Antenna device and radome

Abstract

An antenna device (100) comprises: a board (10); an antenna element (20) that is placed on a surface of the board (10); and a radome (50) of a conductor having a thermal conductivity, the radome (50) covering the surface of the board (10) and having a slot (53) formed therein in a position opposite the antenna element (20). The radome (50) has a heat dissipation fin structure that is formed to protrude from an outer surface of the radome (50) on the side opposite to the board (10) side. The heat dissipation fin structure has at least a heat dissipation fin that is formed to surround the slot (53).

Description

Technical Field

[0001] The present disclosure relates to an antenna device and a radome.

Background Art

[0002] Generally, in an apparatus equipped with an antenna (antenna device) such as an antenna-integrated base station apparatus, a resin radome is used as a radome for protecting the antenna surface of the antenna. However, in the case of a resin radome, in order to improve durability, the thickness of the radome has to be increased. Therefore, in recent years, as disclosed in Patent Document 1, it has been considered to protect the antenna surface by using a housing made of a conductor instead of a resin radome.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in an antenna device, in order to improve reliability, it is required to efficiently release the heat generated inside the device to the outside. However, Patent Document 1 does not describe heat dissipation. Therefore, when trying to realize an antenna device using the technology disclosed in Patent Document 1, it is necessary to attach a heat dissipation mechanism such as heat dissipation fins to the antenna device using a housing made of a conductor. As a result, there is a problem that the antenna device becomes large-sized. Note that as the number of antennas included in the antenna device increases, the number of heat generating components inside the antenna device also tends to increase. Therefore, it is considered that the enlargement of the antenna device becomes remarkable.

[0005] One of the objects of the present disclosure is to provide an antenna device and a radome capable of suppressing the enlargement of the antenna device, which are made to solve the above problems.

Means for Solving the Problems

[0006] The antenna device according to the first aspect of the present disclosure is a substrate, an antenna element disposed on the surface of the substrate, a radome of a conductor having thermal conductivity that covers the surface of the substrate and has a slot formed at a position facing the antenna element, and includes the radome has a heat dissipation fin structure formed to protrude from the outer surface on the side opposite to the substrate side, the heat dissipation fin structure has at least a heat dissipation fin formed so as to surround the slot.

[0007] The antenna device according to the second aspect of the present disclosure is a substrate, a plurality of antenna elements disposed on the surface of the substrate, a radome of a conductor having thermal conductivity that covers the surface of the substrate and has a plurality of slots formed at positions facing the respective ones of the plurality of antenna elements, and includes the radome has a heat dissipation fin structure formed to protrude from the outer surface on the side opposite to the substrate side, the heat dissipation fin structure has at least a plurality of heat dissipation fins formed so as to surround the respective ones of the plurality of slots.

[0008] The radome according to the third aspect of the present disclosure is a radome of a conductor having thermal conductivity, with a slot formed at a position facing the antenna element in a state of covering the surface of the substrate on which the antenna element is disposed, the radome It has a heat dissipation fin structure formed so as to protrude from the outer surface on the side opposite to the substrate side. The heat dissipation fin structure has at least heat dissipation fins formed so as to surround the slot.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to provide an antenna device and a radome that can suppress the enlargement of the antenna device.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 8

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Figure 10

Figure 11

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Figure 14

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that, for the sake of clarity of explanation, the following description and drawings are appropriately omitted and simplified. Also, in each of the following drawings, the same elements are denoted by the same reference numerals, and duplicate explanations are omitted as necessary. In each embodiment, a deviation within a range that does not impair the effects of the present disclosure is allowed in directions such as parallel, horizontal, and vertical. Also, in the drawings for explaining the embodiments, unless otherwise specified, the directions on the drawings shall be referred to.

[0012] <Pre-study before reaching the embodiment> First, before explaining the details of the embodiment, the content of the pre-study before reaching the embodiment will be explained. As an antenna device used for fifth-generation mobile communication, an active antenna system (AAS) is known. By providing a transceiver for each of a plurality of antenna elements constituting a super multi-element antenna array, the AAS enables flexible beamforming, MU-MIMO (Multi User-Multiple Input Multiple), and massive MIMO (Massive-MIMO), etc. Thereby, since the AAS can spatially multiplex a plurality of communication terminals and a plurality of radio signals of a plurality of layers and transmit them in a batch, the cell throughput can be significantly improved, and the frequency utilization efficiency can be improved.

[0013] In an AAS with a full digital beamforming function capable of realizing MU-MIMO, a transceiver including an ADC (analog to digital converter), a DAC (digital to analog converter), a TRX (Transmitter and Receiver), and an RF front end (Radio Frequency Frontend) is provided corresponding to each antenna. Therefore, in this AAS, the larger the number of antennas, the larger the number of transceivers, and accordingly, the power consumption also increases.

[0014] As described above, generally, in an antenna-equipped device (antenna device) such as an antenna-integrated base station device, a resin radome is used as a radome for protecting the antenna surface of the antenna. However, the resin radome may prevent heat generated inside the antenna device from being released to the outside. Therefore, in an AAS using a resin radome, heat is not radiated from the antenna surface to the outside, but radiator fins are provided on the housing provided on the back side opposite to the antenna surface, and heat is radiated from the radiator fins to the outside. Therefore, in an AAS using a resin radome, it is necessary to additionally provide heat dissipation fins such as radiator fins, resulting in an increase in size.

[0015] By the way, as cooling methods for suppressing the temperature rise of internal devices, a forced air cooling method and a natural air cooling method are known. The forced cooling method is a method of cooling internal devices by providing a fan to push outside air into the internal devices or suck out overheated air from the internal devices. The natural air cooling method is a method of enhancing the heat dissipation efficiency by diffusing the heat from the internal devices, guiding the heat to the radiator fins (Radiator Fin), and then ensuring the number of fins and the fin length to expand the heat dissipation area with the external environment.

[0016] In an AAS that employs a forced cooling method, it is possible to improve the heat dissipation efficiency and achieve miniaturization. However, since it is necessary to continuously drive the fan, failures due to continuous driving may occur, leading to a decrease in reliability, and immediate maintenance is required in case of a failure. In addition, in an AAS that employs a forced cooling method, especially when deployed in an urban area, the rotation noise of the fan may cause noise pollution. Therefore, it is highly likely that a natural cooling method will be adopted for the AAS rather than a forced cooling method. Thus, even in an AAS that adopts a natural cooling method, it is desirable to enhance the heat dissipation efficiency while achieving miniaturization and weight reduction. In the present disclosure, an antenna device such as an AAS and a radome that can enhance the heat dissipation efficiency while suppressing an increase in size are realized.

[0017] <Embodiment 1> FIG. 1 is a schematic top view of an antenna device 100 according to Embodiment 1. FIG. 2 is an enlarged view of a part of a radome 50 provided in the antenna device 100 shown in FIG. 1. FIG. 3 is a schematic cross-sectional view of the antenna device 100 shown in FIG. 1. Note that FIG. 3 shows a cross-sectional view of the antenna device 100 when the antenna device 100 shown in FIG. 1 is cut along the cutting line II-II.

[0018] The antenna device 100 is an antenna array including a plurality of antenna elements, and may be, for example, an AAS. Since the antenna device 100 includes a large number of antenna elements, it may also be referred to as an antenna system. As shown in FIGS. 1 to 3, the antenna device 100 includes a substrate 10, a plurality of antenna elements 20, a ground layer 30, a plurality of heat-generating components 40, and a radome 50.

[0019] First, the specific configuration of the antenna device 100 will be described with reference to FIG. 3. As shown in FIG. 3, an electrical wiring pattern is provided on the substrate 10, and a plurality of antenna elements 20 are arranged on the first surface on the positive Z-axis side of the substrate 10. Since the first surface faces the radio wave radiation direction of the antenna element 20, it may also be referred to as the front surface or the upper surface, and the second surface on the opposite side of the first surface in the substrate 10 may also be referred to as the back surface or the lower surface. The plurality of antenna elements 20 are arranged at a predetermined distance interval in the X-axis direction on the surface of the substrate 10. The plurality of antenna elements 20 are electrically connected to the ground layer 30 and the radome 50 via a ground line provided on the surface of the substrate 10. Although not shown, the plurality of antenna elements 20 are also arranged at a predetermined interval in the Y-axis direction.

[0020] A plurality of thermal vias 11, which are through holes penetrating from the front surface to the back surface of the substrate 10, are formed in the substrate 10. The plurality of thermal vias 11 are arranged in the vicinity of the plurality of antenna elements 20. Further, the plurality of thermal vias 11 are formed so as to surround the plurality of antenna elements 20 in a top view (that is, when looking at the surface of the substrate 10 in the negative Z-axis direction). In the present embodiment, the plurality of thermal vias 11 are formed so as to surround all of the plurality of antenna elements 20, but it is not limited thereto. For example, they may be formed so as to surround some of the plurality of antenna elements 20.

[0021] The plurality of antenna elements 20 may be arranged such that the intervals between adjacent antenna elements 20 are equal. Each antenna element 20 is an antenna element to which power is supplied, and is, for example, a patch antenna. Each antenna element 20 is a primary resonator for a transceiver (not shown) arranged on the back surface of the substrate 10 to transmit and receive signals with an external communication device. The antenna device 100 radiates radio waves in the direction in which the surface of the substrate 10 faces from the plurality of slot antenna elements formed by the plurality of antenna elements 20 and the plurality of slot antenna elements formed by a plurality of slots 53 described later, and transmits and receives signals with an external communication device located in that direction.

[0022] On the back surface of the substrate 10, the same number of heat-generating components 40 as the number of antenna elements 20 are arranged via a ground layer 30 made of copper foil or the like. Each heat-generating component 40 may be, for example, an AMP (Amplifier) or the like. The plurality of heat-generating components 40 may be arranged at positions corresponding to each of the plurality of antenna elements 20. Specifically, each heat-generating component 40 and the antenna element 20 corresponding to the heat-generating component 40 may be arranged so as to sandwich the substrate 10 in the Z-axis direction. Here, each heat-generating component 40 is electrically connected to the antenna element 20 corresponding to the heat-generating component 40. Further, each heat-generating component 40 is thermally connected to a radome 50 described later via the ground layer 30. In other words, the antenna device 100 is configured such that the heat generated by each heat-generating component 40 is transmitted to the radome 50 via the thermal via 11 corresponding to the heat-generating component 40. Each thermal via 11 serves as a heat dissipation path for transmitting the heat generated by the heat-generating component 40 corresponding to the thermal via 11 to the radome 50.

[0023] Although omitted in FIG. 3, each heat-generating component 40 is connected to an external circuit via at least one of the signal lines and control lines other than the ground on the substrate 10. Further, the ground pad (GND PAD1) on the back surface of each heat-generating component 40 or the ground pin (GND Pin) disposed around each heat-generating component 40 is connected to the ground pattern surface (GND Pattern) or the ground terminal portion (GND PAD2) for ground pin connection on the substrate 10 by a reflow process using surface mount technology (SMT) or the like. The connection portions between these grounds are connected to the ground layer 30 not only for electrical grounding but also for forming a heat dissipation path.

[0024] The redome 50 is formed of a conductor having thermal conductivity. For example, the redome 50 is formed of a metal such as aluminum, silver, copper, or an alloy containing any of these. Note that the redome 50 may be a resin housing surface plated with a conductor having thermal conductivity. The redome 50 is fixed to the substrate 10 in a state of covering the surface of the substrate 10, and serves as a protection member for protecting a plurality of antenna elements 20 disposed on the surface of the substrate 10. Specifically, the redome 50 includes a flat portion 51 and a wall portion 52.

[0025] The planar portion 51 is arranged parallel to the substrate 10 at a distance equal to the height of the wall portion 52 from the substrate 10, covering the surface of the substrate 10. Here, a plurality of slots 53 equal in number to the plurality of antenna elements 20 arranged on the surface of the substrate 10 are formed at positions on the planar portion 51 that face the plurality of antenna elements 20. The plurality of slots 53 are each formed at a position in the positive Z-axis direction of the plurality of antenna elements 20. Each slot 53 functions as a slot antenna element. Each slot antenna element is a parasitic resonator having the same resonance frequency as the antenna element 20 corresponding to the slot antenna element, and functions as an antenna element that expands the frequency band by coupling and resonating with the antenna element 20. The antenna device 100 can transmit and receive signals using a wider frequency band with a communication device facing the direction in which the outer surface on the side opposite to the surface side of the substrate 10 faces, by each slot 53 functioning as a slot antenna element.

[0026] Further, the planar portion 51 includes at least a plurality of first heat dissipation fins 54 protruding from the outer surface on the side opposite to the substrate 10 side. Each first heat dissipation fin 54 is a fin for discharging the heat generated in the heat generating component 40 to the outside. Each first heat dissipation fin 54 is arranged in the vicinity of any one of the plurality of slots 53 that function as slot antenna elements. Each first heat dissipation fin 54 protrudes from the outer surface of the planar portion 51 in the positive Z-axis direction and perpendicularly. In other words, each first heat dissipation fin 54 protrudes from the outer surface of the planar portion 51 such that the wall portion 52 extends in the positive Z-axis direction. Each first heat dissipation fin 54 discharges the heat of the heat generating component 40 to the outside of the antenna device 100 by transferring the heat of the heat generating component 40 transmitted from the wall portion 52 to the air. In other words, the outside air takes away the heat of the heat generating component 40 transmitted from the wall portion 52 by touching the surface of each first heat dissipation fin 54.

[0027] The wall portion 52 is provided so as to extend in the negative Z-axis direction and perpendicular direction from the inner surface of the planar portion 51 on the substrate 10 side. The wall portion 52 is provided to be connected to the substrate 10 and surround each antenna element 20 in a state where the radome 50 covers the surface of the substrate 10. Specifically, first, the wall portion 52 is provided to be connected to the regions between adjacent antenna elements 20 and the regions near the ends of the substrate 10 on the surface of the substrate 10 in a state where the radome 50 covers the surface of the substrate 10. Here, since the wall portion 52 is connected to the substrate 10 in a state where the radome 50 covers the substrate 10, it is thermally connected to a plurality of heat-generating components 40 arranged on the back surface of the substrate 10, so that the heat of the plurality of heat-generating components 40 can be transmitted to at least the plurality of first heat-radiating fins 54. Specifically, the wall portion 52 is provided at positions covering the respective ends of a plurality of thermal vias 11 formed in the substrate 10 in a state where the radome 50 covers the substrate 10. Thereby, the wall portion 52 can receive the heat of the plurality of heat-generating components 40 via the plurality of thermal vias 11 and transmit it to the plurality of first heat-radiating fins 54.

[0028] Also, as described above, since the wall portion 52 is provided to be connected to the region between two adjacent antenna elements 20 on the surface of the substrate 10, the mutual influence between the plurality of antenna elements 20 can be reduced, and as a result, the antenna characteristics of the antenna device 100 can be improved. In addition, since the wall portion 52 is provided, multiple resonances that may occur in the space inside the conductor housing are suppressed, so that it is not necessary to attach an absorber for suppressing multiple resonances, and as a result, the development cost and the manufacturing cost are suppressed.

[0029] Note that FIG. 3 is a cross-sectional view of the antenna device 100 shown in FIG. 1 when cut along the cutting line II-II passing through the center of each of a plurality of slots 53 arranged in the X-axis direction. However, for the cross-sectional view of the antenna device 100 shown in FIG. 1 when cut along the cutting line passing through the center of each of a plurality of slots 53 arranged in the Y-axis direction, since it is the same except for the heat-radiating fins, the description thereof is omitted.

[0030] Next, the flat portion 51 of the radome 50 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the flat portion 51 further includes a plurality of second heat dissipation fins 55 and a plurality of third heat dissipation fins 56 in addition to the plurality of slots 53 and the plurality of first heat dissipation fins 54 described above. Note that the plurality of first heat dissipation fins 54, the plurality of second heat dissipation fins 55, and the plurality of third heat dissipation fins 56 are collectively referred to as a heat dissipation fin group (heat dissipation fin structure) 57.

[0031] Referring to FIG. 1, each slot 53 has an X-shaped configuration. The shape of each slot 53 will be described in more detail with reference to FIG. 2. Note that FIG. 2 shows only one slot 53 among the plurality of slots 53 formed in the flat portion 51 of the radome 50 and the heat dissipation fin group 57 in its vicinity.

[0032] As shown in FIG. 2, the slot 53 includes, for example, a first opening 53a extending in a first direction at an angle of 45 degrees with respect to the X-axis, and a second opening 53b extending in a second direction different from the first direction, for example, at an angle of 135 degrees (-45 degrees) with respect to the X-axis. The first opening 53a opens in a rectangular shape in the flat portion 51 with the first direction as the longitudinal direction and the second direction as the short direction. The second opening 53b opens in a rectangular shape in the flat portion 51 with the second direction as the longitudinal direction and the first direction as the short direction. The first opening 53a and the second opening 53b intersect at, for example, the center position of the slot 53 to form an opening that opens in an X shape. Each slot 53 can function as a slot antenna element capable of transmitting and receiving two polarized waves by having an opening that opens in an X shape.

[0033] Of course, the angle formed between the first direction and the X-axis, and the angle formed between the second direction and the X-axis are not limited to the above, and may be set to any angle as long as they are not the same as each other. Further, the shapes of the first opening 53a and the second opening 53b do not have to be rectangular. Further, each slot 53 may function as a slot antenna element capable of receiving a plurality of three or more polarization waves, for example, by combining additional openings with the first opening 53a and the second opening 53b.

[0034] The heat dissipation fin group 57 is formed so as to protrude from the outer surface of the flat portion 51 on the side opposite to the substrate 10 side. In other words, the plurality of first heat dissipation fins 54, the plurality of second heat dissipation fins 55, and the plurality of third heat dissipation fins 56 are formed so as to protrude from the outer surface of the flat portion 51 on the side opposite to the substrate 10 side. The heat dissipation fin group 57 is arranged in the vicinity of the plurality of slots 53 that function as slot antenna elements in order to enhance the heat dissipation efficiency.

[0035] Each first heat dissipation fin 54 is arranged between two adjacent slots 53 in the X-axis direction and extends from the end portion of the flat portion 51 in the negative Y-axis direction to the end portion of the flat portion 51 in the positive Y-axis direction. Note that the shape of each first heat dissipation fin 54 shown in FIG. 1 is an example, and other shapes may be used.

[0036] Each second heat dissipation fin 55 is arranged between two adjacent slots 53 in the Y-axis direction and extends from the end portion of the flat portion 51 in the negative X-axis direction to the end portion of the flat portion 51 in the positive X-axis direction.

[0037] Here, the plurality of first heat dissipation fins 54 and the plurality of second heat dissipation fins 55 are formed so as to surround the plurality of slots 53 when viewed from above (that is, when looking at the flat portion 51 of the radome 50 in the negative Z-axis direction). In other words, each slot 53 is surrounded, when viewed from above, by a part of a pair of first heat dissipation fins 54 formed so as to sandwich the slot 53 in the X-axis direction and a part of a pair of second heat dissipation fins 55 formed so as to sandwich the slot 53 in the Y-axis direction. Thereby, the current generated in the vicinity of each slot 53 flows not only along the pair of first heat dissipation fins 54 but also along the pair of second heat dissipation fins 55 in a direction different from that of the pair of first heat dissipation fins 54. Therefore, compared with the case where the current flows only in one direction, the direction of the current is dispersed. Thereby, the influence exerted on the polarization direction transmitted and received in each slot 53 by the current is suppressed. That is, the unintended variation in the polarization direction transmitted and received in each slot 53 due to the current is suppressed. In particular, in each slot 53, since transmission and reception of two polarizations are performed, the unintended variation in the directions of the two polarizations is suppressed, so that the directions of the two polarizations are kept orthogonal, and as a result, the deterioration of the isolation between the two polarizations is suppressed.

[0038] Note that it is preferable that the portions of the heat dissipation fins 54 and 55 surrounding each slot 53 are formed to be point-symmetrical about the central portion (center part) of the slot 53 when viewed from above. In the present embodiment, as shown in FIG. 2, the portions of the heat dissipation fins 54 and 55 surrounding each slot 53 are formed in a rectangular shape so as to be point-symmetrical about the central portion of the slot 53 when viewed from above. Here, the portions of the heat dissipation fins 54 and 55 surrounding each slot 53 constitute a closed circuit. Among the portions of the heat dissipation fins 54 and 55 surrounding the slot 53, the currents flowing through the opposing heat dissipation fins are in opposite directions. Therefore, the influence exerted on the polarization by the currents flowing through the opposing heat dissipation fins is canceled out. Thereby, the deterioration of the isolation between the two polarizations in each slot 53 is effectively suppressed.

[0039] Each third heat dissipation fin 56 is disposed between two adjacent slots 53 in the Y-axis direction. Each third heat dissipation fin 56 is composed of three rectangular heat dissipation fins with the Y-axis direction as the longitudinal direction and the X-axis direction as the short direction. Note that each third heat dissipation fin 56 is not limited to being composed of three heat dissipation fins, and may be composed of any number of one or more heat dissipation fins. Also, since the shape of each third heat dissipation fin 56 is an example, other shapes may be used.

[0040] Subsequently, with reference to FIG. 4, the heat dissipation flow in the antenna device 100 will be described. FIG. 4 is a diagram for explaining the heat dissipation flow in the antenna device 100. FIG. 4 is a diagram obtained by adding white arrows indicating the heat flow generated in the plurality of heat generating components 40 to the schematic cross-sectional view shown in FIG. 3. As shown in FIG. 4, the heat generated in the plurality of heat generating components 40 is transmitted to the wall portion 52 of the radome 50 having thermal conductivity through the ground layer 30 and the plurality of thermal vias 11. Then, the heat of the wall portion 52 is further transmitted to the heat dissipation fin group 57 formed on the surface of the radome 50 and then released to the outside.

[0041] As described above, the antenna device 100 according to the present embodiment includes a radome 50 made of a conductor having thermal conductivity that protects the plurality of antenna elements 20 and also functions as a slot antenna. Here, the radome 50 includes at least a wall portion 52 that receives the heat generated in the antenna device 100 and a heat dissipation fin group (heat dissipation fin structure) 57 that releases the heat received by the wall portion 52 to the outside. Thereby, the antenna device 100 according to the present embodiment can efficiently release the heat generated in the device to the outside without providing a heat dissipation mechanism separately from the radome 50. That is, the antenna device 100 according to the present embodiment can efficiently release the heat generated in the device to the outside while suppressing an increase in size.

[0042] Also, in the antenna device 100 according to the present embodiment, the heat-radiating fin group 57 has at least heat-radiating fins formed so as to surround each slot 53. Thereby, since the direction of the current generated in the vicinity of each slot 53 is dispersed, unintentional fluctuations in the direction of the polarization wave transmitted and received in each slot 53 due to the current are suppressed. In particular, in each slot 53, since transmission and reception of two polarization waves are performed, unintentional fluctuations in the directions of the two polarization waves are suppressed, and the directions of the two polarization waves are kept orthogonal to each other, thereby suppressing deterioration of the isolation between the two polarization waves.

[0043] In addition, in an antenna device, when a resin radome is used to protect the antenna surface, the front surface of the antenna device cannot be used for heat radiation. Therefore, in an antenna device, when a resin radome is used, it is necessary to provide heat-radiating fins on the back surface of the antenna device. On the other hand, in the antenna device 100 according to the present embodiment, since the radome 50 having heat conductivity is used, a heat-radiating mechanism can be provided on the front surface of the antenna device 100, and it is not necessary to provide heat-radiating fins on the back surface of the antenna device 100. Therefore, the antenna device 100 can efficiently release the heat generated inside the device to the outside while suppressing an increase in size.

[0044] Also, in an antenna device, when a resin radome is used to protect the antenna surface, it is necessary to secure a certain amount of space between the antenna element and the resin radome in order to appropriately adjust the antenna characteristics. On the other hand, in the antenna device 100 according to Embodiment 1, since the slot antenna element and the radome 50 are configured by the same member, it is not necessary to secure a space between the antenna element 20 and the radome 50. Therefore, the antenna device 100 can further suppress an increase in size.

[0045] Note that, in addition to the heat dissipation fin group 57, an additional heat dissipation fin group may be provided on the back side of the antenna device 100 according to the antenna device 100 of the present embodiment. Thereby, the antenna device 100 can more efficiently release the heat generated inside the device to the outside. Further, in the antenna device 100 according to the present embodiment, by adjusting the dimensions and positional relationship of the heat dissipation fin group 57, correction of antenna pattern distortion due to the influence of mutual coupling between the plurality of antenna elements 20 may be performed. Thereby, the antenna device 100 can further improve the antenna characteristics.

[0046] In addition, in the present embodiment, the case where a plurality of slots 53 are formed in the radome 50 and heat dissipation fins are formed so as to surround each slot 53 has been described as an example, but the present invention is not limited to this. One slot 53 may be formed in the radome 50, and heat dissipation fins may be formed so as to surround the slot 53.

[0047] Subsequently, some modified examples of the antenna device 100 will be described.

[0048] <First Modified Example of Antenna Device 100> In the antenna device 100, the shape of each slot 53 was X-shaped. On the other hand, in the antenna device 100a which is the first modified example of the antenna device 100, the shape of each slot 53 is a so-called dogbone type. Hereinafter, it will be described with reference to FIG. 5.

[0049] FIG. 5 is an enlarged view of a part of the antenna device 100a according to the first modified example. Note that, in FIG. 5, only one slot 53 out of the plurality of slots 53 formed in the flat portion 51 of the radome 50 and the surrounding heat dissipation fin group 57 are shown. Since the parts of the antenna device 100a other than the shape of each slot 53 are the same as those of the antenna device 100, the description thereof will be omitted.

[0050] The slot 53 shown in FIG. 5 includes a first opening 53a extending in the first direction and a second opening 53b extending in the second direction, similar to the slot 53 shown in FIG. 2. The first opening 53a and the second opening 53b intersect at, for example, the center position of the slot 53 to form an X-shaped opening. Here, in the slot 53 shown in FIG. 5, unlike the slot 53 shown in FIG. 2, both ends of the first opening 53a and both ends of the second opening 53b are each widened.

[0051] More specifically, at each of the end portions 53c and 53d, which are both ends of the first opening 53a, the width in the direction orthogonal to the first direction (the second direction in this example) is wider than the width of the portion other than both ends of the first opening 53a. At each of the end portions 53e and 53f, which are both ends of the second opening 53b, the width in the direction orthogonal to the second direction (the first direction in this example) is wider than the width of the portion other than both ends of the second opening 53b.

[0052] The antenna device 100a according to the first modification can achieve the same effects as the antenna device 100. Further, by adopting the shape shown in FIG. 5 as the shape of each slot 53, the antenna device 100a can broaden the frequency band used for transmission and reception.

[0053] <Second Modification of Antenna Device 100> FIG. 6 is an enlarged view of a part of the antenna device 100b, which is a second modification of the antenna device 100. In FIG. 6, only one slot 53 among the plurality of slots 53 formed in the flat portion 51 of the radome 50 and the surrounding heat radiation fin group 57 are shown. FIG. 7 is a schematic cross-sectional view of a part of the heat radiation fin group 57 provided in the antenna device 100b. In FIG. 7, the cross-section of the heat radiation fin group 57 provided in the antenna device 100b when the antenna device 100b shown in FIG. 6 is cut along the cutting line VII-VII is shown. Among the antenna device 100b, since the parts other than the shape of the heat radiation fin group 57 are the same as those of the antenna device 100, the description thereof is omitted.

[0054] As shown in FIG. 6, a plurality of slits SL are provided in the heat radiation fin group 57 to such an extent that the flow of current is not blocked. Thereby, the water adhering to the outer surface of the radome 50 flows out of the radome 50 through the slits SL without staying on the outer surface of the radome 50.

[0055] The antenna device 100b according to the second modification can achieve the same effects as the antenna device 100. Further, in the antenna device 100b, since a plurality of slits SL are provided in the heat radiation fin group 57, the water adhering to the outer surface of the radome 50 flows out of the radome 50 through the slits SL without staying on the outer surface of the radome 50. Thereby, the antenna device 100b can prevent corrosion of the radome 50 caused by water staying on the outer surface of the radome 50.

[0056] <Third Modification of Antenna Device 100> FIG. 8 is an enlarged view of a part of an antenna device 100c which is a third modification of the antenna device 100. In FIG. 8, only one slot 53 out of the plurality of slots 53 formed in the flat portion 51 of the radome 50 and the heat radiation fin group 57 around it are shown. Among the antenna device 100c, since the parts other than the shape of the heat radiation fin group 57 are the same as those of the antenna device 100, the description thereof is omitted.

[0057] In the heat radiation fin group 57 shown in FIG. 8, the shape of the heat radiation fin 55 is different from that of the heat radiation fin group 57 shown in FIG. 2. Specifically, in the heat radiation fin group 57 shown in FIG. 2, the heat radiation fins 54 and 55 are formed so as to surround the slot 53, whereas in the heat radiation fin group 57 shown in FIG. 8, only the heat radiation fin 55 is formed so as to surround the slot 53.

[0058] Referring to FIG. 8, the heat radiating fins 55 surrounding the slot 53 are formed in a rectangular shape so as to be point-symmetrical about the central portion of the slot 53 in a top view. Here, the heat radiating fins 55 surrounding the slot 53 form a closed circuit. Among the heat radiating fins 55 surrounding the slot 53, since the currents flowing through the respective opposing heat radiating fin portions are in opposite directions, the effects of the currents flowing through the respective opposing heat radiating fin portions on the polarization are canceled out. Thereby, the deterioration of the isolation between the two polarizations in each slot 53 is effectively suppressed.

[0059] The antenna device 100c according to the third modification can achieve the same effects as the antenna device 100. Of course, a plurality of slits SL may be provided in the heat radiating fin group 57 provided in the antenna device 100c.

[0060] <Fourth Modification of Antenna Device 100> FIG. 9 is an enlarged view of a part of an antenna device 100d which is a fourth modification of the antenna device 100. In FIG. 9, only one slot 53 out of the plurality of slots 53 formed in the flat portion 51 of the radome 50 and the surrounding heat radiating fin group 57 are shown. Among the antenna device 100d, since the parts other than the shape of the heat radiating fin group 57 are the same as those of the antenna device 100, the description thereof is omitted.

[0061] In the heat radiating fin group 57 shown in FIG. 9, the shape of the heat radiating fin 55 is different from that of the heat radiating fin group 57 shown in FIG. 2. Specifically, in the heat radiating fin group 57 shown in FIG. 2, the heat radiating fins 54 and 55 were formed so as to surround the slot 53, whereas in the heat radiating fin group 57 shown in FIG. 9, only the heat radiating fin 55 is formed so as to surround the slot 53.

[0062] Referring to FIG. 9, the heat radiating fins 55 surrounding the slot 53 are formed in a circular shape so as to be point-symmetrical about the center of the slot 53 in a top view. Here, the heat radiating fins 55 surrounding the slot 53 form a closed circuit. Among the heat radiating fins 55 surrounding the slot 53, since the currents flowing through the respective opposing heat radiating fin portions are in opposite directions, the effects of the currents flowing through the respective opposing heat radiating fin portions on the polarization are canceled out. Thereby, the degradation of the isolation between the two polarizations in each slot 53 is effectively suppressed.

[0063] The antenna device 100d according to the fourth modification can achieve the same effects as the antenna device 100. Of course, a plurality of slits SL may be provided in the heat radiating fin group 57 provided in the antenna device 100d. Further, each heat radiating fin 55 may be integrally formed with the heat radiating fin 54 corresponding to the heat radiating fin 55.

[0064] <Fifth Modification of Antenna Device 100> FIG. 10 is an enlarged view of a part of the antenna device 100e which is a fifth modification of the antenna device 100. In FIG. 10, only one slot 53 out of the plurality of slots 53 formed in the flat portion 51 of the radome 50 and the surrounding heat radiating fin group 57 are shown. Among the antenna device 100e, since the parts other than the shape of the heat radiating fin group 57 are the same as those of the antenna device 100, the description thereof is omitted.

[0065] In the heat radiating fin group 57 shown in FIG. 10, the shape of the heat radiating fin 55 is different from that of the heat radiating fin group 57 shown in FIG. 2. Specifically, in the heat radiating fin group 57 shown in FIG. 2, the heat radiating fins 54 and 55 were formed so as to surround the slot 53, whereas in the heat radiating fin group 57 shown in FIG. 10, only the heat radiating fin 55 is formed so as to surround the slot 53.

[0066] Referring to FIG. 10, the heat radiating fins 55 surrounding the slot 53 are formed in a hexagonal shape such that they are point-symmetrical about the central portion of the slot 53 when viewed from above. Here, the heat radiating fins 55 surrounding the slot 53 form a closed circuit. Among the heat radiating fins 55 surrounding the slot 53, since the currents flowing through the respective opposing heat radiating fin portions are in opposite directions, the effects of the currents flowing through the respective opposing heat radiating fin portions on the polarization are canceled out. Thereby, the deterioration of the isolation between the two polarizations in each slot 53 is effectively suppressed.

[0067] The antenna device 100e according to the fifth modification can achieve the same effects as the antenna device 100. Note that the heat radiating fins 55 surrounding each slot 53 are not limited to being formed in a hexagonal shape when viewed from above, and may be formed in a polygonal shape that is point-symmetrical about the central portion of the slot 53 when viewed from above. Also, of course, a plurality of slits SL may be provided in the heat radiating fin group 57 provided in the antenna device 100e. Further, each heat radiating fin 55 may be integrally formed with the heat radiating fin 54 corresponding to the heat radiating fin 55.

[0068] <Embodiment 2> FIGS. 11 and 12 are schematic top views of the antenna device 200 according to Embodiment 2. In FIG. 12, the hidden slot portions are represented by broken lines. The antenna device 200 further includes a sealing material 61 as compared with the antenna device 100.

[0069] As shown in FIGS. 11 and 12, the sealing material 61 is provided so as to seal each slot 53 from the outer surface side of the radome 50. The sealing material 61 is made of a resin that transmits radio waves. The sealing material 61 may be formed by filling each slot 53 with a liquid resin such as silicone. Since the other structures of the antenna device 200 are the same as those of the antenna device 100, the description thereof is omitted.

[0070] Thus, the antenna device 200 according to this embodiment can achieve the same effects as the antenna device 100. Furthermore, the antenna device 200 according to this embodiment can improve the airtightness inside the device by sealing each slot 53 with the sealing material 61, so that corrosion inside the device can be prevented.

[0071] <Embodiment 3> FIG. 13 is a schematic cross-sectional view of an antenna device 300 according to Embodiment 3. Note that the schematic cross-sectional view of the antenna device 300 shown in FIG. 13 corresponds to the schematic cross-sectional view of the antenna device 100 shown in FIG. 3.

[0072] As shown in FIG. 13, the antenna device 300 further includes a substrate 70, a ground layer 80, and a plurality of heat transfer members 90 as compared with the antenna device 100. Specifically, the antenna device 300 includes substrates 10 and 70, a plurality of antenna elements 20, ground layers 30 and 80, a plurality of heat generating components 40, a radome 50, and a plurality of heat transfer members 90.

[0073] On the back surface of the substrate 10, instead of a plurality of heat generating components 40, a plurality of heat transfer members 90 having the same number as the number of antenna elements 20 are arranged. The plurality of heat transfer members 90 are arranged at positions corresponding to each of the plurality of antenna elements 20. Specifically, each heat transfer member 90 and the antenna element 20 corresponding to the heat transfer member 90 are arranged so as to sandwich the substrate 10 in the Z-axis direction.

[0074] The substrate 70 is arranged such that the third surface faces the back surface of the substrate 10. That is, the substrate 70 and the substrate 10 are arranged so as to sandwich a plurality of heat transfer members 90 in the Z-axis direction. Note that since the third surface faces the same direction as the surface of the substrate 10, it may be referred to as the front surface or the upper surface, and the fourth surface on the side opposite to the third surface of the substrate 70 may be referred to as the back surface or the lower surface.

[0075] The substrate 70 is formed with a plurality of thermal vias 71 which are through holes penetrating from the front surface to the back surface of the substrate 70. The plurality of thermal vias 71 are arranged in the vicinity of the plurality of heat generating components 40. Further, the plurality of thermal vias 71 are formed so as to surround the plurality of heat generating components 40 in a top view. In the present embodiment, the plurality of thermal vias 71 are formed so as to surround all of the plurality of heat generating components 40, but the present invention is not limited thereto, and for example, the plurality of thermal vias 71 may be formed so as to surround some of the plurality of heat generating components 40.

[0076] On the back surface of the substrate 70, the same number of heat generating components 40 as the number of antenna elements 20 are arranged via a ground layer 80 made of copper foil or the like. The plurality of heat generating components 40 are arranged at positions corresponding to the respective ones of the plurality of antenna elements 20. Specifically, each heat generating component 40 and the antenna element 20 corresponding to the heat generating component 40 are arranged so as to sandwich the substrate 10, the heat transfer member 90 corresponding to the heat generating component 40, and the substrate 70 in the Z-axis direction.

[0077] Here, each heat generating component 40 is thermally connected to the heat transfer member 90 corresponding to the heat generating component 40 via the ground layer 80. Further, each heat transfer member 90 is thermally connected to the radome 50 via the ground layer 30. In other words, the antenna device 300 is configured such that the heat generated by each heat generating component 40 is transmitted to the heat transfer member 90 corresponding to the heat generating component 40 via the thermal via 71 corresponding to the heat generating component 40, and the heat of the heat transfer member 90 is transmitted to the radome 50 via the thermal via 11 corresponding to the heat transfer member. Each thermal via 71 serves as a heat dissipation path for transmitting the heat generated by the heat generating component 40 corresponding to the thermal via 71 to the heat transfer member 90 corresponding to the thermal via 71. Further, each thermal via 11 serves as a heat dissipation path for transmitting the heat of the heat transfer member 90 corresponding to the thermal via 11 to the radome 50.

[0078] Although omitted in FIG. 13, each heat generating component 40 is connected to an external circuit via at least one of the signal lines and control lines other than the ground on the substrate 70. Further, the ground pad (GND PAD1) on the back surface of each heat generating component 40 or the ground pin (GND Pin) disposed around each heat generating component 40 is connected to the ground pattern surface (GND Pattern) or the ground terminal portion (GND PAD2) for ground pin connection on the substrate 70 by a reflow process using surface mount technology (SMT) or the like. The connection portions between these grounds are connected to the ground layer 80 not only for electrical grounding but also for forming a heat dissipation path.

[0079] Each heat transfer member 90 may be, for example, a filter (filter component), a high-frequency coaxial connection line, or the like. When each heat transfer member 90 is a filter, each heat transfer member 90 may be an RF band-pass filter (BPF) having a high thermal conductivity structure. The RF band-pass filter may electrically and thermally connect an RF circuit (not shown), a TRX circuit (not shown), and a digital circuit (not shown) disposed on the substrate 70 to the antenna element 20 disposed on the substrate 10. That is, the RF band-pass filter may be effectively utilized both electrically and as a heat dissipation path between the RF circuit, the TRX circuit, the digital circuit, and each antenna element 20.

[0080] Also, when each heat transfer member 90 is a high-frequency coaxial connection line, the filter is mounted on the back surface of the substrate 10. Then, by exchanging and using the frequency-dependent substrate 10 according to the operating frequency band with respect to the substrate 70 on which a frequency-sharing transceiver (not shown) is disposed, it can be used as a configuration enabling frequency sharing.

[0081] Note that a heat transfer sheet may be disposed between the substrate 10 and the plurality of heat transfer members 90, or between the plurality of heat transfer members 90 and the substrate 70 in order to improve the heat transfer efficiency.

[0082] Next, with reference to FIG. 14, the heat dissipation flow in the antenna device 300 will be described. FIG. 14 is a diagram for explaining the heat dissipation flow in the antenna device 300. FIG. 14 is a diagram obtained by adding white arrows indicating the heat flow generated in the plurality of heat-generating components 40 to the schematic cross-sectional view shown in FIG. 13. As shown in FIG. 14, the heat generated in the plurality of heat-generating components 40 is transmitted to the plurality of heat transfer members 90 via the ground layer 80 and the plurality of thermal vias 71. Thereafter, the heat of the plurality of heat transfer members 90 is transmitted to the wall portion 52 of the heat-conductive radome 50 via the ground layer 30 and the plurality of thermal vias 11. Thereafter, the heat of the wall portion 52 is transmitted to the heat dissipation fin group 57 formed on the surface of the radome 50 and then released to the outside.

[0083] The antenna device 300 according to the present embodiment can achieve the same effects as the antenna devices 100 and 200. That is, the antenna device 300 according to the present embodiment includes a heat-conductive conductor radome 50 that protects the plurality of antenna elements 20 and also functions as a slot antenna. Here, the radome 50 includes at least a wall portion 52 that receives the heat generated in the antenna device 300 and a heat dissipation fin group (heat dissipation fin structure) 57 that releases the heat received by the wall portion 52 to the outside. Thereby, the antenna device 300 according to the present embodiment can efficiently release the heat generated in the device to the outside without providing a heat dissipation mechanism separately from the radome 50. That is, the antenna device 300 according to the present embodiment can efficiently release the heat generated in the device to the outside while suppressing an increase in size.

[0084] In the antenna device 300 according to the present embodiment, the heat dissipation fin group 57 includes at least heat dissipation fins formed so as to surround each slot 53. As a result, the direction of the current generated in the vicinity of each slot 53 is dispersed, so that the unintentional variation in the direction of the polarization wave transmitted and received in each slot 53 due to the current is suppressed. In particular, in each slot 53, since transmission and reception of two polarization waves are performed, the unintentional variation in the direction of the two polarization waves is suppressed, and the directions of the two polarization waves are maintained orthogonal to each other, thereby suppressing the deterioration of the isolation between the two polarization waves.

[0085] Note that the present disclosure is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist thereof. Further, the present disclosure may be implemented by appropriately combining each embodiment.

[0086] In addition, part or all of the above-described embodiments may be described as follows in the following supplementary notes, but are not limited thereto.

[0087] (Supplementary Note 1) A substrate, An antenna element disposed on the surface of the substrate, A radome of a conductor having heat conductivity that covers the surface of the substrate and has a slot formed at a position facing the antenna element, Comprising The radome Has a heat dissipation fin structure formed so as to protrude from the outer surface on the side opposite to the substrate side, The heat dissipation fin structure includes at least heat dissipation fins formed so as to surround the slot, Antenna device.

[0088] (Supplementary Note 2) The heat dissipation fins are formed to be point-symmetrical about the central portion of the slot when viewed from above. The antenna device according to Supplementary Note 1.

[0089] (Supplementary Note 3) The heat-radiating fins are formed in either a polygonal shape or a circular shape when viewed from above. The antenna device according to Addendum 1 or 2.

[0090] (Addendum 4) The heat-radiating fins have one or more slits. The antenna device according to any one of Addenda 1 to 3.

[0091] (Addendum 5) The slot is formed by the intersection of a first opening extending in a first direction and a second opening extending in a second direction different from the first direction. The antenna device according to any one of Addenda 1 to 4.

[0092] (Addendum 6) Both ends of the first opening and the second opening are widened. The antenna device according to Addendum 5.

[0093] (Addendum 7) The radome further has a wall portion protruding from the surface of the substrate to the surface of the substrate on the substrate side. The antenna device according to any one of Addenda 1 to 6.

[0094] (Addendum 8) A substrate, a plurality of antenna elements disposed on the surface of the substrate, a radome of a conductor having thermal conductivity that covers the surface of the substrate and has a plurality of slots formed at positions facing each of the plurality of antenna elements, and is provided with The radome has a heat-radiating fin structure formed so as to protrude from the outer surface on the side opposite to the substrate side, The heat-radiating fin structure has at least a plurality of heat-radiating fins formed so as to surround each of the plurality of slots, Antenna device.

[0095] (Appendix 9) When viewed from above, each of the heat dissipation fins is formed to be point-symmetrical about the center of the slot corresponding to the heat dissipation fin. The antenna device according to Appendix 8.

[0096] (Appendix 10) When viewed from above, each of the heat dissipation fins is formed in either a polygonal shape or a circular shape. The antenna device according to Appendix 8 or 9.

[0097] (Appendix 11) Each of the heat dissipation fins has one or more slits. The antenna device according to any one of Appendices 8 to 10.

[0098] (Appendix 12) Each of the slots is formed by the intersection of a first opening extending in a first direction and a second opening extending in a second direction different from the first direction. The antenna device according to any one of Appendices 8 to 11.

[0099] (Appendix 13) Both ends of the first opening and the second opening are widened. The antenna device according to Appendix 12.

[0100] (Appendix 14) The radome further has a wall portion protruding from the surface of the substrate toward the surface of the substrate on the substrate side. The antenna device according to any one of Appendices 8 to 13.

[0101] (Appendix 15) A radome of a conductor having thermal conductivity, in which a slot is formed at a position facing the antenna element in a state of covering the surface of the substrate on which the antenna element is disposed. The radome has a heat dissipation fin structure formed to protrude from the outer surface on the side opposite to the substrate side. The heat-radiating fin structure is at least provided with heat-radiating fins formed so as to surround the slot redome.

[0102] (Appendix 16) The heat-radiating fins are formed to be point-symmetrical about the central portion of the slot. The redome according to Appendix 15.

[0103] (Appendix 17) The heat-radiating fins are formed in either a polygonal shape or a circular shape when viewed from above. The redome according to Appendix 15 or 16.

[0104] (Appendix 18) The heat-radiating fins have one or more slits. The redome according to any one of Appendices 15 to 17.

[0105] (Appendix 19) The slot is formed by the intersection of a first opening extending in a first direction and a second opening extending in a second direction different from the first direction. The redome according to any one of Appendices 15 to 18.

[0106] (Appendix 20) Both ends of the first opening and the second opening are widened. The redome according to Appendix 19.

[0107] (Appendix 21) The redome further has a wall portion protruding from the surface of the substrate side to the surface of the substrate. The antenna device according to any one of Appendices 8 to 13.

[0108] The present invention has been described with reference to the embodiments above, but the present invention is not limited thereto. Various changes that can be understood by those skilled in the art within the scope of the invention can be made to the configuration and details of the present invention.

Description of Symbols

[0109] 10 Substrate 11 Thermal via 20 Antenna element 30 Ground layer 40 Heat-generating component 50 Radome 51 Planar part 52 Wall part 53 Slot 53a First opening 53b Second opening 53c End part 53d End part 53e End part 53f End part 54 First heat-radiating fin 55 Second heat-radiating fin 56 Third heat-radiating fin 57 Heat-radiating fin group 61 Sealing material 70 Substrate 71 Thermal via 80 Ground layer 90 Heat transfer member 100 Antenna device 100a~100e Antenna device 200 Antenna device 300 Antenna device

Claims

1. A substrate, antenna elements disposed on the surface of the substrate, a radome made of a conductor having thermal conductivity, covering the surface of the substrate and having a slot formed at a position facing the antenna elements, comprising: the radome, has a heat dissipation fin structure formed to protrude from the outer surface on the side opposite to the substrate side, the heat dissipation fin structure has at least heat dissipation fins formed so as to surround the slot, an antenna device.

2. The antenna device according to claim 1, wherein the heat dissipation fins are formed to be point-symmetrical about the central portion of the slot in a top view. The antenna device according to claim 1.

3. The antenna device according to claim 1 or 2, wherein the heat dissipation fins are formed in any one of a polygonal shape and a circular shape in a top view. The antenna device according to claim 1 or 2.

4. The antenna device according to any one of claims 1 to 3, wherein the heat dissipation fins have one or more slits. The antenna device according to any one of claims 1 to 3.

5. The antenna device according to any one of claims 1 to 4, wherein the slot is formed by the intersection of a first opening extending in a first direction and a second opening extending in a second direction different from the first direction. The antenna device according to any one of claims 1 to 4.

6. The antenna device according to claim 5, wherein both ends of the first opening and the second opening are widened. The antenna device according to claim 5.

7. the radome, further has a wall portion protruding from the surface on the substrate side to the surface of the substrate, The antenna device according to any one of claims 1 to 6.

8. A substrate, a plurality of antenna elements disposed on the surface of the substrate, a radome made of a conductor having thermal conductivity, covering the surface of the substrate and having a plurality of slots formed at positions facing the respective antenna elements, comprising: the radome, has a heat dissipation fin structure formed to protrude from the outer surface on the side opposite to the substrate side, the heat dissipation fin structure, has at least a plurality of heat dissipation fins formed so as to surround each of the plurality of slots, an antenna device.

9. The antenna device according to claim 8, wherein each of the heat dissipation fins is formed to be point-symmetrical about the central portion of the slot corresponding to the heat dissipation fin in a top view. The antenna device according to claim 8.

10. A radome made of a conductor having thermal conductivity, with a slot formed at a position facing the antenna element in a state of covering the surface of the substrate on which the antenna element is disposed, the radome, It has a heat dissipation fin structure formed to protrude from the outer surface on the side opposite to the substrate side, The heat dissipation fin structure is, At least has heat dissipation fins formed so as to surround the slot, Dome.

Images