JP2023181038A - Antenna equipment and communication equipment - Google Patents

Abstract

An antenna device having a predetermined directivity and suppressing gain in the back direction is provided. The antenna device includes a substrate including a plurality of layers including at least a metamaterial layer, a ground layer, and a first layer on the opposite side of the ground layer with the metamaterial layer interposed therebetween; A first resonator provided in the first layer and supplied with power; a second resonator constituted by two conductors provided at the same time, and one end of each of the two conductors of the second resonator is connected to the ground layer. [Selection diagram] Figure 7

Description

The present disclosure relates to an antenna device and a communication device.

2. Description of the Related Art Conventionally, there are environments in which a plurality of communication devices each equipped with an antenna device are installed and used in a predetermined space. For example, the predetermined space may be a space inside an aircraft, and the communication device may be a display device provided at each seat in the aircraft. Under such an environment, there is a need to suppress communications between communication devices from interfering with each other and to transmit and receive signals with appropriate directivity. For example, Patent Document 1 discloses the configuration of an antenna that can obtain directivity in a predetermined direction.

International Publication No. 2018/198981

The present disclosure was devised in view of the conventional circumstances described above, and an object of the present disclosure is to provide an antenna device having predetermined directivity.

The present disclosure provides a substrate comprising a plurality of layers including at least a metamaterial layer, a ground layer, and a first layer on the opposite side of the ground layer with the metamaterial layer in between; a first resonator provided in the layer and supplied with power; and a first resonator provided along the longitudinal direction of the first resonator on both sides of the first resonator in the lateral direction in the first layer. a second resonator made up of two conductors, and one end of each of the two conductors of the second resonator is connected to the ground layer.

Further, the present disclosure includes an antenna device, and the antenna device includes a plurality of layers including at least a metamaterial layer, a ground layer, and a first layer on the opposite side of the ground layer with the metamaterial layer interposed therebetween. a first resonator provided in the first layer and supplied with power; a second resonator composed of two conductors provided along the longitudinal direction of the first resonator, and one end of each of the two conductors of the second resonator is connected to the ground. The first layer is located on the front side and the ground layer is located on the back side.

Note that arbitrary combinations of the above components and expressions of the present disclosure converted between devices, systems, etc. are also effective as aspects of the present disclosure.

According to the present disclosure, it is possible to provide an antenna device that suppresses gain in the back direction and has a predetermined directivity.

An external perspective view of a communication device including an antenna device according to Embodiment 1 Schematic diagram showing the outline of the substrate of the antenna device according to Embodiment 1 External view of the antenna device according to Embodiment 1 seen from the front side A diagram showing an example of a cross section of the substrate of the antenna device according to Embodiment 1. A diagram showing an example of a cross section of the substrate of the antenna device according to Embodiment 1. A diagram showing an example of a cross section of the substrate of the antenna device according to Embodiment 1. A diagram showing an example of a layer structure of the antenna device according to Embodiment 1. External view from the front side of a conventional antenna device for comparison Diagram for explaining electric field distribution of the antenna device according to Embodiment 1 A diagram for explaining the gain of the antenna device according to Embodiment 1 Diagram for explaining an example of installation of a communication device according to Embodiment 1 External view of the antenna device according to Embodiment 2 seen from the front side A diagram showing an example of a cross section of a substrate of an antenna device according to Embodiment 2. Diagram for explaining electric field distribution of the antenna device according to Embodiment 2 Diagram for explaining the gain of the antenna device according to Embodiment 2

(Circumstances leading to this disclosure)
BACKGROUND ART Conventionally, there is an environment in which a plurality of communication devices each having an antenna device are provided in a narrow space. Under such an environment, it is desirable to use an antenna device having a predetermined directivity so as not to interfere with the communications of each communication device. In addition, in recent years, it is necessary to take into account constraints that affect communication of antenna devices, such as miniaturization of communication devices and restrictions on the installation position and mounting structure of antenna devices. Particularly in an environment where multiple communication devices are arranged in a narrow space with a certain regularity, it is necessary to reduce the gain in a predetermined direction, for example, toward the back side of the communication device. It is required to suppress interference. For example, in Patent Document 1, the use of the antenna device under the above environment is not sufficiently considered.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments specifically disclosing an antenna device and a communication device according to the present disclosure will be described in detail with reference to the accompanying drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

<Embodiment 1>
In the first embodiment described below, the operating frequency is a frequency in the 2.4 GHz band (for example, 2400 to 2500 MHz), and wireless LAN (Local Area Network) such as Bluetooth (registered trademark) or Wi-Fi (registered trademark) is used. An antenna device that is capable of wireless communication in accordance with the standard will be described as an example. Note that the present invention is not limited to the above standards, and may be applied to wireless communication in frequency bands compliant with other standards.

[Device configuration]
FIG. 1 is an external perspective view showing the external appearance of a communication device 1 equipped with an antenna device 100 according to the present embodiment. In the following description, it will be assumed that the XYZ axes shown in each figure correspond to each other. The X-axis corresponds to the thickness direction of the communication device 1, that is, the front-back direction. The Y-axis corresponds to the width direction of the communication device 1, that is, the longitudinal direction of the antenna device 100. The Z-axis corresponds to the height direction of the communication device 1, that is, the lateral direction of the antenna device 100.

The communication device 1 is, for example, a seat monitor attached to the back of a passenger seat in an aircraft that can use Bluetooth (registered trademark) wireless communication. Note that the communication device 1 in which the antenna device 100 according to the present embodiment is arranged is not limited to a seat monitor. The communication device 1 is provided with a display section (for example, a touch panel) using a panel such as glass on the front side. The communication device 1 is used by a passenger, who is a user, seated in a passenger seat facing the display section. For example, the communication device 1 causes the display unit to display data such as images, and receives user operations via the display unit. Furthermore, the communication device 1 can perform wireless communication using Bluetooth (registered trademark) with a communication device (not shown) such as a smartphone or a tablet terminal held by a user via the antenna device 100. be.

In the antenna device 100, a printed wiring board on which each part is mounted is surrounded by a protective cover (not shown), and is fixedly placed at a predetermined position in the casing of the communication device 1. In the example of FIG. 1, the antenna device 100 is arranged near the lower center of the frame around the display section of the communication device 1. The antenna device 100 is connected to the Bluetooth (registered trademark) 2 from the front of the communication device 1 (for example, the touch panel side) toward the front of the passenger seat on the rear side of the aircraft, that is, toward the user who uses the communication device 1. .Emits polarized waves (electromagnetic waves) in the 4 GHz band. A broken line 10 conceptually shows the range of gain by the antenna device 100. A detailed configuration example and gain of the antenna device 100 will be described later.

FIG. 2 is a schematic diagram showing the outline of the substrate of the antenna device 100 according to the present embodiment. The substrate of antenna device 100 according to this embodiment has a rectangular shape. The length of the substrate in the longitudinal direction (Y-axis direction) is indicated as L, and the length in the transverse direction (Z-axis direction) is indicated as W. Although the shape and size of the substrate are not particularly limited, assuming that the gain on the back side of the substrate, which will be described later, is reduced, W is required to be, for example, 30 mm or more in the 2 GHz band.

When the antenna device 100 is installed in the communication device 1, a metal structure such as a metal frame of the communication device 1 is located around the antenna device 100. Furthermore, the communication device 1 is installed in a passenger seat, and a metal piece for the installation is located around the antenna device 100. In other words, when the antenna device 100 is installed in the communication device 1, it is surrounded by a metal structure, and is easily influenced by surrounding metal, resulting in poor performance as an antenna (for example, gain or VSWR (Voltage)). There is also concern about a decrease in the frequency characteristics of the Standing Wave Ratio.

In this embodiment, a configuration example will be described in which a desired directivity is achieved by suppressing backward gain of the communication device 1 while suppressing deterioration in performance as an antenna device.

FIG. 3 is an external view of the antenna device 100 according to the present embodiment viewed from the front side of the communication device 1 along the X-axis. The antenna device 100 is configured with a laminated substrate having a layered structure including a plurality of layers. FIG. 3 shows a state in which part of the configuration is transparent.

The antenna device 100 according to this embodiment will be described using a dipole antenna as an example. A dipole antenna is formed on a printed wiring board, which is a laminated board having a plurality of layers, and a pattern of the dipole antenna is formed by etching the metal foil on the surface. Each of the plurality of layers is made of, for example, copper foil or glass epoxy. The antenna device 100 according to the present embodiment includes at least an antenna layer 110 as an example of a first layer, an AMC (Artificial Magnetic Conductor) layer 120, and a ground layer 130.

The antenna layer 110 includes an antenna conductor 111 that is a strip conductor as an example of a feeding antenna, and an antenna conductor 112 that is a strip conductor as an example of a non-feeding antenna. A via conductor 113 for feeding power is connected to the antenna conductor 111. A via conductor 114 for connecting to ground (GND) is connected to the antenna conductor 112. Antenna conductors 111 and 112 function as first resonators. In this embodiment, antenna conductors 111 and 112 are each configured to have a longitudinal length of λ/4. Here, λ indicates the frequency.

Furthermore, antenna conductors 115 and 117, which are strip conductors as an example of a non-feeding antenna, are provided so as to sandwich the antenna conductors 111 and 112 on both sides in the Z-axis direction. A via conductor 116 is connected to the antenna conductor 115 for connection to the ground (short circuit). A via conductor 118 is connected to the antenna conductor 117 for connection to ground (short circuit). Via conductor 116 and via conductor 118 are connected to the ends of antenna conductors 115 and 117, respectively, and are arranged on opposite sides in the Y-axis direction. Antenna conductors 115, 117 function as second resonators. In this embodiment, antenna conductors 115 and 117 are each configured to have a longitudinal length of λ/2.

The AMC layer 120 is a metamaterial layer made of a metamaterial having PMC (Perfect Magnetic Conductor) characteristics, and is formed of a predetermined metal pattern. The ground layer 130 is formed using conductive copper foil, for example.

The layered structure of the antenna device 100 will be explained using FIGS. 4 to 7. FIG. 4 shows a cross-sectional shape when viewed along the Z-axis at the position of the first resonator (antenna conductors 111, 112) of the antenna device 100 shown in FIG. Since the antenna conductor 111 functions as a power feeding antenna, it is connected to a power feeding terminal (not shown) via a via conductor 113 provided along the X-axis direction. At this time, the AMC layer 120 is provided with a through hole through which the via conductor 113 passes. Since the antenna conductor 112 functions as a non-feed antenna, it is connected to the GND layer 130 via a via conductor 114 provided along the X-axis direction. Therefore, the antenna conductor 111, which is a feeding antenna, is connected to the feeding terminal and is not connected to the AMC (AMC layer 120) and GND (GND layer 130). On the other hand, the antenna conductor 112, which is a non-feed antenna, is connected to the AMC (AMC layer 120) and GND (GND layer 130), and is not connected to the feed terminal.

Via conductor 113 is formed using conductive copper foil, for example, and constitutes a feed line between the feed point of antenna conductor 111 and a wireless communication circuit (not shown). The wireless communication circuit is, for example, a circuit that is provided inside the communication device 1 and processes various signals for communication. Via conductor 114 is formed using conductive copper foil, for example, and constitutes a ground line between the feeding point of antenna conductor 112 and a wireless communication circuit (not shown).

The antenna conductors 111 and 112 each have a rectangular or substantially rectangular shape so as to constitute, for example, a dipole antenna, and their longitudinal directions extend in a straight line along the Y-axis direction. Further, in order to minimize cancellation of electromagnetic waves radiated from each of the antenna conductors 111 and 112, the opposite ends of the antenna conductors 111 and 112 on the feeding point side are arranged to be separated by a predetermined interval.

FIG. 5 shows a cross-sectional shape of the antenna device 100 shown in FIG. 3 when viewed along the Z-axis at the position of the second resonant section (antenna conductor 115). Since the antenna conductor 115 functions as a non-feed antenna, it is connected to the GND layer 130 via a via conductor 116 provided along the X-axis direction. Therefore, the antenna conductor 115, which is a non-feed antenna, is connected to GND (GND layer 130) and is not connected to the feed terminal and AMC (AMC layer 120).

FIG. 6 shows a cross-sectional shape of the antenna device 100 shown in FIG. 3 when viewed along the Z-axis at the position of the second resonant section (antenna conductor 117). Since the antenna conductor 117 functions as a non-feeding antenna, it is connected to the GND layer 130 via a via conductor 118 provided along the X-axis direction. Therefore, the antenna conductor 117, which is a non-feed antenna, is connected to GND (GND layer 130) and is not connected to the feed terminal and AMC (AMC layer 120).

FIG. 7 is a diagram showing a layered structure of the antenna device 100 and an example of the configuration of each layer. Note that this layered structure is shown focusing only on the portions related to this embodiment, and may include additional layers. As shown in FIG. 7A, the antenna device 100 is provided with an antenna layer 110, a dielectric substrate 140, an AMC layer 120, a dielectric substrate 150, and a ground layer 130 in order from the front side in the X-axis direction. Further, the antenna device 100 is installed so as to be surrounded by a U-shaped frame 1100. In other words, only the front side of the communication device 1 is not surrounded by the frame 1100.

FIG. 7B shows a schematic configuration of the antenna layer 110, the AMC layer 120, and the ground layer 130 as viewed from the front side of the antenna device 100 along the X-axis.

FIG. 8 shows a configuration example of a conventional antenna device 200 for comparison with the antenna device 100 of this embodiment. The antenna device 200 shown in FIG. 8 differs from the antenna device 100 of the present embodiment shown in FIG. 3 in that it does not have the second resonant section (antenna conductors 115, 117). Therefore, antenna conductors 211, 212 and via conductors 213, 214 of antenna device 200 in the conventional configuration are respectively equivalent to antenna conductors 111, 112 and via conductors 113, 114 of antenna device 100 of this embodiment.

FIG. 9 shows an example of electric field distribution of antenna device 100 according to this embodiment. Here, different colors are shown depending on the strength of the electric field. As shown in FIG. 9, the configuration is such that an electric field is generated in the second resonant portion (antenna conductors 115, 117) having a length of λ/2.

[gain]
FIG. 10 is a diagram showing a comparison result of gains between antenna device 100 according to this embodiment and antenna device 200 having a conventional configuration. A range 1001 indicates the gain of the antenna device 100 according to this embodiment, and a range 1002 indicates the gain of the antenna device 200 according to the conventional configuration. Comparing these, as shown in a difference 1003, in the antenna device 100, it is possible to reduce the gain on the rear side (that is, on the back side of the communication device 1) compared to the gain of the conventional antenna device 200. ing. In other words, the two newly provided second resonators reduce the resonance of the ground layer 130 disposed below the AMC layer 120.

FIG. 11 is a conceptual diagram for explaining the gain when the antenna device 100 according to this embodiment and the antenna device 200 with a conventional configuration are installed in an aircraft. Range 1001 corresponds to the gain of antenna device 100 shown in FIG. 10, and range 1002 corresponds to the gain of antenna device 200 shown in FIG. Under such an environment, signal interference can be suppressed by reducing the gain on the back side of the communication device 1. On the other hand, by preventing the gain on the front side of the communication device 1 from being reduced as much as possible, it is possible to suppress interference with communication with devices owned by the user, for example.

As described above, according to the present embodiment, the antenna device 100 is composed of a plurality of layers including at least the AMC layer 120, the ground layer 130, and the antenna layer 110 on the opposite side of the ground layer 130 with the AMC layer 120 in between. a first resonator (antenna conductors 111, 112) provided in the antenna layer 110 and fed with power; a second resonator (antenna conductors 115, 117) formed of two conductors provided along the longitudinal direction of the antenna, each of the two conductors of the second resonator having one end thereof Connected to ground layer 130.

This makes it possible to provide an antenna device that has a predetermined directivity and suppresses gain in the back direction. In particular, it is possible to reduce the resonance of the ground layer disposed below the AMC layer and reduce the gain on the back side of the antenna device 100.

Further, the ends of the two conductors (antenna conductors 115 and 117) connected to the ground layer 130 are located on opposite sides in the longitudinal direction (for example, the Y-axis direction).

As a result, when configuring an antenna device having a predetermined directivity with suppressed gain in the back direction, the connection between each of the two antenna conductors and the ground layer can be made so that they are opposite in the longitudinal direction of the board. Design becomes possible.

Further, the first resonator of the antenna device 100 is composed of two conductors (antenna conductors 111 and 112), one of the two conductors of the first resonator (antenna conductor 111) is fed with power, and the other (antenna conductor 112) is connected to ground layer 130.

This makes it possible to provide an antenna device that uses a dipole antenna and has a predetermined directivity.

Further, the length of the second resonator of the antenna device 100 in the longitudinal direction is half the length of the target frequency λ of the output radio wave of the antenna device 100.

This makes it possible to provide an antenna device having a predetermined directivity corresponding to the frequency λ of interest.

<Embodiment 2>
Embodiment 2 of the present invention will be described. Note that the description of parts that overlap with those in Embodiment 1 will be omitted, and the description will focus on the differences.

FIG. 12 is an external view of the antenna device 300 according to the present embodiment viewed from the front side of the communication device 1 along the X-axis. The difference from the antenna device 100 of the first embodiment shown in FIG. 3 is the position of the via conductor 318. In the antenna device 300, the via conductor 316 and the via conductor 318 are arranged at the same position in the Y-axis direction. That is, the connection configuration between the two antenna conductors 315 and 317 and the GND layer 330 is different from the configuration in the first embodiment. In such a configuration, antenna conductors 315, 317 function as second resonators. The configuration other than the above is the same as that of antenna device 100 of Embodiment 1.

FIG. 13 is a diagram for explaining the layered structure of antenna device 300 according to this embodiment. FIG. 13A shows the cross-sectional shape of the antenna conductor 315, which is one of the second resonators of the antenna device 300 shown in FIG. 12, when viewed along the Z-axis. Since the antenna conductor 315 functions as a non-feed antenna, it is connected to the GND layer 330 via a via conductor 316 provided along the X-axis direction. Therefore, the antenna conductor 315, which is a non-feed antenna, is connected to GND (GND layer 330) and not connected to the feed terminal and AMC (AMC layer 320).

FIG. 13(b) shows a cross-sectional shape when viewed along the Z-axis at the position of the antenna conductor 317, which is one of the second resonant parts of the antenna device 300 shown in FIG. Since the antenna conductor 317 functions as a non-feeding antenna, it is connected to the GND layer 330 via a via conductor 318 provided along the X-axis direction. Therefore, the antenna conductor 317, which is a non-feed antenna, is connected to GND (GND layer 330) and not connected to the feed terminal and AMC (AMC layer 320).

FIG. 14 shows an example of electric field distribution of antenna device 300 according to this embodiment. Here, different colors are shown depending on the strength of the electric field. As shown in FIG. 14, the configuration is such that an electric field is generated in the second resonant portion (antenna conductors 315, 317) having a length of λ/2.

[gain]
FIG. 15 is a diagram showing the gain of the antenna device according to this embodiment. Range 1501 indicates the gain of antenna device 300 according to this embodiment. The upper side of the figure is the forward direction. Referring to FIG. 15, in the antenna device 300, the gain on the rear side (that is, the back side of the communication device 1) can be reduced compared to the gain on the front side. In other words, the same effect as the gain of antenna device 100 shown in Embodiment 1 using FIG. 10 can be produced. In other words, even if the two second resonators (antenna conductors 315 and 317) are connected to the GND layer 330 at the same position in the Y-axis direction, the ground layer 330 located below the AMC layer 320 It is possible to reduce resonance.

As described above, according to this embodiment, the ends of the two conductors (antenna conductors 315, 317) connected to the ground layer 130 are located on the same side in the longitudinal direction (for example, the Y-axis direction).

As a result, when configuring an antenna device with a predetermined directivity that suppresses gain in the back direction, the two antenna conductors are connected to the ground layer on the same side in the longitudinal direction of the board. design becomes possible.

<Other embodiments>
Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear to those skilled in the art that various changes, modifications, substitutions, additions, deletions, and equivalents may be made within the scope of the claims; It is understood that it naturally falls within the technical scope of the present disclosure. Moreover, each component in the various embodiments described above may be combined arbitrarily within a range that does not depart from the spirit of the invention.

In the above embodiment, the antenna device 100 is mounted in a seat monitor that will be installed in the later stage. However, the present invention is not limited to sheet monitors, and is applicable to, for example, base units or slave units of cordless telephones, electronic shelf labels (e.g., card-type devices on which product selling prices are displayed, which are affixed to display shelves in retail stores). It may be installed in many IoT (Internet of Things) devices such as electronic devices), smart speakers, in-vehicle devices, microwave ovens, and refrigerators.

Furthermore, although the antenna device 100 according to the above-described embodiment has been described using an example of an antenna device capable of both transmitting and receiving electromagnetic waves, the present invention can be applied to, for example, an antenna device exclusively for transmitting or exclusively for receiving. Good too.

The present disclosure is useful as an antenna device and a communication device in which a plurality of antenna devices are installed in a predetermined space.

1 Communication device 100, 300 Antenna device 110, 310 Antenna layer 111, 112, 311, 312 Antenna conductor (first resonance part)
113, 114, 116, 118, 313, 314, 316, 318 Via conductor 115, 117, 315, 317 Antenna conductor (second resonance part)
120, 320 AMC layer (metamaterial layer)
130, 330 ground layer

Claims (6)

A substrate composed of a plurality of layers including at least a metamaterial layer, a ground layer, and a first layer on the opposite side of the ground layer with the metamaterial layer in between;
a first resonator provided in the first layer and supplied with power;
a second resonator composed of two conductors provided along the longitudinal direction of the first resonator on both sides of the first resonator in the lateral direction in the first layer;
Equipped with
Each of the two conductors of the second resonator has one end connected to the ground layer.
antenna device. The ends of the two conductors on the side connected to the ground layer are located on opposite sides in the longitudinal direction,
The antenna device according to claim 1. The ends of the two conductors on the side connected to the ground layer are located on the same side in the longitudinal direction,
The antenna device according to claim 1. The first resonator is composed of two conductors,
One of the two conductors of the first resonator is supplied with power, and the other is connected to the ground layer.
The antenna device according to claim 1. The length of the second resonator in the longitudinal direction is half the wavelength of the output radio wave of the antenna device.
The antenna device according to claim 1. comprising the antenna device according to any one of claims 1 to 5,
the first layer is located on the front side,
the ground layer is located on the back side;
Communication device.

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