Antenna equipment and antenna unit

Abstract

The present invention provides an antenna device that widens the radio wave radiation directivity while suppressing an increase in size, and that can be mounted on a circuit board while maintaining that radiation directivity. [Solution] An antenna device comprising: a base on which a radiating element is arranged; four sides that surround the radiating element when viewed from a direction perpendicular to the base; a rectangular prism-shaped recess defined by these recesses, a ground layer arranged on the back side of the base; an element surrounding portion made of a dielectric material; and a power supply portion that connects to the radiating element and supplies power to the radiating element at a position offset from the center of the radiating element along the direction in which the sides face each other when viewed from a direction perpendicular to the base; wherein the outer surface of the element surrounding portion is provided with a projection that protrudes toward the direction perpendicular to the direction from the center toward the position.

Description

Technical Field

[0001] The present invention relates to an antenna device and an antenna unit.

Background Art

[0002] An antenna device is required to have a wide-angle radiation directivity capable of transmitting and receiving radio waves in various directions. For example, Patent Document 1 discloses a technique for obtaining a wide-angle radiation directivity by performing beamforming by giving a phase difference to each antenna in an array antenna in which a plurality of antennas are arranged in an array.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, miniaturization of antenna devices has been desired. On the other hand, the array antenna disclosed in Patent Document 1 requires a space for arranging a plurality of antennas, and thus there is a concern about enlargement. Therefore, there has been a demand for the development of an antenna device that widens the radiation directivity of radio waves while suppressing enlargement. In addition, since the radiation directivity of an antenna device tends to decrease when mounted on a circuit board compared to when it is alone, there has also been a demand for the development of an antenna device that maintains the radiation directivity even when mounted on a circuit board.

[0005] The present invention has been made to solve at least a part of the above-described problems, and an object thereof is to provide an antenna device that can widen the radiation directivity of radio waves while suppressing enlargement and can be mounted on a circuit board while maintaining the radiation directivity.

Means for Solving the Problems

[0006] The present invention has been made to solve at least some of the above-mentioned problems and can be realized in the following forms.

[0007] (1) According to one embodiment of the present invention, an antenna device is provided. This antenna device has a rectangular prism-shaped recess defined by a bottom surface on which a radiating element is arranged and four side surfaces that surround the radiating element when viewed from a direction perpendicular to the bottom surface, and a ground layer is arranged on the back side of the bottom surface, and comprises an element surrounding portion made of a dielectric material, and a power supply portion that is connected to the radiating element at a position offset from the center of the radiating element along the direction in which the side surfaces face each other when viewed from the direction perpendicular to the bottom surface, and supplies power to the radiating element, wherein the outer surface of the element surrounding portion is provided with a projection that protrudes toward the direction perpendicular to the direction toward the center and the position.

[0008] With this configuration, when viewed from an orthogonal direction, the radiating element is surrounded by four sides that define the recessed portion of the element enclosure made of dielectric material. Therefore, the electromagnetic distribution of these sides made of dielectric material can widen the radiation directivity of the radio waves emitted from the radiating element. Furthermore, since it is not necessary to arrange multiple antennas to widen the angle, the size of the antenna device itself can be suppressed. In addition, with this configuration, since a protrusion is provided, when the antenna device is fitted onto the outer edge of a circuit board that has a notch into which the antenna device can be fitted while the protrusion is placed, the opening of the recessed portion of the antenna device can be oriented in a direction along the circuit board. The inventors of this application have found that when the antenna device is mounted on a circuit board in this state, the antenna device can be mounted on the circuit board while maintaining the same radiation directivity as when the antenna device is used alone. Therefore, with this configuration, it is possible to provide an antenna device that widens the radiation directivity of radio waves while suppressing size increase, and that can be mounted on a circuit board while maintaining that radiation directivity.

[0009] (2) In the antenna device according to the above embodiment, the end of the power supply section opposite to the end connected to the radiating element may protrude from the ground layer toward the side opposite to the back surface. With this configuration, when the antenna device is fitted onto the outer edge of a circuit board that has a notch formed therein that allows the antenna device to be fitted while the protruding part is mounted on it, the end of the power supply unit can be positioned on the circuit board. Therefore, the power supply line positioned on the circuit board can be connected to the end of the power supply unit as a power source that supplies high-frequency signals to the power supply unit.

[0010] (3) According to another embodiment of the present invention, an antenna unit is provided. This antenna unit comprises the antenna device described in (1) or (2) above, and a circuit board, A notch is formed on the outer edge of the circuit board, allowing the antenna device to be fitted while the protruding portion is placed on the circuit board. With this configuration, when the antenna device is mounted on a circuit board via the notch, the opening of the recess in the antenna device can be oriented in a direction aligned with the circuit board. The inventors of the present invention have found that when the antenna device is mounted on a circuit board in this state, it is possible to mount the antenna device on the circuit board while maintaining the same radiation directivity as when the antenna device is used alone. Therefore, with this configuration, it is possible to provide an antenna unit that can mount an antenna device with wide-angle radiation directivity on a circuit board while maintaining its radiation directivity.

[0011] Furthermore, the present invention can be realized in various forms, for example, as an antenna device, a communication device, or a component or device comprising these. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of an antenna device according to an embodiment of the present invention. [Figure 2] This is a plan view of the antenna device. [Figure 3]This is a cross-sectional view of the antenna device. [Figure 4] This is an explanatory diagram of a circuit board. [Figure 5] This is an explanatory diagram showing the antenna device mounted on a circuit board. [Figure 6] This is a diagram illustrating the reflection characteristics of an antenna device. [Figure 7] This is an explanatory diagram of the radiation directivity of an antenna device. [Figure 8] This is an explanatory diagram of the radiation directivity of an antenna device. [Modes for carrying out the invention]

[0013] <Embodiment> Figure 1 is a perspective view of an antenna device 1 according to an embodiment of the present invention. Figure 2 is a plan view of the antenna device 1. Figure 3 is a cross-sectional view of the antenna device 1 along the line F3-F3 in Figure 2. Each of Figures 1 to 3 shows mutually orthogonal XYZ axes. The antenna device 1 comprises an element enclosure 10 and a power supply section 20.

[0014] The element enclosure 10 is made of a dielectric material. The element enclosure 10 has a rectangular prism-shaped recess D in the central part when viewed from the +Z axis direction, and in general appearance, it is composed of a rectangular parallelepiped-shaped part BD that encloses the recess D, and protruding parts PL and PR which will be described later. The recess D is defined by a bottom surface B and four side surfaces S1 to S4. A rectangular radiating element R is placed in the central part of the bottom surface B. The radiating element R is an element that radiates radio waves in the +Z axis direction when a high-frequency signal is supplied from a power supply unit 20 which will be described later. The side surfaces S1 to S4 surround the radiating element R when viewed from an orthogonal direction perpendicular to the bottom surface B (in this embodiment, the +Z axis direction) (see Figure 2). Side surfaces S1 and S2 are side surfaces along the YZ plane and are opposite to each other. Side surfaces S3 and S4 are side surfaces along the XZ plane and are opposite to each other.

[0015] Also, as shown in FIG. 3, on the back surface b side of the bottom surface B of the element surrounding portion 10, three ground layers G1 to G3 are arranged. The ground layers G1 to G3 are arranged in the order of the ground layer G1, the ground layer G2, and the ground layer G3 from the side in the +Z-axis direction. As shown in FIGS. 1 and 3, each of the ground layers G1 to G3 is a plate-shaped metal member having the same area as the back surface b. The ground layers G1 to G3 are alternately laminated with the dielectric layers D1 and D2, and are electrically connected to each other through a plurality of vias V penetrating the dielectric layers D1 and D2. Since such ground layers G1 to G3 and the radiation element R are arranged to face each other, the ground of the antenna device 1 is strengthened, which is effective for improving the antenna characteristics.

[0016] As shown in FIG. 3, a feeding via that functions as a feeding portion 20 is connected to the radiation element R. One end portion 21 of the feeding portion 20 can be regarded as the connection position between the radiation element R and the feeding portion 20. As shown in FIGS. 1 and 2, the feeding portion 20 is connected to the radiation element R at a position shifted along the direction (the X-axis direction in this embodiment) in which the side surfaces S1 and S2 face each other from the center O of the radiation element R when viewed from the orthogonal direction, and feeds power to the radiation element R. Specifically, the feeding portion 20 is connected to the radiation element R at a position shifted in the -X-axis direction from the center O of the radiation element R when viewed from the orthogonal direction. Hereinafter, the direction (the X-axis direction in this embodiment) toward the position shifted along the direction (the X-axis direction in this embodiment) in which the side surfaces S1 and S2 face each other from the center O of the radiation element R may be referred to as the shift direction. Also, as shown in FIG. 3, the end portion 22 of the feeding portion 20 on the side opposite to the end portion 21 connected to the radiation element R protrudes to the side opposite to the side of the back surface b (+Z-axis direction side) from the ground layer G3 (-Z-axis direction side).

[0017] On the outer surface of the element surrounding portion 10, protruding portions PL and PR protruding to the side in the direction orthogonal to the above-described shift direction (the Y-axis direction in this embodiment) are provided. The protruding portion PL is a portion protruding in a rectangular parallelepiped shape to the +Y-axis direction side on the outer surface of the element surrounding portion 10. The protruding portion PR is a portion protruding in a rectangular parallelepiped shape to the -Y-axis direction side on the outer surface of the element surrounding portion 10.

[0018] FIG. 4 is an explanatory diagram of the circuit board 2. The circuit board 2 is a board on which the antenna device 1 described in FIGS. 1 to 3 is mounted and on which circuit components (not shown) forming a high-frequency circuit for processing high-frequency signals transmitted and received by the antenna device 1 are mounted. As the circuit board 2, for example, a PCB board such as a glass epoxy board can be used. On the surface of the circuit board 2, a power supply line PS and a ground conductor GC are arranged. Also, a plurality of vias vs are arranged along the power supply line PS. Further, on the outer edge of the circuit board 2, a notch C is formed which can fit the antenna device 1 while placing the protruding portions PL, PR on the circuit board 2. Details will be described using FIG. 5 below.

[0019] FIG. 5 is an explanatory diagram showing a state where the antenna device 1 is mounted on the circuit board 2. When the antenna device 1 is mounted on the circuit board 2, the three-dimensional shape portion (the rectangular parallelepiped portion BD in this embodiment) which is the origin of the protrusion of the protrusion portions PL, PR in the element surrounding portion 10 fits into the notch C, and the protrusion portions PL, PR in the element surrounding portion 10 are placed on the circuit board 2 existing around the notch C. At this time, the antenna device 1 is mounted on the circuit board 2 by adhering the protrusion portions PL, PR placed on the circuit board 2 to the circuit board 2 via an adhesive member such as solder. As shown in FIG. 5, the antenna device 1 is mounted on the circuit board 2 with the opening OP (shown in FIG. 5), which is the entrance of the recess D, facing the side opposite to the central side of the circuit board 2 (the side in the +Z-axis direction). Such an antenna device 1 and the circuit board 2 are collectively referred to as an antenna unit U.

[0020] In the state shown in FIG. 5, the end portion 22 of the power supply portion 20 is arranged on the circuit board 2. Specifically, the end portion 22 is connected to the power supply line PS arranged on the circuit board 2. By such a connection, the power supply portion 20 can secure a supply source for supplying a high-frequency signal.

[0021] Figure 6 is an explanatory diagram of the reflection characteristics of antenna device 1. The reflection characteristics are obtained by simulating the VSWR (Voltage Standing Wave Ratio), which represents the relationship between the input signal and the reflected signal, according to the frequency. In Figure 6, the VSWR of antenna device 1 when mounted on circuit board 2 is shown by a solid line, and the VSWR of antenna device 1 in a standalone state is shown by a dashed line. Antenna device 1 when mounted on circuit board 2 is the same as antenna device 1 in the state shown in Figure 5. Antenna device 1 in a standalone state is, in other words, antenna device 1 in a standalone state that is not mounted on circuit board 2.

[0022] As shown in Figure 6, in all states of the antenna device 1, the reflection characteristics showed a minimum VSWR around a frequency of 27-28 GHz, and the VSWR deteriorated as the frequency increased from there to both lower and higher frequencies. In other words, it was confirmed that the antenna device 1 can maintain the same reflection characteristics as when it is mounted on the circuit board 2.

[0023] Figures 7 and 8 are explanatory diagrams of the radiation directivity of antenna device 1. In Figures 7 and 8, the radiation directivity of antenna device 1 mounted on circuit board 2 is shown by a solid line, while the radiation directivity of antenna device 1 in its standalone state is shown by a dashed line. In Figure 7, the radiation directivity shown by both the solid and dashed lines represents the radiation directivity in the XZ plane. In Figure 8, the radiation directivity shown by both the solid and dashed lines represents the radiation directivity in the YZ plane.

[0024] As shown by the solid and dashed lines in Figures 7 and 8, respectively, it was confirmed that in all states of antenna device 1, the gain peaked when the direction of radiation was in the +Z axis direction, and that the gain decreased as the direction of radiation shifted from the +Z axis direction to the X or Y axis direction. Furthermore, it was confirmed that the radiation directivity of the radio waves was widened in all states of antenna device 1. This widening of the radiation directivity is thought to be due to the fact that the radiating element R is surrounded by sides S1 to S4 made of dielectric material. In other words, it was confirmed that antenna device 1 can maintain the same radiation directivity as when it is mounted on the circuit board 2.

[0025] According to the antenna device 1 of the embodiment described above, the radiating element R is surrounded by four side surfaces S1 to S4 that define the recessed portion D of the element surrounding portion 10, which is made of dielectric material, when viewed from an orthogonal direction (the +Z axis direction in this embodiment). Therefore, the electromagnetic distribution of the side surfaces S1 to S4 made of dielectric material can be used to widen the radiation directivity of the radio waves radiated from the radiating element R. Furthermore, according to the antenna device 1 of the embodiment, it is not necessary to arrange multiple antennas to widen the directivity, thus preventing the antenna device 1 itself from becoming larger.

[0026] Furthermore, according to the antenna device 1 of this embodiment, since protrusions PL and PR are provided, when the antenna device 1 is fitted onto the outer edge of the circuit board 2, which has a notch C into which the antenna device 1 can be fitted while the protrusions PL and PR are placed (see Figures 4 and 5), the opening OP of the recess D of the antenna device 1 can be oriented in a direction along the circuit board 2 (in the +Z axis direction in Figure 5). The inventors of this application have found that when the antenna device 1 is mounted on the circuit board 2 in this state, the antenna device 1 can be mounted on the circuit board 2 while maintaining the same radiation directivity as when the antenna device 1 is used alone. Therefore, according to the antenna device 1 of this embodiment, it is possible to provide an antenna device 1 that can be mounted on a circuit board 2 while suppressing an increase in size and widening the radiation directivity of radio waves, while maintaining that radiation directivity.

[0027] Furthermore, in the antenna device 1 of this embodiment, the end 22 opposite to the end 21 connected to the radiating element R protrudes from the ground layer G3 to the side opposite to the back surface b (the side in the +Z axis direction) (the side in the -Z axis direction) (see Figure 3). Therefore, when the antenna device 1 is fitted onto the outer edge of the circuit board 2, the end 22 can be positioned on the circuit board 2 (see Figure 5). As a result, the feed line PS, which is located on the circuit board 2, can be connected to the end 22 as a source for supplying high-frequency signals to the feed unit 20.

[0028] Furthermore, when the antenna device 1 and the circuit board 2 are combined to form an antenna unit U, the antenna device 1, which has a wide-angle radiation directivity of radio waves, can be mounted on the circuit board 2 while maintaining its radiation directivity.

[0029] <Modified form of this embodiment> The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit, for example, the following modifications are also possible.

[0030] In the above embodiment, the radiating element R was rectangular in shape, but it may be any shape, such as a circle or a polygon.

[0031] In the above embodiment, the circuit board 2 was shown in Figure 2 as having a notch C and being rectangular in general shape, but it is not limited to this. As long as the circuit board 2 has a notch C that can fit into the antenna device 1, it may have any shape depending on the circuit scale, housing shape, size, etc. of the wireless device on which the antenna device 1 is mounted.

[0032] In the above embodiment, the three-dimensional portion that is the source of the protrusions PL and PR within the element surrounding portion 10 was a rectangular parallelepiped portion BD, but it is not limited to this. The three-dimensional portion that is the source of the protrusions PL and PR may be any three-dimensional shape. The shape of the notch C is adjusted according to the shape of the three-dimensional portion that is the source of the protrusions PL and PR within the element surrounding portion 10. In other words, the shape of the three-dimensional portion that is the source of the protrusions PL and PR within the element surrounding portion 10, and the shape of the notch C, may be any shape as long as the three-dimensional portion that is the source of the protrusions PL and PR and the notch C can fit together.

[0033] In the above embodiment, each of the protrusions PL and PR protruded in a rectangular parallelepiped shape along the Y-axis direction, but this is not limited to this. Each of the protrusions PL and PR is not limited to a shape along the Y-axis direction, but can be any shape as long as it includes a component extending in the Y-axis direction. In other words, each of the protrusions PL and PR can be any shape as long as the three-dimensional shape portion that is the source of the protrusions PL and PR of the element surrounding portion 10 fits into the notch C and is able to be placed on the circuit board 2 and fixed to the circuit board 2.

[0034] In the above embodiment, the end portion 22 protruded from the ground layer G3 toward the side opposite to the back surface b, but the end portion 22 does not necessarily have to protrude toward that opposite side. Of course, if the power supply line PS arranged on the circuit board 2 is used as a source of high-frequency signals, it is preferable for the end portion 22 to protrude toward that opposite side.

[0035] The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate. [Explanation of Symbols]

[0036] 1…Antenna device 2…Circuit board 10... Elements surrounding area 20... Power supply section 21…End 22...end B…Bottom surface BD…Rectangular parallelepiped part C... Notch D... recessed area G1~G3...Grand Layer GC... Ground Conductor O…center OP...Opening PL...Protruding part PR…Protrusion PS...Power supply line R... Radiation S1~S4…side V...Beer b…Back side vs... Beer

Claims

1. An antenna device, The element has a rectangular prism-shaped recess defined by a bottom surface on which a radiating element is placed, and four sides surrounding the radiating element when viewed from a direction perpendicular to the bottom surface, with a ground layer placed on the back side of the bottom surface and an element surrounding portion made of a dielectric material, The system includes a power supply unit that is connected to the radiating element at a position offset from the center of the radiating element along the direction in which the side surface faces the radiating element, when viewed from the orthogonal direction, and supplies power to the radiating element, An antenna device characterized in that the outer surface of the element surrounding portion is provided with a projection that protrudes toward a direction perpendicular to the direction toward the position from the center.

2. The antenna device according to claim 1, An antenna device characterized in that the end of the power supply section opposite to the end connected to the radiating element protrudes from the ground layer toward the side opposite to the back surface.

3. It is an antenna unit, An antenna device according to claim 1 or claim 2, A circuit board and, An antenna unit characterized in that a notch is formed on the outer edge of the circuit board, allowing the antenna device to be fitted while the protruding portion is placed on the circuit board.

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