Vehicle-mounted antenna device

Abstract

The present invention provides a vehicle-mounted antenna device capable of stably using an antenna with high radiation efficiency in a wide band. The vehicle-mounted antenna device (10) comprises a first antenna element (100) disposed on a ground plane (20) and a second antenna element (200) disposed on the ground plane (20), wherein at least a portion of the first antenna element (100) and at least a portion of the second antenna element (200) are capacitively coupled.

Description

Technical Field

[0001] The present invention relates to a vehicle-mounted antenna device. Background Art

[0002] In recent years, demand for communications using frequency bands such as LTE (Long Term Evolution), 4G (4th Generation Mobile Communications System), and 5G (5th Generation Mobile Communications System) has increased. Furthermore, there is a demand for compact antennas that can operate stably and with high radiation efficiency across wide frequency bands, such as those from 698 MHz to 6 GHz, 617 MHz to 5 GHz, and 5.9 GHz to 7.1 GHz.

[0003] Patent Document 1 describes an antenna comprising a polygonal conductive plate whose lower side, on the ground side, is shorter than its upper side. The conductive plate includes an open-ended slot near the feed point on the lower side of the conductor. This antenna achieves a return loss of -5dB or less in the 748MHz to 960MHz, 1450MHz to 2175MHz, and 2490MHz to 2690MHz frequency bands.

[0004] Patent Document 2 describes an antenna having a triangular conductor. This antenna achieves a VSWR (Voltage Standing Wave Ratio) of 5 or less in the frequency bands of approximately 700 MHz to 1000 MHz and approximately 1500 MHz to 3000 MHz.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2017 / 191811

[0008] Patent Document 2: U.S. Patent No. 10305162 Summary of the Invention

[0009] One example of an object of the present invention is to enable stable use of an antenna with high radiation efficiency over a wide band.

[0010] One embodiment of the present invention is a vehicle-mounted antenna device comprising:

[0011] a first antenna element disposed on a ground plane; and

[0012] The second antenna element is arranged on the ground plane.

[0013] At least a portion of the first antenna element and at least a portion of the second antenna element are capacitively coupled.

[0014] Effects of the Invention

[0015] According to the above configuration, the capacitive coupling between the first antenna element and the second antenna element contributes to low VSWR and high radiation efficiency in the low frequency band, thereby enabling the antenna to be used stably with high radiation efficiency over a wide frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a perspective view of the vehicle-mounted antenna device according to the first embodiment.

[0017] Figure 2 This is a perspective view of a comparative vehicle-mounted antenna device.

[0018] Figure 3 This is a graph showing the VSWR characteristics of the vehicle-mounted antenna device according to the first embodiment and a vehicle-mounted antenna device according to a comparative embodiment.

[0019] Figure 4 This is a graph showing radiation efficiency characteristics of the vehicle-mounted antenna device according to the first embodiment and a vehicle-mounted antenna device according to a comparative embodiment.

[0020] Figure 5 Yes Figure 1 FIG. 1 is a diagram of a modified example of .

[0021] Figure 6 This is a graph showing VSWR characteristics of the vehicle-mounted antenna device according to the modification and the vehicle-mounted antenna device according to the first embodiment.

[0022] Figure 7 Graphs showing radiation efficiency characteristics of the vehicle-mounted antenna device according to the modification and the vehicle-mounted antenna device according to the first embodiment.

[0023] Figure 8 This is a perspective view of a vehicle-mounted antenna device according to a second embodiment.

[0024] Figure 9 This is a graph showing the VSWR characteristics of the vehicle-mounted antenna device according to the second embodiment and the vehicle-mounted antenna device according to the first embodiment.

[0025] Figure 10 This is a graph showing radiation efficiency characteristics of the vehicle-mounted antenna device according to the second embodiment and the vehicle-mounted antenna device according to the first embodiment.

[0026] Figure 11 This is a perspective view of a first example of the entire vehicle-mounted antenna device according to the second embodiment.

[0027] Figure 12 yes Figure 11 The left side view of the first example of the overall vehicle-mounted antenna device is shown.

[0028] Figure 13 It is from Figure 11 Image with antenna housing removed.

[0029] Figure 14 This is a perspective view of a second example in which the antenna case is removed from the entire vehicle-mounted antenna device according to the second embodiment.

[0030] Figure 15 yes Figure 14 This is a left side view of a second example of the vehicle-mounted antenna device.

[0031] Figure 16 Is used to illustrate Figure 14 A cross-sectional view showing an example of mechanical bonding between the first and second blocks.

[0032] Figure 17 This is a perspective view of a third example in which the antenna case is entirely removed from the vehicle-mounted antenna device of the second embodiment.

[0033] Figure 18 yes Figure 17 This is a left side view of a third example of the vehicle-mounted antenna device.

[0034] Figure 19 This is a perspective view of a vehicle-mounted antenna device according to a third embodiment.

[0035] Figure 20 This is a graph showing the VSWR characteristics of the vehicle-mounted antenna device according to the third embodiment and the vehicle-mounted antenna device according to the first embodiment.

[0036] Figure 21 This is a graph showing radiation efficiency characteristics of the vehicle-mounted antenna device according to the third embodiment and the vehicle-mounted antenna device according to the first embodiment.

[0037] Figure 22 This is a perspective view of a vehicle-mounted antenna device according to a fourth embodiment.

[0038] Figure 23 This is a graph showing the VSWR characteristics of the vehicle-mounted antenna device according to the fourth embodiment and the vehicle-mounted antenna device according to the first embodiment.

[0039] Figure 24 Graphs showing radiation efficiency characteristics of the vehicle-mounted antenna device according to the fourth embodiment and the vehicle-mounted antenna device according to the first embodiment.

[0040] Description of Reference Numerals

[0041] 10 Vehicle-mounted antenna device

[0042] 20 Ground plane

[0043] 100 1st antenna element

[0044] 100A 1st antenna element

[0045] 100B 1st antenna element

[0046] 102 End 1

[0047] 102A Terminal 1

[0048] 102B Terminal 1

[0049] 102a Power feeder

[0050] 104 Second End

[0051] 104A Terminal 2

[0052] 104B Second End

[0053] 106 The 5th End

[0054] 106A Terminal 5

[0055] 106B Terminal 5

[0056] 110 Area 1

[0057] 110A Area 1

[0058] 112 Part 1

[0059] 112A Part 1

[0060] 114 Part 2

[0061] 114A Part 2

[0062] 116 The first level of the difference

[0063] 116A 1st floor difference

[0064] 120 Area 2

[0065] 120A Area 2

[0066] 122 Part 5

[0067] 124 Part 6

[0068] 126 The Second Layer

[0069] 150 dielectric

[0070] 150A 1st dielectric

[0071] 150B Second dielectric

[0072] 160 substrate

[0073] 200 Second antenna element

[0074] 200A Second antenna element

[0075] 200B Second antenna element

[0076] 202 End 3

[0077] 202A Terminal 3

[0078] 202B Terminal 3

[0079] 202a Short-circuit section

[0080] 204 4th End

[0081] 204A Terminal 4

[0082] 204B 4th terminal

[0083] 212 Part 3

[0084] 214 Part 4

[0085] 300A Cage

[0086] 300B Cage

[0087] 310A Block 1

[0088] 310B Block 1

[0089] 320A Block 2

[0090] 320B Block 2

[0091] 330A convex part

[0092] 342A 1st protrusion

[0093] 344A Second protrusion

[0094] 352A 3rd protrusion

[0095] 362A Support

[0096] 362Aa 1st support

[0097] 362Ab Second Support

[0098] 410 1st Antenna Unit

[0099] 420 Second Antenna Unit

[0100] 510 antenna base

[0101] 520 base plate

[0102] 530 antenna housing

[0103] X 1st direction

[0104] Y 2nd direction

[0105] Z 3rd direction DETAILED DESCRIPTION

[0106] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[0107] In this specification, unless otherwise specified, ordinal numbers such as "1st", "2nd", and "3rd" are only used to distinguish structures with the same name, and do not indicate specific characteristics of the structure (such as order or importance).

[0108] (Implementation 1)

[0109] Figure 1 It is a perspective view of the vehicle-mounted antenna device 10 according to the first embodiment.

[0110] exist Figure 1 In the figure, the first direction X, the second direction Y, and the third direction Z respectively indicate the front-back direction, the left-right direction, and the top-bottom direction of the vehicle-mounted antenna device 10. Specifically, the direction of the arrow indicating the first direction X, i.e., the positive direction of the first direction X, indicates the front of the vehicle-mounted antenna device 10. The opposite direction of the arrow indicating the first direction X, i.e., the negative direction of the first direction X, indicates the rear of the vehicle-mounted antenna device 10. The direction of the arrow indicating the second direction Y, i.e., the positive direction of the second direction Y, indicates the left of the vehicle-mounted antenna device 10. The opposite direction of the arrow indicating the second direction Y, i.e., the negative direction of the second direction Y, indicates the right of the vehicle-mounted antenna device 10. The direction of the arrow indicating the third direction Z, i.e., the positive direction of the third direction Z, indicates the top of the vehicle-mounted antenna device 10. The opposite direction of the arrow indicating the third direction Z, i.e., the negative direction of the third direction Z, indicates the bottom of the vehicle-mounted antenna device 10.

[0111] The terms "front," "rear," "left," "right," "up," and "down" associated with the first direction X, second direction Y, and third direction Z in this embodiment are determined by the vehicle in which the vehicle-mounted antenna device 10 is installed. Specifically, the front direction refers to the vehicle's forward direction, and the rear direction refers to the vehicle's backward direction. Furthermore, the left direction refers to the left when viewed from the rear of the vehicle toward the front, and the right direction refers to the right when viewed from the rear toward the front. Furthermore, the top direction refers to the top of the vehicle, and the bottom direction refers to the bottom of the vehicle. However, the first direction X, second direction Y, and third direction Z may differ from the vehicle's front-to-back, left-to-right, and up-to-down directions, respectively. For example, the vehicle-mounted antenna device 10 may be used with the first direction X oriented toward the left-to-right direction of the vehicle and the second direction Y oriented toward the front-to-back direction of the vehicle. Alternatively, the vehicle-mounted antenna device 10 may be used with the positive direction of the first direction X oriented toward the rear of the vehicle and the negative direction of the first direction X oriented toward the front of the vehicle.

[0112] Hereinafter, as needed, the first direction X, the second direction Y, and the third direction Z will be referred to as the front-to-back direction, the left-to-right direction, and the up-to-down direction, respectively, of the vehicle-mounted antenna apparatus 10 or the first antenna element 100, the second antenna element 200, and other components that constitute the vehicle-mounted antenna apparatus 10. Furthermore, as needed, the positive direction of the first direction X, the negative direction of the first direction X, the positive direction of the second direction Y, the negative direction of the second direction Y, the positive direction of the third direction Z, and the negative direction of the third direction Z will be referred to as the front, rear, left, right, top, and bottom, respectively, of the vehicle-mounted antenna apparatus 10 or the first antenna element 100, the second antenna element 200, and other components that constitute the vehicle-mounted antenna apparatus 10.

[0113] The vehicle-mounted antenna device 10 includes a first antenna element 100 and a second antenna element 200. The first antenna element 100 and the second antenna element 200 are arranged on a ground plane 20. The ground plane 20 is, for example, a roof of a car.

[0114] The first antenna element 100 is formed by bending a metal plate, but the method of forming the first antenna element 100 is not limited thereto.

[0115] The first antenna element 100 has a first end 102 and a second end 104 .

[0116] The first end 102 of the first antenna element 100 serves as the base end of the first antenna element 100. The first end 102 includes a power feeder 102a. Power feeder 102a can be supplied via a connecting member passing through a through-hole formed in the ground plane 20. The second end 104 of the first antenna element 100 serves as the tip end of the first antenna element 100. Furthermore, the second end 104 of the first antenna element 100 serves as an open end located farther from the ground plane 20 than the first end 102 of the first antenna element 100. In this embodiment, the first end 102 is located on the positive side of the first direction X relative to the second end 104, and the second end 104 is located on the negative side of the first direction X relative to the first end 102. Furthermore, the first end 102 is located on the negative side of the second direction Y relative to the second end 104, and the second end 104 is located on the positive side of the second direction Y relative to the first end 102. Furthermore, the first end 102 is located on the negative side of the third direction Z relative to the second end 104 , and the second end 104 is located on the positive side of the third direction Z relative to the first end 102 .

[0117] The first antenna element 100 has a generally L-shaped shape when viewed from the positive or negative direction of the second direction Y. Specifically, the first antenna element 100 includes a first portion 112, a second portion 114, and a first step portion 116. The first portion 112, the first step portion 116, and the second portion 114 are arranged in this order from the first end 102 to the second end 104. The first portion 112 is the portion of the first antenna element 100 extending from the first end 102 to the first step portion 116. Specifically, the first portion 112 includes a portion extending from the first end 102 toward the positive side of the second direction Y and a portion extending from the front side of the first antenna element 100 to the rear side of the first antenna element 100, i.e., the first step portion 116. Furthermore, first portion 112 is bent between a portion of first portion 112 extending from first end 102 toward the positive side of second direction Y and a portion of first portion 112 extending from the front side of first antenna element 100 to the rear side of first antenna element 100. Consequently, the end of first portion 112 on the first step portion 116 side is located closer to the positive side of second direction Y than the end of first portion 112 on the first end 102 side. First step portion 116 extends from first portion 112 to second portion 114, from the positive side of second direction Y toward the negative side of second direction Y. Second portion 114 extends from first step portion 116 to second end 104, toward the positive side of third direction Z. When first step portion 116 is provided, the total length between first end 102 and second end 104 of first antenna element 100 can be extended compared to a case where first portion 112 and second portion 114 are directly connected without first step portion 116 .

[0118] The width of the first antenna element 100 increases gradually or in stages from the first end 102 to the second end 104. Therefore, the width of the first antenna element 100 near the second end 104 is greater than the width near the first end 102, i.e., near the feeder 102a. Thus, the first antenna element 100 has a self-similarly curved shape.

[0119] In addition, self-similar antennas include biconical antennas and bow-tie antennas, which have similar shapes even when their proportions (size ratios) are changed. A self-similar antenna is premised on the electrical characteristics of the antenna showing the same characteristics in principle even when the antenna size or frequency changes. In actual design, the shape of the isosceles triangle radiating element of a biconical antenna or bow-tie antenna can be deformed to a shape such as the first antenna element 100 in this embodiment to adjust impedance, etc. Even in such cases, the specific electrical characteristics obtained by the self-similar shape can be utilized. In this embodiment, the first antenna element 100, which is part of a self-similar radiating element, is arranged opposite to the ground plane 20, thereby simulating the effect of a tapered slot antenna and a bow-tie antenna. The ground plane 20 provides the effect of having another radiating element arranged opposite to the opposite side.

[0120] The second antenna element 200 is formed of a metal plate.

[0121] The second antenna element 200 has a third end 202 and a fourth end 204 .

[0122] The third end 202 of the second antenna element 200 serves as the base end of the second antenna element 200. The third end 202 includes a short-circuit portion 202a. The short-circuit portion 202a is short-circuited to the ground plane 20. In this embodiment, the third end 202 and the short-circuit portion 202a are located rearward of the first end 102 and the feeder 102a. However, the third end 202 and the short-circuit portion 202a may also be located forward of the first end 102 and the feeder 102a. In other words, the first end 102 and the feeder 102a, and the third end 202 and the short-circuit portion 202a, may be separated from each other. The fourth end 204 of the second antenna element 200 serves as the tip end of the second antenna element 200. Furthermore, the fourth end 204 of the second antenna element 200 serves as an open end, located farther from the ground plane 20 than the third end 202 of the second antenna element 200. In this embodiment, the third end 202 is located on the positive side of the first direction X relative to the fourth end 204, and the fourth end 204 is located on the negative side of the first direction X relative to the third end 202. Furthermore, the third end 202 and the fourth end 204 are aligned without being offset in the second direction Y. Furthermore, the third end 202 is located on the negative side of the third direction Z relative to the fourth end 204, and the fourth end 204 is located on the positive side of the third direction Z relative to the third end 202.

[0123] When the third end 202 and the ground plane 20 are short-circuited by the short-circuit portion 202a, better characteristics in the low-frequency band can be maintained compared to when the third end 202 is electrically open. However, the third end 202 does not need to have the short-circuit portion 202a. For example, the third end 202 may be electrically open relative to the ground plane 20.

[0124] The second antenna element 200 has a substantially L-shape when viewed from the positive or negative direction of the second direction Y. Specifically, the second antenna element 200 includes a third portion 212 and a fourth portion 214. The third portion 212 extends from the third end 202 toward the positive side of the third direction Z. The fourth portion 214 extends from the end of the third portion 212 opposite the third end 202 to the fourth end 204 toward the negative side of the first direction X.

[0125] The width of the second antenna element 200 increases gradually or in stages from the third end 202 to the fourth end 204. Therefore, the width of the second antenna element 200 near the fourth end 204 is greater than the width near the third end 202, i.e., near the short-circuit portion 202a. Thus, the second antenna element 200 has a shape that is bent in a self-similar shape.

[0126] In this embodiment, at least a portion of the first antenna element 100 is capacitively coupled to at least a portion of the second antenna element 200. Specifically, at least a portion of the second end 104 of the first antenna element 100 and at least a portion of the fourth end 204 of the second antenna element 200 overlap in the second direction Y, thereby forming a capacitive coupling. Furthermore, the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 are spaced apart from each other.

[0127] The second end 104 of the first antenna element 100 is tilted relative to the ground plane 20, that is, relative to a plane parallel to the XY plane. More specifically, the second end 104 tilts toward the positive side of the third direction Z as it moves from the positive side of the first direction X toward the negative side of the first direction X. The tilt of the second end 104, that is, the shape of the second end 104, adjusts the area of ​​overlap between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 in the second direction Y, thereby adjusting the capacitance component between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200. Furthermore, by adjusting the area of ​​overlap between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 in the second direction Y, the capacitance component between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 can be adjusted by adjusting the shape of the fourth end 204. Furthermore, the capacitance component between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 can also be adjusted by adjusting the distance between the second end 104 and the fourth end 204.

[0128] The first antenna element 100 and the second antenna element 200 do not overlap in the second direction Y except for portions near the first end 102 , the third end 202 , the second end 104 , and the fourth end 204 .

[0129] The length between the third end 202 and the fourth end 204 of the second antenna element 200 is preferably substantially equal to the length between the first end 102 and the second end 104 of the first antenna element 100. For example, the difference between the length between the first end 102 and the second end 104 of the first antenna element 100 and the length between the third end 202 and the fourth end 204 of the second antenna element 200 can be set to within ±25% of the length between the first end 102 and the second end 104 of the first antenna element 100 or the length between the third end 202 and the fourth end 204 of the second antenna element 200. This allows the antenna to be used stably and with high radiation efficiency over a wide bandwidth. Here, the length between the third end 202 and the fourth end 204 of the second antenna element 200 may refer to the length of the outer edge between the third end 202 and the fourth end 204 of the second antenna element 200, or the length of the inner edge between the third end 202 and the fourth end 204 of the second antenna element 200. Similarly, the length between the first end 102 and the second end 104 of the first antenna element 100 may refer to the length of the outer edge between the first end 102 and the second end 104 of the first antenna element 100, or the length of the inner edge between the first end 102 and the second end 104 of the first antenna element 100. Alternatively, it may refer to the length of the centerline of the width of each of the first antenna element 100 and the second antenna element 200.

[0130] The vehicle-mounted antenna device 10 of the present embodiment is presumed to operate according to the following principle.

[0131] In the high to mid-frequency range of the operating frequency band of the vehicle-mounted antenna device 10, the first portion 112 of the first antenna element 100 functions as a self-similar-shaped or conical antenna, and the second portion 114 of the first antenna element 100 functions as a monopole antenna when the first portion 112 functions as a transmission path.

[0132] In the mid-frequency band to the low-frequency band of the operating frequency band of the vehicle-mounted antenna device 10, the second portion 114 of the first antenna element 100 functions as a monopole antenna when the first portion 112 functions as a transmission path, and the second portion 114 of the first antenna element 100 and the second antenna element 200 function as a loop antenna or a split-loop antenna when the first portion 112 functions as a transmission path.

[0133] As can be seen from the above, the first antenna element 100 and the second antenna element 200 can operate in a wide band, specifically, at least in the range of 698 MHz to 6 GHz. In addition, in this embodiment, although the first antenna element 100 and the second antenna element are designed to operate in the range of 698 MHz to 6 GHz, as will be described later, Figure 3-4 It is speculated that the first antenna element 100 and the second antenna element 200 can operate in other frequency bands, such as 617 MHz to 5 GHz or 5.9 GHz to 7.1 GHz, in addition to or instead of 698 MHz to 6 GHz. Therefore, the design can also meet the requirements of wider frequency bands or higher frequency bands.

[0134] Figure 2 2 is a perspective view of a comparative vehicle-mounted antenna device 10. The comparative vehicle-mounted antenna device 10 is the same as the vehicle-mounted antenna device 10 of the first embodiment except that the second antenna element 200 is not provided.

[0135] Figure 3 This is a graph showing the VSWR characteristics of the vehicle-mounted antenna device 10 according to the first embodiment and a vehicle-mounted antenna device 10 of a comparative embodiment. Figure 4 This is a graph showing radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the first embodiment and a vehicle-mounted antenna device 10 of a comparative embodiment.

[0136] Figure 3 The horizontal axis of the graph shows frequency. Figure 3 The vertical axis of the graph shows VSWR. Figure 3 The solid line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the first embodiment. Figure 3 The dotted line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 as a comparison.

[0137] Figure 4 The horizontal axis of the graph shows frequency. Figure 4 The vertical axis of the graph shows radiation efficiency. Figure 4 The solid line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the first embodiment. Figure 4 The dotted line in the graph shows the radiation efficiency characteristics of the comparative vehicle-mounted antenna device 10 .

[0138] like Figure 3 As shown in FIG. 1 , in the relatively low frequency band of about 700 MHz to 1750 MHz, the VSWR of the first embodiment is lower than the VSWR of the comparative embodiment. Figure 4 As shown, in the relatively low frequency band of approximately 700 MHz to 1750 MHz, the radiation efficiency of Embodiment 1 is higher than that of the comparative embodiment. This suggests that the capacitive coupling between the first antenna element 100 and the second antenna element 200 contributes to low VSWR and high radiation efficiency in the relatively low frequency band.

[0139] like Figure 3As shown in FIG, the VSWR of the embodiment 1 is as low as less than 3.5 in the wide band range of 700MHz to 6500MHz. Figure 4 As shown, the radiation efficiency of Embodiment 1 is as high as over 60% across a wide frequency band of 700 MHz to 6500 MHz. In contrast, the antenna of Patent Document 1 achieves a return loss of -5 dB or greater in the frequency band of approximately 960 MHz to 1450 MHz. Furthermore, the antenna of Patent Document 2 achieves a VSWR of 5 or greater in the frequency band of approximately 1000 MHz to 1500 MHz. Therefore, the vehicle-mounted antenna device 10 of Embodiment 1 can be used with high and stable radiation efficiency over a wide frequency band, compared to the antennas of Patent Documents 1 and 2.

[0140] Figure 5 Yes Figure 1 The vehicle-mounted antenna device 10 of the modified example is the same as the vehicle-mounted antenna device 10 of the first embodiment except for the following points.

[0141] The vehicle-mounted antenna device 10 further includes a dielectric 150. As will be described in detail later, the vehicle-mounted antenna device 10 includes the dielectric 150 in at least a portion of the first antenna element 100 or the second antenna element 200.

[0142] Dielectric 150 is attached to at least a portion of first antenna element 100. Specifically, dielectric 150 is attached to the inner surface of first portion 112 of first antenna element 100. Alternatively, dielectric 150 may be attached to at least one of the inner and outer surfaces of first portion 112. Furthermore, dielectric 150 may be attached to at least a portion of second antenna element 200. For example, dielectric 150 may be attached to at least one of the surfaces of second antenna element 200 facing the positive direction in second direction Y and the negative direction in second direction Y. Furthermore, at least a portion of dielectric 150 may be provided across at least a portion of first antenna element 100 and at least a portion of second antenna element 200.

[0143] Figure 6 Graphs showing VSWR characteristics of the vehicle-mounted antenna device 10 according to the modification and the vehicle-mounted antenna device 10 according to the first embodiment. Figure 7 Graphs showing radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the modification and the vehicle-mounted antenna device 10 according to the first embodiment.

[0144] Figure 6 The horizontal axis of the graph shows frequency. Figure 6 The vertical axis of the graph shows VSWR. Figure 6 The solid line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the modified example. Figure 6 The dotted line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0145] Figure 7 The horizontal axis of the graph shows frequency. Figure 7 The vertical axis of the graph shows radiation efficiency. Figure 7 The solid line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the modified example. Figure 7 The dotted line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0146] like Figure 6 As shown in FIG. 1 , the VSWR of the modification and embodiment 1 is as low as less than 3.5 in the wide band range of 700 MHz to 6500 MHz. Figure 7 As shown, the radiation efficiency of the modification and the first embodiment is as high as over 60% in the wide band range of 700 MHz to 6500 MHz.

[0147] like Figure 6 As shown, the VSWR of the modified example is less than 3 at any frequency in the frequency band above 1000 MHz. In contrast, the VSWR of the first embodiment is greater than 3 at around 1250 MHz in the frequency band above 1000 MHz. Therefore, it can be said that the dielectric 150 of the modified example contributes to smoothing the VSWR characteristics.

[0148] like Figure 7 As shown, the radiation efficiency of the modified example is greater than 75% at all frequencies in the frequency band above 1000 MHz. In contrast, the radiation efficiency of the first embodiment is less than 75% at around 1250 MHz in the frequency band above 1000 MHz. Therefore, it can be said that the dielectric 150 of the modified example contributes to smoothing the radiation efficiency characteristics.

[0149] (Implementation Method 2)

[0150] Figure 8 1 is a perspective view of the vehicle-mounted antenna device 10 according to Embodiment 2. The vehicle-mounted antenna device 10 according to Embodiment 2 is the same as the vehicle-mounted antenna device 10 according to Embodiment 1 except for the following points.

[0151] The first antenna element 100 has a fifth end 106 in addition to a first end 102 and a second end 104. The second end 104 and the fifth end 106 are located on opposite sides of the first end 102. The first end 102, namely, the feeder 102a, is located approximately in the center of the first antenna element 100.

[0152] The fifth end 106 of the first antenna element 100 forms the tip of the first antenna element 100. Furthermore, the fifth end 106 of the first antenna element 100 forms an open end located farther from the ground plane 20 than the first end 102 of the first antenna element 100. In this embodiment, the first end 102 is located on the positive side of the first direction X relative to the fifth end 106, and the fifth end 106 is located on the negative side of the first direction X relative to the first end 102. Furthermore, the first end 102 is located on the positive side of the second direction Y relative to the fifth end 106, and the fifth end 106 is located on the negative side of the second direction Y relative to the first end 102. Furthermore, the first end 102 is located on the negative side of the third direction Z relative to the fifth end 106, and the fifth end 106 is located on the positive side of the third direction Z relative to the first end 102.

[0153] When deployed, the first antenna element 100 has a generally U-shaped configuration. Specifically, in addition to the first portion 112, the second portion 114, and the first step portion 116, the first antenna element 100 also includes a fifth portion 122, a sixth portion 124, and a second step portion 126. The fifth portion 122, the sixth portion 124, and the second step portion 126 have shapes that are generally symmetrical with the first portion 112, the second portion 114, and the first step portion 116 with respect to the first end 102. The fifth portion 122, the second step portion 126, and the sixth portion 124 are arranged in this order from the first end 102 to the fifth end 106. The fifth portion 122 extends from the first end 102 toward the negative side of the first direction X. Furthermore, the fifth portion 122 is bent between the first end 102 and the second step portion 126. As a result, the end of the fifth portion 122 on the second step portion 126 side is located on the negative side of the second direction Y relative to the end of the fifth portion 122 on the first end 102 side. The second step portion 126 extends from the fifth portion 122 to the sixth portion 124, from the negative side of the second direction Y toward the positive side of the second direction Y. The sixth portion 124 extends from the second step portion 126 to the second end 104 toward the positive side of the third direction Z. Providing the second step portion 126 allows the overall length between the first end 102 and the fifth end 106 of the first antenna element 100 to be extended compared to a case where the fifth portion 122 and the sixth portion 124 are directly connected without the second step portion 126.

[0154] Similar to the width of first antenna element 100 from first end 102 to second end 104 described in Embodiment 1, the width of first antenna element 100 increases in a stepwise or gradual manner from first end 102 to fifth end 106. Therefore, the width of first antenna element 100 near fifth end 106 is greater than the width near first end 102 of first antenna element 100, i.e., near feeder 102a. Here, "increasing in a stepwise manner" means increasing in steps, for example, while "increasing gradually" means increasing in a smooth, gradual manner, for example, without steps.

[0155] First antenna element 100 includes a first region 110, which includes a first portion 112, a second portion 114, and a first step portion 116, located on one side of second antenna element 200, i.e., on the positive side of second antenna element 200 in the second direction Y. Furthermore, first antenna element 100 includes a second region 120, which includes a fifth portion 122, a sixth portion 124, and a second step portion 126, located on the other side of second antenna element 200, opposite to the first side, i.e., on the negative side of second antenna element 200 in the second direction Y.

[0156] At least a portion of the first region 110 of the first antenna element 100 is capacitively coupled to at least a portion of the second antenna element 200. Furthermore, at least a portion of the second region 120 of the first antenna element 100 is capacitively coupled to at least a portion of the second antenna element 200. Specifically, as in Embodiment 1, at least a portion of the second end 104 of the first antenna element 100 and at least a portion of the fourth end 204 of the second antenna element 200 overlap in the second direction Y, thereby forming a capacitive coupling. Furthermore, the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 are spaced apart from each other. Furthermore, at least a portion of the fifth end 106 of the first antenna element 100 and at least a portion of the fourth end 204 of the second antenna element 200 overlap in the second direction Y, thereby forming a capacitive coupling. Furthermore, the fifth end 106 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 are spaced apart from each other.

[0157] Similar to second end 104 of first antenna element 100 described in Embodiment 1, fifth end 106 of first antenna element 100 is tilted relative to ground plane 20, that is, relative to a plane parallel to the XY plane. More specifically, fifth end 106 tilts toward the positive side of third direction Z as it moves from the positive side of first direction X toward the negative side of first direction X.

[0158] The first region 110 of the first antenna element 100 and the second antenna element 200 do not overlap in the second direction Y, except for the portions surrounding the first end 102 and the third end 202, and the portions surrounding the second end 104 and the fourth end 204. Furthermore, the second region 120 of the first antenna element 100 and the second antenna element 200 do not overlap in the second direction Y, except for the portions surrounding the first end 102 and the third end 202, and the portions surrounding the fifth end 106 and the fourth end 204.

[0159] Figure 9 Graphs showing VSWR characteristics of the vehicle-mounted antenna device 10 according to the second embodiment and the vehicle-mounted antenna device 10 according to the first embodiment. Figure 10 Graphs showing radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the second embodiment and the vehicle-mounted antenna device 10 according to the first embodiment.

[0160] Figure 9 The horizontal axis of the graph shows frequency. Figure 9 The vertical axis of the graph shows VSWR. Figure 9 The solid line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the second embodiment. Figure 9 The dotted line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0161] Figure 10 The horizontal axis of the graph shows frequency. Figure 10 The vertical axis of the graph shows radiation efficiency. Figure 10 The solid line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the second embodiment. Figure 10 The dotted line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0162] like Figure 9 As shown, the VSWR of Embodiment 2 is less than 2.5 at all frequencies in the frequency band above 1000 MHz. In contrast, the VSWR of Embodiment 1 exceeds 2.5 at around 1250 MHz in the frequency band above 1000 MHz. Therefore, it can be said that the second region 120 of the first antenna element 100 of Embodiment 2 contributes to smoothing the VSWR characteristics.

[0163] like Figure 10 As shown, the radiation efficiency of Embodiment 2 exceeds 85% at any frequency in the frequency band above 1000 MHz. In contrast, the radiation efficiency of Embodiment 1 is less than 85% at around 1250 MHz in the frequency band above 1000 MHz. Therefore, it can be said that the second region 120 of the first antenna element 100 of Embodiment 2 contributes to smoothing the radiation efficiency characteristics.

[0164] Figure 11 It is a perspective view of a first example of the entire vehicle-mounted antenna device 10 according to the second embodiment. Figure 12 yes Figure 11 The left side view of the first example of the entire vehicle-mounted antenna device 10 is shown. Figure 13 It is from Figure 11 The figure shows the antenna housing 530 removed. Figure 11 and Figure 12 , the left side portion of the antenna housing 530 is removed.

[0165] The vehicle-mounted antenna device 10 includes an antenna base 510, a substrate 520, and an antenna housing 530. The antenna base 510 is a conductive base, such as a metal base. Alternatively, the antenna base 510 may include both a conductive base and an insulating base. The antenna base 510 may include a conductive base, an insulating base, and a metal plate, or a metal plate and an insulating base. The substrate 520 is, for example, a PCB (Printed Circuit Board). The substrate 520 is provided on the upper surface of the antenna base 510. Two antennas are provided on the upper surface of the substrate 520: a rear antenna including a first antenna element 100A and a second antenna element 200A, and a front antenna including a first antenna element 100B and a second antenna element 200B. The antenna base 510 and the antenna housing 530 form a storage space for the substrate 520 and the two antennas.

[0166] The first antenna element 100A at the rear and Figure 8 The first antenna element 100 shown in FIG. 1 has a first end 102A, a second end 104A, and a fifth end 106A. The second antenna element 200A at the rear is Figure 8 The second antenna element 200 shown similarly has a third end 202A and a fourth end 204A.

[0167] The first antenna element 100B in front and Figure 8 The first antenna element 100 shown in the figure has a first end 102B, a second end 104B and a fifth end 106B. The second antenna element 200B in the front is Figure 8 The second antenna element 200 shown similarly has a third end 202B and a fourth end 204B.

[0168] In this embodiment, an antenna comprising first antenna element 100A and second antenna element 200A, and an antenna comprising first antenna element 100B and second antenna element 200B are arranged in the front-to-rear direction of vehicle-mounted antenna device 10. The electric field is strong in the capacitively coupled portions of these two antennas: namely, the capacitively coupled portions between second end 104A and fourth end 204A, and between fifth end 106A and fourth end 204A of the rear antenna, and the capacitively coupled portions between second end 104B and fourth end 204B, and between fifth end 106B and fourth end 204B of the front antenna. Therefore, if the capacitive coupling portions of the rear antenna's second end 104A and fourth end 204A, and fifth end 106A and fourth end 204A, are arranged in close proximity to the capacitive coupling portions of the front antenna's second end 104B and fourth end 204B, and fifth end 106B and fourth end 204B, respectively, the capacitive coupling portions may couple with each other, potentially causing the antennas (rear antenna and front antenna) to no longer function as independent antennas. Therefore, it is desirable to separate the capacitive coupling portions of the two antennas. In this embodiment, the distance between the capacitive coupling portions of the antennas can be increased compared to a case where the two antennas are arranged in the left-right direction of the vehicle-mounted antenna device 10. Furthermore, the two antennas may also be arranged in a direction different from the front-to-back direction of the vehicle-mounted antenna device 10, such as the left-to-right direction of the vehicle-mounted antenna device 10. That is, as long as the distance between the capacitive coupling parts of each antenna is large, any configuration is acceptable. For example, the antennas may be configured so that the capacitive coupling parts of the second end 104A and the fourth end 204A, and the fifth end 106A and the fourth end 204A of the rear antenna are facing rearward, and the capacitive coupling parts of the second end 104B and the fourth end 204B, and the fifth end 106B and the fourth end 204B of the front antenna are facing forward.

[0169] In the area where the front antenna including the first antenna element 100B and the second antenna element 200B is located, the height of the antenna housing 530 is low. It is preferable that the first antenna element 100B and the second antenna element 200B be high. In this embodiment, the second end 104B and the fifth end 106B are located behind the first end 102B, and the fourth end 204B is located behind the third end 202B. In this case, the height of the first antenna element 100B and the second antenna element 200B can be increased compared to a case where the second end 104B and the fifth end 106B are located in front of the first end 102B and the fourth end 204B is located in front of the third end 202B. However, the second end 104B and the fifth end 106B may be located in front of the first end 102B, and the fourth end 204B may be located in front of the third end 202B.

[0170] Figure 14This is a perspective view of a second example in which the antenna case is entirely removed from the vehicle-mounted antenna device 10 according to the second embodiment. Figure 15 yes Figure 14 FIG. 2 is a left side view of a second example of the vehicle-mounted antenna device 10 shown. Figure 16 Is used to illustrate Figure 14 FIG. 1 is a cross-sectional view showing an example of mechanical bonding between the first block 310A and the second block 320A. Figures 14 to 16 The vehicle-mounted antenna device 10 of the second example shown is similar to the vehicle-mounted antenna device 10 except for the following points. Figures 11 to 13 The vehicle-mounted antenna device 10 of the first example shown is the same.

[0171] At least a portion of the first antenna element 100A has rounded corners. Specifically, Figure 14 and Figure 15 As shown, the angle between the upper edge and the rear edge of second end 104A, i.e., the angle of the portion of first antenna element 100A that capacitively couples with at least a portion of second antenna element 200A, is rounded. This reduces the risk of injuries to assemblers of vehicle-mounted antenna device 10 or damage to other components caused by the angle, compared to situations where the angle is sharp. Alternatively, an angle other than the angle between the upper edge and the rear edge of second end 104A, such as the angle between the upper edge and the front edge of second end 104A, may also be rounded.

[0172] like Figure 14 As shown, similar to the angle between the upper edge and the rear edge at the second end 104A, at least a portion of the corners of the first antenna element 100A, for example, the angle between the upper edge and the rear edge at the fifth end 106A, is also rounded.

[0173] like Figure 14 and Figure 15 As shown, similar to the angle between the upper edge and the rear edge at the second end 104A, at least a portion of the angle of the second antenna element 200A, for example, the angle between the upper end and the rear end at the fourth end 204A, is also rounded.

[0174] exist Figure 14 and Figure 15 In the example shown, the first front antenna element 100B and the second front antenna element 200B also have the same configuration as that described above with respect to the first rear antenna element 100A and the second rear antenna element 200A.

[0175] The vehicle-mounted antenna device 10 includes a holder 300A, which is attached to a rear antenna having a first antenna element 100A and a second antenna element 200A. The holder 300A is positioned between at least a portion of the first antenna element 100A and at least a portion of the second antenna element 200A. At least a portion of the first antenna element 100A and the second antenna element 200A are supported by the holder 300A. In this case, compared to a case without the holder 300A, the effects of vibrations of the vehicle in which the vehicle-mounted antenna device 10 is mounted on the mechanical properties of at least one of the first antenna element 100A and the second antenna element 200A can be suppressed. Furthermore, compared to a case where the retaining frame 300A is not provided, fluctuations in the distance in the second direction Y between the second end 104A and the fourth end 204A and / or fluctuations in the area of ​​overlap between the second end 104A and the fourth end 204A in the second direction Y due to vibration of the vehicle on which the vehicle-mounted antenna device 10 is mounted are suppressed, thereby suppressing fluctuations in the capacitance between the second end 104A and the fourth end 204A. Similarly, fluctuations in the distance in the second direction Y between the fifth end 106A and the fourth end 204A and / or fluctuations in the area of ​​overlap between the fifth end 106A and the fourth end 204A in the second direction Y due to vibration of the vehicle on which the vehicle-mounted antenna device 10 is mounted are suppressed, thereby suppressing fluctuations in the capacitance between the fifth end 106A and the fourth end 204A.

[0176] like Figure 14 As shown, holder 300A includes a first block 310A and a second block 320A. First block 310A and second block 320A are, for example, resin blocks. First block 310A is located between second antenna element 200A and first region 110A of first antenna element 100A. Second block 320A is located between second antenna element 200A and second region 120A of first antenna element 100A.

[0177] like Figure 16As shown, a protrusion 330A is provided on the surface of the first block 310A on the negative side in the second direction Y. The protrusion 330A extends along the second direction Y through a hole provided in the second antenna element 200A. Furthermore, the protrusion 330A is mechanically joined by fitting into a recess provided on the surface of the second block 320A on the positive side in the second direction Y. This integrates the first block 310A, the second block 320A, and the second antenna element 200A. This makes it easier to assemble the first block 310A, the second block 320A, and the second antenna element 200A as a whole, compared to a case where the first block 310A and the second block 320A are not mechanically joined via the protrusion 330A but are mechanically separated from each other. In addition, compared to the case where the first block 310A and the second block 320A are not mechanically joined via the protrusion 330A but are mechanically separated from each other, changes in the distance in the second direction Y between the second end 104A and the fourth end 204A and / or changes in the area of ​​overlap between the second end 104A and the fourth end 204A in the second direction Y caused by the vibration of the vehicle equipped with the vehicle antenna device 10 are suppressed, thereby suppressing changes in the capacitance between the second end 104A and the fourth end 204A. Similarly, compared to a case where the first block 310A and the second block 320A are not mechanically joined via the protrusion 330A but are mechanically separated from each other, this suppresses fluctuations in the distance between the fifth end 106A and the fourth end 204A in the second direction Y and / or fluctuations in the area of ​​overlap between the fifth end 106A and the fourth end 204A in the second direction Y due to vibrations of the vehicle on which the vehicle-mounted antenna device 10 is mounted, thereby suppressing fluctuations in the capacitance between the fifth end 106A and the fourth end 204A. Furthermore, the first block 310A and the second block 320A may not be mechanically joined via the protrusion 330A, or may be mechanically separated from each other.

[0178] exist Figure 16 In the example shown, the convex portion 330A provided on the first block 310A is mechanically joined to the concave portion provided on the second block 320A. However, the convex portion 330A may also be provided on the second block 320A. In this case, the convex portion 330A provided on the second block 320A is mechanically joined to the concave portion provided on the first block 310A.

[0179] like Figure 14As shown, the surface of the first block 310A on the positive side in the second direction Y has a shape that follows the concave and convex shapes of the first portion 112A, the first step portion 116A, and the second portion 114A of the first region 110A. In this case, compared to a case where the surface of the first block 310A on the positive side in the second direction Y does not have a shape that follows the concave and convex shapes of the first portion 112A, the first step portion 116A, and the second portion 114A, for example, a gap is formed between the surface of the first block 310A on the positive side in the second direction Y and the first portion 112A, the first step portion 116A, and the second portion 114A. This can suppress vibrations of the first region 110A caused by vibrations during travel of a vehicle equipped with the vehicle-mounted antenna device 10. In addition, compared to the case where the surface on the positive side of the second direction Y of the first block 310A is not a concave-convex shape along the first part 112A, the first step portion 116A and the second part 114A, the change in the distance in the second direction Y between the second end 104A and the fourth end 204A and / or the change in the area of ​​overlap between the second end 104A and the fourth end 204A in the second direction Y caused by the vibration of the vehicle equipped with the vehicle-mounted antenna device 10 is suppressed, thereby suppressing the change in capacitance between the second end 104A and the fourth end 204A.

[0180] Similar to the surface of the first block 310A on the positive side in the second direction Y, the surface of the second block 320A on the negative side in the second direction Y can also be formed into a shape that conforms to the concave and convex shapes of the second region 120A.

[0181] like Figure 14 and Figure 15 As shown, a first protrusion 342A and a second protrusion 344A are provided at the end portion on the positive side in the first direction X of at least one of the first block 310A and the second block 320A. The first protrusion 342A is located on the positive side in the third direction Z relative to the first end 102A of the first antenna element 100A. The second protrusion 344A is located on the negative side in the third direction Z relative to the first end 102A of the first antenna element 100A. The first end 102A is pressed in the third direction Z by the first protrusion 342A and the second protrusion 344A. Therefore, positioning and fixing the first end 102A in the third direction Z are easier than in a case where the first protrusion 342A and the second protrusion 344A are not provided. Alternatively, the first protrusion 342A and the second protrusion 344A may be omitted.

[0182] like Figure 14 and Figure 15As shown, a third protrusion 352A is provided on the positive side of the first block 310A in the second direction Y, which engages with a hole provided in the second portion 114A. The third protrusion 352A mechanically engages with the hole provided in the second portion 114A through, for example, a snap fit. The provision of the third protrusion 352A makes it easier to align the first block 310A with the second portion 114A than without it. Furthermore, the structure in which the third protrusion 352A of the retaining frame 300A engages with the hole provided in the second portion 114A of the first antenna element 100A also functions as a fixing mechanism between the first antenna element 100A and the retaining frame 300A. Alternatively, the third protrusion 352A may engage with a hole provided in a portion of the first region 110A different from the second portion 114A, rather than the hole provided in the second portion 114A. Furthermore, a plurality of third protrusions 352A may be provided on the positive side of the first block 310A in the second direction Y. In this case, the plurality of third protrusions 352A can be engaged with a plurality of holes provided in at least a portion of the first portion 112A, the first step portion 116A, and the second portion 114A.

[0183] Similar to the third protrusion 352A provided on the first block 310A, a protrusion that engages with a hole provided in the second region 120A can also be provided on the negative side in the second direction Y of the second block 320A.

[0184] like Figure 14 and Figure 15 As shown, a support portion 362A for supporting the first region 110A is provided on the negative side of the first block 310A in the first direction X. The support portion 362A includes a first support body 362Aa and a second support body 362Ab.

[0185] At least a portion of the first support 362Aa is positioned on the negative side of the first direction X relative to the end of the second portion 114A on the negative side of the first direction X. Therefore, the first support 362Aa can support the second portion 114A from the negative side of the first direction X. Providing the first support 362Aa makes it easier to align the first region 110A in the first direction X than when the first support 362Aa is not provided. Furthermore, providing the first support 362Aa can suppress the effects on the mechanical properties of the first region 110A caused by vibration during travel of a vehicle equipped with the vehicle-mounted antenna device 10, compared to when the first support 362Aa is not provided. Moreover, when the first support body 362Aa is provided, compared with the case where the first support body 362Aa is not provided, the change in the overlapping area of ​​the second end 104A and the fourth end 204A in the second direction Y caused by the vibration of the vehicle equipped with the vehicle-mounted antenna device 10 is suppressed, thereby suppressing the change in the capacitance between the second end 104A and the fourth end 204A.

[0186] At least a portion of the second support body 362Ab is positioned on the positive side of the second portion 114A in the second direction Y. Therefore, the second support body 362Ab can support the second portion 114A from the positive side in the second direction Y. When the second support body 362Ab is provided, deflection of the first region 110A in the second direction Y can be suppressed compared to when the second support body 362Ab is not provided. Furthermore, when the second support body 362Ab is provided, the effects on the mechanical properties of the first region 110A caused by vibration during travel of a vehicle equipped with the vehicle-mounted antenna device 10 can be suppressed compared to when the second support body 362Ab is not provided. Moreover, when the second support body 362Ab is provided, compared with the case where the second support body 362Ab is not provided, the change in the distance in the second direction Y between the second end 104A and the fourth end 204A caused by the vibration of the vehicle equipped with the vehicle-mounted antenna device 10 is suppressed, thereby suppressing the change in the capacitance between the second end 104A and the fourth end 204A.

[0187] Similar to the support portion 362A provided in the first block 310A, a support portion that supports the second region 120A can also be provided on the negative side in the first direction X of the second block 320A.

[0188] The structure of the holder 300A is not limited to Figures 14 to 16 For example, the holder 300A may include only one of the first block 310A and the second block 320A. Figure 1 、 Figure 2 or Figure 5 or the following Figure 19 or Figure 22 When the holder 300A includes only the first region 110A as in the illustrated first antenna element 100 , the holder 300A may include only the first block 310A located between the second antenna element 200A and the first region 110A.

[0189] The vehicle-mounted antenna device 10 further includes a holder 300B provided on the front antenna including the first antenna element 100B and the second antenna element 200B. Figure 14 and Figure 15 In the example shown, the front holder 300B has the same structure as that described above for the rear holder 300A. Furthermore, the height of the first block 310B and the second block 320B of the front holder 300B in the third direction Z is lower than the height of the first block 310A and the second block 320A of the rear holder 300A in the third direction Z, in accordance with the shape of the antenna housing (not shown).

[0190] Figure 17 This is a perspective view of a third example in which the antenna case is entirely removed from the vehicle-mounted antenna device 10 according to the second embodiment. Figure 18 yes Figure 17 FIG. 2 is a left side view of a third example of the vehicle-mounted antenna device 10 shown. Figure 17 and Figure 18 The vehicle-mounted antenna device 10 of the third example shown is similar to the vehicle-mounted antenna device 10 except for the following points. Figures 14 to 16 The vehicle-mounted antenna device 10 of the second example shown is the same.

[0191] The vehicle-mounted antenna device 10 further includes a first antenna unit 410 and a second antenna unit 420. The first antenna unit 410 and the second antenna unit 420 are located in the first direction X between the rear antenna comprising the first antenna element 100A and the second antenna element 200A and the front antenna comprising the first antenna element 100B and the second antenna element 200B. The first antenna unit 410 is located on the positive side of the second direction Y relative to an imaginary line passing through the rear second antenna element 200A and the front second antenna element 200B parallel to the first direction X. The second antenna unit 420 is located on the negative side of the second direction Y relative to an imaginary line passing through the rear second antenna element 200A and the front second antenna element 200B parallel to the first direction X.

[0192] The first antenna unit 410 and the second antenna unit 420 are, for example, LTE antennas, Wi-Fi (registered trademark) antennas, or MIMO (Multiple-Input and Multiple-Output) antennas. The first antenna unit 410 and the second antenna unit 420 may be of the same type or different types.

[0193] If used Figures 11 to 13 As described above, the rear antenna, comprising first antenna element 100A and second antenna element 200A, and the front antenna, comprising first antenna element 100B and second antenna element 200B, are arranged with a suitable space between them along first direction X, so that the two antennas function as independent antennas. First antenna unit 410 and second antenna unit 420 are arranged within this space. Therefore, compared to a case where first antenna unit 410 and second antenna unit 420 are arranged in an area separate from this space, the space within the antenna housing can be more efficiently utilized.

[0194] The arrangement of the first antenna unit 410 and the second antenna unit 420 is not limited to Figure 17 and Figure 18 For example, the first antenna unit 410 and the second antenna unit 420 may be arranged along the first direction X. Furthermore, one of the first antenna unit 410 and the second antenna unit 420 may not be provided. Furthermore, in addition to the first antenna unit 410 and the second antenna unit 420, at least one other antenna unit may be provided.

[0195] (Implementation 3)

[0196] Figure 19 3 is a perspective view of the vehicle-mounted antenna device 10 according to Embodiment 3. The vehicle-mounted antenna device 10 according to Embodiment 3 is the same as the vehicle-mounted antenna device 10 according to Embodiment 1 except for the following points.

[0197] The third portion 212 of the second antenna element 200 includes not only a portion extending from the third end 202 to the fourth portion 214 toward the positive side of the third direction Z, but also portions extending in other directions. Specifically, the third portion 212 includes, in order from the third end 202 to the fourth portion 214, a portion extending toward the positive side of the third direction Z, a portion extending toward the positive side of the first direction X, a portion extending toward the positive side of the second direction Y, and a portion extending toward the positive side of the third direction Z. In this case, for example, as in the example Figure 1Compared to the case where the third portion 212 includes only the portion extending in the positive direction of the third direction Z from the third end 202 to the fourth portion 214 as shown, the length of the second antenna element 200 in the first direction X can be shortened while maintaining the total length of the second antenna element 200 from the third end 202 to the fourth end 204.

[0198] The vehicle-mounted antenna device 10 further includes a first dielectric 150A and a second dielectric 150B. The first dielectric 150A is attached to at least a portion of the first antenna element 100. Specifically, the first dielectric 150A is attached to the inner surface of the first portion 112 of the first antenna element 100. Alternatively, the dielectric 150 may be attached to at least one of the inner or outer surfaces of the first portion 112. The second dielectric 150B is provided across at least a portion of the first antenna element 100 and at least a portion of the second antenna element 200. Specifically, the second dielectric 150B is provided across at least a portion of the second end 104 of the first antenna element 100 and at least a portion of the fourth end 204 of the second antenna element 200.

[0199] Furthermore, in this embodiment, the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 do not overlap in the second direction Y. Even in this case, the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 are capacitively coupled to each other due to their proximity. Since the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 do not overlap in the second direction Y, the capacitance component between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 can be adjusted to be smaller than the capacitance component that would occur if the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 overlapped in the second direction Y.

[0200] In this embodiment, for example, Figures 11 to 13 When an antenna comprising first antenna element 100A and second antenna element 200A and an antenna comprising first antenna element 100B and second antenna element 200B are arranged in the front-to-back direction of vehicle-mounted antenna device 10 as shown, the length of each antenna in the front-to-back direction can be shortened compared to, for example, the antenna comprising first antenna element 100 and second antenna element 200 in Embodiment 1. Consequently, the isolation between the two antennas can be further ensured compared to, for example, the antenna comprising first antenna element 100 and second antenna element 200 in Embodiment 1. Furthermore, an antenna of another medium can be positioned between the two antennas.

[0201] Figure 20Graphs showing VSWR characteristics of the vehicle-mounted antenna device 10 according to the third embodiment and the vehicle-mounted antenna device 10 according to the first embodiment. Figure 21 Graphs showing radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the third embodiment and the vehicle-mounted antenna device 10 according to the first embodiment.

[0202] Figure 20 The horizontal axis of the graph shows frequency. Figure 20 The vertical axis of the graph shows VSWR. Figure 20 The solid line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the third embodiment. Figure 20 The dotted line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0203] Figure 21 The horizontal axis of the graph shows frequency. Figure 21 The vertical axis of the graph shows radiation efficiency. Figure 21 The solid line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the third embodiment. Figure 21 The dotted line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0204] like Figure 20 As shown in FIG, the VSWR of the embodiment 3 and the embodiment 1 is as low as less than 3.5 in the wide band range of 700MHz to 1000MHz and 1500MHz to 6500MHz. Figure 21 As shown, the radiation efficiency of Embodiment 3 and Embodiment 1 is as high as over 60% in a wide band of 700 MHz to 6500 MHz, except for around 1250 MHz in Embodiment 3.

[0205] (Implementation 4)

[0206] Figure 22 1 is a perspective view of the vehicle-mounted antenna device 10 according to Embodiment 4. The vehicle-mounted antenna device 10 according to Embodiment 4 is the same as the vehicle-mounted antenna device 10 according to Embodiment 1 except for the following points.

[0207] The vehicle-mounted antenna device 10 includes a substrate 160, such as a PCB (Printed Circuit Board). The first antenna element 100 is a conductive pattern formed on the surface of the substrate 160 on the positive side in the second direction Y. The second antenna element 200 is a conductive pattern formed on the surface of the substrate 160 on the negative side in the second direction Y. Furthermore, in this embodiment, the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 do not overlap in the thickness direction of the substrate 160, i.e., in the second direction Y. Even in this case, the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 are capacitively coupled to each other due to their proximity. The second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 do not overlap in the second direction Y, thereby enabling the capacitance component between the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 to be adjusted to be smaller than the capacitance component when the second end 104 of the first antenna element 100 and the fourth end 204 of the second antenna element 200 overlap in the second direction Y.

[0208] Figure 23 Graphs showing VSWR characteristics of the vehicle-mounted antenna device 10 according to the fourth embodiment and the vehicle-mounted antenna device 10 according to the first embodiment. Figure 24 Graphs showing radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the fourth embodiment and the vehicle-mounted antenna device 10 according to the first embodiment.

[0209] Figure 23 The horizontal axis of the graph shows frequency. Figure 23 The vertical axis of the graph shows VSWR. Figure 23 The solid line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the fourth embodiment. Figure 23 The dotted line in the graph shows the VSWR characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0210] Figure 24 The horizontal axis of the graph shows frequency. Figure 24 The vertical axis of the graph shows radiation efficiency. Figure 24 The solid line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the fourth embodiment. Figure 24 The dotted line in the graph shows the radiation efficiency characteristics of the vehicle-mounted antenna device 10 according to the first embodiment.

[0211] like Figure 23 As shown in FIG, the VSWR of the embodiment 4 and the embodiment 1 is as low as less than 3.5 in the wide band range of 700MHz to 6500MHz. Figure 24As shown, the radiation efficiency of Embodiment 4 and Embodiment 1 is as high as over 60% in a wide band range of 700 MHz to 6500 MHz.

[0212] In addition, in embodiment 4, the first antenna element 100 and the second antenna element 200 are arranged on the substrate 160 using a conductor pattern. Therefore, compared with the case where the antenna elements are formed from metal plates, it is possible to prevent collisions between the antenna elements due to vehicle vibration. In addition, it is possible to prevent changes in the spacing between the antenna elements due to vehicle vibration or assembly work, thereby stably fixing the capacitive coupling.

[0213] As mentioned above, although embodiment and modification of this invention were described with reference to drawings, these are illustrations of this invention, and various structures other than the above-mentioned can also be adopted.

[0214] For example, in each embodiment and each modification, the second end 104 of the first antenna element 100 has an upper edge that is inclined relative to the ground plane 20. However, the upper edge of the second end 104 of the first antenna element 100 may be, for example, triangular, quadrilateral, semicircular, or semi-elliptical. Figures 11 to 18 The same applies to the first antenna element 100A, the first antenna element 100B, the second antenna element 200A, and the second antenna element 200B described above.

[0215] In each embodiment and each modification, the first antenna element 100 includes the feeder 102a and the second antenna element 200 includes the short-circuit portion 202a. However, the first antenna element 100 may include the short-circuit portion 202a and the second antenna element 200 may include the feeder 102a. Figures 11 to 18 The same applies to the first antenna element 100A, the first antenna element 100B, the second antenna element 200A, and the second antenna element 200B described above.

[0216] According to this specification, the following scheme is provided.

[0217] (Scheme 1)

[0218] Solution 1 is a vehicle-mounted antenna device having:

[0219] a first antenna element disposed on a ground plane; and

[0220] The second antenna element is arranged on the ground plane.

[0221] At least a portion of the first antenna element and at least a portion of the second antenna element are capacitively coupled.

[0222] According to solution 1, the capacitive coupling between the first and second antenna elements contributes to low VSWR and high radiation efficiency in the low frequency band. This allows the antenna to be used stably with high radiation efficiency over a wide frequency band.

[0223] (Scheme 2)

[0224] Solution 2: In the vehicle-mounted antenna device described in Solution 1,

[0225] The first antenna element has a feeding portion.

[0226] The second antenna element includes a short-circuited portion short-circuited to the ground plane.

[0227] According to the second embodiment, compared with the case where the second antenna element is electrically open with respect to the ground plane, good characteristics in the low frequency band can be obtained.

[0228] (Scheme 3)

[0229] Solution 3: In the vehicle-mounted antenna device described in Solution 1 or 2,

[0230] The first antenna element includes a first region located on one side of the second antenna element and a second region located on the other side of the second antenna element opposite to the first side.

[0231] At least a portion of the first region of the first antenna element is capacitively coupled to at least a portion of the second antenna element.

[0232] At least a portion of the second region of the first antenna element is capacitively coupled to at least a portion of the second antenna element.

[0233] According to Solution 3, capacitive coupling between the first region of the first antenna element and the second antenna element, and capacitive coupling between the second region of the first antenna element and the second antenna element, contributes to low VSWR and high radiation efficiency in the low-frequency band. This enables stable use of the antenna with high radiation efficiency across a wide frequency band.

[0234] (Scheme 4)

[0235] A fourth aspect is the vehicle-mounted antenna device according to any one of the first to third aspects,

[0236] The first antenna element has a first end and a second end located farther from the ground plane than the first end.

[0237] The second antenna element has a third end and a fourth end located farther from the ground plane than the third end.

[0238] At least a portion of the second end of the first antenna element and at least a portion of the fourth end of the second antenna element are capacitively coupled.

[0239] According to solution 4, capacitive coupling between the second end of the first antenna element and the fourth end of the second antenna element contributes to low VSWR and high radiation efficiency in the low frequency band. This allows the antenna to be used stably with high radiation efficiency over a wide frequency band.

[0240] (Scheme 5)

[0241] Solution 5: In the vehicle-mounted antenna device described in Solution 4,

[0242] The width of the first antenna element increases stepwise or gradually from the first end to the second end.

[0243] According to claim 5, the first antenna element can function as an antenna having a self-similar shape. Specifically, depending on the operating frequency band, it can function as a self-similar shape or a conical antenna based on the self-similar shape, as a monopole antenna, or as a loop antenna or a split-loop antenna. This allows the antenna to be used stably with high radiation efficiency over a wide frequency band.

[0244] (Scheme 6)

[0245] Solution 6: In the vehicle-mounted antenna device described in Solution 4 or 5,

[0246] The width of the second antenna element increases stepwise or gradually from the third end to the fourth end.

[0247] According to the sixth aspect, since the second antenna element functions as an antenna having a self-similar shape, it is possible to stably use the antenna with high radiation efficiency over a wide band.

[0248] (Scheme 7)

[0249] A seventh aspect is the vehicle-mounted antenna device according to any one of the fourth to sixth aspects,

[0250] The second end of the first antenna element is inclined with respect to the ground plane.

[0251] According to solution 7, by tilting the second end, the overlapping area of ​​the second end of the first antenna element and the fourth end of the second antenna element is adjusted, thereby adjusting the capacitance component between the second end of the first antenna element and the fourth end of the second antenna element.

[0252] (Scheme 8)

[0253] Aspect 8 is the vehicle-mounted antenna device according to any one of aspects 1 to 7,

[0254] At least a portion of the first antenna element or the second antenna element includes a dielectric.

[0255] According to claim 8, the VSWR characteristics can be smoothed by the dielectric.

[0256] (Scheme 9)

[0257] A ninth aspect is the vehicle-mounted antenna device according to any one of the first to eighth aspects,

[0258] A difference between the length of the first antenna element and the length of the second antenna element is within ±25% of the length of the first antenna element or the length of the second antenna element.

[0259] According to solution 9, it is possible to use the antenna stably with high radiation efficiency over a wide band.

[0260] (Scheme 10)

[0261] A tenth embodiment is the vehicle-mounted antenna device according to any one of the first to ninth embodiments,

[0262] The at least one portion of the first antenna element has a rounded corner.

[0263] According to claim 10, compared with a case where the corner of the first antenna element is sharp, it is possible to suppress the occurrence of problems such as an assembler of the vehicle-mounted antenna device being injured by the corner or other components being damaged by the corner.

[0264] (Scheme 11)

[0265] Aspect 11 is the vehicle-mounted antenna device according to any one of aspects 1 to 10,

[0266] further comprising a holder positioned between at least a portion of the first antenna element and at least a portion of the second antenna element,

[0267] At least a portion of the first antenna element and the second antenna element is supported by the holding frame.

[0268] According to claim 11, compared to a case where no retaining bracket is provided, the effects of vibration of a vehicle equipped with the vehicle antenna device on the mechanical characteristics of at least one of the first and second antenna elements can be suppressed. Furthermore, compared to a case where no retaining bracket is provided, fluctuations in the distance between at least a portion of the capacitive coupling between the first and second antenna elements and / or in the area of ​​overlap between at least a portion of the capacitive coupling between the first and second antenna elements due to vibration of the vehicle equipped with the vehicle antenna device are suppressed, thereby suppressing fluctuations in the capacitance between the first and second antenna elements.

[0269] This application claims the benefit of priority based on Japanese patent application No. 2020-053910, filed on March 25, 2020, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A vehicle-mounted antenna device, characterized in that: have: a first antenna element disposed on a ground plane; and a second antenna element disposed on the ground plane, At least a portion of the first antenna element and at least a portion of the second antenna element are capacitively coupled. The first antenna element has a first end and a second end located farther from the ground plane than the first end. The second antenna element has a third end and a fourth end located farther from the ground plane than the third end. At least a portion of the second end of the first antenna element and at least a portion of the fourth end of the second antenna element overlap in a predetermined direction to be capacitively coupled. The first antenna element and the second antenna element do not overlap in the predetermined direction except for a portion near the first end, a portion near the third end, a portion near the second end, and a portion near the fourth end.

2. The vehicle-mounted antenna device according to claim 1, wherein The first antenna element has a feeding portion. The second antenna element includes a short-circuited portion short-circuited to the ground plane.

3. The vehicle-mounted antenna device according to claim 1, wherein The first antenna element includes a first region located on one side of the second antenna element and a second region located on the other side of the second antenna element opposite to the first side. At least a portion of the first region of the first antenna element is capacitively coupled to at least a portion of the second antenna element. At least a portion of the second region of the first antenna element is capacitively coupled to at least a portion of the second antenna element.

4. The vehicle-mounted antenna device according to claim 1, wherein The width of the first antenna element increases stepwise or gradually from the first end to the second end.

5. The vehicle-mounted antenna device according to claim 1, wherein The width of the second antenna element increases stepwise or gradually from the third end to the fourth end.

6. The vehicle-mounted antenna device according to claim 1, wherein The second end of the first antenna element is inclined with respect to the ground plane.

7. The vehicle-mounted antenna device according to any one of claims 1 to 3, wherein: A dielectric is included in at least a portion of the first antenna element or the second antenna element.

8. The vehicle-mounted antenna device according to any one of claims 1 to 3, wherein: A difference between the length of the first antenna element and the length of the second antenna element is within ±25% of the length of the first antenna element or the length of the second antenna element.

9. The vehicle-mounted antenna device according to any one of claims 1 to 3, wherein: The corners of at least a portion of the first antenna element are rounded.

10. The vehicle-mounted antenna device according to any one of claims 1 to 3, wherein: further comprising a holder positioned between at least a portion of the first antenna element and at least a portion of the second antenna element, At least a portion of the first antenna element and the second antenna element is supported by the holding frame.

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