Antenna device

Abstract

An antenna device comprising a first planar antenna for linear polarization having a first feed unit, and a second planar antenna for linear polarization having a second feed unit overlapping the first feed unit when viewed in plan from a direction perpendicular to a predetermined surface of the first planar antenna. The linear polarization of the first planar antenna and the linear polarization of the second planar antenna intersect each other.

Description

[Technical Field]

[0001] The present invention relates to an antenna device. [Background technology]

[0002] Patent Document 1 discloses an antenna device including two dipole antennas arranged parallel to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-176139 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of an antenna device including two linearly polarized antennas arranged parallel to each other, the direction in which the gain drops may coincide for the two antennas, which may impair the freedom of installation of the antenna device.

[0005] One example of an object of the present invention is to improve the degree of freedom in installing an antenna device including a plurality of antennas. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0006] One aspect of the present invention is an antenna device comprising a first planar antenna for linear polarization having a first power feed portion, and a second planar antenna for linear polarization having a second power feed portion that overlaps with the first power feed portion in a planar view seen from a direction perpendicular to a predetermined surface of the first planar antenna, wherein the linear polarization of the first planar antenna and the linear polarization of the second planar antenna intersect.

[0007] According to the above aspects of the present invention, it is possible to improve the degree of freedom in installing an antenna device including a plurality of antennas. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of the antenna device 10. [Figure 2] FIG. 2 is a plan view of the antenna device 10. [Figure 3] FIG. 2 is a plan view of the first antenna 30. [Figure 4] 2 is an enlarged view of the periphery of a connection portion 52 of the first antenna 30. FIG. [Figure 5] 3 is a diagram showing the radiation patterns of the first antenna 30 and the second antenna 40 on the XY plane. FIG. [Figure 6] 3 is a diagram showing the radiation patterns of the first antenna 30 and the second antenna 40 in the YZ plane. FIG. [Figure 7] 3 is a diagram showing the radiation patterns of the first antenna 30 and the second antenna 40 in the ZX plane. FIG. [Figure 8A] FIG. 2 is a perspective view of an antenna device 70X. [Figure 8B] FIG. 2 is a perspective view of an antenna device 70. [Figure 9A] 10 is a diagram showing the radiation patterns of a first antenna 71X and a second antenna 72X on the XY plane. FIG. [Figure 9B] 2 is a diagram showing the radiation patterns of a first antenna 71 and a second antenna 72 on the XY plane. FIG. [Figure 10A] 10 is a diagram showing the radiation patterns of a first antenna 71X and a second antenna 72X on the YZ plane. FIG. [Figure 10B] 10 is a diagram showing the radiation patterns of a first antenna 71 and a second antenna 72 on the YZ plane. FIG. [Figure 11A] 10 is a diagram showing the radiation patterns of a first antenna 71X and a second antenna 72X on the ZX plane. FIG. [Figure 11B] 10 is a diagram showing the radiation patterns of a first antenna 71 and a second antenna 72 on the ZX plane. FIG. [Figure 12A] 10 is a diagram showing a first modified example of the internal conductor side connecting portion 54 and the separating portion 58 of the first antenna 30. FIG. [Figure 12B] 10 is a diagram showing a second modified example of the internal conductor side connecting portion 54 and the separating portion 58 of the first antenna 30. FIG. [Figure 12C] 10 is a diagram showing a third modified example of the internal conductor side connecting portion 54 and the separating portion 58 of the first antenna 30. FIG. [Figure 13] FIG. 2 is an explanatory diagram of an antenna 80A. [Figure 14] FIG. 10 is an explanatory diagram of an antenna 80X. [Figure 15] 10 is a graph showing an example of frequency characteristics of an antenna 80A and an antenna 80X. [Figure 16] 10 is an enlarged view of a portion of the low frequency band of a graph showing an example of the frequency characteristics of antenna 80A and antenna 80X. [Figure 17A] FIG. 2 is an explanatory diagram of an antenna 80A. [Figure 17B] FIG. 10 is an explanatory diagram of an antenna 80B. [Figure 17C] FIG. 10 is an explanatory diagram of an antenna 80C. [Figure 18] 10 is a graph showing an example of frequency characteristics of antennas 80A to 80C. [Figure 19] 10 is an enlarged view of a portion of the low frequency band of a graph showing an example of the frequency characteristics of antennas 80A to 80C. FIG. [Figure 20] FIG. 10 is an explanatory diagram of an antenna 80D. [Figure 21] 10 is a graph showing an example of frequency characteristics of an antenna 80D and an antenna 80X. [Figure 22A] FIG. 2 is an explanatory diagram of an antenna 80A. [Figure 22B] FIG. 10 is an explanatory diagram of an antenna 80E. [Figure 23] 10 is a graph showing an example of frequency characteristics of an antenna 80A and an antenna 80E. [Figure 24A] FIG. 10 is an explanatory diagram of an antenna 80F. [Figure 24B] FIG. 10 is an explanatory diagram of an antenna 80G. [Figure 25] FIG. 10 is an explanatory diagram of an antenna 80H. [Figure 26A]FIG. 10 is an explanatory diagram of an antenna 80I. [Figure 26B] FIG. 10 is an explanatory diagram of an antenna 80J. DETAILED DESCRIPTION OF THE INVENTION

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings.

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0011] ==Antenna device 10== <<Outline of Antenna Device 10>> First, an overview of an antenna device 10 including a first antenna 30 and a second antenna 40 will be described with reference to FIGS.

[0012] Fig. 1 is a perspective view of the antenna device 10. Fig. 2 is a plan view of the antenna device 10.

[0013] 1 and 2, the direction perpendicular to the surface of the first antenna 30 (the surface of the main body portion 50 described later) on which the connecting portion 52 described later is provided is defined as the X direction. The side from the main body portion 50 of the second antenna 40 toward the main body portion 50 of the first antenna 30 is defined as the +X direction, and the opposite side (the side from the main body portion 50 of the first antenna 30 toward the main body portion 50 of the second antenna 40) is defined as the -X direction. Note that the X direction is also the direction perpendicular to the surface of the second antenna 40 (the surface of the main body portion 50) on which the connecting portion 52 is provided.

[0014] 1 and 2, the direction perpendicular to the X direction is defined as the Y direction. The direction from a second outer conductor side element 41 (described later) toward a first outer conductor side element 31 (described later) is defined as the +Y direction, and the opposite side (the side from the first outer conductor side element 31 toward the second outer conductor side element 41) is defined as the -Y direction.

[0015] 1 and 2, the direction perpendicular to the X and Y directions is defined as the Z direction. The direction from the first outer conductor element 31 toward a second inner conductor element 42 (described later) is defined as the +Z direction, and the opposite side (the side from the second inner conductor element 42 toward the first outer conductor element 31) is defined as the -Z direction.

[0016] The antenna device 10 is an antenna device that includes multiple antennas. The antenna device 10 of this embodiment includes two antennas: a first antenna 30 and a second antenna 40. However, the antenna device 10 may include three or more antennas.

[0017] Furthermore, the antenna device 10 is an antenna device that performs communication using MIMO (Multiple-Input Multiple-Output), for example. In MIMO communication, data is transmitted from each of multiple antennas and received simultaneously by the multiple antennas. In the antenna device 10 of this embodiment, data is transmitted from each of the first antenna 30 and the second antenna 40 provided in the antenna device 10, and data is received simultaneously by the first antenna 30 and the second antenna 40. However, the antenna device 10 may also be used for communication other than MIMO, as long as it is a device including multiple antennas.

[0018] The antenna device 10 of this embodiment is compatible with a wide range of frequency bands, such as 698 MHz to 5 GHz for 4G, 5G, and LTE. However, the antenna device 10 is not limited to this, and may be compatible with some of the frequency bands for 4G, 5G, and LTE (for example, only for 5G), may be compatible with a frequency band for telematics, or may be compatible with frequency bands other than those for 4G, 5G, and LTE.

[0019] The antenna device 10 includes a first antenna 30, a second antenna 40, a first feed line 36, and a second feed line 46.

[0020] The first antenna 30 and the second antenna 40 are both antennas for linear polarization. In this embodiment, the first antenna 30 and the second antenna 40 are both antennas for linear polarization. Linear polarization is sometimes called vertical polarization when the polarization plane is perpendicular to the ground, and horizontal polarization when the polarization plane is horizontal to the ground. More specifically, the first antenna 30 and the second antenna 40 are wideband antennas based on bowtie antennas or dipole antennas. However, the first antenna 30 and the second antenna 40 may be bowtie antennas, dipole antennas, or linearly polarized antennas other than bowtie antennas or dipole antennas.

[0021] In the antenna device 10 of this embodiment, the first antenna 30 and the second antenna 40 have the same shape (external shape) and configuration. Here, "similar shape and configuration" does not mean that the shape and configuration of the first antenna 30 and the shape and configuration of the second antenna 40 exactly match. For example, the shape of the first antenna 30 may be partially different from the shape of the second antenna 40. Furthermore, the first antenna 30 may have a different configuration from the second antenna 40, and conversely, the second antenna 40 may have a different configuration from the first antenna 30.

[0022] The first antenna 30 and the second antenna 40 will be described in detail later.

[0023] The first feed line 36 is a feed line connected to the first antenna 30. The second feed line 46 is a feed line connected to the second antenna 40. By feeding power to each of the first antenna 30 and the second antenna 40, the first antenna 30 and the second antenna 40 each have a feed section (a first feed section 37 and a second feed section 47, which will be described later). The first feed line 36 and the second feed line 46 are, for example, coaxial cables. The first feed line 36 and the second feed line 46 are provided with a magnetic core (for example, a ferrite core). By providing a magnetic core, leakage current can be reduced. It is not necessary to provide a magnetic core.

[0024] <<Outline of first antenna 30>> Fig. 3 is a plan view of the first antenna 30. Fig. 4 is an enlarged view of the periphery of the connection portion 52 of the first antenna 30.

[0025] 1 and 2, as well as Figures 3 and 4. As described above, the first antenna 30 and the second antenna 40 have similar shapes and configurations, and therefore, the description of the first antenna 30 also applies to the second antenna 40 unless otherwise noted.

[0026] In the following description, the first antenna 30 may be referred to as "first" and the second antenna 40 as "second." For example, the element to which the outer conductor of the first feeder 36 of the first antenna 30 is electrically connected may be referred to as the "first outer conductor side element 31." Furthermore, when describing both the first antenna 30 and the second antenna 40 or when describing either the first antenna 30 or the second antenna 40 as a representative, the terms "first" and "second" may be omitted. For example, either the first inner conductor side element 32 of the first antenna 30, which is an element to which the inner conductor of the first feeder 36 is electrically connected, or the second inner conductor side element 42 of the second antenna 40, which is an element to which the inner conductor of the second feeder 46 is electrically connected, may be simply referred to as the "internal conductor side element." Furthermore, both the first inner conductor side element 32 of the first antenna 30 and the second inner conductor side element 42 of the second antenna 40 may be simply referred to as the "internal conductor side element." Similarly, either the first outer conductor side element 31 provided in the first antenna 30 and electrically connected to the outer conductor of the first feed line 36, or the second outer conductor side element 41 provided in the second antenna 40 and electrically connected to the outer conductor of the second feed line 46 may be simply referred to as the "external conductor side element," or both may be simply referred to as the "external conductor side element."

[0027] <<Overall shape of first antenna 30>> In this embodiment, the first antenna 30 is a planar antenna. A "planar antenna" is an antenna whose elements are mainly formed of plate-like materials. However, not all of the antenna elements need to be formed of plate-like materials, and the antenna elements may have portions formed of materials other than plate-like materials. A "planar antenna" is a shape having a predetermined width. In the following description, the first antenna may be referred to as a "first planar antenna."

[0028] As shown in FIGS. 1 to 3, the first antenna 30 includes a main body portion 50 and a bent portion 51. As shown in FIGS.

[0029] The main body 50 is provided with a connection portion 52 to which the first feed line 36 is connected. The main body 50 is formed as a plate-like member having a predetermined width. The first antenna 30 has the main body 50 formed as a plate-like member, thereby increasing the area (width) of the element. This allows the first antenna 30 to support a wide frequency band.

[0030] In this embodiment, the bent portion 51 is formed by bending an end of the main body portion 50 formed of a metal plate. However, the bent portion 51 may be a metal plate separate from the main body portion 50 and connected (joined) to extend from an end of the main body portion 50. Alternatively, the main body portion 50 may be formed of a conductive pattern provided on a substrate, the bent portion 51 may be formed of a metal plate, and the main body portion 50 and the bent portion 51 may be electrically connected. Alternatively, the main body portion 50 may be formed of a metal plate, the bent portion 51 may be formed of a conductive pattern provided on a substrate, and the main body portion 50 and the bent portion 51 may be electrically connected. Alternatively, the main body portion 50 and the bent portion 51 may be formed of a conductive pattern provided on a substrate, and the main body portion 50 and the bent portion 51 may be electrically connected. Furthermore, when the bent portion 51 and the main body portion 50 are separate bodies, they may be connected (jointed) so as to extend from a location other than the end of the main body portion 50. The bent portion 51 may be bent at an obtuse angle, a right angle, or an acute angle relative to the main body portion 50, or may be curved. Furthermore, the first antenna 30 may not have the bent portion 51 and may be composed only of the main body portion 50. In other words, the first antenna 30 may be formed only from a plate-like member.

[0031] The first antenna 30 and the second antenna 40 may be configured by conductor patterns respectively provided on a single substrate. Specifically, the first antenna 30 may be formed by a conductor pattern provided on one surface of a single substrate, and the second antenna 40 may be formed by another conductor pattern provided on the other surface of the single substrate. In this case, the first antenna 30 and the second antenna 40 do not have the bent portion 51 and are configured only by the main body portion 50.

[0032] 1 and 2, the first antenna 30 and the second antenna 40 are arranged such that the main body portion 50 of the first antenna 30 and the main body portion 50 of the second antenna 40 are spaced a predetermined distance from each other. Preferably, the main body portion 50 of the first antenna 30 and the main body portion 50 of the second antenna 40 are arranged so as to be parallel to each other. Here, "parallel" does not necessarily mean strictly parallel, but also includes cases where they are misaligned within a predetermined angle.

[0033] 1 and 2, the bent portion 51 of the first antenna 30 and the bent portion 51 of the second antenna 40 are formed to extend in directions facing each other. Specifically, the bent portion 51 of the first antenna 30 is formed to extend toward the second antenna 40 (+X direction), and the bent portion 51 of the second antenna 40 is formed to extend toward the first antenna 30 (-X direction). This allows the size of the antenna device 10 to be reduced compared to when the bent portion 51 of the first antenna 30 and the bent portion 51 of the second antenna 40 are formed to extend in directions away from each other.

[0034] <<Configuration of first antenna 30>> As shown in FIG. 3, the first antenna 30 includes a first outer conductor element 31, a first inner conductor element 32, and a first feeding portion 37.

[0035] 3 and 4, the first outer conductor side element 31 is the element of the first antenna 30 to which the outer conductor 56 of the first feed line 36 is connected. Also, the first inner conductor side element 32 is the element to which the core wire 57 (inner conductor) of the first feed line 36 is connected. Also, the first feeding portion 37 is a region including the feeding point in the first antenna 30.

[0036] In this embodiment, the first feeding portion 37 is located between the first outer conductor side element 31 and the first inner conductor side element 32, as shown in Fig. 3. Specifically, the first feeding portion 37 is located at the center of a line segment connecting the end of the first outer conductor side element 31 closest to the first inner conductor side element 32 and the end of the first inner conductor side element 32 closest to the first outer conductor side element 31, as shown in Fig. 4. Note that the "center" is not limited to the exact center, but also includes a position shifted a predetermined distance from the center.

[0037] In this embodiment, the outer shapes of the first outer conductor element 31 and the first inner conductor element 32 are symmetrical with respect to an axis A1 (hereinafter sometimes referred to as the "first axis") passing through the first feeding portion 37, as shown in FIG. Here, the outer shapes of one element and the other element being "symmetrical" with respect to the axis A1 means that when one element is inverted about the axis A1, the outer shapes of the first element match those of the other element. However, the outer shapes of the first outer conductor element 31 and the first inner conductor element 32 do not have to be completely symmetrical with respect to the axis A1. For example, the outer shape of the first outer conductor element 31 may be partially different from the outer shape of the first inner conductor element 32.

[0038] As described above, by providing the first outer conductor side element 31, the first inner conductor side element 32, and the first power supply portion 37, the first antenna 30 is configured to have a pair of elements (the first outer conductor side element 31 and the first inner conductor side element 32) extending in directions away from each other from the first power supply portion 37.

[0039] In this embodiment, the first outer conductor element 31 and the first inner conductor element 32 are each shaped to have a curved outline (outer edge) that bulges outward toward the first feeding portion 37 so as to reduce the area of ​​the opposing space between them. Specifically, at least a portion of the shapes of the first outer conductor element 31 and the first inner conductor element 32 is arc-shaped. That is, the area of ​​the opposing space between the first outer conductor element 31 and the first inner conductor element 32 in this embodiment is smaller than when the outer conductor element and the inner conductor element are each formed in a triangular shape with the feeding point at its apex, or when the outline (outer edge) is linearly deformed so that two sides of the triangle that sandwich the apex are convex outward. An antenna having such a shape is called a wideband antenna based on a bowtie antenna. In this way, when the opposing spatial area between the first outer conductor element 31 and the first inner conductor element 32 is small and the capacitance between them is large, better band characteristics can be obtained over a wide band.

[0040] <<Relationship between the first antenna 30 and the second antenna 40>> As described above, the second antenna 40 has the same shape (external shape) and configuration as the first antenna. For example, in the second antenna 40, the external shape of the second outer conductor side element 41 and the external shape of the second inner conductor side element 42 are symmetrical with respect to an axis A2 (hereinafter sometimes referred to as the "second axis") passing through the second power supply portion 47, as shown in Fig. 2. Therefore, the second antenna 40 is provided so as to have a pair of elements (the second outer conductor side element 41 and the second inner conductor side element 42) extending in directions away from each other from the second power supply portion 47.

[0041] In this embodiment, the first antenna 30 and the second antenna 40 are arranged such that the first power supply portion 37 and the second power supply portion 47 overlap in the plan view shown in Fig. 2. Furthermore, in this embodiment, the extension direction of the pair of elements of the first antenna 30 intersects with the extension direction of the pair of elements of the second antenna 40.

[0042] Here, the term "overlapping" the first power supply section 37 and the second power supply section 47 includes both a situation in which, in a plan view, the range of the first power supply section 37 and the range of the second power supply section 47 coincide with each other, and a situation in which, in a plan view, the range of the first power supply section 37 coincides with a situation in which, in a plan view, the range of the second power supply section 47 coincides with each other. Furthermore, in a plan view, the range of the first power supply section 37 may include the range of the second power supply section 47, and conversely, in a plan view, the range of the second power supply section 47 may include the range of the first power supply section 37.

[0043] Furthermore, as a result, in a planar view, a portion of the first outer conductor side element 31 of the first antenna 30 overlaps with at least a portion of the second outer conductor side element 41 and the second inner conductor side element 42 of the second antenna 40, and a portion of the first inner conductor side element 32 of the first antenna 30 overlaps with at least a portion of the second outer conductor side element 41 and the second inner conductor side element 42 of the second antenna 40.

[0044] Furthermore, the expression "the extension direction of the pair of elements of the first antenna 30 and the extension direction of the pair of elements of the second antenna 40 intersect" means that a straight line along the extension direction of the pair of elements of the first antenna 30 and a straight line along the extension direction of the pair of elements of the second antenna 40 intersect at a certain point. In other words, this means that the straight line along the extension direction of the pair of elements of the first antenna 30 and the straight line along the extension direction of the pair of elements of the second antenna 40 are not parallel in a plan view.

[0045] As described above, the first antenna 30 and the second antenna 40 are arranged to intersect with each other around the first power feed section 37 (or the second power feed section 47) in a plan view. In this case, the first antenna 30 and the second antenna 40 are arranged to form an angle greater than 0° and smaller than 180° around the first power feed section 37 (or the second power feed section 47). In other words, the first antenna 30 and the second antenna 40 are arranged so that the linearly polarized wave of the first antenna 30 and the linearly polarized wave of the second antenna 40 intersect with each other.

[0046] Furthermore, in this embodiment, the first antenna 30 and the second antenna 40 are arranged so as to be orthogonal to each other in a plan view. Here, "orthogonal" means intersecting at an angle of 90°. That is, the first antenna 30 and the second antenna 40 are arranged so as to form an angle of 90° with the first power feed portion 37 (or the second power feed portion 47) as the center. In this case, the axis A1 passing through the first power feed portion 37 and the axis A2 passing through the second power feed portion 47 are orthogonal to each other, as shown in FIG. 2 . That is, in this embodiment, the angle formed by the axis A1 and the axis A2 is 90°. However, the first antenna 30 and the second antenna 40 may intersect at an angle other than 90°, and the angle formed by the axis A1 and the axis A2 may be greater than 0° and less than 180°.

[0047] 2, the first antenna 30 and the second antenna 40 are housed in, for example, a quadrilateral housing section 67. At this time, the first antenna 30 and the second antenna 40 are housed in the housing section 67 so that the first axis A1 and the second axis A2 are positioned on diagonal lines of the housing section 67. This makes it possible to reduce the size of the housing section 67 while ensuring the lengths of the first antenna 30 and the second antenna 40.

[0048] However, if the first antenna 30 and the second antenna 40 are arranged parallel to each other in a plan view (i.e., arranged at an angle of 0°), the radiation pattern of the first antenna 30 and the radiation pattern of the second antenna 40 may match, resulting in the direction in which the gain drops being the same for the first antenna 30 and the second antenna 40. In this case, the installation of the antenna device 10 must be considered in light of the matched directivities of the first antenna 30 and the second antenna 40, which may reduce the degree of freedom in installing the antenna device 10. Furthermore, if the first antenna 30 and the second antenna 40 are arranged parallel to each other in a plan view, the isolation between the first antenna 30 and the second antenna 40 may deteriorate, which may result in a deterioration in communication performance such as throughput and coverage.

[0049] Therefore, in the antenna device 10 of this embodiment, as described above, the first antenna 30 and the second antenna 40 are arranged so that the linearly polarized wave of the first antenna 30 and the linearly polarized wave of the second antenna 40 intersect, thereby preventing the directions in which the gain drops from the first antenna 30 and the second antenna 40 from coinciding. That is, in the antenna device 10 of this embodiment, when the first antenna 30 and the second antenna 40 are used, a radiation pattern that obtains the maximum value of the gain at each azimuth angle of each antenna is realized as a so-called omnidirectional radiation pattern. Therefore, the degree of freedom in installing the antenna device 10 can be improved without being restricted by the respective directivities of the first antenna 30 and the second antenna 40 that constitute the antenna device 10. In this embodiment, the first antenna 30 and the second antenna 40 are arranged to form a 90° angle with the first feeder 37 (or the second feeder 47) as the center. However, if the angle is greater than 0° and less than 180° around the first power supply section 37 (or the second power supply section 47), the direction in which the gain of the first antenna 30 drops does not coincide with the direction in which the gain of the second antenna 40 drops, thereby improving the degree of freedom in installing the antenna device 10.

[0050] <<Directivity of the First Antenna 30 and the Second Antenna 40>> Fig. 5 is a diagram showing the radiation patterns of the first antenna 30 and the second antenna 40 on the XY plane. Fig. 6 is a diagram showing the radiation patterns of the first antenna 30 and the second antenna 40 on the YZ plane. Fig. 7 is a diagram showing the radiation patterns of the first antenna 30 and the second antenna 40 on the ZX plane.

[0051] As shown in Figures 5 and 7, there are no angles in the XY plane and the ZX plane where the gain of the first antenna 30 and the second antenna 40 drops noticeably. On the other hand, as shown in Figure 6, in the YZ plane, the gain of the first antenna 30 drops, for example, around 315° and around 135°. Around these angles, the gain of the second antenna 40 is greatest. The gain of the second antenna 40 also drops, for example, around 45° and around 225°. Around these angles, the gain of the first antenna 30 is greatest.

[0052] Therefore, in the antenna device 10 of this embodiment, the angles at which the gain of the first antenna 30 drops do not match those of the second antenna 40. By arranging the first antenna 30 and the second antenna 40 so that the linearly polarized waves of the first antenna 30 and the linearly polarized waves of the second antenna 40 intersect, a relationship is created in which the angle at which the gain of one antenna drops is compensated for by the gain of the other antenna. Therefore, in the antenna device 10 of this embodiment, a so-called omnidirectional radiation pattern is realized when the first antenna 30 and the second antenna 40 are used. This improves the degree of freedom in installing the antenna device 10 without being restricted by the directivity of each of the first antenna 30 and the second antenna 40 that constitute the antenna device 10.

[0053] <<Comparative Example>> Below, using a comparative example, the effect of arranging the first antenna 30 and the second antenna 40 of this embodiment so that they cross each other will be verified.

[0054] FIG. 8A is a perspective view of an antenna device 70X of a comparative example, and FIG. 8B is a perspective view of the antenna device 70 of this embodiment.

[0055] Here, for simplicity, a bowtie antenna model is used to verify the radiation pattern of the antenna device 70X of the comparative example and the radiation pattern of the antenna device 70 of this embodiment. As shown in FIGS. 8A and 8B, the antenna device 70X shown in FIG. 8A has a first antenna 71X and a second antenna 72X. The antenna device 70 shown in FIG. 8B has a first antenna 71 and a second antenna 72. The first antenna 71X and the first antenna 71 are simplified models of the first antenna 30 shown in FIGS. 1 and 2 described above, and the second antenna 72X and the second antenna 72 are simplified models of the second antenna 40 shown in FIGS. 1 and 2 described above.

[0056] In antenna device 70X of the comparative example, first antenna 71X and second antenna 72X are arranged so that first power feeding portion 37 and second power feeding portion 47 overlap in a plan view seen in the X direction. Also in antenna device 70 of this embodiment, first antenna 71 and second antenna 72 are arranged so that first power feeding portion 37 and second power feeding portion 47 overlap in a plan view seen in the X direction.

[0057] In this verification, the angles at which the first antenna and the second antenna are arranged are different between antenna device 70X of the comparative example and antenna device 70 of the present embodiment. That is, in antenna device 70X of the comparative example, first antenna 71X and second antenna 72X are arranged parallel to each other, as shown in FIG. 8A. That is, first antenna 71X and second antenna 72X are arranged so that a first axis A1 passing through first power feed portion 37 and in which first antenna 71X extends, and a second axis A2 passing through second power feed portion 47 and in which second antenna 72X extends, overlap in a plan view seen in the X direction. On the other hand, in antenna device 70 of the present embodiment, as shown in FIG. 8B, the first antenna 71 and the second antenna 72 are arranged to intersect at 90° with respect to first power feed portion 37 (or second power feed portion 47) in a plan view seen in the X direction. That is, the first antenna 71 and the second antenna 72 are arranged so that the first axis A1, which passes through the first power supply section 37 and is the direction in which the first antenna 71 extends, and the second axis A2, which passes through the second power supply section 47 and is the direction in which the second antenna 72 extends, intersect at 90° with the first power supply section 37 (or the second power supply section 47) as the center in a plan view in the X direction.

[0058] Fig. 9A is a diagram showing the radiation patterns of the first antenna 71X and the second antenna 72X on the XY plane, and Fig. 9B is a diagram showing the radiation patterns of the first antenna 71 and the second antenna 72 on the XY plane. Fig. 10A is a diagram showing the radiation patterns of the first antenna 71X and the second antenna 72X on the YZ plane, and Fig. 10B is a diagram showing the radiation patterns of the first antenna 71 and the second antenna 72 on the YZ plane. Fig. 11A is a diagram showing the radiation patterns of the first antenna 71X and the second antenna 72X on the ZX plane, and Fig. 11B is a diagram showing the radiation patterns of the first antenna 71 and the second antenna 72 on the ZX plane.

[0059] As shown in Fig. 9A, in the XY plane, there is no angle at which the gain of the first antenna 71X of the comparative example and the second antenna 72X of the comparative example drops noticeably. However, as shown in Fig. 10A and Fig. 11A, in the YZ plane and the ZX plane, the angles at which the gain of both antennas of the comparative example drops coincide, for example, near 0° and near 180°.

[0060] 9B and 11B, in the XY plane and the ZX plane, there is no angle at which the gain of the first antenna 71 of this embodiment and the second antenna 72 of this embodiment drops noticeably, but in the ZX plane, as shown in Fig. 10B, the gain of both antennas of this embodiment complements each other. Thus, it can be seen that the antenna device 70 of this embodiment achieves an omnidirectional radiation pattern compared to the antenna device 70X of the comparative example, and the degree of freedom in installation of the antenna device 70 is improved.

[0061] <<Element configuration>> 1 to 4, the configurations of the outer conductor side elements and the inner conductor side elements will be described below. Here, when describing both the outer conductor side elements and the outer conductor side elements in common, or when describing either the outer conductor side elements or the inner conductor side elements as a representative, they may be simply referred to as "elements." Therefore, unless otherwise noted, the following description of the element configuration applies to both the outer conductor side elements and the inner conductor side elements.

[0062] As shown in FIGS. 1 to 3, the element has a connecting portion 52, a slit 60, and a rib 66.

[0063] The connection portion 52 is a portion of the element where the feeder is connected to the element. As shown in Fig. 4, the connection portion 52 includes an outer conductor side connection portion 53 where the outer conductor 56 of the first feed line 36 is connected to the first outer conductor side element 31, and an inner conductor side connection portion 54 where the core 57 of the first feed line 36 is connected to the first inner conductor side element 32.

[0064] In this embodiment, the feeding section (first feeding section 37) is located in the center between the outer conductor side connecting section 53 and the inner conductor side connecting section 54, as shown in Fig. 4. As a result, as described above, the first feeding section 37 is located in the center of the line segment connecting the end of the first outer conductor side element 31 closest to the first inner conductor side element 32 and the end of the first inner conductor side element 32 closest to the first outer conductor side element 31. Note that "center" is not limited to the exact center, but also includes a position shifted a predetermined distance from the center.

[0065] As shown in FIG. 4, the element has a separation portion 58. The separation portion 58 is provided in a portion of the periphery of the connection portion 52 and separates the connection portion 52 from the area other than the connection portion 52. In this embodiment, the separation portion 58 is formed by cutting (holing) the element. This makes it difficult for heat to escape when soldering the power supply line to the connection portion 52, thereby improving workability. For this reason, the separation portion 58 may be formed by inserting a heat insulating material into the space formed by cutting out the element. The element does not necessarily have to have the separation portion 58.

[0066] The slit 60 is a cutout formed in the element to improve the frequency characteristics of the antenna. As shown in FIG. 3 , the slit 60 has an open end 61 at the outer edge of the element and a closed end 62 inside. As shown in FIG. 3 , when an axis A3 is defined as an axis perpendicular to the axis A1 and passing through the first power supply 37, the slit 60 has a portion extending from the open end 61 toward the axis A3, a bent portion 63, and a portion extending toward the closed end 62 in a direction away from the first power supply 37. As shown in FIG. 3 , a portion of the path of the slit 60 from the open end 61 to the closed end 62 passes through at least a region of the element on the opposite side of the axis A3 from the open end 61. However, as will be described later, the shape of the slit 60 is not limited to that shown in FIG. 3 . The element need not necessarily have the slit 60. Details of the slit 60 will be described later.

[0067] In this embodiment, the slits 60 are formed only on the inner conductor element (first inner conductor element 32, second inner conductor element 42) side, as shown in FIGS. 1 to 3 . If the slits 60 were formed on the outer conductor element (first outer conductor element 31, second outer conductor element 41) side, the feed lines (first feed line 36, second feed line 46) would interfere with the slits 60, possibly degrading the antenna characteristics. Therefore, by forming the slits 60 only on the inner conductor element side, it is possible to prevent the antenna characteristics from deteriorating due to the feed lines interfering with the slits 60. However, if the above-described degradation of the antenna characteristics is tolerable, the slits 60 may be formed on the outer conductor element side.

[0068] The ribs 66 are portions of the element that are thicker than the remaining portions of the element. The ribs 66 are formed on the element in which the above-described slits 60 are provided. Forming the ribs 66 on the element can increase the strength of the element in which the slits 60 are formed. In this embodiment, the element has two ribs 66 as shown in FIG. 3, and the slits 60 are located between two adjacent ribs 66. This can further increase the strength of the element. However, the shape, number, and arrangement of the ribs 66 are not limited to those shown in FIG. 3. For example, the ribs 66 may be shaped to fit the shape of the slits 60, or multiple ribs 66 may be arranged to fit the shape of the slits 60, or ribs 66 may be arranged only on the side where the open end 61 is provided. The element may also not have the ribs 66.

[0069] <<Modifications of the connecting portion 52 and the separating portion 58>> The following describes modified shapes of the connecting portion 52 and the separating portion 58. Although the following describes the inner conductor side connecting portion 54, similar modifications are also possible for the outer conductor side connecting portion 53.

[0070] 12A to 12C are diagrams showing modified examples of the internal conductor side connecting portion 54 and the separating portion 58 of the first antenna 30. In FIG.

[0071] 4, the above-described inner conductor side connection part 54 has a periphery where the part on the first power supply part 37 side is connected to the element, and a separation part 58 is provided in the part other than the part connected to the element. However, the shapes of the inner conductor side connection part 54 and the separation part 58 are not limited to those shown in FIG.

[0072] For example, as in a first modified example shown in Fig. 12A, the internal conductor side connection portion 54 may be connected to the element only on either the left or right side in plan view (only the right side in Fig. 12A). Furthermore, as in a second modified example shown in Fig. 12B, the internal conductor side connection portion 54 may be connected to the element on both the left and right sides in plan view. Furthermore, as in a third modified example shown in Fig. 12C, the internal conductor side connection portion 54 may be connected to the element at a portion of its periphery opposite to the first power supply portion 37. That is, as shown in Figs. 12A to 12C, it is sufficient that at least a portion of the outer periphery of the internal conductor side connection portion 54 is connected to the element.

[0073] However, in the case shown in Fig. 12A, the inner conductor side connection portion 54 is connected to the element only on the left or right side, which breaks symmetry and may result in significant degradation of radio waves. Also, in the case shown in Fig. 12C, the connection portion with the element is separated from the first power supply portion 37, which may result in significant degradation of radio waves. Therefore, if such degradation of radio waves is acceptable, the connection portion 52 shown in Figs. 12A to 12C may be used, but a connection that maintains symmetry and reduces degradation of radio waves is preferable.

[0074] In the first to third modified examples described above, at least a portion of the outer periphery of the internal conductor side connecting portion 54 is connected to the element. However, the outer periphery of the internal conductor side connecting portion 54 does not have to be connected to the element. In other words, the separating portion 58 may surround the outer periphery of the internal conductor side connecting portion 54. In this case, a portion of the internal conductor side connecting portion 54 other than the outer periphery (for example, the interior of the internal conductor side connecting portion 54) may be connected to the element.

[0075] <<Slit 60>> As described above, the antenna device 10 of this embodiment is compatible with a wide frequency band, such as 698 MHz to 5 GHz for 4G, 5G, and LTE. In an antenna device compatible with such a wide band, the voltage standing wave ratio (VSWR) characteristic in the frequency band being used needs to be a certain value or less (for example, VSWR of 3.0 or less).

[0076] As described above, the elements of the first antenna 30 and the second antenna 40 constituting the antenna device 10 are formed as plate-like members, thereby increasing the area (width) of the elements, thereby realizing an antenna device that supports a wide band.

[0077] Furthermore, the first antenna 30 is formed to have a curved outline that bulges out convexly toward the first power supply 37 so as to narrow the opposing spatial area between the elements, and the second antenna 40 is also formed to have a curved outline (arc shape) that bulges out convexly toward the second power supply 47 like the first antenna 30 so as to narrow the opposing spatial area between the elements. This achieves an antenna device that can obtain better band characteristics over a wide band.

[0078] However, in such wideband antenna devices, it may be difficult to improve characteristics, especially in the low frequency band, simply by increasing the area (width) of the elements or reducing the opposing spatial area between the elements. Therefore, in the antenna device 10 of this embodiment, slits 60 are formed in some of the antenna elements (in this embodiment, the first inner conductor side element 32 and the second inner conductor side element 42), thereby improving the characteristics in the low frequency band. The improvement in antenna characteristics due to the slits 60 will be described below.

[0079] In the following, the effect of the slit 60 of the antenna 80A of this embodiment will be verified using the antenna 80X of the reference example.

[0080] FIG. 13 is an explanatory diagram of the antenna 80A of the present embodiment. FIG. 14 is an explanatory diagram of the antenna 80X of the reference example.

[0081] Here, similar to the antenna device 70 described above, using a model of a bow-tie antenna, the frequency characteristics of the antenna 80A of the present embodiment and the frequency characteristics of the antenna 80X of the reference example are verified. The antenna 80A of the present embodiment has a slit 60 in the inner conductor side element 82. On the other hand, the antenna 80X of the reference example does not have a slit 60 in either the outer conductor side element 81 or the inner conductor side element 82. In FIGS. 13 and 14, 83 is a feeding portion. In the following verification, the frequency characteristics when the length L of the slit 60 is changed are also verified. Here, the length L of the slit 60 is the distance along the slit 60, and is the length of the path from the open end 61 to the closed end 62 of the slit 60.

[0082] FIG. 15 is a graph showing an example of the frequency characteristics of the antenna 80A and the antenna 80X. FIG. 16 is an enlarged view of a part of the low frequency band of the graph showing an example of the frequency characteristics of the antenna 80A and the antenna 80X. In these figures, the horizontal axis represents the frequency, and the vertical axis represents the voltage standing wave ratio (VSWR). Also, in FIGS. 15 and 16, the calculation results for the antenna 80X of the reference example are shown by a dotted line, and the calculation results when the length L of the slit 60 of the antenna 80A is changed to L1, L2, and L3 are shown by a solid line, a broken line, and a one-dot chain line, respectively. Note that L1, L2, and L3 are in the relationship of L1 < L2 < L3. Also, in FIG. 16, the ○ mark on the dotted line, the ▲ mark on the solid line, the ■ mark on the broken line, and the ● mark on the one-dot chain line indicate the minimum values in their respective graphs. In other words, in the low frequency band shown in FIG. 16, they indicate points where the VSWR characteristics are good.

[0083] As shown in Fig. 15, when comparing the calculation results of the antenna 80X in the reference example with the calculation of the antenna 80A in this embodiment, it can be seen that, for example, in the range of 1000 MHz to 1500 MHz, the maximum value of the graph has shifted to the lower frequency side. Further, when comparing the case where the length L of the slit 60 in the antenna 80A of this embodiment is changed to L1, L2, L3 (L1 < L2 < L3), it can be seen that, for example, in the range of 1000 MHz to 1500 MHz, the maximum value of the graph has shifted to the lower frequency side.

[0084] Therefore, it can be seen that by providing the slit 60 in the antenna, there is an effect of canceling a predetermined frequency band (for example, 1000 MHz to 1500 MHz). Also, it can be seen that by increasing the length L of the slit 60, the frequency band to be canceled moves to the lower frequency side.

[0085] Also, as shown in Fig. 16, when comparing the calculation results of the antenna 80X in the reference example with the calculation of the antenna 80A in this embodiment, it can be seen that the minimum value of the graph has shifted to the lower frequency side. Further, when comparing the case where the length L of the slit 60 in the antenna 80A of this embodiment is changed to L1, L2, L3 (L1 < L2 < L3), it can be seen that the minimum value of the graph has shifted to the lower frequency side.

[0086] Therefore, by providing the slit 60 in the antenna, the VSWR characteristics in the particularly low frequency band can be improved. Also, it can be seen that by increasing the length L of the slit 60, the frequency band in which the VSWR characteristics can be improved moves to the lower frequency side.

[0087] Next, using the antennas 80A to 80C of this embodiment, the effect of the shape of the slit 60 is verified.

[0088] Fig. 17A is an explanatory diagram of the antenna 80A. Fig. 17B is an explanatory diagram of the antenna 80B. Fig. 17C is an explanatory diagram of the antenna 80C.

[0089] Here, similar to the antenna 80A described above, a bowtie antenna model is used to verify the frequency characteristics of antennas 80A to 80C each having a slit 60. In each of the antennas 80A to 80C of this embodiment, the inner conductor side element 82 has a slit 60. Similar to the antenna 80A shown in FIG. 13, the slit 60 of the antenna 80A shown in FIG. 17A has a portion extending inward from the open end 61 and a portion extending in a direction away from the power supply portion 83 via a bent portion 63. Furthermore, the slit 60 of the antenna 80B shown in FIG. 17B and the slit 60 of the antenna 80C shown in FIG. 17C further have a bent portion 64, unlike the antenna 80A. Furthermore, when comparing the slit 60 of antenna 80B with the slit 60 of antenna 80C, the bent portion 64 of antenna 80B is located closer to the open end 61 of the slit 60 than the bent portion 63, while the bent portion 64 of antenna 80C is located on the opposite side of the bent portion 63 from the open end 61 of the slit 60.

[0090] Here, two lengths LA and LB are defined for the length of the slit 60 of antennas 80A to 80C, and verification is performed. The length LA of the slit 60 shown in Figures 17A to 17C is the distance along the slit 60, similar to the length L of the slit 60 in Figure 13, and is the length of the path from the open end 61 to the closed end 62 of the slit 60. The length LB of the slit 60 shown in Figures 17A to 17C is the sum of the distance along the slit 60 from the open end 61 to the farthest point (bend 63 in antennas 80A and 80B, and bend 64 in antenna 80C) and the shortest distance between the farthest point from the open end 61 and the closed end 62. In addition, the "shortest distance between the point farthest from the open end 61 and the closed end 62" is the distance connecting the bent portion 63 and the closed end 62 in the case of antenna 80A shown in Figure 17A and antenna 80B shown in Figure 17B, and is the distance connecting the bent portion 64 and the closed end 62 in the case of antenna 80C shown in Figure 17C.

[0091] 17A to 17C, with regard to length LA, the length LA of the slit 60 is longer in antennas 80B and 80C than in antenna 80A, and the length LA of the slit 60 is the same in antennas 80B and 80C. Also, as shown in Figures 17A to 17C, with regard to length LB, the length LB of the slit 60 is longer in antenna 80C than in antennas 80A and 80B, and the length LB of the slit 60 is the same in antennas 80A and 80B.

[0092] Fig. 18 is a graph showing an example of the frequency characteristics of antennas 80A to 80C. Fig. 19 is an enlarged view of a portion of the low frequency band of a graph showing an example of the frequency characteristics of antennas 80A to 80C. In these figures, the horizontal axis represents frequency and the vertical axis represents voltage standing wave ratio (VSWR). In Figs. 18 and 19, the calculation results for antenna 80A are shown by a solid line, the calculation results for antenna 80B are shown by a dashed line, and the calculation results for antenna 80C are shown by a dashed line.

[0093] 18 and 19, for example, in the range of 1000 MHz to 1500 MHz, when the calculation results for antenna 80A are compared with those for antennas 80B and 80C, it can be seen that the frequency band with good VSWR characteristics shifts lower as the length LA increases. Also, as shown in Fig. 18 and 19, when the calculation results for antennas 80A and 80B are compared with those for antenna 80C, for example, in the range of 500 MHz to 1000 MHz, it can be seen that the frequency band with good VSWR characteristics shifts lower as the length LB increases.

[0094] Next, the position of the open end 61 of the slit 60 will be examined using the antenna 80D of this embodiment.

[0095] FIG. 20 is an explanatory diagram of the antenna 80D.

[0096] Here, similar to the above-described antenna 80A, a bowtie antenna model is used to verify the frequency characteristics of antenna 80D, which has a different position of open end 61 of slit 60. Here, as shown in Fig. 20, length OE is defined as the length of the outer edge of the element (here, inner conductor side element 82) from feed portion 83 to open end 61. In the following verification, the frequency characteristics are verified when length OE is changed.

[0097] FIG. 21 is a graph showing an example of the frequency characteristics of antennas 80D and 80X. In these graphs, the horizontal axis represents frequency, and the vertical axis represents voltage standing wave ratio (VSWR). In FIG. 21, the dotted line indicates the calculation results for antenna 80X (without slit 60) of the reference example, and the solid line, dashed line, and dashed-dotted line indicate the calculation results when the length OE of antenna 80D is changed to OE1, OE2, and OE3, respectively. Note that OE1, OE2, and OE3 have a relationship of OE1>OE2>OE3. In FIG. 21, the circles on the dotted line, the triangles on the solid line, the squares on the dashed line, and the circles on the dashed line indicate the minimum values ​​in the respective graphs. In other words, they indicate points where the VSWR characteristics are good in the low frequency band shown in FIG. 21.

[0098] 21, when comparing antenna 80D of this embodiment, which includes slit 60, with antenna 80X of the reference example, which does not include slit 60, it can be seen that the minimum values ​​of the graph for antenna 80D in all cases of OE1, OE2, and OE3 are shifted to the lower frequency side than for antenna 80X. Furthermore, when comparing cases in which the length OE of antenna 80D of this embodiment is changed to OE1, OE2, and OE3 (OE1>OE2>OE3), it can be seen that the minimum values ​​of the graph are shifted to the lower frequency side.

[0099] Therefore, it can be seen that by bringing the position of the open end 61 of the slit 60 closer to the power feeding portion 83, the frequency band in which the VSWR characteristics can be improved shifts to the lower frequency side.

[0100] Next, the orientation of the slit 60 will be examined using the antennas 80A and 80E of this embodiment.

[0101] FIG. 22 is an explanatory diagram of the antenna 80A and the antenna 80E.

[0102] Here, similar to the antenna 80A described above, a bow-tie antenna model is used to verify the frequency characteristics of antennas 80A to 80C each having a slit 60. In the antennas 80A and 80E of the present embodiment, the inner conductor element 82 each has a slit 60. In the antenna 80A shown in FIG. 22A, similar to the antenna 80A shown in FIG. 13, the path of the slit 60 from the bent portion 63 to the closed end 62 has a portion that extends in a direction away from the power feed portion 83. On the other hand, in the antenna 80E shown in FIG. 22B, the path of the slit 60 from the bent portion 63 to the closed end 62 has a portion that extends in a direction toward the power feed portion 83. Note that the path lengths of the slit 60 are the same in the antennas 80A and 80E, and the length OE from the power feed portion 83 to the open end 61 is also the same. That is, antenna 80A and antenna 80E have different distances between power feed portion 83 and closed end 62, with the distance between power feed portion 83 and closed end 62 in antenna 80A being greater than the distance between power feed portion 83 and closed end 62 in antenna 80E.

[0103] Fig. 23 is a graph showing an example of the frequency characteristics of antennas 80A and 80E. In this graph, the horizontal axis represents frequency, and the vertical axis represents voltage standing wave ratio (VSWR). In Fig. 23, the dotted line represents the calculation results for antenna 80X (without slit 60) of the reference example, the solid line represents the calculation results for antenna 80A, and the dashed line represents the calculation results for antenna 80E. In Fig. 23, the circles on the dotted line, the triangles on the solid line, and the squares on the dashed line represent the minimum values ​​in the respective graphs; in other words, they represent points where the VSWR characteristics are good in the low frequency band shown in Fig. 23.

[0104] 18 and 19, when comparing antenna 80A and antenna 80E of this embodiment, which are provided with slit 60, with antenna 80X of a reference example, which is not provided with slit 60, it can be seen that the minimum values ​​of the graphs for both antenna 80A and antenna 80E are shifted to the lower frequency side than for antenna 80X. Furthermore, when comparing the calculation results for antenna 80A with the calculation results for antenna 80E, it can be seen that antenna 80A has better VSWR characteristics than antenna 80E, particularly in the low frequency band (for example, 600 MHz to 700 MHz).

[0105] Therefore, it can be seen that in antenna 80A, the path of slit 60 up to closed end 62 has a portion that extends in a direction away from power supply portion 83, i.e., the distance between closed end 62 and power supply portion 83 is increased, thereby providing good VSWR characteristics.

[0106] <<Modification of the slit 60>> The above-described slits 60 are formed only on the inner conductor element (the first inner conductor element 32, the second inner conductor element 42, or the inner conductor element 82) side. However, the position of the element where the slits 60 are formed is not limited to this.

[0107] FIG. 24A is an explanatory diagram of antenna 80F, and FIG. 24B is an explanatory diagram of antenna 80G.

[0108] The antenna 80F shown in Fig. 24A has slits 60 formed only on the outer conductor side element 81 side. The antenna 80G shown in Fig. 24B has slits 60 formed on the inner conductor side element 82 side and also has slits 60 formed on the outer conductor side element 81 side. Although detailed verification results are omitted, the frequency characteristics of the antenna, particularly in the low frequency band, can be improved in both the antenna 80F shown in Fig. 24A and the antenna 80G shown in Fig. 24B.

[0109] Furthermore, the above-described slit 60 has a portion that extends linearly inward from the open end 61 and a portion that extends linearly via a bend in a direction away from the power supply portion 83. However, the shape of the slit 60 is not limited to this.

[0110] FIG. 25 is an explanatory diagram of the antenna 80H.

[0111] Antenna 80H shown in Fig. 25 has slit 60 that extends in a gently curved shape from open end 61 to closed end 62. Although detailed verification results are omitted, even antenna 80H shown in Fig. 25 can improve the frequency characteristics of the antenna, particularly in the low frequency band.

[0112] Furthermore, the slit 60 described above has only one bent portion, but the shape of the slit 60 is not limited to this.

[0113] FIG. 26A is an explanatory diagram of antenna 80I, and FIG. 26B is an explanatory diagram of antenna 80J.

[0114] Antenna 80I shown in Fig. 26A has a slit 60 formed with two bent portions 63, 64. Antenna 80J shown in Fig. 26B has a slit 60 formed with three bent portions 63, 64, 65. Although detailed verification results will be omitted, it is possible to improve the frequency characteristics of the antenna, particularly in the low frequency band, with antenna 80I shown in Fig. 26A and antenna 80J shown in Fig. 26B.

[0115] ==Summary== The antenna device 10 of this embodiment has been described above. As shown in, for example, FIGS. 1, 2, and 8B, the antenna device 10 of this embodiment includes a first planar antenna (first antenna 30, 71) for linear polarization having a first feed portion 37, and a second planar antenna (second antenna 40, 72) for linear polarization having a second feed portion 47 that overlaps with the first feed portion 37 in a plan view seen from a direction (X direction) perpendicular to a predetermined surface (surface of the main body portion 50) of the first planar antenna (first antenna 30, 71). The linearly polarized waves of the first planar antenna and the linearly polarized waves of the second planar antenna intersect. The antenna device 10 of this embodiment can improve the degree of freedom in installing the antenna device 10, which includes multiple antennas (first planar antenna and second planar antenna).

[0116] 1 and 2, in the antenna device 10 of this embodiment, for example, the first planar antenna (first antenna 30) and the second planar antenna (second antenna 40) each have an outer conductor side element (first outer conductor side element 31 or second outer conductor side element 41) to which an outer conductor 56 of a feeder line (first feeder line 36 or second feeder line 46) is connected, and an inner conductor side element (first inner conductor side element 32 or second inner conductor side element 42) to which a core wire 57 of the feeder line is connected, and the first feeding section 37 is The second feeding section 47 is located between the second outer conductor side element 41 and the second inner conductor side element 42 of the second antenna 40, the outer shapes of the first outer conductor side element 31 and the first inner conductor side element 32 of the first antenna 30 are approximately symmetrical with each other about a first axis (A1) passing through the first feeding section 37, the outer shapes of the second outer conductor side element 41 and the second inner conductor side element 42 of the second antenna 40 are approximately symmetrical with each other about a second axis (A2) passing through the second feeding section 47, and each of the outer conductor side element and the inner conductor side element has a connecting section 52 to which a feed line is connected. This improves isolation between the first planar antenna and the second planar antenna, making it possible to realize an antenna device 10 that supports a wide band.

[0117] 3, 13, 17A to 17C, 20, 22A and 22B, 24A and 24B, 25, 26A and 26B, for example, in the antenna device 10 of this embodiment, at least one of the outer conductor side element (the first outer conductor side element 31, the second outer conductor side element 41, or the outer conductor side element 81) and the inner conductor side element (the first inner conductor side element 32, the second inner conductor side element 42, or the inner conductor side element 82) has a slit 60, and the slit 60 has an open end 61 at the outer edge of the element having the slit 60 and a closed end 62 inside. This can improve the frequency characteristics of the antenna included in the antenna device 10, particularly in the low frequency band.

[0118] 1, 2, and 3, in the first planar antenna, the inner conductor side connecting portion 54 of the connecting portion 52 is located between the slit 60 and the first power feeding portion 37. This improves the frequency characteristics of the antenna included in the antenna device 10, particularly in the low frequency band.

[0119] 17, for example, in a plan view of the first planar antenna (antennas 80A to 80C), there is provided a third axis (A3) that is approximately perpendicular to the first axis (A1) and passes through the first feed portion (feed portion 83), and at least a portion of the path from the open end 61 to the closed end 62 of the slit 60 passes through at least an area on the opposite side of the third axis to the open end 61. This can improve the frequency characteristics of the antenna included in the antenna device 10, particularly in the low frequency band.

[0120] 13, 17, 22, 24A and 24B, 25, 26A and 26B, for example, in a plan view of the first planar antenna (antennas 80A to 80C), there is provided a third axis (A3) that is substantially perpendicular to the first axis (A1) and passes through the first feed portion (feed portion 83), and in the first planar antenna (antennas 80A to 80C, 80E to 80J), the slit 60 has at least a portion that extends from the open end 61 toward the third axis (A3) and a portion that extends in a direction away from the first feed portion (feed portion 83). This can improve the frequency characteristics of the antenna included in the antenna device 10, particularly in the low frequency band.

[0121] 1 to 3, the element in which the slit 60 is formed has at least one rib 66, and the rib 66 is thicker than the portion of the element other than the rib 66. This increases the strength of the element in which the slit 60 is formed.

[0122] 1 to 3, the element in which the slit 60 is formed has two or more ribs 66, and the slit 60 is located between two adjacent ribs 66. This can increase the strength of the element in which the slit 60 is formed.

[0123] 1 to 3, 13, 17, 20, 22, 25, 26A and 26B, the slits 60 are formed only on the inner conductor element (first inner conductor element 32, second inner conductor element 42 or inner conductor element 82) side. This makes it possible to prevent the antenna characteristics from deteriorating due to interference of the feed line with the slits 60.

[0124] 4, the connection portion 52 includes an outer conductor side connection portion 53 through which a feeder line (first feeder line 36 or second feeder line 46) is connected to the outer conductor side element (first outer conductor side element 31 or second outer conductor side element 41), and an inner conductor side connection portion 54 through which a feeder line is connected to the inner conductor side element (first inner conductor side element 32 or second inner conductor side element 42). The first feed portion 37 is located at the center between the outer conductor side connection portion 53 and the inner conductor side connection portion 54 in the first planar antenna (first antenna 30), and the second feed portion 47 is located at the center between the outer conductor side connection portion 53 and the inner conductor side connection portion 54 in the second planar antenna (second antenna 40). This improves the frequency characteristics of the antenna included in the antenna device 10, particularly in the low frequency band.

[0125] 4 and 12A to 12C, at least one of the outer conductor element and the inner conductor element has a separation portion 58 formed around the periphery of the connection portion 52 to separate the connection portion 52 from an area other than the connection portion 52. This makes it possible to suppress heat loss when soldering the power feeder to the connection portion 52, thereby improving workability.

[0126] 1, 2 and 8B, the outer conductor side element (first outer conductor side element 31) and the inner conductor side element (first inner conductor side element 32) in the first planar antenna (first antenna 30, 71) each have a curved outer edge that bulges convexly toward the first power supply portion 37, and the outer conductor side element (second outer conductor side element 41) and the inner conductor side element (second inner conductor side element 42) in the second planar antenna (second antenna 40, 72) each have a curved outer edge that bulges convexly toward the second power supply portion 47. This reduces the opposing spatial area between the outer conductor side element and the inner conductor side element, increases the capacitance between them, and achieves better band characteristics over a wide band.

[0127] In a plan view, the second planar antenna is disposed relative to the first planar antenna at an angle greater than 0° and less than 180° centered on the first power supply portion 37 or the second power supply portion 47. This improves the degree of freedom in installing antenna device 10 including multiple antennas (first planar antennas and second planar antennas).

[0128] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Furthermore, the present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. [Explanation of symbols]

[0129] 10,70,70X antenna equipment 30,71,71X First antenna 31 First outer conductor side element 32 First inner conductor side element 36 1st feeder line 37 First power supply section 40,72,72X Second antenna 41 Second outer conductor side element 42 Second inner conductor side element 46 2nd feeder line 47 Second power supply section 50 Main body part 51 Bending part 52 Connection 53 Outer conductor side connection part 54 Inner conductor side connection part 56 Outer conductor 57 Core Wire 58 Separation part 60 slits 61 Open end 62 Closed end 63,64,65 Bend 66 Ribs 67 Storage unit 80A~80J Antenna 81 Outer conductor element 82 Inner conductor element 83 Power supply unit

Claims

1. a first planar antenna for linear polarization having a first feeding portion; a second planar antenna for linear polarization having a second feed portion that overlaps with the first feed portion in a plan view seen from a direction perpendicular to a predetermined plane of the first planar antenna; Equipped with the linearly polarized wave of the first planar antenna and the linearly polarized wave of the second planar antenna intersect with each other, At least one of the first planar antenna and the second planar antenna has a pair of elements arranged on both sides of the first feeding portion or the second feeding portion along a predetermined axis in the plan view, At least one of the pair of elements has a slit in which at least a part of a path from the open end to the closed end passes through at least a region on the opposite side of the predetermined axis from the open end side. Antenna device.

2. A first planar antenna for linear polarization having a first power supply portion; a second planar antenna for linear polarization having a second feed portion that overlaps with the first feed portion in a plan view seen from a direction perpendicular to a predetermined plane of the first planar antenna; Equipped with the linearly polarized wave of the first planar antenna and the linearly polarized wave of the second planar antenna intersect with each other, At least one of the first planar antenna and the second planar antenna has a pair of elements arranged on both sides of the first feeding portion or the second feeding portion along a predetermined axis in the plan view, At least one of the pair of elements has a slit having at least a portion extending from an open end toward the predetermined axis and a portion extending in a direction away from the first feeding portion or the second feeding portion. Antenna device.

3. Each of the first planar antenna and the second planar antenna includes, as the pair of elements, an outer conductor side element to which an outer conductor of a power feeder line is connected, and an inner conductor side element to which a core wire of the power feeder line is connected, and the first feeding portion is located between the outer conductor element and the inner conductor element of the first planar antenna, the second feeding portion is located between the outer conductor element and the inner conductor element of the second planar antenna, an outer shape of the outer conductor side element of the first planar antenna and an outer shape of the inner conductor side element are substantially symmetrical with each other with respect to a first axis passing through the first power supply portion, an outer shape of the outer conductor side element of the second planar antenna and an outer shape of the inner conductor side element are substantially symmetrical with each other with respect to a second axis passing through the second power feeding portion, each of the outer conductor element and the inner conductor element has a connection portion to which the power supply line is connected; 3. The antenna device according to claim 1 or 2.

4. In the first planar antenna, the connection portion is located between the slit and the first feeding portion. The antenna device according to claim 3 .

5. The element in which the slit is formed has at least one rib; The rib has a thickness greater than that of the portion of the element other than the rib.

3. The antenna device according to claim 1 or 2.

6. The element in which the slit is formed has two or more of the ribs, The slit is located between two adjacent ribs.

6. The antenna device according to claim 5.

7. the slit is formed only on the inner conductor element side. The antenna device according to claim 3 .

8. the connection portion includes an outer conductor side connection portion where the power feed line is connected to the outer conductor side element, and an inner conductor side connection portion where the power feed line is connected to the inner conductor side element, the first feeding portion is located at a center between the outer conductor side connecting portion and the inner conductor side connecting portion of the first planar antenna, the second feeding portion is located at the center between the outer conductor side connecting portion and the inner conductor side connecting portion of the second planar antenna. The antenna device according to claim 3 .

9. At least one of the outer conductor element and the inner conductor element has a separation portion formed around the connection portion, the separation portion separating the connection portion from a region other than the connection portion.

9. The antenna device according to claim 8.

10. each of the outer conductor element and the inner conductor element of the first planar antenna has a curved outer edge that bulges out toward the first feeding portion; each of the outer conductor element and the inner conductor element of the second planar antenna has a curved outer edge that bulges out toward the second feeding portion; The antenna device according to claim 3 .

11. In the plan view, the second planar antenna is disposed at an angle greater than 0° and smaller than 180° with the first power supply portion or the second power supply portion as a center relative to the first planar antenna.

3. The antenna device according to claim 1 or 2.

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