Antenna device

Abstract

To provide an antenna device capable of adapting to radio waves of a wide frequency band.SOLUTION: An antenna device includes a first element, a second element capacitively coupled to the first element, and a base portion to which the first element and the second element are connected, where the first element is configured to operate in at least a radio wave of a first frequency band together with the second element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses an antenna device including an antenna for a low frequency band and an antenna for a high frequency band. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-81500 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the telephone antenna of Patent Document 1 has a narrow bandwidth, particularly in the low frequency band, making it difficult for the antenna device to handle radio waves in a wide band from low to high frequencies.

[0005] One object of the present invention is to realize an antenna device that can handle radio waves in a wide frequency band. 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 element, a second element capacitively coupled to the first element, and a base to which the first element and the second element are connected, wherein the first element, together with the second element, is compatible with radio waves in at least a first frequency band. [Effects of the Invention]

[0007] According to one aspect of the present invention, an antenna device that can handle radio waves in a wide frequency band can be realized. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an exploded perspective view of an antenna device 1A according to a first embodiment. [Figure 2] 2A is a plan view of the antenna device 1A, FIG. 2B is a front view of the antenna device 1A, and FIG. 2C is a right side view of the antenna device 1A. [Figure 3] 10 is a diagram showing the periphery of the bottom surface of a base portion 30A to which a second element 21A is connected. [Figure 4] 4A is a circuit diagram of a high-pass filter 41, FIG. 4B is a circuit diagram of a band-pass filter 42, and FIG. 4C is a circuit diagram of a band-elimination filter 43. [Figure 5] FIG. 1 is a perspective view of an antenna device 1X of a comparative example. [Figure 6] 6A and 6B are graphs showing an example of the frequency characteristics in the low frequency band of the antenna 10A of the first embodiment and the antenna 10X of the comparative example, where FIG. 6A is a graph of the VSWR in the low frequency band of the antenna 10A and the antenna 10X, and FIG. 6B is a graph of the isolation in the low frequency band of the antenna 10A and the antenna 10X. [Figure 7] 7A and 7B are graphs showing an example of frequency characteristics in the mid-frequency band of the antenna 10A of the first embodiment and the antenna 10X of the comparative example, where FIG. 7A is a graph of the VSWR in the mid-frequency band of the antenna 10A and the antenna 10X, and FIG. 7B is a graph of the isolation in the mid-frequency band of the antenna 10A and the antenna 10X. [Figure 8] 8A is a graph showing an example of the frequency characteristics in the high frequency band of the antenna 10A of the first embodiment and the antenna 10X of the comparative example, where FIG. 8A is a graph of the VSWR in the high frequency band of the antenna 10A and the antenna 10X, and FIG. 8B is a graph of the isolation in the high frequency band of the antenna 10A and the antenna 10X. [Figure 9]FIG. 10 is an exploded perspective view of an antenna device 1B according to a first example of a second embodiment. [Figure 10] FIG. 10 is an exploded perspective view of an antenna device 1C according to a second example of the second embodiment. [Figure 11] 11A is a plan view of the antenna device 1C, FIG. 11B is a front view of the antenna device 1C, and FIG. 11C is a right side view of the antenna device 1C. [Figure 12] 12A and 12B are diagrams showing the front and bottom surfaces of a second example of an antenna device 1C of the second embodiment, where FIG. 12A is an enlarged view of the front surface of a first element 11C, and FIG. 12B is a diagram showing the area around the bottom surface of a base 30C to which a second element 21C is connected. [Figure 13] 13A is a graph showing an example of the frequency characteristics in the low frequency band of antennas 10B and 10C of the second embodiment, where FIG. 13A is a graph of the VSWR in the low frequency band of antennas 10B and 10C, and FIG. 13B is a graph of the radiation efficiency in the low frequency band of antennas 10B and 10C. [Figure 14] 14A and 14B are graphs showing an example of the frequency characteristics in the mid-frequency band of antennas 10B and 10C of the second embodiment, where FIG. 14A is a graph of the VSWR in the mid-frequency band of antennas 10B and 10C, and FIG. 14B is a graph of the radiation efficiency in the mid-frequency band of antennas 10B and 10C. [Figure 15] 15A is a graph showing an example of the frequency characteristics of antennas 10B and 10C of the second embodiment in the high frequency band, where FIG. 15A is a graph of the VSWR of antennas 10B and 10C in the high frequency band, and FIG. 15B is a graph of the radiation efficiency of antennas 10B and 10C in the high frequency band. [Figure 16] 16A and 16B are perspective views of an antenna device 1D according to a third example of the second embodiment, where FIG. 16A is an overall perspective view of the antenna device 1D and FIG. 16B is a perspective view of the antenna device 1D with the case 2 removed. [Figure 17]17A and 17B are graphs showing an example of frequency characteristics of the antenna 10D of the second embodiment in the low frequency band, where FIG. 17A is a graph of the VSWR of the antenna 10D in the low frequency band, and FIG. 17B is a graph of the radiation efficiency of the antenna 10D in the low frequency band. [Figure 18] 18A is a graph showing an example of the frequency characteristics of the antenna 10D of the second embodiment in the mid-frequency band, and FIG. 18B is a graph showing the VSWR of the antenna 10D in the mid-frequency band, and FIG. 18B is a graph showing the radiation efficiency of the antenna 10D in the mid-frequency band. [Figure 19] 19A and 19B are graphs showing an example of frequency characteristics of the antenna 10D of the second embodiment in the high frequency band, where FIG. 19A is a graph of the VSWR of the antenna 10D in the high frequency band, and FIG. 19B is a graph of the radiation efficiency of the antenna 10D in the high frequency band. 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] ==First Embodiment== Fig. 1 is an exploded perspective view of the antenna device 1A of the first embodiment. Fig. 2 is a three-view diagram of the antenna device 1A of the first embodiment. Fig. 2A is a plan view of the antenna device 1A, Fig. 2B is a front view of the antenna device 1A, and Fig. 2C is a right side view of the antenna device 1A.

[0012] Fig. 1 shows an exploded perspective view of the antenna device 1A with a case 2 (described later) moved to the upper side in order to illustrate the internal configuration of the antenna device 1A. In Fig. 2, the case 2 of the antenna device 1A is not shown.

[0013] <<Definition of direction etc.>> First, with reference to FIG. 1, directions (left-right direction, front-rear direction, and up-down direction) in the antenna device 1A will be defined.

[0014] 1, the direction in which a first element 11A (described later) and a second element 21A (described later) are aligned is defined as the left-right direction. Also, in FIG. 1, the side from the second element 21A toward the first element 11A is defined as the left direction, and the opposite direction (the side from the first element 11A toward the second element 21A) is defined as the right direction.

[0015] 1, the direction in which the extending portion 13A (described later) extends relative to the standing portion 12A (described later) is defined as the front-rear direction. The direction from the extending portion 13A toward the standing portion 12A is defined as the front direction, and the opposite direction (the direction from the standing portion 12A toward the extending portion 13A) is defined as the rear direction.

[0016] 1, the direction perpendicular to the left-right and front-rear directions is defined as the up-down direction. The direction from the ground section 3 (described later) toward the antenna 10A is defined as the up direction, and the opposite direction (the direction from the antenna 10A toward the ground section 3) is defined as the down direction.

[0017] The front-to-back direction is sometimes called the "X direction," the left-to-right direction is sometimes called the "Y direction," and the up-to-down direction is sometimes called the "Z direction." As shown in Figure 1, the rear direction is sometimes called the +X direction, the left direction is sometimes called the +Y direction, and the up-to-down direction is sometimes called the +Z direction. The left-to-right direction is sometimes called the "horizontal direction" or "width direction," and the up-to-down direction is sometimes called the "vertical direction" or "height direction."

[0018] The above definitions of directions and the like are common to other embodiments in this specification unless otherwise specified.

[0019] <<Outline of Antenna Device 1A>> Next, an overview of the antenna device 1A according to this embodiment will be described with reference to FIGS.

[0020] The antenna device 1A is a vehicle antenna device used in a vehicle (not shown). In this embodiment, the antenna device 1A is mounted, for example, on the roof or inside the instrument panel of the vehicle. However, the antenna device 1A may be located in a portion of the vehicle other than the roof or inside the instrument panel, such as a spoiler or an overhead console of the vehicle. Furthermore, the antenna device 1A may be an antenna device for a vehicle other than that used in a vehicle.

[0021] The antenna device 1A includes a case 2, a ground portion 3, an antenna 10A, an antenna 20A, a base portion 30A, and a filter 40 shown in FIG. 3, which will be described later.

[0022] <Case 2> The case 2 is a member that constitutes the upper surface of the antenna device 1A. In this embodiment, the case 2 is formed of, for example, insulating resin. However, the case 2 may be formed of a material other than insulating resin that transmits radio waves. Furthermore, the case 2 may be composed of a portion made of insulating resin and a portion made of another material that transmits radio waves, and members may be freely combined.

[0023] The case 2 is fixed to the ground part 3 by a plurality of screws (not shown). However, the case 2 is not limited to being fixed by screws, and may be fixed to the ground part 3 by snap fitting, welding, adhesive, or the like. In this case, the antenna 10A, the antenna 20A, the base part 30A, and the filter 40 are disposed in an accommodation space formed by the case 2 that forms the top surface of the antenna device 1A and the ground part 3 that forms the bottom surface of the antenna device 1A.

[0024] Furthermore, the case 2 may be fixed to something other than the ground portion 3. For example, the case 2 may be fixed to a base (not shown) that is a separate member from the ground portion 3. The base is formed, for example, from an insulating resin. However, the base may be formed from a material other than insulating resin that transmits radio waves. The base may also be composed of an insulating resin portion and a material other than insulating resin that transmits radio waves, and components may be freely combined. The ground portion 3, the antenna 10A, the antenna 20A, the base 30A, and the filter 40 may be disposed in a storage space formed by the case 2 that forms the top surface of the antenna device 1A and the base that forms the bottom surface of the antenna device 1A.

[0025] <Ground section 3> The ground section 3 is a member that functions as a ground for the antennas (here, antennas 10A and 20A) included in the antenna device 1A. In this embodiment, the ground section 3 functions as a common ground for the antennas 10A and 20A. However, the ground section 3 may also function as a ground for some of the antennas included in the antenna device 1A. For example, the ground section 3 may function as a ground for the antenna 10A, and another ground section may function as a ground for the antenna 20A.

[0026] 1 and 2, the ground section 3 is formed as a single metal plate (sheet metal). However, the ground section 3 may be made up of multiple separate metal plates. For example, the ground section 3 may be configured such that a metal plate on which the antenna 10A is provided and another metal plate on which the antenna 20A is provided are electrically connected to each other.

[0027] The ground section 3 may be formed in a shape other than a plate, as long as it functions as the ground of the antenna of the antenna device 1A. Furthermore, the ground section 3 may be formed by freely combining metal and non-metallic members, as long as it functions as the ground of the antenna of the antenna device 1A. For example, the ground section 3 may be formed including a metal plate and a resin insulator. Furthermore, the ground section 3 may be formed by a single board on which a conductor pattern is formed, such as a printed circuit board (PCB).

[0028] 2A, the ground section 3 is formed of a substantially quadrilateral member in a plan view when viewed in the -Z direction (downward). In the following description, "substantially quadrilateral" refers to a shape consisting of four sides, including, for example, a square or a rectangle, and may have at least some corners cut out at an angle to the sides, or may have at least some corners that include curves. Furthermore, the "substantially quadrilateral" shape may have cutouts (recesses) or protrusions (protrusions) on some of the sides.

[0029] In this embodiment, the ground section 3 has a pedestal 4 that supports the base 30A. The pedestal 4 is formed by bending a portion of the ground section 3 through bending processing, so that it protrudes upward. The base 30A is then placed above the pedestal 4. As a result, the base 30A is positioned a predetermined distance above the front surface (the surface on the +Z direction side) of the ground section 3.

[0030] Note that, as long as the base 30A can be positioned above the front surface of the ground portion 3 at a predetermined distance, the base 30A may be supported by, for example, a holder (not shown) or the case 2. In this case, the ground portion 3 does not need to have the pedestal 4. Note that when the base 30A is supported by the case 2, an antenna element such as a first element 11A (described later) may be fixed to the base 30A via solder or an M-shaped spring. Also, the ground portion 3 may not have the pedestal 4, and the base 30A may be disposed directly on the front surface of the ground portion 3. In other words, the base 30A may be positioned without being spaced apart from the front surface of the ground portion 3.

[0031] <Antenna 10A> The antenna 10A is a wideband antenna for mobile communications based on an inverted-F antenna. In this embodiment, the antenna 10A is compatible with radio waves in the 699 MHz to 5000 MHz band for GSM, UMTS, LTE, and 5G, for example. However, the antenna 10A is not limited to this, and may be compatible with radio waves in some of the frequency bands for GSM, UMTS, LTE, and 5G (for example, only for 5G).

[0032] Furthermore, the antenna 10A may be compatible with radio waves in frequency bands other than those for GSM, UMTS, LTE, and 5G. The antenna 10A may be an antenna compatible with radio waves in frequency bands used for, for example, telematics, V2X (Vehicle to Everything: vehicle-to-vehicle communication, road-to-vehicle communication), Wi-Fi, Bluetooth, etc. Furthermore, the antenna 10A may be compatible with communication using MIMO (Multiple-Input Multiple-Output), as will be described later.

[0033] In the following description, a predetermined frequency band on the lower side of the frequency band of radio waves supported by the antenna 10A may be referred to as a “low frequency band.” In this embodiment, the low frequency band is, for example, a band of 699 MHz to 960 MHz.

[0034] Furthermore, among the frequency bands of radio waves that the antenna 10A supports, a predetermined frequency band on the higher side may be called a “high frequency band.” In this embodiment, the high frequency band is, for example, a band of 3300 MHz to 5000 MHz.

[0035] Furthermore, among the frequency bands of radio waves that the antenna 10A supports, a predetermined frequency band between the low frequency band and the high frequency band may be called a “medium frequency band.” In this embodiment, the medium frequency band is, for example, a band of 1710 MHz to 2690 MHz.

[0036] As described above, the low frequency band is a frequency band lower than the mid frequency band, the mid frequency band is a frequency band higher than the low frequency band and lower than the high frequency band, and the high frequency band is a frequency band higher than the mid frequency band.

[0037] The mid-frequency band and the high-frequency band may collectively be referred to as the "mid-high frequency band." The frequency band values ​​exemplified above for the low-frequency band, mid-frequency band, and high-frequency band are not limited to these, and may vary depending on the frequency band of radio waves supported by antenna 10A.

[0038] The antenna 10A includes a first element 11A and a feeding portion .

[0039] The first element 11A is an element that resonates in a frequency band of radio waves corresponding to the antenna 10A (for example, a low frequency band and a mid- to high frequency band). As shown in FIGS. 1 and 2B, the first element 11A is connected to the base 30A. Here, "connected" is not limited to being physically connected but also includes being electrically connected. Therefore, "the first element 11A is connected to the base 30A" is not limited to connecting the first element 11A and the base 30A with a conductor, but includes connecting them with an electronic circuit, electronic component, or the like.

[0040] The first element 11A has an upright portion 12A, an extension portion 13A, and a short-circuit portion 17A.

[0041] The standing portion 12A is a portion of the first element 11A that is formed to stand up relative to the base portion 30A. In this embodiment, the standing portion 12A is formed to stand up relative to the base portion 30A. The direction in which the standing portion 12A stands up relative to the base portion 30A is not limited to the upward direction (+Z direction), and may be inclined at a predetermined angle relative to the base portion 30A.

[0042] In this embodiment, the standing portion 12A has a self-similar shape as shown in FIG. 2B. This makes it possible to achieve a broader bandwidth. Here, a self-similar shape is a shape that remains similar even when the scale (size ratio) is changed. However, the standing portion 12A does not necessarily have to have a self-similar shape.

[0043] 2B, a first element connecting portion 19 is provided at the end portion in the downward direction (-Z direction) of the standing portion 12A. The first element connecting portion 19 is a portion of the first element 11A that is connected to the base portion 30A. This connects the first element 11A to the base portion 30A.

[0044] Depending on the frequency band supported by the first element 11A, the first element 11A may be connected to the base 30A by screwing. In this case, bosses for screwing are formed on the case 2, and by screwing together with the base 30A, it is possible to achieve both mechanical support for the first element 11A and electrical connection to the base 30A. In this case, by adjusting the length of the screws, it is also possible to operate the first element 11A as part of the antenna.

[0045] The extension portion 13A is a portion formed to extend from the standing portion 12A. The extension portion 13A is also a portion formed to face the ground portion 3. In this embodiment, the extension portion 13A is formed to extend from the upper end of the standing portion 12A, as shown in FIG. 1 . However, the extension portion 13A may be formed to extend from a position other than the upper end of the standing portion 12A. That is, the extension portion 13A may be formed to extend from the middle of the standing portion 12A in the vertical direction. The extension direction of the extension portion 13A is not limited to a direction parallel to the surface of the ground portion 3, but may be a direction inclined at a predetermined angle from a direction parallel to the surface of the ground portion 3.

[0046] The extension portion 13A has a main portion 14A, a first additional portion 15A, and a second additional portion 16A.

[0047] The main portion 14A is a portion of the extending portion 13A that extends from the standing portion 12A. In Figures 1 and 2A, the main portion 14A is shown in an area other than the two areas surrounded by dashed lines (an area corresponding to the first additional portion 15A and an area corresponding to the second additional portion 16A).

[0048] The first additional portion 15A is a portion extending from the main portion 14A and positioned away from the standing portion 12A. In this embodiment, the first additional portion 15A extends rearward from the rear end of the main portion 14A, then bends rightward and extends further. In FIGS. 1 and 2A, the first additional portion 15A is shown as the region positioned on the rear side (+X direction side) of the two regions surrounded by dashed lines. Here, "positioned away from the standing portion 12A" means that, in terms of the positional relationship between the first additional portion 15A and the second additional portion 16A, one (the first additional portion 15A) is positioned farther away from the other (the second additional portion 16A). In other words, the distance between the standing portion 12 and the first additional portion 15A is greater than the distance between the standing portion 12 and the second additional portion 16A.

[0049] The second additional portion 16A is a portion that extends from the main portion 14A and is located close to the standing portion 12A. In FIGS. 1 and 2A, the second additional portion 16A is shown as the region located on the front side (negative X direction side) of the two regions surrounded by dashed lines. Here, "located close to the standing portion 12A" means that, in terms of the positional relationship between the first additional portion 15A and the second additional portion 16A, one (the second additional portion 16A) is located closer to the standing portion 12A than the other (the first additional portion 15A).

[0050] Short-circuit portion 17A is a portion that branches off from extension portion 13A and is connected to base portion 30A. Short-circuit portion 17A is also electrically connected to ground portion 3. Having first element 11A short-circuit portion 17A makes it easier to achieve impedance matching in the frequency band of radio waves that antenna 10A supports.

[0051] The short-circuiting portion 17A may be connected to the base portion 30A by soldering, welding, or the like, or by screwing. In this case, bosses for screwing may be formed on the case 2, and by screwing together with the base portion 30A, it is possible to achieve both mechanical support for the short-circuiting portion 17A and electrical connection to the base portion 30A. In this case, by adjusting the length of the screws, it is also possible to operate the short-circuiting portion 17A as part of the antenna.

[0052] The antenna 10A of this embodiment mainly supports the low frequency band by the standing portion 12A, the main portion 14A, the first addition portion 15A, and the short-circuit portion 17A. That is, the portion of the first element 11A that is composed of the standing portion 12A, the main portion 14A, the first addition portion 15A, and the short-circuit portion 17A is formed to have a length and width according to the wavelength used in the low frequency band (for example, a wavelength at 699 MHz).

[0053] Furthermore, the antenna 10A of this embodiment mainly supports the mid-frequency band by the standing portion 12A, the main portion 14A, the second additional portion 16A, and the short-circuit portion 17A. That is, the portion of the first element 11A that is configured by the standing portion 12A, the main portion 14A, the second additional portion 16A, and the short-circuit portion 17A is formed to have a length and width according to the wavelength used in the mid-frequency band (for example, a wavelength at 2 GHz).

[0054] Furthermore, the antenna 10A of this embodiment mainly supports the high frequency band by the standing portion 12A. That is, the portion of the first element 11A that is configured by the standing portion 12A is formed to have a length and width according to the wavelength used in the high frequency band (for example, a wavelength at 5 GHz).

[0055] The power supply portion 18 is a region including the power supply point of the antenna 10A. In this embodiment, the power supply portion 18 is located at a portion where the first element 11A is connected to the base portion 30A (first element connection portion 19), as shown in FIG.

[0056] <Antenna 20A> The antenna 20A is a wideband antenna for mobile communications based on a monopole antenna. In this embodiment, the antenna 20A supports radio waves in a frequency band different from the frequency band of radio waves supported by the antenna 10A. The antenna 20A supports, for example, radio waves in the 1710 MHz to 5000 MHz band for Sub6. However, the antenna 20A may also support radio waves in a frequency band other than Sub6. The antenna 20A may also be an antenna that supports radio waves in a frequency band used for, for example, telematics, V2X, Wi-Fi, Bluetooth, etc.

[0057] The antenna 20A may be compatible with radio waves in the same frequency band as the radio wave frequency band compatible with the antenna 10A. That is, the antenna 20A may be compatible with radio waves in the 699 MHz to 5000 MHz band for GSM, UMTS, LTE, and 5G, for example. In this case, the antenna device 1A may be, for example, an antenna device that performs MIMO communication. In MIMO communication, data is transmitted from each of multiple antennas and received simultaneously by the multiple antennas. In the antenna device 1A that performs MIMO communication, data is transmitted from each of the antennas 10A and 20A that constitute the antenna device 1A, and the data is received simultaneously by the antennas 10A and 20A.

[0058] The antenna 20A has a second element 21A and a power feeding section 27. The second element 21A also has an antenna section 22 and an additional element section .

[0059] Antenna section 22 is an element that resonates in the frequency band of radio waves supported by antenna 20A (for example, the 1710 MHz to 5000 MHz band for Sub6). Antenna section 22 is formed to have a length and width according to the frequency band of radio waves supported by antenna 20A (here, the 1710 MHz to 5000 MHz band for Sub6).

[0060] The antenna portion 22 has an upright portion 24 and an extension portion 25, similar to the upright portion 12A and the extension portion 13A of the first element 11A described above.

[0061] The standing portion 24 is a portion of the antenna portion 22 that is formed to stand up relative to the base portion 30A. In this embodiment, the standing portion 24 is formed to stand up relative to the base portion 30A. The direction in which the standing portion 24 stands up relative to the base portion 30A is not limited to the upward direction (+Z direction), and may be a direction inclined at a predetermined angle relative to the base portion 30A.

[0062] 2B, a second element connecting portion 26 is provided at the end portion in the downward direction (-Z direction) of the standing portion 24. The second element connecting portion 26 is a portion of the second element 21A that is connected to the base portion 30A. This connects the second element 21A to the base portion 30A.

[0063] The extension portion 25 is a portion formed to extend from the standing portion 24. The extension portion 25 is also a portion formed to face the ground portion 3. In this embodiment, the extension portion 25 is formed to extend from the upper end of the standing portion 24, as shown in FIGS. 1 and 2C. However, the extension portion 25 may be formed to extend from a position other than the upper end of the standing portion 24. That is, the extension portion 25 may be formed to extend from the middle of the standing portion 24 in the up-down direction. The extension direction of the extension portion 25 is not limited to a direction parallel to the surface of the ground portion 3, but may be a direction inclined at a predetermined angle from a direction parallel to the ground portion 3.

[0064] The additional element portion 23 is a portion formed to extend further from the extension portion 25 of the antenna portion 22. The additional element portion 23 is a portion that resonates together with the antenna portion 22 in the frequency band of radio waves corresponding to the antenna 20A (for example, the 1710 MHz to 5000 MHz band for Sub6). The additional element portion 23 also has a portion that is capacitively coupled to the first element 11A.

[0065] 1, 2A, and 2C, the additional element section 23 extends in the +X direction from the extension section 25 of the antenna section 22. The additional element section 23 then bends in the +Y direction from there, so that the end of the additional element section 23 is disposed close to the end of the first addition section 15A in the extension section 13A of the first element 11A. Therefore, in this embodiment, the additional element section 23 is disposed so as to be capacitively coupled to the end of the first element 11A.

[0066] Here, when the end of the additional element portion 23 is close to the end of the first element 11A, the "end" does not mean the exact end, but rather a predetermined region including the end.

[0067] In this embodiment, the end of the additional element portion 23 and the end of the first additional portion 15A are positioned so as to overlap in the plan view shown in Fig. 2A, but are spaced apart in the vertical direction in the front view shown in Fig. 2B. However, the positional relationship between the end of the additional element portion 23 and the end of the first additional portion 15A is not limited to that shown in Fig. 2A and 2B.

[0068] In this embodiment, as shown in FIG. 2B, the end of the first additional portion 15A is located above the end of the additional element portion 23, but the end of the additional element portion 23 may also be located above the end of the first additional portion 15A.

[0069] Furthermore, the end of the additional element portion 23 and the end of the first additional portion 15A may be spaced apart in the left-right direction in the plan view shown in Fig. 2A, for example. In this case, the end of the additional element portion 23 and the end of the first additional portion 15A may be at the same or different positions in the up-down direction in the side view shown in Fig. 2B, for example.

[0070] 2A, the end of the additional element 23 and the end of the first additional portion 15A may be different from each other in the front-to-rear direction. For example, the end of the additional element 23 may be located forward of the end of the first additional portion 15A, or may be located so as to overlap at least partially in the front-to-rear direction, or may be located so as to be spaced apart from each other in the front-to-rear direction.

[0071] As described above, the end of the additional element section 23 and the end of the first addition section 15A may be provided in close proximity to each other so that the first element 11A and the second element 21A are capacitively coupled.

[0072] In the antenna device 1A of this embodiment, as described above, the end of the first element 11A and the end of the second element 21A are provided at positions where they are capacitively coupled, thereby realizing the capacitive coupling section .

[0073] As a result, in the low frequency band, two resonances can be generated between the first element 11A of the antenna 10A and the second element 21A of the antenna 20A having the additional element portion 23. In other words, by superimposing two resonances, namely the resonance of the first element 11A of the antenna 10A alone and the resonance of the antenna 10A taking capacitive coupling into consideration, the low frequency band corresponding to the first element 11A can be extended further toward the lower frequency side. Therefore, the antenna device 1A of this embodiment can easily achieve a broadband of the antenna 10A.

[0074] The power supply portion 27 is a region including the power supply point of the antenna 20A. In this embodiment, the power supply portion 27 is located at the portion where the second element 21A is connected to the base portion 30A (second element connection portion 26), as shown in FIG.

[0075] <Base 30A> The base 30A is a plate-like member to which the first element 11A of the antenna 10A and the second element 21A of the antenna 20A are connected. The base 30A may be provided with elements, circuits, etc. that process signals from the antennas 10A and 20A.

[0076] In the antenna device 1A of this embodiment, the base 30A is, for example, a printed circuit board (PCB). The base 30A has a conductor pattern formed on a resin material such as glass epoxy resin. However, the base 30A may have a conductor pattern formed on a resin material other than glass epoxy resin, such as phenol resin. The base 30A may also be, for example, a flexible substrate.

[0077] However, the entire base 30A does not need to be formed in a plate shape, and the base 30A may have a portion formed in a shape other than a plate. For example, the base 30A may be a part of the case 2, or may be a part of a holder (not shown) that holds the first element 11A and the second element 21A described above. In this case, the case 2 and the holder (not shown) may be made of, for example, resin.

[0078] The base 30A is not limited to the above configuration and may be configured only with a conductor pattern. Furthermore, when the base 30A is configured by forming a conductor pattern on a resin material, for example, MID (Molded Interconnect Device) technology may be used. This allows a conductor pattern to be formed on a resin material having a complex three-dimensional shape. For example, a conductor pattern can be formed on a resin material having a shape similar to that of the base 30A shown in FIGS. 1 and 2 using MID technology.

[0079] However, when antennas 10A and 20A are arranged close to each other so as to be capacitively coupled, as in the antenna device 1A of this embodiment, the isolation between antennas 10A and 20A may deteriorate. Specifically, when antennas 10A and 20A are arranged close to each other, they may be affected by signals in the frequency bands that the other antenna supports. For example, signals in the radio frequency range that antenna 10A supports may be transmitted to the base 30A via the power feed 27 of antenna 20A. As a result, antenna 10A may be affected by antenna 20A arranged close to it, and the characteristics of antenna 10A in the low frequency band may deteriorate, for example.

[0080] Therefore, the antenna device 1A of this embodiment includes a filter 40, as will be described later, to improve the isolation between the antenna 10A and the antenna 20A.

[0081] <Filter 40> FIG. 3 is a diagram showing the periphery of the bottom surface of the base portion 30A to which the second element 21A is connected.

[0082] The filter 40 is a circuit element that suppresses signals in a predetermined frequency band. In this embodiment, the filter 40 suppresses signals in an undesired frequency band among the frequency bands of radio waves supported by the antenna 20A. In this embodiment, the undesired frequency band is, for example, a low frequency band (699 MHz to 960 MHz) among the frequency bands of radio waves supported by the antenna 10A. Note that the filter 40 does not have to suppress signals in the entire low frequency band, and may suppress signals in a portion of the low frequency band.

[0083] 3, in the antenna device 1A of this embodiment, a power line (microstrip line) formed of a conductor is provided between the second element connection portion 26 and the feeder line connection portion 5 to which the feeder line is connected. The filter 40 is provided so as to be connected in series to the microstrip line. Specifically, the filter 40 is provided between a first region 31 and a second region 32. Here, the first region 31 is a conductive region of the microstrip line of the base 30A on the side to which the feeder line of the antenna device 1A is connected. Furthermore, the second region 32 is a conductive region of the microstrip line of the base 30A on the side to which the second element 21A is connected.

[0084] 3, in the present embodiment, the filter 40 is disposed on the microstrip line of the base 30A closer to the second element connection portion 26 than the feed line connection portion 5 to which the feed line is connected (i.e., closer to the feed portion 27 of the antenna 20A). This makes it possible to suppress signal degradation due to coupling between transmission lines in the microstrip line. However, if the problem of signal degradation due to coupling between transmission lines is tolerable, the filter 40 may be disposed on the side closer to the feed line connection portion 5 than the second element connection portion 26.

[0085] 3, filter 40 is shown as a single block enclosed by a dashed line for convenience's sake. However, filter 40 actually includes two circuit elements: an inductor L and a capacitor C, as shown in FIG. 4, which will be described later.

[0086] Fig. 4 is a circuit diagram showing an example of a filter 40. Fig. 4A is a circuit diagram of a high-pass filter 41, Fig. 4B is a circuit diagram of a band-pass filter 42, and Fig. 4C is a circuit diagram of a band elimination filter 43.

[0087] The filter 40 may be, for example, a high-pass filter (HPF) 41 as shown in Fig. 4A. The high-pass filter 41 is, for example, a circuit element that suppresses low-frequency band signals and passes mid- to high-frequency band signals. As shown in Fig. 4A, the high-pass filter 41 includes a capacitor C and an inductor L connected to ground potential.

[0088] 4B, the filter 40 may be a band-pass filter 42 (BPF). The band-pass filter 42 is a circuit element that passes only signals in a specific frequency band (here, the mid- to high-frequency band) and suppresses signals in other frequency bands (here, the low-frequency band). As shown in FIG. 4B, the band-pass filter 42 includes an inductor L, a capacitor C, and a parallel circuit of the inductor L and the capacitor C connected to ground.

[0089] 4C, the filter 40 may be a band elimination filter 43 (BEF). The band elimination filter 43 is a circuit element that suppresses signals in a specific frequency band (here, the low frequency band) and passes signals in other frequency bands (here, the mid- to high frequency bands). As shown in FIG. 4C, the band elimination filter 43 includes a series circuit made up of an inductor L and a capacitor C, both connected to ground, and a parallel circuit made up of the inductor L and the capacitor C.

[0090] 4A to 4C, one terminal IN is connected to, for example, the first region 31, and the other terminal OUT is connected to, for example, the second region 32. In this way, the filter 40 is connected in series to the microstrip line.

[0091] As described above, the antenna device 1A of this embodiment can improve isolation between the antennas 10A and 20A by including the filter 40, which is composed of the high-pass filter 41, the band-pass filter 42, or the band elimination filter 43. The filter 40 of this embodiment is a circuit element that suppresses signals in a predetermined frequency band, but a SAW (Surface Acoustic Wave) filter, for example, may also be used. If the isolation problem is tolerable due to the communication standards of the antennas 10A and 20A and the level of the received signal, the antenna device 1A does not need to include the filter 40.

[0092] <Other Configurations of Antenna Device 1A> The antenna device 1A may have a holder (not shown) that supports at least one of the antenna 10A, the antenna 20A, and the base 30A. The holder is made of resin and is provided on the ground portion 3. However, the holder may be made of a material other than resin.

[0093] However, instead of using the holders described above, antennas 10A and 20A may be fixed to case 2 by screwing, welding, adhesive, snap-fitting, or the like. This improves the ease of assembly of antenna device 1A. Furthermore, the proximity distance between the end of first element 11A and the end of second element 21A can be stabilized, thereby stabilizing capacitive coupling. Furthermore, holes may be drilled in first element 11A of antenna 10A or second element 21A of antenna 20A for welding to case 2.

[0094] The antenna device 1A may have another antenna other than the antenna 10A and the antenna 20A. The other antenna may be, for example, a planar antenna for a Global Navigation Satellite System (GNSS), a Satellite Digital Audio Radio Service (SDARS), or an Electronic Toll Collection (ETC).

[0095] The planar antenna for GNSS or SDARS may be a multi-layer or multi-stage antenna if there are no strict restrictions on the vertical size of the antenna device 1A. This allows the planar antenna to support radio waves in multiple frequency bands. The planar antenna may also support radio waves in multiple frequency bands by having a radiating element with an opening such as a slot.

[0096] Furthermore, the antenna other than antenna 10A and antenna 20A is not limited to those described above, and may be an antenna compatible with radio waves in the frequency bands used for telematics, V2X, Wi-Fi, Bluetooth, and DAB.

[0097] <<Comparative example of antenna device 1X>> As described above, in the antenna device 1A of this embodiment, the end of the first element 11A and the end of the second element 21A form the capacitive coupling portion 35. This allows the low frequency band corresponding to the first element 11A to be extended further to the lower frequency side in the antenna device 1A of this embodiment. Below, the characteristics of the antenna 10A of the antenna device 1A of this embodiment will be examined using a comparative example. First, the antenna device 1X of the comparative example shown in FIG. 5 will be described.

[0098] Fig. 5 is a perspective view of an antenna device 1X of a comparative example, in which the case 2 of the antenna device 1X, which is the same as that of the antenna device 1A of this embodiment, is not shown.

[0099] 5, in the antenna device 1X of the comparative example, the second element 21X of the antenna 20X does not have a configuration equivalent to the additional element portion 23 in the antenna device 1A of the present embodiment. Therefore, the antenna device 1X of the comparative example does not have the capacitive coupling portion 35 in the antenna device 1A of the present embodiment. Furthermore, the antenna device 1X of the comparative example does not have a configuration equivalent to the filter 40.

[0100] The configuration of the antenna device 1X of the comparative example is the same as that of the antenna device 1A of the present embodiment, except that it does not have the above-mentioned additional element portion 23 or filter 40. Specifically, the antenna device 1X of the comparative example has an antenna 10X similar to the antenna 10A in the antenna device 1A of the present embodiment, and a base 30X similar to the base 30A in the antenna device 1A of the present embodiment. Furthermore, a first element 11X of the antenna 10X and a second element 21X of the antenna 20X are connected to the base 30X.

[0101] The configuration of first element 11X of antenna 10X of the comparative example is the same as the configuration of first element 11A of antenna 10A of the present embodiment. Specifically, first element 11X has standing portion 12X similar to standing portion 12A of the present embodiment, extension portion 13X similar to extension portion 13A of the present embodiment, and short-circuit portion 17X similar to short-circuit portion 17A of the present embodiment. Although detailed illustration is omitted, first element 11X has portions corresponding to the low frequency band, the medium frequency band, and the high frequency band, similar to antenna device 1A of the present embodiment.

[0102] Next, the frequency characteristics of the antenna 10A of this embodiment and the antenna 10X of the comparative example will be compared.

[0103] <<Frequency characteristic comparison>> Fig. 6 is a graph showing an example of frequency characteristics in the low frequency band of the antenna 10A of the first embodiment and the antenna 10X of the comparative example. Fig. 6A is a graph of the VSWR in the low frequency band of the antenna 10A and the antenna 10X, and Fig. 6B is a graph of the isolation in the low frequency band of the antenna 10A and the antenna 10X.

[0104] 7A and 7B are graphs showing an example of frequency characteristics in the mid-frequency band of the antenna 10A of the first embodiment and the antenna 10X of the comparative example. Note that Fig. 7A is a graph of the VSWR in the mid-frequency band of the antenna 10A and the antenna 10X, and Fig. 7B is a graph of the isolation in the mid-frequency band of the antenna 10A and the antenna 10X.

[0105] 8A and 8B are graphs showing an example of the frequency characteristics in the high frequency band of the antenna 10A of the first embodiment and the antenna 10X of the comparative example. Note that Fig. 8A is a graph of the VSWR in the high frequency band of the antenna 10A and the antenna 10X, and Fig. 8B is a graph of the isolation in the high frequency band of the antenna 10A and the antenna 10X.

[0106] In each of Figures 6A, 7A, and 8A, the horizontal axis represents frequency and the vertical axis represents VSWR. In each of Figures 6B, 7B, and 8B, the horizontal axis represents frequency and the vertical axis represents isolation. In each graph, the results for the comparative antenna 10X are shown by a dashed dotted line.

[0107] The frequency characteristics of the antenna 10A of this embodiment are compared between the antenna 10A without the filter 40 (antenna 10A without filter 40) and the antenna 10A with the filter 40 (antenna 10A with filter 40). In each graph, the results for the antenna 10A without the filter 40 are shown by a solid line, and the results for the antenna 10A with the filter 40 are shown by a dashed line.

[0108] First, as shown in Fig. 6A, the VSWR characteristics (dashed line) of the antenna 10X of the comparative example are compared with the VSWR characteristics (solid line) of the antenna 10A of the present embodiment without the filter 40. This shows that the VSWR characteristics of the antenna 10A of the present embodiment without the filter 40 are improved over the antenna 10X of the comparative example in most of the low frequency band.

[0109] Next, as shown in Fig. 6A, the VSWR characteristics (dashed line) of the antenna 10X of the comparative example are compared with the VSWR characteristics (dashed line) of the antenna 10A of the present embodiment with the filter 40. Similarly, in this case, it can be seen that the VSWR characteristics of the antenna 10A of the present embodiment with the filter 40 are improved compared to the antenna 10X of the comparative example over most of the low frequency band. However, as shown in Fig. 6A, the degree of improvement in the VSWR characteristics of the antenna 10A of the present embodiment with the filter 40 is smaller than that of the antenna 10A without the filter 40 described above.

[0110] 6B, the isolation (dashed line) of the antenna 10X of the comparative example is compared with the isolation (solid line) of the antenna 10A of the present embodiment without the filter 40. This shows that the isolation of the antenna 10A of the present embodiment without the filter 40 is worse than that of the antenna 10X of the comparative example in all bands in the low frequency band.

[0111] 6B, the isolation (solid line) of the antenna 10A without the filter 40 of this embodiment is compared with the isolation (dashed line) of the antenna 10A with the filter 40 of this embodiment. This shows that the isolation of the antenna 10A with the filter 40 is improved over the antenna 10A without the filter 40 of this embodiment in all bands in the low frequency band. It is also shown that, with some exceptions, the isolation of the antenna 10A with the filter 40 is improved over the antenna 10X of the comparative example.

[0112] Therefore, the above verification results show that the antenna device 1A of this embodiment has improved frequency characteristics in the low frequency band compared to the antenna device 1X of the comparative example. As described above, in the antenna device 1A of this embodiment, the end of the first element 11A and the end of the second element 21A are positioned close to each other, thereby achieving capacitive coupling. This realizes the capacitive coupling section 35, and in the antenna device 1A of this embodiment, the low frequency band corresponding to the first element 11A can be further extended to the lower frequency side.

[0113] Furthermore, the antenna device 1A of this embodiment includes the filter 40, thereby improving isolation.

[0114] Although detailed description will be omitted, as shown in FIGS. 7 and 8, the antenna 10A of this embodiment has good characteristics (VSWR and isolation) even in the medium to high frequency bands, although there are some exceptions.

[0115] ==Second Embodiment== In the antenna device 1A of the first embodiment described above, the capacitive coupling portion 35 is realized by the end of the first element 11A and a part of the antenna 20A (the end of the second element 21A). However, as in antenna devices 1B and 1C of this embodiment described later, the second elements (second elements 21B to 21D) may be configured as parasitic elements.

[0116] <<First Example of Antenna Device 1B>>

[0117] Fig. 9 is an exploded perspective view of the antenna device 1B according to the first example of the second embodiment. Note that Fig. 9 shows an exploded perspective view of the antenna device 1B with the case 2 moved upward to illustrate the internal configuration of the antenna device 1B.

[0118] In the antenna device 1B of the first example of this embodiment, the second element 21B, which realizes the capacitive coupling portion 35, is a parasitic element. The second element 21B rises from the ground portion 3 and is formed so as to be close to the first addition portion 15B of the first element 11B of the antenna 10B.

[0119] This also allows the antenna device 1B of the first example of this embodiment to generate two resonances in the low frequency band between the first element 11B of the antenna 10B and the second element 21B, which is a parasitic element, and thus the low frequency band corresponding to the first element 11B can be extended further to the lower frequency side. Therefore, the antenna device 1B of this embodiment can also easily achieve a broadband of the antenna 10B.

[0120] The configuration of antenna device 1B of the first example of this embodiment, other than the configuration of second element 21B described above, is the same as that of antenna device 1A of the first embodiment described above, although the shape is slightly different. That is, like antenna device 1A of the first embodiment, first element 11B of antenna 10B is connected to base 30B and has standing portion 12B, extension portion 13B having main portion 14B, first addition portion 15B and second addition portion 16B, and a short-circuit portion not shown in FIG.

[0121] Furthermore, the antenna device 1B of the first example of this embodiment mainly supports low frequency bands by virtue of the standing portion 12B, main portion 14B, first addition portion 15B, and a short-circuit portion (not shown). The antenna device 1B of the first example of this embodiment mainly supports medium frequency bands by virtue of the standing portion 12B, main portion 14B, second addition portion 16B, and a short-circuit portion (not shown). The antenna device 1B of the first example of this embodiment mainly supports high frequency bands by virtue of the standing portion 12B.

[0122] In the antenna device 1B of the first example of this embodiment described above, the standing portion 12B of the first element 11B is formed to stand on the upper part of the base portion 30B. However, the configuration of the first element is not limited to this.

[0123] <<Antenna device 1C of second example>> FIG. 10 is an exploded perspective view of an antenna device 1C according to a second example of the second embodiment. FIG. 11 is a three-view diagram of the antenna device 1C according to the second example of the second embodiment. FIG. 11A is a plan view of the antenna device 1C, FIG. 11B is a front view of the antenna device 1C, and FIG. 11C is a right side view of the antenna device 1C. FIG. 12 is a diagram showing the front and bottom surfaces of the antenna device 1C according to the second example of the second embodiment. FIG. 12A is an enlarged view of the front surface of the first element 11C, and FIG. 12B is a diagram showing the periphery of the bottom surface of the base 30C to which the second element 21C is connected.

[0124] 10 shows an exploded perspective view of the antenna device 1C with the case 2 moved upward to illustrate the internal configuration of the antenna device 1C. In addition, in FIG. 11, the case 2 of the antenna device 1C is not shown.

[0125] The antenna device 1C of the second example of this embodiment has an antenna 10C and a base portion 30C, similar to the antenna device 1A of the first embodiment and the antenna device 1B of the first example of this embodiment.

[0126] Similarly to the antenna 10A in the first embodiment and the antenna 10B in the first embodiment, the antenna 10C in the second embodiment includes a first element 11C and a power supply portion 18. Furthermore, the first element 11C in the second embodiment has a configuration similar to the first element 11A in the first embodiment and the first element 11B in the first embodiment. That is, the first element 11C includes a standing portion 12C, an extension portion 13C having a main portion 14C, a first additional portion 15C, and a second additional portion 16C, and a short-circuit portion 17C (shown in FIGS. 11B and 11C). However, unlike the standing portion 12A in the first embodiment and the standing portion 12B in the first embodiment, the standing portion 12C in the second embodiment is spaced apart from the base portion 30C, as will be described later.

[0127] Like the first element 11A of the first embodiment, the first element 11C of the second example of this embodiment mainly supports low frequency bands by virtue of the standing portion 12C, main portion 14C, first addition portion 15C, and short-circuit portion 17C. The antenna device 1C of the second example of this embodiment mainly supports mid frequency bands by virtue of the standing portion 12C, main portion 14C, second addition portion 16C, and short-circuit portion 17C. The antenna device 1C of the second example of this embodiment mainly supports high frequency bands by virtue of the standing portion 12C.

[0128] In the antenna 10C of the second example of this embodiment, the standing portion 12C is spaced apart from the base 30C in the +X direction. In other words, the standing portion 12C is positioned (offset) a predetermined distance from the base 30C in the +X direction. Similarly, the end of the first element 11C on the base 30C side (i.e., the end of the main portion 14C on the base 30C side) is also positioned (offset) a predetermined distance in the +X direction from the end of the base 30C on the first element 11C side, as shown in FIG. 11A .

[0129] In the antenna 10C of the second example of this embodiment, the standing portion 12C is spaced apart from the base portion 30C, so that the standing portion 12C can be provided so as to extend further toward the ground portion 3 than the base portion 30C. Note that in the antenna device 1C of the second example of the second embodiment, the standing portion 12C and the ground portion 3 are not electrically connected, as shown in Fig. 12A.

[0130] 12A, similar to the base 30A of the first embodiment, the base 30C is located between the extension 13C and the ground portion 3. That is, the base 30C is located above the ground portion 3. In contrast to the base 30C located in this manner, in the antenna device 1C of the second example of this embodiment, the lower end of the standing portion 12C can be provided so as to extend further toward the ground portion 3.

[0131] For example, if there are strict restrictions on the size of the antenna device 1C in the vertical direction, it may be difficult to ensure the length of the standing portion 12C. Furthermore, if the base portion 30C is located above the ground portion 3, as in the antenna device 1C of the second example of this embodiment, and the standing portion 12C is provided to stand up from the base portion 30C, it becomes even more difficult to ensure the length of the standing portion 12C in the vertical direction.

[0132] Therefore, as in the antenna 10C of the second example of this embodiment, the lower end of the standing portion 12C is provided so as to extend further toward the ground portion 3, thereby making it easier to ensure the vertical length of the standing portion 12C. This makes it easier to form the standing portion 12C so as to have a length according to the wavelength used in the low frequency band (for example, the wavelength at 699 MHz).

[0133] 10 and 11A, in the antenna device 1C of the second example of this embodiment, a first element connecting portion 19 is provided at the end portion in the downward direction (-Z direction) of the standing portion 12C. The first element connecting portion 19 is a portion of the first element 11C that is connected to the base portion 30C. As a result, the first element 11C is connected to the base portion 30C.

[0134] In the antenna device 1C of the second example of this embodiment, as in the first example, the second element 21C in which the capacitive coupling portion 35 is realized is a parasitic element. The second element 21C in the second example of this embodiment has an erect portion 28 and an extension portion 29.

[0135] The standing portion 28 is a portion of the second element 21C that is formed to stand up relative to the base portion 30C. In the second example of this embodiment, the standing portion 28 is formed to stand up relative to the base portion 30C. The direction in which the standing portion 28 stands up relative to the base portion 30C is not limited to the upward direction (+Z direction), and may be a direction inclined at a predetermined angle relative to the base portion 30C.

[0136] In the antenna device 1C of the second example of this embodiment, a second element connecting portion 26 is provided at the end of the standing portion 28 in the downward direction (-Z direction), as shown in Fig. 10. The second element connecting portion 26 is a portion of the second element 21C that is connected to the base portion 30C. As a result, the second element 21C is connected to the base portion 30C.

[0137] The extension portion 29 is a portion formed to extend from the standing portion 28. The extension portion 29 is also a portion formed to face the ground portion 3. In a second example of this embodiment, the extension portion 29 is formed to extend from the upper end of the standing portion 28, as shown in FIGS. 10 and 11C. However, the extension portion 29 may be formed to extend from a position other than the upper end of the standing portion 28. That is, the extension portion 29 may be formed to extend from the middle of the standing portion 28 in the up-down direction. The extension direction of the extension portion 29 is not limited to a direction parallel to the surface of the ground portion 3, but may be a direction inclined at a predetermined angle from a direction parallel to the ground portion 3.

[0138] Furthermore, in the antenna device 1C of the second example of this embodiment, the end of the extension portion 29 is provided so as to be close to the end of the first addition portion 15C of the extension portion 13C of the first element 11C. Therefore, in the second example of this embodiment, the extension portion 29 is provided so as to be capacitively coupled to the end of the first element 11C. As a result, the capacitive coupling portion 35 is realized at the end of the extension portion 29 in the second example of this embodiment as well.

[0139] 12B, in an antenna device 1C according to a second example of this embodiment, a circuit element 50 is provided at the connection portion of the second element 21C with the base portion 30C. In the second example of this embodiment, the circuit element 50 is a resistor. However, the circuit element 50 may be configured to include other circuit elements, such as a filter, in addition to the resistor. Furthermore, the circuit element 50 may be an attenuator instead of a resistor. This allows signals in the low frequency band supported by the antenna 10C to be terminated, thereby improving the characteristics of the antenna 10C in the low frequency band.

[0140] 12B, in an antenna device 1C of a second example of this embodiment, a circuit element 50 is provided between the second element connecting portion 26 and a region of the base portion 30C connected to the ground portion 3. Specifically, the circuit element 50 is provided between a third region 33 and a fourth region 34. Here, the third region 33 is a conductive region on the side connected to the ground portion 3. Furthermore, the fourth region 34 is a conductive region on the side connected to the second element 21C. This can improve the characteristics of the antenna (here, antenna 10C) included in the antenna device 1C in the low frequency band (699 MHz to 960 MHz).

[0141] <<Verification of frequency characteristics>> Below, the frequency characteristics of the antenna 10B and the antenna 10C of this embodiment will be compared.

[0142] Fig. 13 is a graph showing an example of the frequency characteristics in the low frequency band of the antennas 10B and 10C of the second embodiment. Fig. 13A is a graph of the VSWR in the low frequency band of the antennas 10B and 10C, and Fig. 13B is a graph of the radiation efficiency in the low frequency band of the antennas 10B and 10C.

[0143] 14A and 14B are graphs showing an example of the frequency characteristics in the mid-frequency band of the antennas 10B and 10C of the second embodiment. Fig. 14A is a graph of the VSWR in the mid-frequency band of the antennas 10B and 10C, and Fig. 14B is a graph of the radiation efficiency in the mid-frequency band of the antennas 10B and 10C.

[0144] 15A and 15B are graphs showing an example of the frequency characteristics in the high frequency band of the antennas 10B and 10C of the second embodiment. Fig. 15A is a graph of the VSWR in the high frequency band of the antennas 10B and 10C, and Fig. 15B is a graph of the radiation efficiency in the high frequency band of the antennas 10B and 10C.

[0145] In each of Figures 13A, 14A, and 15A, the horizontal axis represents frequency and the vertical axis represents VSWR. In each of Figures 13B, 14B, and 15B, the horizontal axis represents frequency and the vertical axis represents radiation efficiency. In each graph, the results for antenna 10B are shown by a solid line, and the results for antenna 10C are shown by a solid line.

[0146] As shown in Figure 13A, the VSWR characteristics of antenna 10B (solid line) are compared with the VSWR characteristics of antenna 10C (dashed line). This shows that in the low frequency band, particularly in the low range (e.g., 600 MHz to 700 MHz), the VSWR characteristics of antenna 10C are improved compared to antenna 10B. Similarly, as shown in Figure 13B, the radiation efficiency of antenna 10C is improved compared to antenna 10B in the low frequency band, particularly in the low range (e.g., 600 MHz to 700 MHz).

[0147] In other words, in antenna 10C, as described above, the lower end of standing portion 12C can be arranged to extend further toward ground portion 3, making it easier to ensure the vertical length of standing portion 12C, and therefore it can be easily formed to have a length corresponding to the wavelength used in the low frequency band (for example, the wavelength at 699 MHz).

[0148] Although detailed description will be omitted, as shown in Figures 14 and 15, antennas 10B and 10C of this embodiment have good characteristics (VSWR and radiation efficiency) even in the medium and high frequency bands, with some exceptions.

[0149] In the antenna device 1C of the second example of this embodiment, similarly to the antenna device 1A of the first embodiment, the antenna 10C and the base 30C are arranged in the housing space formed by the case 2 and the ground part 3. However, as in the antenna device 1D of the third example of this embodiment described later, a part of the first element 11D of the antenna 10D may be arranged outside the housing space.

[0150] <<Third Example of Antenna Device 1D>> Fig. 16 is a perspective view of an antenna device 1D according to a third example of the second embodiment. Fig. 16A is an overall perspective view of the antenna device 1D, and Fig. 16B is a perspective view of the antenna device 1D with the case 2 removed. In Fig. 16B, the case 2 is not shown in order to illustrate the internal configuration of the antenna device 1D.

[0151] In the antenna device 1D of the third example of this embodiment, the configuration other than the positions where the first element 11D and the second element 21D are arranged is similar to that of the antenna device 1D of the second example of this embodiment described above, although the shape is slightly different. Therefore, the following mainly describes the differences from the antenna device 1D of the second example of this embodiment.

[0152] 16A, in an antenna device 1D of a third example of this embodiment, a portion of a first element 11D of an antenna 10D is disposed outside the case 2. A portion of a second element 21D is also disposed outside the case 2. Specifically, a portion of an upper side of an upright portion 12D of the first element 11D is disposed forward of the case 2, and the entirety of an extension portion 13D of the first element 11D is disposed above the case 2. A portion of an upper side of an upright portion 28 of the second element 21D is disposed forward of the case 2, and the entirety of an extension portion 29 of the second element 21D is disposed above the case 2.

[0153] In the antenna device 1D of the third example of this embodiment, as in the antenna 10C of the second example of this embodiment, the end of the extension portion 29 is provided so as to be close to the end of the first addition portion 15D of the extension portion 13D of the first element 11D. Therefore, in the third example of this embodiment, the extension portion 29 is provided so as to be capacitively coupled to the end of the first element 11D. As a result, in the third example of this embodiment, a capacitive coupling portion 35 is realized at the end of the extension portion 29, as shown in FIG. 16B.

[0154] 16. The entire first element 11D and the entire second element 21D may be disposed outside the case 2, or the entire second element 21D may be disposed outside the case 2. All or part of the first element 11D may be disposed outside the case 2, while the entire second element 21D may be disposed inside the case 2. Furthermore, the entire first element 11D may be disposed inside the case 2, while the entire second element 21D may be disposed outside the case 2.

[0155] <<Verification of frequency characteristics>> The frequency characteristics of the antenna 10D of this embodiment will be verified below.

[0156] Fig. 17 is a graph showing an example of frequency characteristics in the low frequency band of the antenna 10D of the second embodiment. Fig. 17A is a graph of the VSWR in the low frequency band of the antenna 10D, and Fig. 17B is a graph of the radiation efficiency in the low frequency band of the antenna 10D.

[0157] 18A and 18B are graphs showing an example of frequency characteristics in the mid-frequency band of the antenna 10D of the second embodiment, where Fig. 18A is a graph of the VSWR in the mid-frequency band of the antenna 10D, and Fig. 18B is a graph of the radiation efficiency in the mid-frequency band of the antenna 10D.

[0158] Also, Figure 19 is a graph showing an example of the frequency characteristics of the antenna 10D of the second embodiment in the high frequency band, where Figure 19A is a graph of the VSWR of the antenna 10D in the high frequency band, and Figure 19B is a graph of the radiation efficiency of the antenna 10D in the high frequency band.

[0159] In each of Figures 17A, 18A, and 19A, the horizontal axis represents frequency and the vertical axis represents VSWR. In each of Figures 17B, 18B, and 19B, the horizontal axis represents frequency and the vertical axis represents radiation efficiency. In each graph, the results for antenna 10D are shown by a solid line.

[0160] As shown in Figure 17A, the VSWR of antenna 10D is, for example, a desired value of 3.5 or less in the low frequency band, indicating good characteristics. Similarly, as shown in Figure 17B, the radiation efficiency of antenna 10D is also good in the low frequency band.

[0161] Therefore, the above verification results show that the frequency characteristics in the low frequency band are also improved in the antenna device 1D of this embodiment. As described above, in the antenna device 1D of this embodiment, the end of the first element 11D and the end of the second element 21D are positioned close to each other, thereby achieving capacitive coupling. This realizes the capacitive coupling section 35, and in the antenna device 1D of this embodiment, the low frequency band corresponding to the first element 11D can be extended even further toward the lower frequency side.

[0162] Although detailed explanation will be omitted, as shown in Figures 18 and 19, the antenna 10D of the third example of this embodiment has good characteristics (VSWR and radiation efficiency) even in the medium and high frequency bands, with some exceptions.

[0163] ==Summary== The antenna devices 1A to 1D according to the embodiments of the present invention have been described above.

[0164] 1 and 2, the antenna device 1A of the first embodiment includes a first element 11A, a second element 21A capacitively coupled to the first element 11A, and a base 30A to which the first element 11A and the second element 21A are connected. The first element 11A, together with the second element 21A, is compatible with radio waves in at least the low frequency band (699 MHz to 960 MHz). This makes it possible to realize the antenna device 1A that can handle radio waves in a wide frequency band.

[0165] 9, an antenna device 1B according to a first example of the second embodiment includes a first element 11B, a second element 21B that is capacitively coupled to the first element 11B, and a base 30B to which the first element 11B and the second element 21B are connected. The first element 11B, together with the second element 21B, is compatible with radio waves in at least the low frequency band (699 MHz to 960 MHz). This makes it possible to realize an antenna device 1B that is compatible with radio waves in a wide frequency band.

[0166] 10 and 11, an antenna device 1C according to a second example of the second embodiment includes a first element 11C, a second element 21C that is capacitively coupled to the first element 11C, and a base 30C to which the first element 11C and the second element 21C are connected. The first element 11C, together with the second element 21C, is compatible with radio waves in at least the low frequency band (699 MHz to 960 MHz). This allows for the realization of an antenna device 1C that is compatible with radio waves in a wide frequency band.

[0167] 16, an antenna device 1C according to a third example of the second embodiment includes a first element 11D, a second element 21D capacitively coupled to the first element 11D, and a base 30D to which the first element 11D and the second element 21D are connected. The first element 11D, together with the second element 21D, is compatible with radio waves in at least the low frequency band (699 MHz to 960 MHz). This makes it possible to realize an antenna device 1D that is compatible with radio waves in a wide frequency band.

[0168] Here, the low frequency band (699 MHz to 960 MHz) corresponds to the "first frequency band."

[0169] 1 and 2, the second element 21A of the antenna device 1A of the first embodiment supports radio waves in a frequency band (for example, a Sub6 frequency band of 1710 MHz to 5000 MHz) different from the low frequency band (699 MHz to 960 MHz). This makes it possible to realize the antenna device 1A that can support radio waves in a wide frequency band.

[0170] 4, for example, in the antenna device 1A of the first embodiment, the base 30A has a first region 31 to which a feeder line is connected and a second region 32 to which the second element 21A is connected, and a filter 40 that suppresses signals in a low frequency band (699 MHz to 960 MHz) is provided between the first region 31 and the second region 32. This can improve isolation between the antenna having the first element 11A (antenna 10A in this case) and the antenna having the second element 21A (antenna 20A in this case).

[0171] In addition, in the antenna device 1B of the first example of the second embodiment, the second element 21B is a parasitic element, as shown in Fig. 9. This allows two resonances to be generated by the first element 11B of the antenna 10B and the second element 21B, which is a parasitic element, and makes it possible to realize the antenna device 1B that can handle radio waves in a wide frequency band.

[0172] In addition, in the antenna device 1C of the second example of the second embodiment, the second element 21C is a parasitic element, as shown in Figures 10 and 11. This allows two resonances to be generated by the first element 11C of the antenna 10C and the second element 21C, which is a parasitic element, and realizes the antenna device 1C that can handle radio waves in a wide frequency band.

[0173] In addition, in an antenna device 1D according to a third example of the second embodiment, the second element 21D is a parasitic element, as shown in Fig. 16. This allows two resonances to be generated by the first element 11D of the antenna 10D and the second element 21D, which is a parasitic element, and makes it possible to realize an antenna device 1D that can handle radio waves in a wide frequency band.

[0174] 12B, for example, in the antenna device 1C of the second example of the second embodiment, the base 30C has a third region 33 connected to the ground portion 3 and a fourth region 34 to which the second element 21C is connected, and is provided with a circuit element 50 that connects the third region 33 and the fourth region 34. This can improve the characteristics of the antenna (here, the antenna 10C) included in the antenna device 1C in the low frequency band (699 MHz to 960 MHz).

[0175] Although not shown, the antenna device 1B of the first example of the second embodiment may also be provided with a circuit element 50. This can improve the characteristics of the antenna (antenna 10B in this case) of the antenna device 1B in the low frequency band (699 MHz to 960 MHz).

[0176] Although not shown, the antenna device 1D of the third example of the second embodiment may also be provided with a circuit element 50. This can improve the characteristics of the antenna (antenna 10D in this case) of the antenna device 1D in the low frequency band (699 MHz to 960 MHz).

[0177] 12B, the circuit element 50 is a resistor that terminates signals in the first frequency band. The circuit element 50 may be an attenuator instead of a resistor. This improves the characteristics of the antenna (antenna 10C in this example) included in the antenna device 1C in the low frequency band (699 MHz to 960 MHz).

[0178] Although not shown, the circuit element 50 may also be a resistor in the antenna device 1B of the first example of the second embodiment, thereby improving the characteristics of the antenna (antenna 10B in this case) of the antenna device 1B in the low frequency band (699 MHz to 960 MHz).

[0179] Although not shown, the circuit element 50 may also be a resistor in the antenna device 1D of the third example of the second embodiment, which improves the characteristics of the antenna (antenna 10D in this case) of the antenna device 1D in the low frequency band (699 MHz to 960 MHz).

[0180] 10, 11, and 12A, an antenna device 1C according to a second example of the second embodiment includes a ground portion 3, and a first element 11C has an upright portion 12C formed to stand relative to the ground portion 3 and an extension portion 13C extending from the upright portion 12C to face the ground portion 3. In the top view shown in FIG. 11A, the upright portion 12C is spaced apart from the base portion 30C, and in the side view shown in FIG. 11B, the base portion 30C is located between the extension portion 13C and the ground portion 3, and the upright portion 12C extends closer to the ground portion 3 than the base portion 30C. This can improve the characteristics of the antenna (here, antenna 10C) included in the antenna device 1C in the low frequency band (699 MHz to 960 MHz).

[0181] 16, an antenna device 1D according to a third example of the second embodiment includes a ground portion 3, and a first element 11D has an upright portion 12D formed to stand relative to the ground portion 3, and an extension portion 13D extending from the upright portion 12D to face the ground portion 3. The upright portion 12D is spaced apart from a base portion 30D, and the base portion 30D is located between the extension portion 13D and the ground portion 3, with the upright portion 12D extending further toward the ground portion 3 than the base portion 30D. This can improve the characteristics of the antenna (here, antenna 10D) included in the antenna device 1D in the low frequency band (699 MHz to 960 MHz).

[0182] 12A, for example, in antenna device 1C of the second example of the second embodiment, standing portion 12C is not electrically connected to ground portion 3. This can improve the characteristics of the antenna (antenna 10C in this case) included in antenna device 1C in the low frequency band (699 MHz to 960 MHz).

[0183] 16, for example, in the antenna device 1D of the third example of the second embodiment, the standing portion 12D and the ground portion 3 are not electrically connected to each other. This can improve the characteristics of the antenna (here, the antenna 10D) included in the antenna device 1D in the low frequency band (699 MHz to 960 MHz).

[0184] 10 and 11, in an antenna device 1C of a second example of the second embodiment, an extension portion 13C has a main portion 14C extending from an upright portion 12C, a first addition portion 15C extending from the main portion 14C and positioned away from the upright portion 12C, and a second addition portion 16C extending from the main portion 14C and positioned close to the upright portion 12C. This allows the antenna (antenna 10C in this case) of the antenna device 1C to be compatible with radio waves in frequency bands other than the low frequency band (699 MHz to 960 MHz).

[0185] 16, for example, in an antenna device 1D of a third example of the second embodiment, an extension portion 13D has a main portion 14D extending from an upright portion 12D, a first addition portion 15D extending from the main portion 14D and positioned away from the upright portion 12D, and a second addition portion 16D extending from the main portion 14D and positioned close to the upright portion 12D. This allows the antenna (antenna 10D in this case) of the antenna device 1D to be compatible with radio waves in frequency bands other than the low frequency band (699 MHz to 960 MHz).

[0186] 10 and 11, in an antenna device 1C according to a second example of the second embodiment, a first element 11C has a short-circuit portion 17C connected to the ground portion 3. The second element 21C, the standing portion 12C, the main portion 14C, the first addition portion 15C, and the short-circuit portion 17C correspond mainly to a low frequency band (699 MHz to 960 MHz). The standing portion 12C, the main portion 14C, the second addition portion 16C, and the short-circuit portion 17C correspond mainly to a medium frequency band (1710 MHz to 2690 MHz), which is a frequency band higher than the low frequency band. The standing portion 12C corresponds mainly to a frequency band higher than the medium frequency band (for example, a high frequency band / 3300 MHz to 5000 MHz). This allows the antenna (here, antenna 10C) included in antenna device 1C to also support radio waves in frequency bands other than the low frequency band (699 MHz to 960 MHz).

[0187] Although not shown, in an antenna device 1D according to a third example of the second embodiment, the first element 11D may also have a short-circuit portion connected to the ground portion 3. The second element 21D, the standing portion 12D, the main portion 14D, the first additional portion 15D, and the short-circuit portion may be configured to primarily support a low frequency band (699 MHz to 960 MHz). The standing portion 12D, the main portion 14D, the second additional portion 16D, and the short-circuit portion may be configured to primarily support a medium frequency band (1710 MHz to 2690 MHz), which is a frequency band higher than the low frequency band. The standing portion 12D may also be configured to primarily support a frequency band higher than the medium frequency band (e.g., a high frequency band / 3300 MHz to 5000 MHz). This allows the antenna (here, antenna 10D) included in the antenna device 1D to support radio waves in frequency bands other than the low frequency band (699 MHz to 960 MHz).

[0188] Here, the mid-frequency band (1710 MHz to 2690 MHz) corresponds to the "second frequency band."

[0189] 1 and 2, in the antenna device 1A of the first embodiment, the first element 11A has a short-circuit portion 17A connected to the ground portion 3. This makes it easier to achieve impedance matching in the antenna (antenna 10A in this case) included in the antenna device 1A.

[0190] Similarly, in the antenna device 1B of the first example of the second embodiment, for example, although not shown, the first element 11B may have a short-circuit part connected to the ground part 3. This makes it easier to achieve impedance matching in the antenna (antenna 10B in this case) included in the antenna device 1B.

[0191] Similarly, in the antenna device 1C of the second example of the second embodiment, for example, as shown in Fig. 11C, the first element 11C may have a short-circuit portion 17C connected to the ground portion 3. This makes it easier to achieve impedance matching in the antenna (antenna 10C in this case) included in the antenna device 1C.

[0192] Similarly, in the antenna device 1D of the third example of the second embodiment, although not shown, the first element 11D may have a short-circuit part connected to the ground part 3. This makes it easier to achieve impedance matching in the antenna (antenna 10D in this case) included in the antenna device 1D.

[0193] 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]

[0194] 1A~1D,1X Antenna equipment 2 cases 3 Ground section 4 Base 5 Power supply line connection 10A~10D,10X,20A,20X Antenna 11A~11D,11X First element 12A~12D,12X Standing section 13A~13D,13X extension part 14A~14D Main section 15A~15D First additional part 16A~16D Second additional part 17A, 17C, 17X short circuit 18,27 Power supply unit 19 First element connection part 21A~21D, 21X Second element 22 Antenna section 23 Additional element section 24,28 Standing section 25,29 Extension part 26 Second element connection part 30A~30D,30X base 31 First area 32 Second area 33 Third area 34 4th area 35 Capacitive coupling section 40 filters 41 High Pass Filter (HPF) 42 Bandpass Filter (BPF) 43 Band Elimination Filter (BEF) 50 Circuit Elements

Claims

1. A first element; a second element capacitively coupled to the first element; a base portion to which the first element and the second element are connected, The first element, together with the second element, corresponds to radio waves in at least a first frequency band. Antenna device.

2. the second element corresponds to radio waves in a frequency band different from the first frequency band; The antenna device according to claim 1 .

3. the base portion has a first region to which a power supply line is connected and a second region to which the second element is connected; a filter that suppresses signals in the first frequency band is provided between the first region and the second region; The antenna device according to claim 2 .

4. the second element is a parasitic element; The antenna device according to claim 1 .

5. the base portion has a third region connected to ground and a fourth region to which the second element is connected; a circuit element connecting the third region and the fourth region; 5. The antenna device according to claim 4.

6. the circuit element terminates signals in the first frequency band; 6. The antenna device according to claim 5.

7. Equipped with a ground section, The first element is an upright portion formed to stand upright relative to the ground portion; an extension portion extending from the standing portion and formed to face the ground portion, When viewed from above, the standing portion is spaced apart from the base portion, When viewed from a side, the base portion is located between the extension portion and the ground portion, and the standing portion extends closer to the ground portion than the base portion.

7. An antenna device according to claim 1.

8. The standing portion and the ground portion are not electrically connected to each other.

8. The antenna device according to claim 7.

9. The extension portion is a main portion extending from the standing portion; a first additional portion extending from the main portion and positioned away from the standing portion; a second additional portion extending from the main portion and positioned adjacent to the standing portion; 9. The antenna device according to claim 7, wherein:

10. the first element has a short-circuit portion connected to the ground portion, the second element, the standing portion, the main portion, the first additional portion, and the short-circuit portion correspond to the first frequency band, the standing portion, the main portion, the second additional portion, and the short-circuit portion correspond to a second frequency band that is a frequency band higher than the first frequency band, The upright portion corresponds to a frequency band higher than the second frequency band.

10. The antenna device according to claim 9.

11. the first element has a short-circuit portion connected to ground; 10. An antenna device according to any one of claims 1 to 9.

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