Millimeter wave radio communication device

Abstract

The present invention provides a millimeter wave radio communication device that can be fabricated easily.　The millimeter wave radio communication device includes a first power feed circuit layer, an antenna layer, and a bonding part. The first power feed circuit layer includes: a first substrate made of glass or ceramic and having a first surface and a second surface; a metal layer provided on the second surface and having a first opening; and a first transmission line formed from a microstrip line, strip line, coplanar line, slot line, or post-wall waveguide formed on the first substrate. The antenna layer includes: a second substrate made of resin or glass and having a third surface and a fourth surface; and an antenna element which is formed on the fourth surface and which communicates in the millimeter-wave band. The bonding part bonds the metal layer provided on the second surface of the first substrate of the first power feed circuit layer and the third surface of the second substrate of the antenna layer. The first opening and the antenna element are electrically coupled such that power can be fed from the first transmission line to the antenna element through the first opening.

Description

Millimeter-wave wireless communication device

[0001] The present disclosure relates to a millimeter wave wireless communication device.

[0002] Conventionally, there has been a technique for fabricating a millimeter wave antenna by forming a copper layer on each of a plurality of glass wafers by physical vapor deposition (PVD) and plating, and then bonding the glass wafers together by thermocompression bonding (TCB) (see, for example, Non-Patent Document 1).

[0003] A W-Band Corporate-Fed Hollow-Waveguide Slot Array Antenna by Glass Micromachining, Yaxiang Wu, Tian Yu, Miao Zhang, Daquan Yu, Jiro Hirokawa, Qing Huo Liu, Proceedings of ISAP2020, Osaka, Japan

[0004] Incidentally, millimeter wave antennas, which are fabricated by bonding together multiple glass wafers as described above, are difficult to fabricate and are therefore not suitable for mass production.

[0005] Therefore, an object of the present invention is to provide a millimeter wave wireless communication device that can be easily manufactured.

[0006] a first feed circuit layer having a metal layer provided on the second surface and having a first opening, and a first transmission line formed on the first substrate, the first transmission line being a microstrip line, a strip line, a coplanar line, a slot line, or a post-wall waveguide; a second substrate having a third surface and a fourth surface and made of resin or glass; an antenna layer having an antenna element formed on the fourth surface and communicating in the millimeter wave band; and an adhesive portion that bonds the metal layer provided on the second surface of the first substrate of the first feed circuit layer to the third surface of the second substrate of the antenna layer, wherein the first opening and the antenna element are electrically coupled, and power can be supplied to the antenna element from the first transmission line through the first opening.

[0007] It is possible to provide a millimeter wave wireless communication device that can be easily manufactured.

[0008] 3A is a diagram showing an example of an exploded state of the millimeter-wave wireless communication device 100 of the embodiment. FIG. 3B is a diagram showing an example of a cross-sectional configuration of the millimeter-wave wireless communication device 100. FIG. 3C is a diagram showing an example of an actual millimeter-wave wireless communication device 100. FIG. 3D is an enlarged view of the millimeter-wave wireless communication device 100 shown in FIG. 3A. FIG. 3D is a diagram showing an example of the frequency characteristic of the S11 parameter. FIG. 3E is a diagram showing an example of the frequency characteristic of the maximum gain. FIG. 3F is a diagram showing an example of the frequency characteristic of the efficiency and the antenna efficiency. FIG. 3G is a diagram showing an example of the configuration of a cavity 110B provided in a feed circuit layer 110. FIG. 3H is a diagram showing an example of the cross-sectional configuration of a millimeter-wave wireless communication device 100M1 of a first modified example of the embodiment. FIG. 3I is a diagram showing an example of an exploded state of a millimeter-wave wireless communication device 100M2 of a second modified example of the embodiment. FIG. 3I is a diagram showing an example of the cross-sectional configuration of a millimeter-wave wireless communication device 100M2 of the second modified example. FIG. 3I is a diagram showing an example of the cross-sectional configuration of a millimeter-wave wireless communication device 100M2 of another form of the second modified example. FIG. 3I is a diagram showing an example of the cross-sectional configuration of a millimeter-wave wireless communication device 100M3 of a third modified example of the embodiment.

[0009] Hereinafter, embodiments to which the millimeter wave wireless communication device of the present disclosure is applied will be described. In the following, the same elements will be given the same reference numerals, and duplicated descriptions may be omitted.

[0010] In the following description, the XYZ coordinate system is defined. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to each other. For ease of explanation, the -Z direction side may be referred to as the lower side or bottom, and the +Z direction side as the upper side or top, but this does not represent a universal vertical relationship. Furthermore, a planar view refers to a view from an XY plane.

[0011] In the following description, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand. Furthermore, terms such as parallel, right angle, orthogonal, horizontal, vertical, up and down, etc., are permitted to be deviated to the extent that the effect of the embodiment is not impaired.

[0012] In the following description, "radio waves" refers to a type of electromagnetic wave, and generally, electromagnetic waves below 3 THz are called radio waves. In the following, electromagnetic waves emitted from outdoor base stations or relay stations will be called "radio waves," and electromagnetic waves in general will be called "electromagnetic waves." In the following, "millimeter waves" or "millimeter wave band" will refer to the frequency band of 30 GHz to 300 GHz.

[0013] The frequency (communication frequency) of radio waves transmitted or received by the millimeter wave wireless communication device of the embodiment is preferably 30 GHz or higher and 300 GHz or lower, for example. Such a frequency band is higher than the 1 GHz to 30 GHz frequency band including the millimeter wave band and Sub-6 of the fifth generation mobile communication system (5G), and may be adopted for fixed stations, integrated access and backhaul (IAB), wireless backhaul / wireless fronthaul, fixed wireless access (FWA), etc., as well as communication systems of the next generation after the fifth generation mobile communication system (5G).

[0014] Furthermore, the radio waves transmitted or received by the millimeter wave wireless communication device of the embodiment may be the millimeter wave band of the fifth generation mobile communication system (5G), Sub-6, LTE (Long Term Evolution), LTE-A (LTE-Advanced), or UMB (Ultra Mobile Broadband). Furthermore, the radio waves transmitted or received by the millimeter wave wireless communication device of the embodiment may be IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-Wideband), Bluetooth (registered trademark), or LPWA (Low Power Wide Area), etc. In the following, unless otherwise specified, radio waves of 30 GHz or more and 300 GHz or less will be used as an example for explanation.

[0015] <Embodiment> Fig. 1 is a diagram showing an example of an exploded state of a millimeter wave wireless communication device 100 according to an embodiment. Fig. 2 is a diagram showing an example of a cross-sectional configuration of the millimeter wave wireless communication device 100. The cross section shown in Fig. 2 corresponds to the cross section seen from the arrow A-A in Fig. 1 when the millimeter wave wireless communication device 100 is assembled. Fig. 2 shows an enlarged view of a portion of the entire millimeter wave wireless communication device 100 that corresponds to two antenna elements 132.

[0016] <Millimeter-wave wireless communication device 100> The millimeter-wave wireless communication device 100 includes a feed circuit layer 110, an adhesive layer 120, and an antenna layer 130. The feed circuit layer 110 is an example of a first feed circuit layer. The adhesive layer 120 is an example of an adhesive portion. The millimeter-wave wireless communication device 100 may be even larger in the X and Y directions.

[0017] The millimeter wave wireless communication device 100 is, for example, a device capable of beamforming by using a phase shifter (not shown) to adjust the phase of millimeter wave band radio waves transmitted and received by the multiple antenna elements 132 of the antenna layer 130 as a phased array antenna. The millimeter wave band is, for example, a band between 30 GHz and 300 GHz.

[0018] Before describing the detailed configuration of the millimeter wave wireless communication device 100, the background of problems that arise when wireless communication is performed using millimeter wave radio waves in the 30 GHz to 300 GHz frequency band will be described. Here, a millimeter wave wireless communication device that is not included in the embodiments will be used for the description. The millimeter wave wireless communication device that is not included in the embodiments has a phased array antenna composed of multiple antenna elements.

[0019] <Background of wireless communication using millimeter-wave band radio waves> When wireless communication is performed using millimeter-wave band radio waves, which fall within the frequency band of 30 GHz to 300 GHz, signal loss in RF (Radio Frequency) circuits such as transmission lines connected to the antenna element becomes very large, so it is desirable to position the antenna element and the RF circuit very close to each other and integrate them into one unit.

[0020] In a phased array antenna, integrating an RF circuit with multiple antenna elements is necessary to improve the performance of millimeter-wave wireless communication devices, but signal loss occurs at the connection between the antenna elements and the RF circuit, resulting in a decrease in communication performance. Furthermore, while integrating the RF circuit with the antenna elements is expected to improve communication performance, the wavelength in free space is 3 mm or less, particularly in high-frequency bands above 100 GHz, making implementation extremely difficult.

[0021] In a phased array antenna, the connection structure between an antenna layer having multiple antenna elements and a power supply circuit layer that supplies power to the multiple antenna elements is an important factor that directly affects communication performance. Conventionally, connection structures using vias or through holes have been used to transmit signals in frequency bands lower than the millimeter wave band, but parasitic inductance and capacitance make this difficult to apply, especially in high-frequency bands above 100 GHz.

[0022] In connection structures using vias or through holes, metal cylindrical components that penetrate the antenna layer and the power supply circuit layer are used, which creates parasitic inductance and parasitic capacitance between the antenna layer and the power supply circuit layer. These parasitic components have a significant impact on impedance matching between the antenna layer and the power supply circuit layer, potentially degrading communication performance. This problem becomes more pronounced as the frequency increases.

[0023] To address these issues, a connection structure using a slot and electromagnetic coupling has been proposed as a connection structure between the antenna layer and the feed circuit layer. A connection structure using a slot utilizes electromagnetic coupling without using vias or through holes, so that desired impedance matching can be achieved by the shape of the slot and the antenna element, even when handling radio waves in the millimeter wave band.

[0024] However, in a connection structure using a slot, the large difference in relative permittivity between the feed circuit layer and the antenna layer can cause reflection, which can lead to reflection loss and reduced communication performance. Reflection loss occurs due to the large difference in relative permittivity between the feed circuit layer and the antenna layer, causing part of the power input to the antenna element to be reflected back toward the feed circuit layer, resulting in problems such as reduced efficiency and directivity of the antenna element.

[0025] <Overview of Millimeter-Wave Wireless Communication Device 100> In order to address the problem of impedance matching between the antenna layer and the feed circuit layer against the background described above, the millimeter-wave wireless communication device 100 of the embodiment employs, as an example, a configuration in which power is fed to the antenna element 132 of the antenna layer 130 using the slot 115 of the feed circuit layer 110. Note that impedance matching can also be achieved using a configuration other than the slot 115, and such a configuration will be described later with reference to FIG.

[0026] Furthermore, in order to address the problem of reflection loss in the above-described background, the millimeter-wave wireless communication device 100 of the embodiment employs a structure in which the feed circuit layer 110 and the antenna layer 130 are bonded together with an adhesive layer 120 in order to easily realize a connection structure between the feed circuit layer 110 and the antenna layer 130, which have a small difference in relative dielectric constant. Each component of the millimeter-wave wireless communication device 100 will now be described.

[0027] <Feed Circuit Layer 110> The feed circuit layer 110 has a substrate 111, metal layers 112 and 113, vias 114, and slots 115. The feed circuit layer 110 also has a transmission path for transmitting millimeter-wave radio waves. The transmission path of the feed circuit layer 110 is an example of a first transmission path.

[0028] Substrate 111 is an example of a first substrate. The bottom surface of substrate 111 is an example of a first surface, and the top surface of substrate 111 is an example of a second surface. Slot 115 is an example of a first opening. Metal layer 113 is an example of a metal layer provided on the second surface and having a first opening.

[0029] Here, a configuration will be described in which the transmission line of the feed circuit layer 110 is a post-wall waveguide 110A, as an example. The post-wall waveguide 110A is composed of a substrate 111, metal layers 112 and 113, and vias 114. A plurality of vias 114 are arranged in the Y direction at the positions of the four vias 114 shown in Fig. 2, and the post-wall waveguide 110A is provided in the area surrounded by the metal layers 112, 113, and vias 114. Fig. 2 shows cross sections of two post-wall waveguides 110A. The post-wall waveguide 110A extends in the Y direction, as an example, in the cross section of the millimeter-wave wireless communication device 100 shown in Fig. 2, but may also have a portion extending in the X direction.

[0030] The transmission line of the feed circuit layer 110 is not limited to the post-wall waveguide 110A, but may be a microstrip line, a strip line, a coplanar line, or a slot line.

[0031] <Substrate 111> The substrate 111 is provided with a transmission path for the feed circuit layer 110, and is therefore made of a material with low loss of millimeter-wave band radio waves, such as glass or ceramic. Examples of such materials with low loss of millimeter-wave band radio waves include quartz glass and LTCC (low-temperature co-fired ceramics). The relative dielectric constant of the substrate 111 is greater than the relative dielectric constant of the substrate 131 of the antenna layer 130. The linear expansion coefficient of the substrate 111 is smaller than the linear expansion coefficient of the substrate 131. Details of the relative dielectric constants and linear expansion coefficients of the substrates 111 and 131 will be described later.

[0032] <Metal Layer 112> The metal layer 112 is provided on the lower surface of the substrate 111 and is maintained at ground potential (reference potential). The metal layer 112 is, for example, a copper foil or an aluminum foil, and may be formed on the lower surface of the substrate 111 by vapor deposition or the like.

[0033] <Metal Layer 113> The metal layer 113 is provided on the upper surface of the substrate 111 and is maintained at ground potential (reference potential). A slot 115 is formed in the metal layer 113. The metal layer 113 is, for example, a copper foil or an aluminum foil, and may be formed on the upper surface of the substrate 111 by vapor deposition or the like. The metal layer 113 may be formed of, for example, the same metal as the metal layer 112.

[0034] <Via 114> The via 114 is formed inside a through hole that penetrates the substrate 111 in the Z direction. The via 114 can be formed, for example, from copper or aluminum, and for example, from the same metal as the metal layers 112 and 113. For example, the via 114 can be formed by creating a through hole that penetrates the substrate 111 in the Z direction by laser processing or the like before forming the metal layers 112 and 113 on the substrate 111, and then filling the through hole with metal by plating or the like. The lower end and upper end of the via 114 are connected to the metal layers 112 and 113, respectively.

[0035] The vias 114 form the side walls of the post-wall waveguide 110A, for example, and may be formed on both sides of the post-wall waveguide 110A at appropriate intervals along the extension direction of the post-wall waveguide 110A to prevent leakage of millimeter waves. In the cross section shown in Figure 2, one post-wall waveguide 110A is provided between the first and second vias 114 from the -X direction side, and another post-wall waveguide 110A is provided between the third and fourth vias 114 from the -X direction side.

[0036] <Slots 115> The slots 115 are provided in the metal layer 113. One slot 115 is provided corresponding to each antenna element 132 of the antenna layer 130. Note that the antenna layer 130 is required to have at least one antenna element 132, and therefore, when there is one antenna element 132, the feed circuit layer 110 may have one slot 115.

[0037] The shape of the slot 115 in a plan view may be, for example, rectangular, circular, elliptical, or cross-shaped. The slot 115 is provided at a position overlapping with each antenna element 132 of the antenna layer 130 in a plan view. The slot 115 may be located inside the outer edge of the antenna element 132 in a plan view, or at least a portion of the slot 115 may be located inside the outer edge of the antenna element 132. Here, as an example, the shape of the slot 115 in a plan view is assumed to be rectangular, with the longitudinal direction extending in the Y direction.

[0038] The slot 115 is electromagnetically coupled to the antenna element 132. When the antenna element 132 transmits radio waves, the slot 115 transmits the radio waves propagating through the post-wall waveguide 110A in the +Z direction and functions as a slot antenna, thereby feeding power to the antenna element 132. When the antenna element 132 receives radio waves, the slot 115 feeds the radio waves fed from the antenna element 132 into the interior of the post-wall waveguide 110A.

[0039] When a microstrip line, a strip line, a coplanar line, or a slot line is used as a transmission line instead of the post-wall waveguide 110A, the following procedure can be adopted.

[0040] In the case of a microstrip line, for example, metal layer 113 is held at ground potential, and a signal transmission wiring is provided on metal layer 112 so that the tip of the wiring overlaps slot 115 in plan view. The tip of the wiring and slot 115 are electromagnetically coupled, allowing power to be supplied from the wiring to slot 115.

[0041] In the case of a strip line, the metal layers 112 and 113 are held at ground potential, and a signal transmission wiring is provided between the metal layers 112 and 113 so that the tip of the wiring overlaps the slot 115 in a plan view. The tip of the wiring and the slot 115 are electromagnetically coupled, allowing power to be supplied from the wiring to the slot 115.

[0042] In the case of a coplanar line, the coplanar line is provided on the metal layer 112 so that the tip of the signal transmission wiring of the coplanar line overlaps the slot 115 in a plan view. The tip of the wiring and the slot 115 are electromagnetically coupled, allowing power to be supplied from the wiring to the slot 115.

[0043] In the case of a slot line, a slot is provided in the metal layer 112 so that the tip of the slot overlaps the slot 115 in a plan view. The tip of the slot and the slot 115 are electromagnetically coupled, allowing power to be fed from the wiring to the slot 115.

[0044] <Adhesive Layer 120> The adhesive layer 120 bonds the power supply circuit layer 110 and the antenna layer 130. A resin adhesive layer or a conductive adhesive layer can be used as the adhesive layer 120, but here, as an example, a form in which the adhesive layer 120 is formed of a resin adhesive layer will be described. Note that an adhesive layer 120M1 formed of a conductive adhesive layer will be described later with reference to FIG. 7 .

[0045] The relative dielectric constant of the adhesive layer 120 may be equal to or less than the relative dielectric constant of the substrate 111. The relative dielectric constant of the adhesive layer 120 is preferably greater than the relative dielectric constant of the substrate 131 and smaller than the relative dielectric constant of the substrate 111. Details of the relative dielectric constant of the adhesive layer 120 will be described later.

[0046] Examples of resin adhesive layers that can be used as adhesive layer 120 include thermoplastic resins, thermosetting resins, bonding sheets that do not contain conductors, prepregs, adhesive resins that contain resin films, and liquid adhesives.

[0047] The adhesive layer 120 bonds the feed circuit layer 110 and the antenna layer 130, which are formed separately. The millimeter-wave wireless communication device 100 can be fabricated simply by bonding the feed circuit layer 110 and the antenna layer 130 together with the adhesive layer 120. This eliminates the need for a conventional process in which copper layers are formed on both sides of multiple glass wafers by physical vapor deposition (PVD) and plating, and then the multiple glass wafers are bonded together by solid-state diffusion bonding such as thermocompression bonding (TCB).

[0048] <Antenna Layer 130> The antenna layer 130 has a substrate 131 and an antenna element 132. The substrate 131 is an example of a second substrate. The lower surface of the substrate 131 is an example of a third surface, and the upper surface of the substrate 131 is an example of a fourth surface, and as shown in FIG. 1 , for example, a plurality of antenna elements 132 are provided on the substrate 131.

[0049] <Substrate 131> As an example, the substrate 131 is a substrate that has the same size and shape in a planar view as the substrate 111 of the power feed circuit layer 110. However, the size and shape of the substrate 131 do not have to be the same as the size and shape of the substrate 111 in a planar view.

[0050] The substrate 131 is, for example, a resin or glass substrate having a dielectric constant lower than that of the substrate 111 of the feed circuit layer 110 and exhibiting low loss of millimeter-wave radio waves. Examples of such resin materials include thermoplastic resins or thermosetting resins, which have low dielectric constants and exhibit low loss of millimeter-wave radio waves. Examples of such glass materials include quartz glass or porous quartz glass, which have low dielectric constants and exhibit low loss of millimeter-wave radio waves. Composite substrates formed by laminating or mixing multiple resin materials, or composite substrates formed by laminating or mixing a resin material and a glass material, may also be used. In this case, the dielectric constant refers to the effective dielectric constant of the substrate. For example, the linear expansion coefficient of the substrate 131 is greater than that of the substrate 111. Details of the dielectric constants and linear expansion coefficients of the substrates 131 and 111 will be described later.

[0051] <Antenna element 132> The antenna element 132 is, for example, a radiating element made of metal foil that is rectangular in plan view. As an example, a plurality of antenna elements 132 are arranged in an array on the upper surface of the substrate 131. While Fig. 1 shows, as an example, a configuration in which 16 antenna elements 132 are arranged in a 4x4 array in the X direction and the Y direction, it is sufficient for the millimeter wave wireless communication device 100 to include at least one antenna element 132.

[0052] The antenna element 132 may be made of, for example, copper foil or aluminum foil, and may be formed by vapor deposition or the like on the upper surface of the substrate 131. As an example, a plurality of antenna elements 132 may be used as a phased array antenna, and beam formation and beam scanning may be enabled by adjusting the amplitude and phase of radio waves transmitted and received by the plurality of antenna elements 132.

[0053] <Regarding the relative dielectric constants and linear expansion coefficients of the substrates 111 and 131 and the adhesive layer 120> Here, the relationship between the relative dielectric constants of the substrate 111, the adhesive layer 120, and the substrate 131, and the relationship between the linear expansion coefficients of the substrates 111 and 131 will be described.

[0054] As an example, one of the development goals of the millimeter wave wireless communication device 100 is to reduce the loss of millimeter wave radio waves in the millimeter wave band, in order to enable transmission and reception of millimeter waves in the high frequency band of 100 GHz or higher within the millimeter wave band of 30 GHz to 300 GHz.

[0055] In millimeter-wave transceivers operating in the high-frequency band above 100 GHz, IC chip size and power amplifier heat dissipation are key issues, leading to the use of segmented phased array antenna designs. For example, in a transmitter, multiple antenna elements are fed by an RF chain consisting of a single phase shifter and power amplifier, while in a receiver, multiple antenna elements are connected to an RF chain consisting of a single LNA and phase shifter. An example of such transmitter and receiver circuits is a configuration similar to that of IC chip 160 mounted on a feed circuit layer 140A, which will be described later with reference to FIG. 10 . In such a segmented phased array antenna, the transmit signal is upconverted to a millimeter-wave signal in the high-frequency band above 100 GHz and then routed from the feed circuit layer to each antenna element. The receive signal is downconverted using the reverse process.

[0056] Therefore, from the viewpoint of the operating bandwidth, it is desirable to adopt a parallel-feeding power supply method. In the parallel-feeding method, it is necessary to form a power supply circuit layer capable of supplying in-phase signals to all of the transmit RF chains, receive RF chains, and antenna elements, which increases the overall power supply path length. For this reason, the large loss caused by the power supply circuit layer becomes an issue.

[0057] From this perspective, the substrate 111 is made of a material with low loss of millimeter-wave radio waves in order to reduce loss of millimeter-wave radio waves in the feed circuit layer 110. Examples of materials for the substrate 111 include glass and ceramic, and quartz glass is particularly preferred.

[0058] For the substrate 111 of the feeder circuit layer 110, a material with a high relative dielectric constant, such as quartz glass, is used, which has a large wavelength shortening effect, and in FIG. 2, the width of the post-wall waveguide 110A in the X direction can be reduced to a certain extent.

[0059] When multiple antenna elements 132 are arranged, the pitch between adjacent antenna elements 132 is approximately 0.5λ to λ, where λ is the free space wavelength at the frequency of the radio waves (operating frequency) used for communication by the millimeter-wave wireless communication device 100. The pitch is the distance between the centers of adjacent antenna elements 132 in the X or Y direction.

[0060] The length of each antenna element 132 in the X and Y directions is approximately half the electrical length λe of the free space wavelength λ at the operating frequency. The electrical length λe is shorter than the free space wavelength λ due to the shortening effect caused by the relative dielectric constant of the substrate 131. Under these constraints, it is necessary to provide a gap between adjacent antenna elements 132.

[0061] While arranging the multiple antenna elements 132 at such pitch and intervals, it is necessary to arrange the post-wall waveguides 110A in the feed circuit layer 110 in accordance with the antenna elements 132. As an example, in the cross section shown in Figure 2, two post-wall waveguides 110A are arranged in accordance with the pitch of two adjacent antenna elements 132.

[0062] Under the above constraints, in order to reduce reflection loss and ensure the radiation efficiency and bandwidth of the antenna element, the relative dielectric constant of substrate 131 is set to be equal to or lower than the relative dielectric constant of substrate 111. By satisfying this relationship of relative dielectric constants, reflection loss can be reduced, making it easier to achieve transmission of millimeter-wave band radio waves with low loss.

[0063] Therefore, the relative dielectric constant of the substrate 131 only needs to be equal to or less than the relative dielectric constant of the substrate 111. By using such a relationship of the relative dielectric constants, the reflection loss between the slot 115 and the antenna element 132 can be effectively reduced.

[0064] Furthermore, the relative dielectric constant of the substrate 111 is ε １ Then, the relative dielectric constant ε of the substrate 131 is ２ is √ε １ That's it, ε １ It is more preferable that the relative dielectric constant ε of the substrate 131 is equal to or less than 0. ２This is because, when θ is set to a value within this range, the reflection loss between the slot 115 and the antenna element 132 can be effectively reduced.

[0065] In addition, the relative dielectric constant ε of the substrate 131 ２ is the relative dielectric constant ε of the substrate 111 １ It is more preferable that the value is smaller than 1 / 2, because the reflection loss between the slot 115 and the antenna element 132 can be reduced more effectively.

[0066] Regarding the adhesive layer 120, the relative dielectric constant ε ３ is √ε １ That's it, ε １ The relative dielectric constant ε of the adhesive layer 120 located between the feed circuit layer 110 and the antenna layer 130 is preferably equal to or less than 1. ３ This is because, when θ is set to a value within this range, the reflection loss between the slot 115 and the antenna element 132 can be effectively reduced.

[0067] In addition, the relative dielectric constant ε of the adhesive layer 120 ３ is the relative dielectric constant ε of the substrate 131 ２ is larger than the relative dielectric constant ε of the substrate 111. １ The relative dielectric constant ε of the adhesive layer 120 is more preferably smaller than ３ is the relative dielectric constant ε of the substrate 131. ２ and the relative dielectric constant ε of the substrate 111 １ By taking a value between these values, the relationship between the relative dielectric constants of the power feed circuit layer 110, the adhesive layer 120, and the antenna layer 130 changes stepwise, thereby mitigating the difference in relative dielectric constant between the power feed circuit layer 110 and the antenna layer 130 and more effectively reducing the reflection loss between the slot 115 and the antenna element 132.

[0068] Furthermore, the linear expansion coefficient of the substrate 131 is preferably greater than the linear expansion coefficient of the substrate 111. In other words, the linear expansion coefficient of the substrate 111 is preferably equal to or less than the linear expansion coefficient of the substrate 131. For example, when multiple antenna elements 132 are used as a phased array antenna, an IC (Integrated Circuit) chip incorporating a phase shifter and an amplifier may be mounted on a substrate provided below the feed circuit layer 110. Because IC chips dissipate a large amount of heat, the substrate 111 of the feed circuit layer 110 and the substrate 131 of the antenna layer 130 located above the feed circuit layer 110 may be heated, and the millimeter wave wireless communication device 100 may be distorted due to differences in the linear expansion coefficients of the substrate on which the IC chip is mounted, the substrate 111, and the substrate 131. In order to suppress distortion due to such heat dissipation, it is preferable that the linear expansion coefficient of the substrate 111 is small so as to suppress distortion of the substrate on which the IC chip is mounted. From this viewpoint, it is preferable that the linear expansion coefficient of the substrate 111 is equal to or less than the linear expansion coefficient of the substrate 131. In other words, it is preferable that the linear expansion coefficient of the substrate 131 is greater than the linear expansion coefficient of the substrate 111.

[0069] <Configuration of Actual Millimeter-Wave Wireless Communication Device 100> Fig. 3A is a diagram showing an example of an actual millimeter-wave wireless communication device 100. Fig. 3A shows a partial cross section of a portion of the actual millimeter-wave wireless communication device 100. Fig. 3B is an enlarged view of the millimeter-wave wireless communication device 100 shown in Fig. 3A.

[0070] 3A and 3B, the arrangement of the slot 115 and the via 114 will be described. In the partial cross sections of Figures 3A and 3B, in which the antenna layer 130 and the adhesive layer 120 are omitted, the slot 115 and the via 114 are visible. As an example, the slot 115 has a longitudinal direction extending in the Y direction, and both ends in the longitudinal direction widen in a circular shape.

[0071] 3A, the vias 114 are difficult to see, but as shown in FIG. 3B, the upper ends of many of the vias 114 are arranged to surround the multiple slots 115. The many vias 114 surrounding the slots 115 form the post-wall waveguide 110A (see FIG. 2).

[0072] In this way, in the actual millimeter-wave wireless communication device 100, the post-wall waveguide 110A is formed by a large number of vias 114. Since the vias 114 are side walls of the post-wall waveguide 110A, the vias 114 do not transmit signals.

[0073] <Simulation Results> An electromagnetic field simulation was performed on the millimeter wave wireless communication device 100 having the cross-sectional configuration shown in Fig. 2. Fig. 4A is a diagram showing an example of the frequency characteristics of the S11 parameter (dB). Fig. 4B is a diagram showing an example of the frequency characteristics of the maximum gain (dBi). Fig. 4C is a diagram showing an example of the frequency characteristics of the efficiency (dB) and the antenna efficiency (dB). Figs. 5A and 5B are diagrams showing an example of the radiation characteristics.

[0074] 4A represents a reflection coefficient indicating the proportion of radio waves input to the post-wall waveguide 110A that return to the post-wall waveguide 110A. Radio waves that are not reflected pass from the post-wall waveguide 110A through the slot 115 and are radiated from the antenna element 132.

[0075] As an example, when the S11 parameter was evaluated at a level of −10 dB, it was −10 dB or less in the band from about 140 GHz to about 149 GHz.

[0076] <Frequency Characteristics of Maximum Gain (dBi) (FIG. 4B)> The frequency characteristics of maximum gain (dBi) shown in FIG. 4B showed good values ​​of approximately 19 (dBi) to approximately 19.5 (dBi) in the band of approximately 140 GHz to approximately 149 GHz.

[0077] <Frequency characteristics of efficiency (dB) (FIG. 4C)> In FIG. 4C, the efficiency (Rad. Efficiency) (dB) is shown by a solid line, and the antenna efficiency (Total Efficiency) (dB) is shown by a dashed line. As shown in FIG. 4C, both the maximum efficiency and the radiation efficiency were good values ​​of -1 (dB) in the band from approximately 140 GHz to approximately 149 GHz.

[0078] <Radiation Characteristics (FIG. 5A)> FIG. 5A shows the radiation characteristics in the polar angle (zenith angle) direction on the XZ plane (phi = 0 deg.). Taking the origin of the XYZ coordinate system as the center of the top surface of one antenna element 132, the radiation characteristics in the polar angle direction on the XZ plane were calculated for radio wave frequencies from 140 GHz to 150 GHz in 1 GHz increments. In FIG. 5A, the radiation characteristics are expressed in realized gain (dB). The 0 degree direction is the +Z direction, the -180 degree direction is the -X direction, and the +180 degree direction is the +X direction.

[0079] As shown in FIG. 5A, at all frequencies from 140 GHz to 150 GHz, the radiation characteristics in the polar angle direction on the XZ plane were such that the radiation intensity was greatest at the center (0 degrees) and was approximately symmetrical from −180 degrees to +180 degrees about the center (0 degrees).

[0080] <Radiation Characteristics (FIG. 5B)> FIG. 5B shows the radiation characteristics in the polar angle (zenith angle) direction in the YZ plane (phi = 90 deg.). Taking the origin of the XYZ coordinates as the center of the top surface of one antenna element 132, the radiation characteristics in the polar angle direction in the YZ plane were calculated for radio wave frequencies from 140 GHz to 150 GHz in 1 GHz increments. In FIG. 5B, the radiation characteristics are expressed in realized gain (dB). The 0-degree direction is the +Z direction, the -180-degree direction is the -Y direction, and the +180-degree direction is the +Y direction.

[0081] As shown in FIG. 5B, at all frequencies between 140 GHz and 150 GHz, the radiation characteristics in the polar angle direction in the YZ plane were such that the radiation intensity was greatest at the center (0 degrees) and was approximately symmetrical from −180 degrees to +180 degrees relative to the center (0 degrees).

[0082] <Effects> The millimeter-wave wireless communication device 100 according to the embodiment of the present disclosure includes a feed circuit layer 110 (first feed circuit layer) having a substrate 111 (first substrate) made of glass or ceramic and having a first surface and a second surface, a metal layer 113 provided on the second surface and having a slot 115 (first opening), and a post-wall waveguide 110A (first transmission line) formed on the substrate 111, the post-wall waveguide 110A being a microstrip line, a strip line, a coplanar line, a slot line, or a post-wall waveguide, and a resin substrate 111 having a third surface and a fourth surface. Alternatively, the millimeter-wave wireless communication device 100 may include a glass substrate 131 (second substrate), an antenna layer 130 having an antenna element 132 formed on a fourth surface thereof and configured to communicate in the millimeter wave band, and an adhesive layer 120 (adhesive portion) that bonds a metal layer 113 provided on the second surface of the substrate 111 of the feed circuit layer 110 to a third surface of the substrate 131 of the antenna layer 130, wherein the slot 115 and the antenna element 132 are electrically coupled, and power can be fed from the post-wall waveguide 110A to the antenna element 132 through the slot 115. Therefore, by simply bonding the feed circuit layer 110 and the antenna layer 130 together with the adhesive layer 120, a millimeter-wave wireless communication device 100 capable of feeding power from the slot 115 to the antenna element 132 can be easily fabricated. In other words, this device can be fabricated very easily without the need for a difficult and unproductive process such as bonding multiple glass wafers with copper layers formed thereon by thermocompression bonding (TCB) processing, as in the prior art.

[0083] This makes it possible to provide an easily fabricated millimeter-wave wireless communication device 100. Because the signal transmission path of the millimeter-wave wireless communication device 100 does not include connection structures using vias, through-holes, or the like that cause parasitic inductance and parasitic capacitance, it is capable of transmitting and receiving millimeter-wave band radio waves of 30 GHz to 300 GHz with low loss, and is particularly suited to transmitting and receiving millimeter-wave band radio waves in the high-frequency band of 100 GHz or higher.

[0084] Furthermore, the relative dielectric constant of substrate 131 may be equal to or less than the relative dielectric constant of substrate 111. By satisfying such a relationship between the relative dielectric constants, reflection loss can be reduced, making it easier to achieve transmission of millimeter-wave band radio waves in a low-loss state.

[0085] Furthermore, the relative dielectric constant of the substrate 111 is ε １Then, the relative dielectric constant ε of the substrate 131 is ２ is √ε １ That's it, ε １ By satisfying such a relationship in the relative dielectric constant, it is possible to reduce the reflection loss and easily achieve transmission of millimeter-wave band radio waves in a low-loss state.

[0086] Furthermore, the relative dielectric constant of the substrate 111 is ε １ Then, the relative dielectric constant ε of the adhesive layer 120 ３ is √ε １ That's it, ε １ If the relative dielectric constant of the adhesive layer 120 located between the feed circuit layer 110 and the antenna layer 130 satisfies this relationship, reflection loss can be reduced, and it becomes easier to transmit millimeter-wave band radio waves in a low-loss state.

[0087] In addition, the relative dielectric constant ε of the adhesive layer 120 ３ is the relative dielectric constant ε of the substrate 131 ２ is larger than the relative dielectric constant ε of the substrate 111. １ By setting the relative dielectric constants of the feed circuit layer 110, the adhesive layer 120, and the antenna layer 130 in a stepwise manner, reflection loss can be reduced, making it easier to transmit millimeter-wave band radio waves in a low-loss state.

[0088] The linear expansion coefficient of the substrate 131 may be larger than the linear expansion coefficient of the substrate 111. When an IC chip incorporating a phase shifter or an amplifier is mounted on a substrate or the like provided below the feed circuit layer 110, even if the IC chip dissipates heat, the small linear expansion coefficient of the substrate 111 makes it possible to suppress overall distortion of the millimeter wave wireless communication device 100.

[0089] The adhesive layer 120 may be an adhesive resin sheet or prepreg. The resin sheet or prepreg allows the feed circuit layer 110 and the antenna layer 130 to be easily bonded together, thereby providing an easily fabricated millimeter wave wireless communication device 100.

[0090] The first opening may also be a slot 115 provided in the metal layer 113. The slot 115 functions as a slot antenna, allowing power to be fed to the antenna element 132.

[0091] The millimeter wave band may be 30 GHz to 300 GHz, and it is possible to provide a millimeter wave wireless communication device 100 that can be easily manufactured and is capable of transmitting and receiving radio waves in the millimeter wave band of 30 GHz to 300 GHz.

[0092] Although the above description has been given of a configuration in which the slot 115 is used as the first opening of the metal layer 113 of the power feed circuit layer 110, the first opening is not limited to the slot 115.

[0093] For example, when a microstrip line, a strip line, a coplanar line, or a slot line is used as a transmission line instead of the post-wall waveguide 110A, a cavity as shown in FIG. 6 may be provided between the metal layers 112 and 113 of the feed circuit layer 110.

[0094] 6 is a diagram showing an example of the configuration of a cavity 110B provided in the power supply circuit layer 110. FIG. 6 shows the arrangement of a plurality of vias 114 provided between the metal layers 112 and 113, and the position of an opening 115A as a first opening provided in the metal layer 113.

[0095] That is, the feed circuit layer 110 has a cavity 110B between the metal layer 113 and the first transmission line (microstrip line, strip line, coplanar line, or slot line) that can transmit millimeter-wave band radio waves.

[0096] The vias 114 are arranged at intervals to prevent leakage of millimeter waves, similar to the vias 114 that form the sidewall of the post-wall waveguide 110A. The cavity 110B has a cavity portion 110B1 in which the vias 114 are arranged to form a circle in a plan view, and a connection portion 110B2 in which the vias 114 are arranged outward in a plan view with a portion of the circle interrupted. As an example, no vias 114 are provided at the end of the connection portion 110B2.

[0097] Radio waves are introduced into the cavity 110B1 via the connection 110B2. The connection 110B2 is connected to an IC chip including a phase shifter and an amplifier. In the cavity 110B1, standing waves of radio waves at the operating frequency of the millimeter-wave wireless communication device 100 are generated. In the cavity 110B1, radio waves in bands other than the operating frequency are lost without becoming standing waves. The radio waves at the operating frequency propagate to the antenna element 132 through the opening 115A while becoming standing waves within the cavity 110B1. In this way, the antenna element 132 can be fed using the cavity 110B.

[0098] In this way, the millimeter wave wireless communication device 100 can feed power to the antenna element 132 using the first opening other than the slot 115 .

[0099] 7 is a diagram showing an example of a cross-sectional configuration of a millimeter wave wireless communication device 100M1 according to a first modification of the embodiment. The cross section shown in FIG. 7 corresponds to the cross section shown in FIG.

[0100] The millimeter wave wireless communication device 100M1 differs from the millimeter wave wireless communication device 100 (see Figure 2) in that it uses an adhesive layer 120M1 made of a conductive adhesive layer instead of the adhesive layer 120 (see Figure 2) made of a resin adhesive layer.

[0101] The adhesive layer 120M1, which is made of a conductive adhesive layer, has an opening 121, as shown in FIG. 7 . The opening 121 is an example of a second opening communicating with the slot 115. As an example, the opening 121 has the same shape and size as the slot 115 in a plan view and is aligned with the slot 115. One opening 121 is provided corresponding to each slot 115. Note that the opening 121 only needs to be large enough not to enter the slot 115 in a plan view, and may be larger than the slot 115. Furthermore, one opening 121 may be provided for multiple slots 115.

[0102] The conductive adhesive layer may be a conductive bonding sheet, solder, or conductive paste, etc. An example of the conductive paste is silver paste.

[0103] The adhesive layer 120M1 is made of a conductive material and has a second opening that communicates with the slot 115. Therefore, radio waves radiated in the +Z direction from the slot 115 reach the antenna element 132 through the opening 121, and the millimeter wave wireless communication device 100M1 operates in the same manner as the millimeter wave wireless communication device 100 shown in FIG.

[0104] Furthermore, since the adhesive layer 120M1 is made of a conductive adhesive, a shield is provided between the power supply circuit layer 110 and the antenna layer 130, thereby improving resistance to external noise and the like.

[0105] <Second Modification> Fig. 8 is a diagram showing an example of an exploded state of a millimeter wave wireless communication device 100M2 according to a second modification of the embodiment. Fig. 9A is a diagram showing an example of a cross-sectional configuration of the millimeter wave wireless communication device 100M2 according to the second modification. The cross section shown in Fig. 9A corresponds to the cross section seen from the arrow B-B in Fig. 8 when the millimeter wave wireless communication device 100M2 according to the second modification is assembled. The cross section shown in Fig. 9A corresponds to the cross section shown in Fig. 2.

[0106] 2 in that the millimeter wave wireless communication device 100M2 includes an adhesive portion 120M2 instead of the adhesive layer 120. Since the other configurations are the same as those of the millimeter wave wireless communication device 100M2 shown in FIGS. 1 and 2, only the configuration of the adhesive portion 120M2 will be described here.

[0107] <Adhesive Section 120M2> The adhesive section 120M2 has two adhesive layers 120A and 120B and a spacer 125. The adhesive layer 120A is an example of a first adhesive layer, and the adhesive layer 120B is an example of a second adhesive layer.

[0108] The two adhesive layers 120A and 120B can be resin adhesive layers or conductive adhesive layers, similar to the adhesive layer 120 shown in Fig. 1 or the adhesive layer 120M1 shown in Fig. 7. Here, as an example, a configuration in which the adhesive layers 120A and 120B are resin adhesive layers will be described.

[0109] The resin adhesive layer that can be used as adhesive layers 120A and 120B is the same as the resin adhesive layer that can be used as adhesive layer 120 shown in Figures 1 and 2, so a detailed description will be omitted. The resin adhesive layer used as adhesive layer 120A and the resin adhesive layer used as adhesive layer 120B may be different, but it is more preferable that they are the same. Note that adhesive layers 120A and 120B may be conductive adhesive layers, and the configuration in that case will be described later.

[0110] In addition, the relative dielectric constant ε of the adhesive layer 120A ３ is the relative dielectric constant ε of the substrate 111 １ The relative dielectric constant ε of the adhesive layer 120A is preferably equal to or less than 1. ３ is √ε １ That's it, ε １ It is preferable that ε is equal to or less than ε. １ is the relative dielectric constant of the substrate 111. Also, the relative dielectric constant ε of the adhesive layer 120A ３ is the relative dielectric constant ε of the substrate 131 ２ is larger than the relative dielectric constant ε of the substrate 111. １ The same applies to the relative dielectric constant of adhesive layer 120B.

[0111] <Spacer 125> The spacer 125 is provided between the adhesive layers 120A and 120B. Therefore, in the second modification, the spacer 125 is attached onto the power feed circuit layer 110 via the adhesive layer 120A, and the antenna layer 130 is attached onto the spacer 125 via the adhesive layer 120B. Therefore, by using spacers 125 with different thicknesses in the Z direction, the distance in the Z direction between the power feed circuit layer 110 and the antenna layer 130 can be adjusted.

[0112] As an example, the spacer 125 may be made of metal, silicon, resin, glass, or the like. As an example, the spacer 125 is frame-shaped in a plan view as shown in FIG. 8 and has a through-hole 125A in the center. The through-hole 125A is an opening that is opened so as not to overlap any of the slots 115 and any of the antenna elements 132 in a plan view. This is to avoid affecting the coupling between the slots 115 and the antenna elements 132.

[0113] Although the spacer 125 is described here as having a frame shape in a plan view, the spacer 125 may be divided into multiple pieces along the outer edge of the frame. Also, the through-hole 125A may be divided into multiple pieces as long as it does not overlap with all of the slots 115 and all of the antenna elements 132 in a plan view.

[0114] In the millimeter wave wireless communication device 100M2, radio waves radiated from the slot 115 pass through the adhesive layer 120A, pass through the through-hole 125A of the spacer 125, and pass through the adhesive layer 120B to reach the antenna element 132. Therefore, the millimeter wave wireless communication device 100M2 operates in the same manner as the millimeter wave wireless communication device 100 shown in FIG. 2 and achieves the same effects.

[0115] Furthermore, the spacer 125 is made of metal, silicon, resin, or glass, and is therefore easily fabricated. In the second modification, it is possible to provide an easily fabricated millimeter wave wireless communication device 100M2 that includes the easily fabricated spacer 125.

[0116] Furthermore, if the spacer 125 is made of metal, a shield is provided between the feed circuit layer 110 and the antenna layer 130, thereby improving resistance to external noise and the like.

[0117] The millimeter wave wireless communication device 100M2 of the second modified example may have a configuration as shown in Fig. 9B. Fig. 9B is a diagram showing an example of a cross-sectional configuration of the millimeter wave wireless communication device 100M2 of another form of the second modified example.

[0118] In the millimeter wave wireless communication device 100M2 shown in Fig. 9B, the feed circuit layer 110 has a via 116 that penetrates the substrate 111, and the adhesive part 120M2 has a via 122 that penetrates the adhesive layer 120A. In the millimeter wave wireless communication device 100M2 shown in Fig. 9B, the spacer 125 is made of metal.

[0119] Via 116 penetrates substrate 111 in the same manner as via 114, and has a lower end connected to metal layer 112 and an upper end connected to metal layer 113. Via 116 may or may not be used as a sidewall of post-wall waveguide 110A. Via 116 can be fabricated in the same manner as via 114.

[0120] The via 122 penetrates the adhesive layer 120A and, for example, is provided at the same position as the via 116 in a plan view. The via 122 has a lower end connected to the metal layer 113 and an upper end connected to the lower surface of the spacer 125. Like the vias 114 and 116 of the power supply circuit layer 110, the via 122 can be formed of, for example, copper or aluminum.

[0121] 9B , the spacer 125 is connected to the metal layer 113 through the via 122, and therefore the potential of the spacer 125 can be set to ground potential. Therefore, by providing a shield constituted by the spacer 125 at ground potential between the feed circuit layer 110 and the antenna layer 130, it is possible to improve resistance to external noise and the like.

[0122] 10 is a diagram illustrating an example of a cross-sectional configuration of a millimeter wave wireless communication device 100M3 according to a third modification of the embodiment. The cross section illustrated in FIG. 10 corresponds to the cross section illustrated in FIG.

[0123] The millimeter wave wireless communication device 100M3 has a configuration in which a feed circuit layer 140A and the like are further provided below the metal layer 112 of the millimeter wave wireless communication device 100 shown in Fig. 2. The feed circuit layer 140A is an example of a second feed circuit layer.

[0124] In the millimeter wave wireless communication device 100M3, the antenna layer 130 has a via 133 and a terminal 134 in addition to a substrate 131 and an antenna element 132. The lower end of the via 133 extends downward from the lower surface of the substrate 131, passes through the adhesive layer 120, and is connected to the upper surface of the metal layer 113. The upper end of the via 133 extends to the upper surface of the substrate 131 and is connected to a terminal 134 provided on the upper surface of the substrate 131. The terminal 134 is provided near the antenna element 132.

[0125] The layer on which the antenna element 132 and the terminal 134 are located is the L1 layer, the layer on which the metal layer 113 is located is the L2 layer, and the layer on which the metal layer 112 is located is the L3 layer.

[0126] The power feed circuit layer 140A is provided below the power feed circuit layer 110 and is, for example, configured as a multilayer substrate having wiring or ground layers L4, L5, and L6, an insulating layer on the L4 layer, and an insulating layer provided between the wiring or ground layers L4, L5, and L6. The power feed circuit layer 140A is located below the L3 layer of the power feed circuit layer 110. The power feed circuit layer 140A is, for example, a build-up substrate.

[0127] For example, the wiring on the L4 layer of the power feed circuit layer 140A and the metal layer 113, which is the L3 layer, are electrically coupled via a slot or the like. Alternatively, the wiring on the L4 layer of the power feed circuit layer 140A and the metal layer 113, which is the L3 layer, may be connected via a wiring or the like (not shown).

[0128] The power supply circuit layer 140B is connected to the wiring of the L6 layer of the power supply circuit layer 140A via a connection portion 150. The power supply circuit layer 140B is, for example, a build-up substrate, similar to the power supply circuit layer 140A. The connection portion 150 may be any wiring or the like that can connect the wiring of the power supply circuit layers 140A and 140B, and is, for example, an FPC (Flexible Printed Circuit).

[0129] An IC chip 160 is mounted on the lower surfaces of the feed circuit layers 140A and 140B. The IC chip 160 incorporates, for example, a phase shifter that adjusts the phase of a transmission signal supplied to a plurality of antenna elements 132 serving as a phased array antenna, an amplifier that amplifies the transmission signal, and the like. The phase shifter similarly adjusts the phase of a received signal. The IC chip 160 also incorporates an amplifier that amplifies the received signal.

[0130] The feed circuit layer 110 and the antenna layer 130, which are bonded together with the adhesive layer 120, are capable of transmitting and receiving millimeter-wave band radio waves. By disposing the IC chip 160 directly below the feed circuit layer 110 and the antenna layer 130, the millimeter-wave wireless communication device 100M3 reduces signal transmission loss between the IC chip 160 and the feed circuit layer 110, thereby achieving a configuration capable of transmitting millimeter-wave band signals.

[0131] Although exemplary millimeter wave wireless communication devices according to the present disclosure have been described above, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0132] This international application claims priority based on Japanese Patent Application No. 2023-192790, filed on November 13, 2023, the entire contents of which are incorporated herein by reference.

[0133] 100, 100M1, 100M2, 100M3 Millimeter-wave wireless communication device 110 Power supply circuit layer (an example of a first power supply circuit layer) 110A Post-wall waveguide 111 Substrate (an example of a first substrate) 112 Metal layer 113 Metal layer (an example of a metal layer provided on a second surface and having a first opening) 114 Via 115 Slot (an example of a first opening) 120, 120M1 Adhesive layer (an example of an adhesive portion) 120M2 Adhesive portion 120A Adhesive layer (an example of a first adhesive layer) 120B Adhesive layer (an example of a second adhesive layer) 121 Opening (an example of a second opening) 125 Spacer 130 Antenna layer 131 Substrate (an example of a second substrate) 132 Antenna element 140A Power supply circuit layer (an example of a second power supply circuit layer) 140B Power supply circuit layer 160 IC chips

Claims

1. A millimeter wave wireless communication device comprising: a first substrate made of glass or ceramic and having a first surface and a second surface; a first feed circuit layer having a metal layer provided on the second surface and having a first opening, and a first transmission path formed on the first substrate, the first transmission path being a microstrip line, a strip line, a coplanar line, a slot line, or a post-wall waveguide; a second substrate made of resin or glass and having a third surface and a fourth surface; and an antenna layer having an antenna element formed on the fourth surface for communicating in the millimeter wave band; and an adhesive portion that bonds the metal layer provided on the second surface of the first substrate of the first feed circuit layer to the third surface of the second substrate of the antenna layer, wherein the first opening and the antenna element are electrically coupled, and power can be supplied to the antenna element from the first transmission path through the first opening.

2. The millimeter wave wireless communication device according to claim 1, wherein the relative dielectric constant of the second substrate is equal to or lower than the relative dielectric constant of the first substrate.

3. The relative dielectric constant of the first substrate is ε １ Then, the relative dielectric constant ε of the second substrate ２ is √ε １ That's it, ε １ 3. The millimeter wave wireless communication device according to claim 2, wherein:

4. The relative dielectric constant of the first substrate is ε １ Then, the relative dielectric constant ε ３ is √ε １ That's it, ε １ 3. The millimeter wave wireless communication device according to claim 2, wherein:

5. The relative dielectric constant ε of the adhesive joint ３ is the relative dielectric constant ε of the second substrate ２ and the relative dielectric constant ε of the first substrate is greater than １ The millimeter wave wireless communication device according to claim 4 .

6. A millimeter wave wireless communication device according to any one of claims 1 to 5, wherein the linear expansion coefficient of the second substrate is greater than the linear expansion coefficient of the first substrate.

7. A millimeter wave wireless communication device as described in any one of claims 1 to 6, further comprising a second feed circuit layer having a dielectric layer provided on the first surface side of the first substrate, and a second transmission path provided on the dielectric layer and connected to the first transmission path or electrically coupled to the first transmission path.

8. A millimeter wave wireless communication device according to any one of claims 1 to 7, wherein the adhesive portion has a second opening communicating with the first opening and is made of a conductive material.

9. The millimeter wave wireless communication device according to any one of claims 1 to 8, wherein the adhesive portion is an adhesive resin sheet or prepreg.

10. A millimeter wave wireless communication device as described in any one of claims 1 to 8, wherein the adhesive portion has: a first adhesive layer adhered to the metal layer provided on the second surface; a second adhesive layer adhered to the third surface; and a spacer adhered between the first adhesive layer and the second adhesive layer.

11. The millimeter wave wireless communication device according to claim 10, wherein the spacer is made of metal, silicon, resin, or glass.

12. The millimeter wave wireless communication device according to any one of claims 1 to 11, wherein the first opening is a slot provided in the metal layer.

13. A millimeter wave wireless communication device according to any one of claims 1 to 12, wherein the first power supply circuit layer has a cavity between the metal layer and the first transmission path that is capable of transmitting radio waves in the millimeter wave band, and the first opening is an opening provided above the cavity.

14. A millimeter wave wireless communication device according to any one of claims 1 to 13, wherein the millimeter wave band is 30 GHz to 300 GHz.

Images