuration is denoted by the same reference numeral, and overlapping descriptions are omitted or simplified.

[0028] In this specification, terms indicating the relationship between elements such as parallel or perpendicular, terms indicating the shape of elements such as circular or square, and numerical ranges are not expressions representing only strict meanings, but are expressions meaning substantially equivalent ranges, for example, including differences of about several percent.

[0029] In addition, in this specification, the terms "upper" and "lower" do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition, but are used as terms defined by the relative positional relationship based on the stacking order in the stacked structure. Also, the terms "upper" and "lower" are applicable not only when two components are spaced apart from each other and there is another component between the two components, but also when two components are arranged in close contact with each other and the two components are in contact.

[0030] Note that in this specification, the thickness direction of the multilayer wiring board is regarded as the "vertical direction". Specifically, with reference to the multilayer wiring board, the side where the first antenna and the second antenna are arranged, that is, the direction from the second main surface to the first main surface, is the "upper side" or "upward", and the side where the semiconductor element is arranged, that is, the direction from the first main surface to the second main surface, is the "lower side" or "downward".

[0031] In addition, in this specification and the drawings, the x-axis, y-axis, and z-axis represent the three axes of a three-dimensional orthogonal coordinate system. In each embodiment, the z-axis direction is the thickness direction (vertical direction) of the multilayer wiring board.

[0032] In addition, in this specification, ordinal numbers such as "first" and "second" do not mean the number or order of components, unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between the same type of components.

[0033] (Embodiment) [Configuration] First, the outline of the antenna module according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view showing the cross-sectional configuration of the antenna module according to this embodiment.

[0034] As shown in FIG. 1, the antenna module 1 includes a multilayer wiring substrate 10, a transmission antenna 21, a reception antenna 22, an RFIC 30, via wirings 41 and 42, electrode terminals 51 and 52, and a plurality of electromagnetic wave absorbers 60. In FIG. 1, for convenience of illustration, the laminated substrate 11, the transmission antenna 21, the reception antenna 22, and the RFIC 30 are not shaded to represent the cross section.

[0035] The multilayer wiring substrate 10 has main surfaces 10a and 10b. The main surface 10a is an example of a first main surface. The main surface 10b is an example of a second main surface on the opposite side of the first main surface.

[0036] The multilayer wiring substrate 10 includes a laminated substrate 11, an RF substrate 12, and a base material 13.

[0037] The laminated substrate 11 includes a plurality of dielectric layers laminated in the thickness direction (z-axis direction). In FIG. 1, an example in which the laminated substrate 11 includes four dielectric layers 11a, 11b, 11c, and 11d is shown, but the number of dielectric layers included in the laminated substrate 11 is not particularly limited.

[0038] The dielectric layers 11a, 11b, 11c, and 11d are formed using a resin material such as PTFE (polytetrafluoroethylene) or a glass fiber-containing epoxy resin, for example. At least one of the dielectric layers 11a, 11b, 11c, and 11d may be formed with a circuit such as a power supply circuit for the RFIC 30, a digital circuit, an analog circuit for a baseband signal, and / or a wiring pattern mainly containing a conductive material. The conductive material is a metal material containing at least one selected from the group consisting of aluminum, titanium, SUS, copper, brass, silver, gold, and platinum, for example.

[0039] The RF substrate 12 is a substrate for mounting the transmission antenna 21 and the reception antenna 22. The upper surface of the RF substrate 12 (the main surface on the opposite side of the laminated substrate 11) is the main surface 10a of the multilayer wiring substrate 10.

[0040] The substrate 13 is a support substrate for mounting the RFIC 30. The lower surface of the substrate 13 (the main surface on the opposite side to the laminated substrate 11) is the main surface 10b of the multilayer wiring substrate 10.

[0041] As the substrate 13, for example, a circuit board having a structure in which a low dielectric loss dielectric layer and a high conductivity conductor foil are alternately laminated can be used. Thereby, attenuation of high frequency signals can be suppressed. The conductor foil is formed using, for example, a metal material containing at least one selected from the group consisting of aluminum, titanium, SUS, copper, brass, silver, gold, and platinum.

[0042] The transmission antenna 21 is an example of a first antenna disposed on the main surface 10a. The transmission antenna 21 acquires the high frequency transmission signal processed by the RFIC 30 via the via wiring 41 and transmits (radiates) it as an electromagnetic wave in the millimeter wave band. The transmission antenna 21 is realized by a discrete component mounted on the main surface 10a via a conductive member such as an electrode terminal (not shown), but is not limited thereto. The transmission antenna 21 may be a pattern antenna formed by a conductive pattern formed on the main surface 10a.

[0043] The reception antenna 22 is an example of a second antenna disposed on the main surface 10a. The reception antenna 22 receives an electromagnetic wave in the millimeter wave band and outputs it to the RFIC 30 as a high frequency reception signal via the via wiring 42. The reception antenna 22 is realized by a discrete component mounted on the main surface 10a via a conductive member such as an electrode terminal (not shown), but is not limited thereto. The reception antenna 22 may be a pattern antenna formed by a conductive pattern formed on the main surface 10a.

[0044] The RFIC 30 is an example of a semiconductor element disposed on the main surface 10b. The RFIC 30 is a signal processing circuit that processes high frequency transmission signals and high frequency reception signals. The RFIC 30 is mounted on the main surface 10b via electrode terminals 51 and 52.

[0045] The via wiring 41 is an example of a first via wiring that penetrates the multilayer wiring substrate 10 in the thickness direction (z-axis direction) and connects the transmission antenna 21 and the RFIC 30. The via wiring 41 functions, for example, as a part of a power supply line for the transmission antenna 21, and transmits the high-frequency transmission signal processed by the RFIC 30 to the transmission antenna 21. The upper end of the via wiring 41 is connected to the transmission antenna 21, and the lower end of the via wiring 41 is connected to the RFIC 30 via the electrode terminal 51. Note that the electrode terminal 51 is, for example, a bump electrode made of metal, but is not limited thereto. The electrode terminal 51 may not be provided.

[0046] The via wiring 42 is an example of a second via wiring that penetrates the multilayer wiring substrate 10 in the thickness direction (z-axis direction) and connects the reception antenna 22 and the RFIC 30. The via wiring 42 functions, for example, as a part of a power supply line for the reception antenna 22, and transmits the high-frequency reception signal received by the reception antenna 22 to the RFIC 30. The upper end of the via wiring 42 is connected to the reception antenna 22, and the lower end of the via wiring 42 is connected to the RFIC 30 via the electrode terminal 52. Note that the electrode terminal 52 is, for example, a bump electrode made of metal, but is not limited thereto. The electrode terminal 52 may not be provided.

[0047] The via wirings 41 and 42 are each a conductive member mainly composed of metal. Specifically, the via wirings 41 and 42 are formed using a metal material containing at least one selected from the group consisting of gold, silver, copper, aluminum, and iron. The electrode terminals 51 and 52 are conductive members mainly composed of metal. Specifically, the electrode terminals 51 and 52 are formed using a metal material containing at least one selected from the group consisting of gold, silver, copper, aluminum, and iron.

[0048] Note that the via wirings 41 and 42 each penetrate straight through from the main surface 10a to the main surface 10b of the multilayer wiring board 10, but are not limited thereto. That is, the upper end and the lower end of the via wiring 41 may not overlap in a plan view of the main surface 10a. For example, the via wiring 41 may include a plurality of blind vias (and buried vias) and wirings provided on the multilayer wiring board 10. The same applies to the via wiring 42.

[0049] The plurality of electromagnetic wave absorbers 60 penetrate at least a part of the multilayer wiring board 10 in the thickness direction (z-axis direction). The shape of each of the plurality of electromagnetic wave absorbers 60 is columnar or frustum-shaped. Specifically, the columnar shape is a circular column, an elliptical column, or a prismatic shape such as a square column, a hexagonal column, or an octagonal column. The frustum shape is a frustum of a circular cone, a frustum of an elliptical cone, or a frustum of a pyramid such as a frustum of a square pyramid, a frustum of a hexagonal pyramid, or a frustum of an octagonal pyramid. In the case of the frustum shape, the area of the upper end is larger than the area of the lower end, but the reverse may also be true.

[0050] In the present embodiment, the plurality of electromagnetic wave absorbers 60 have the same shape and the same size as each other. In a plan view of the main surface 10a, the plurality of electromagnetic wave absorbers 60 are periodically arranged between the via wiring 41 and the via wiring 42. Specifically, in a plan view of the main surface 10a, the plurality of electromagnetic wave absorbers 60 are arranged in a lattice pattern between the via wiring 41 and the via wiring 42. By being arranged periodically or in a lattice pattern, the plurality of electromagnetic wave absorbers 60 resonate with each other. Thereby, the absorption effect of electromagnetic waves can be enhanced. Specific arrangement examples of the plurality of electromagnetic wave absorbers 60 will be described later.

[0051] In the present embodiment, the plurality of electromagnetic wave absorbers 60 are formed using the same material as each other. Specifically, the plurality of electromagnetic wave absorbers 60 have the same composition as each other. For example, the electromagnetic wave absorber 60 includes a magnetic material. Further, the electromagnetic wave absorber 60 may further include a dielectric material. For example, the electromagnetic wave absorber 60 has a higher relative dielectric constant than the dielectric layers 11a, 11b, 11c, and 11d of the multilayer wiring board 10.

[0052] The magnetic material includes at least one selected from the group consisting of ε-iron oxide, strontium ferrite, and barium ferrite. The dielectric material includes at least one selected from the group consisting of black titanium oxide, barium titanate, conductive carbon, and carbon nanotubes. Note that the material of the electromagnetic wave absorber 60 is not particularly limited as long as it can absorb a desired electromagnetic wave. The electromagnetic wave absorber 60 may include a polymer and / or a dispersant for dispersing the magnetic material and / or the dielectric material, and other additives.

[0053] Also, for example, the relative permittivity of the electromagnetic wave absorber 60 can be 20 or more and 70 or less. Also, for example, the dielectric loss tangent (tanδ) of the electromagnetic wave absorber 60 can be 0.01 or more and 0.1 or less. The relative permeability of the electromagnetic wave absorber 60 can be 1.0 or more and 1.2 or less.

[0054] [Arrangement Example of Electromagnetic Wave Absorber] Subsequently, arrangement examples of a plurality of electromagnetic wave absorbers 60 will be described with reference to FIGS. 2 to 4. FIGS. 2 to 4 are each a plan view showing an example of the arrangement of a plurality of electromagnetic wave absorbers included in the antenna module 1 according to the present embodiment. FIGS. 2 to 4 all represent a plan view of the antenna module 1 as viewed from the main surface 10a, and illustration of configurations other than the electromagnetic wave absorber 60 is omitted. The cross section along the line I-I in each figure corresponds to the cross section shown in FIG. 1. Via wirings 41 and 42 are arranged in the vicinity of both ends of the line I-I, respectively. The broken-line rectangular frames in FIGS. 2 to 4 represent the approximate range in which the plurality of electromagnetic wave absorbers 60 are arranged, and correspond to, for example, the region between the transmission antenna 21 and the reception antenna 22.

[0055] In the example shown in FIG. 2, the plurality of electromagnetic wave absorbers 60 are arranged at the vertices of a square lattice. The plurality of electromagnetic wave absorbers 60 are arranged at equal intervals along each of the x-axis direction and the y-axis direction. Here, 16 electromagnetic wave absorbers 60 are shown, but the number is not particularly limited.

[0056] In the example shown in FIG. 3, a plurality of electromagnetic wave absorbers 60 are arranged at the vertices of two square lattices having the same lattice interval with respect to each other. The two square lattices are arranged such that one vertex is located at the center of the other square. In FIG. 3, 16 electromagnetic wave absorbers 60 arranged at each vertex of one of the two square lattices are shown as electromagnetic wave absorbers 60a, and 9 electromagnetic wave absorbers 60 arranged at the other extended points of the two square lattices are shown as electromagnetic wave absorbers 60b. The 16 electromagnetic wave absorbers 60a are arranged at equal intervals along each of the x-axis direction and the y-axis direction. Also, the 9 electromagnetic wave absorbers 60b are similarly arranged at equal intervals along each of the x-axis direction and the y-axis direction. The interval between adjacent electromagnetic wave absorbers 60a and the interval between adjacent electromagnetic wave absorbers 60b are equal to each other. Here, a total of 25 electromagnetic wave absorbers 60 are shown, but the number is not particularly limited.

[0057] In the example shown in FIG. 4, a plurality of electromagnetic wave absorbers 60 are arranged at the vertices of a regular triangular lattice. The plurality of electromagnetic wave absorbers 60 are arranged at equal intervals along the x-axis direction and the direction inclined by 60° with respect to the x-axis direction, respectively. Here, 18 electromagnetic wave absorbers 60 are shown, but the number is not particularly limited.

[0058] In FIGS. 2 to 4, let the arrangement interval (lattice interval) of the electromagnetic wave absorbers 60 be L. The arrangement interval corresponds to the center-to-center distance between two adjacent electromagnetic wave absorbers 60 in a plan view. Also, let the frequency of the electromagnetic wave to be absorbed by the electromagnetic wave absorber 60 be f. Let the relative permittivity of the electromagnetic wave absorber 60 be ε r Let c0 be the speed of light, that is, the speed of the electromagnetic wave. n is an integer. At this time, the electromagnetic wave absorbers 60 are arranged so as to satisfy the following formula (1).

[0059]

Equation

[0060] Note that the frequency f of the electromagnetic wave to be absorbed by the electromagnetic wave absorber 60 is, for example, the frequency of the high-frequency transmission signal transmitted from the transmission antenna 21. In the present embodiment, since electromagnetic waves in the millimeter-wave band are used, the frequency f is in the range of 30 GHz or more and 300 GHz or less.

[0061] In the present embodiment, in the region between the via wiring 41 and the via wiring 42, the electric field of unnecessary electromagnetic waves tends to concentrate at the vertices of the lattice. Therefore, by arranging a plurality of electromagnetic wave absorbers 60 in a lattice pattern (periodically), the concentrated magnetic field (electromagnetic wave) can be efficiently absorbed by the magnetic material contained in the electromagnetic wave absorber 60a. By using a magnetic material such as ε-iron oxide that has high absorption efficiency for electromagnetic waves in the millimeter-wave band, the absorption efficiency of electromagnetic waves can be increased.

[0062] Note that the arrangement interval L does not necessarily have to satisfy the formula (1). For example, the arrangement interval L may be in the range within ±10% of the right side of the formula (1). Even in this case, high absorption efficiency of electromagnetic waves can be obtained.

[0063] Also, according to the example shown in FIG. 3, more electromagnetic wave absorbers 60 can be arranged within the same range compared to the example shown in FIG. 2. In this case, even if the relative permittivity of each electromagnetic wave absorber 60 is reduced, high absorption efficiency of electromagnetic waves can be maintained. Therefore, the range of selection of the dielectric material contained in the electromagnetic wave absorber 60 is widened, and the degree of freedom in material design is increased.

[0064] When the electromagnetic wave absorber 60 is cylindrical, its diameter in plan view is, for example, 200 μm or more. Thereby, the relative permittivity can be made 70 or less. Also, the diameter in plan view is, for example, 1000 μm or less. Thereby, an increase in the size of the multilayer wiring substrate 10 can be suppressed. When the electromagnetic wave absorber 60 has a shape other than cylindrical, the size can be adjusted so that the bottom area is equal to the area in the case of a cylinder.

[0065] [Modification Example] Next, a modification of the embodiment will be described with reference to FIG. 5.

[0066] FIG. 5 is a cross-sectional view showing a modification of a plurality of electromagnetic wave absorbers included in the antenna module according to the present embodiment. FIG. 5 corresponds to a view obtained by enlarging the region between via wiring 41 and via wiring 42 in the cross-section of FIG. 1. In FIG. 5, the illustration of the configuration other than the electromagnetic wave absorber 61, the metal film 62, and the dielectric layers 11a, 11b, and 11c is omitted.

[0067] As shown in FIG. 5, the antenna module includes a plurality of metal films 62 provided corresponding to each of the plurality of electromagnetic wave absorbers 61. Note that the electromagnetic wave absorber 61 has an inverted trapezoidal cross-sectional shape and is the same as the electromagnetic wave absorber 60 except that it penetrates only one dielectric layer. That is, the plurality of electromagnetic wave absorbers 61 according to this modification are also arranged in a lattice pattern in a plan view of the main surface 10a.

[0068] The plurality of metal films 62 contain a material different from that of the plurality of electromagnetic wave absorbers 61. Specifically, the plurality of metal films 62 are formed using a metal material containing at least one selected from the group consisting of gold, silver, copper, aluminum, and iron, for example. The plurality of metal films 62 can reflect electromagnetic waves.

[0069] In this modification, the plurality of metal films 62 cover the corresponding electromagnetic wave absorbers 61 in a plan view of the main surface 10a. Specifically, the metal films 62 are provided so as to completely cover the upper surface and the lower surface of the electromagnetic wave absorber 61, respectively. Further, the structure including the metal film 62 and the corresponding electromagnetic wave absorber 61 is laminated two or more times in the thickness direction (z-axis direction) of the multilayer wiring substrate 10.

[0070] In this way, by reflecting electromagnetic waves with the metal film 62, leakage of electromagnetic waves in the z-axis direction can be suppressed. Therefore, the absorption efficiency of electromagnetic waves by the plurality of electromagnetic wave absorbers 61 can be enhanced. Further, by laminating the structure including the metal film 62 and the electromagnetic wave absorber 61, the confinement effect of electromagnetic waves in the z-axis direction can be enhanced, and the absorption efficiency of electromagnetic waves can be enhanced.

[0071] Note that in this modification example, an example in which the electromagnetic wave absorber 61 is provided for each dielectric layer is shown, but it is not limited thereto. The electromagnetic wave absorber 61 may continuously penetrate two or more dielectric layers. Further, the structure including the metal film 62 and the electromagnetic wave absorber 61 may not be laminated in the z-axis direction. For example, as shown in FIG. 1, the metal film 62 may be provided so as to cover the upper surface and / or the lower surface of the electromagnetic wave absorber 60 that penetrates from the main surface 10a to the main surface 10b. The metal film 62 covers the entire upper surface or lower surface of the electromagnetic wave absorber 60 or 61, but may cover only a part thereof.

[0072] (Other embodiments) As described above, the antenna module according to one or more aspects has been described based on the embodiments, but the present disclosure is not limited to these embodiments. As long as the gist of the present disclosure is not deviated from, various modifications conceived by those skilled in the art applied to these embodiments, and forms constructed by combining components in different embodiments are also included in the scope of the present disclosure.

[0073] For example, in the above embodiment, an example was shown in which the transmission antenna 21 and the reception antenna 22 transmit and receive millimeter-wave electromagnetic waves, and the electromagnetic wave absorber 60 absorbs millimeter-wave electromagnetic waves, but the present invention is not limited to this. For example, the transmission antenna 21 and the reception antenna 22 may transmit and receive sub-millimeter-wave electromagnetic waves or terahertz waves, and the electromagnetic wave absorber 60 may absorb sub-millimeter-wave electromagnetic waves or terahertz waves. The sub-millimeter-wave electromagnetic waves mean electromagnetic waves with a wavelength in the range of 0.1 mm or more and 1 mm or less, or a frequency in the range of 300 GHz or more and 3 THz or less. Terahertz waves mean electromagnetic waves with a wavelength in the range of 30 μm or more and 3 mm or less, or a frequency in the range of 100 GHz or more and 10 THz or less. Alternatively, the transmission antenna 21 and the reception antenna 22 may transmit and receive microwave electromagnetic waves, and the electromagnetic wave absorber 60 may absorb microwave electromagnetic waves. Microwave electromagnetic waves mean electromagnetic waves with a wavelength in the range of 1 mm or more and 1 m or less, or a frequency in the range of 300 MHz or more and 300 GHz or less.

[0074] In the above embodiment, an example was shown in which the transmission antenna 21 and the reception antenna 22 are connected to one RFIC 30, but the present invention is not limited to this. For example, the antenna module 1 may include a plurality of RFICs. One of the plurality of RFICs may be connected to the transmission antenna 21, and another one of the plurality of RFICs may be connected to the reception antenna 22.

[0075] In the above embodiment, as an example of the arrangement of the plurality of electromagnetic wave absorbers 60, one or two square lattices, or a regular triangular lattice were shown, but the present invention is not limited to this. For example, an oblique lattice, a rhombic lattice, a centered rectangular lattice, an isosceles triangular lattice, a rectangular lattice, a parallelepiped lattice, etc. may be used. That is, the interval between adjacent electromagnetic wave absorbers 60 in the x-axis direction and the interval between adjacent electromagnetic wave absorbers 60 in the y-axis direction may be different. Also, the arrangement direction of the electromagnetic wave absorbers 60 may be the x-axis direction or a direction inclined at an arbitrary angle with respect to the x-axis direction.

[0076] Further, for example, the plurality of electromagnetic wave absorbers 60 may include electromagnetic wave absorbers having different sizes, different shapes, and different compositions. For example, in the example shown in FIG. 3, the electromagnetic wave absorber 60a and the electromagnetic wave absorber 60b may have different sizes, shapes, or compositions.

[0077] Also, in each of the above embodiments, various changes, replacements, additions, omissions, etc. can be made within the scope of the claims or the equivalent scope thereof.

Industrial Applicability

[0078] The present disclosure can be used as an antenna module having a high electromagnetic wave shielding effect, and can be used, for example, in various communication devices such as communication devices such as mobile phones or base stations, and communication systems.

Explanation of Signs

[0079] 1 Antenna module 10 Multilayer wiring board 10a, 10b Main surfaces 11 Stacked substrate 11a, 11b, 11c, 11d Dielectric layers 12 RF substrate 13 Base material 21 Transmission antenna 22 Reception antenna 30 RFIC 41, 42 Via wiring 51, 52 Electrode terminals 60, 60a, 60b, 61 Electromagnetic wave absorbers 62 Metal film

Claims

1. A multilayer wiring board having a first main surface and a second main surface opposite to the first main surface, a first antenna and a second antenna disposed on the first main surface, a semiconductor element disposed on the second main surface, a first via wiring that penetrates the multilayer wiring board in the thickness direction and connects the first antenna and the semiconductor element, a second via wiring that penetrates the multilayer wiring board in the thickness direction and connects the second antenna and the semiconductor element, a plurality of electromagnetic wave absorbers that penetrate at least a part of the multilayer wiring board in the thickness direction, and the plurality of electromagnetic wave absorbers are arranged in a lattice pattern between the first via wiring and the second via wiring in a plan view of the first main surface, an antenna module.

2. The electromagnetic wave absorber contains a magnetic material, the magnetic material contains at least one selected from the group consisting of ε-iron oxide, strontium ferrite, and barium ferrite, The antenna module according to claim 1.

3. The electromagnetic wave absorber further contains a dielectric material, the dielectric material contains at least one selected from the group consisting of black titanium oxide, barium titanate, conductive carbon, and carbon nanotubes, The antenna module according to claim 2.

4. The plurality of electromagnetic wave absorbers are two square lattices having the same lattice interval with respect to each other, and are arranged at the vertices of each of the two square lattices such that one vertex is located at the center of the other square, The antenna module according to any one of claims 1 to 3.

5. A plurality of metal films provided corresponding to each of the plurality of electromagnetic wave absorbers, the plurality of metal films contain materials different from those of the plurality of electromagnetic wave absorbers, The antenna module according to any one of claims 1 to 3.

6. Each of the plurality of metal films covers the corresponding electromagnetic wave absorber in a plan view of the first main surface, The antenna module according to claim 5.

7. Structures including the metal film and the electromagnetic wave absorber corresponding to the metal film are laminated two or more times in the thickness direction of the multilayer wiring board, The antenna module according to claim 6.

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