Low profile composite antenna device

Abstract

Provided is a low-profile composite antenna device that can be made compact while ensuring antenna transmission and reception characteristics. A low-profile composite antenna device for a vehicle is composed of a base plate (10), a circuit substrate (20), a radome (30), a first element (40), and a second element (50). The radome (30) has a ridge portion (31) oriented in the longitudinal direction toward the vehicle travel direction and side portions (32) extending from both sides of the ridge portion (31). The first element (40) is disposed on the left side in the vehicle travel direction and is disposed in a manner inclined with respect to the base plate (10) as viewed from the front in the vehicle travel direction, with the upper end edge (41) disposed in the vicinity of the ridge portion (31). The second element (50) is disposed on the right side in the vehicle travel direction, with the upper end edge (51) disposed in the vicinity of the ridge portion (31) in a manner spaced apart from the first element (40), and the second element (50) is disposed opposite the first element (40) toward the base plate (10) from the ridge portion (31).

Description

Technical Field

[0001] This invention relates to a low-profile composite antenna device, and more particularly to a low-profile composite antenna device for vehicles. Background Technology

[0002] Currently, various antenna devices are installed in vehicles, including antennas for AM / FM radios that can receive broadcasts such as AM and FM radio. As an antenna for an AM / FM radio, a rod antenna is generally used. A rod antenna includes: an element section, which is formed by covering an element (a spiral element) made of a helical conductor with a cover; and a base section for mounting the element section.

[0003] When this rod-shaped antenna is installed on the vehicle body, the component protrudes significantly from the body, which detracts from the vehicle's aesthetics and design. It may also be damaged when entering a garage or washing the car. In addition, since it is installed outside the vehicle, the component may also be stolen.

[0004] To address this issue, a low-profile antenna device was proposed: the overall height of the antenna device is lower than that of a rod antenna, and the components are housed within the antenna housing to protect them from exposure to the outside of the vehicle. Considering the overall vehicle design after antenna installation, the antenna housing is constructed in a shark fin shape. Due to legal and regulatory constraints, such low-profile antenna devices are mostly less than 70mm in height and approximately 200mm in length.

[0005] However, such low-profile antenna devices suffer from the following problems: the radiation efficiency is easily reduced due to conductor loss (shortened element length) caused by the low orientation (below 70mm), leading to sensitivity degradation. Furthermore, there is a recent demand for composite antenna devices that can mount various antennas, such as TEL antennas, GPS antennas, and V2X antennas for vehicle-to-vehicle and road-to-road communication, onto vehicles. However, the narrow internal space of low-profile antenna devices results in the inability to adequately achieve the required distance between multiple antennas, leading to deterioration of antenna transmit / receive characteristics.

[0006] Therefore, for example, Patent Document 1 discloses an antenna device in which a plate-shaped second antenna is positioned above a first antenna, and the first antenna is positioned to avoid the point of maximum voltage of the standing wave in the frequency band of the first antenna generated by the second antenna. This results in an antenna device that can suppress the reduction of antenna gain while simultaneously achieving miniaturization.

[0007] Furthermore, Patent Document 2 discloses an antenna device in which a DTTB element is disposed between left and right capacitive load elements, and a notch filter circuit for notching the FM band is connected to the power supply of the DTTB element. This results in an antenna device that can prevent interference with the FM band while simultaneously achieving miniaturization in the front-rear direction.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Re-evaluation No. 2017 / 141635

[0011] Patent Document 2: Japanese Patent Application Publication No. 2019-012960 Summary of the Invention

[0012] The problem the invention aims to solve

[0013] However, in the pursuit of further miniaturization of antenna devices, in recent years there has been a demand for, for example, further widening of TEL antennas and enlargement of TEL antennas, with the expectation of developing antenna devices that can be configured in narrow internal spaces while ensuring antenna transmission and reception characteristics.

[0014] In view of this actual situation, the present invention aims to provide a low-profile composite antenna device that can ensure antenna transmission and reception characteristics while miniaturizing the device.

[0015] Solution for solving the problem

[0016] To achieve the aforementioned objective of the present invention, the low-profile composite antenna device of the present invention comprises: a base plate fixed to a vehicle, with its longitudinal direction facing the vehicle's travel direction; a circuit board disposed on the base plate, having a power supply section for a first element and a power supply section for a second element; an antenna radome fitted to the base plate, having a ridge portion with its longitudinal direction facing the vehicle's travel direction and side portions extending from both sides of the ridge portion, the cross-sectional shape of the antenna radome being mountain-shaped when viewed from the front in the vehicle's travel direction; and a plate-shaped first element housed in the antenna radome, disposed on one of the left or right sides in the vehicle's travel direction, and positioned relative to the front in the vehicle's travel direction. The base plate is arranged in an inclined manner. The upper edge of the first element is arranged near the ridge. The first element is connected to the first element of the circuit board by a power supply unit and functions as an antenna for the first frequency band. The plate-shaped second element is housed in an antenna cover and is arranged on the other side of the left and right directions of the vehicle's travel direction. The upper edge of the second element is arranged near the ridge with a gap between it and the first element. The second element is arranged opposite to the first element from the ridge towards the base plate. The second element is connected to the second element of the circuit board by a power supply unit and functions as an antenna for the second frequency band, which is different from the first frequency band.

[0017] The first and second components are configured such that, when viewed from the front in the direction of vehicle travel, at least the upper part resembles the Japanese character "ハ".

[0018] Alternatively, at least the upper portion of the first element and / or the second element may be arranged along the side portion of the radome.

[0019] Additionally, the second component can be bent into an S-shape when viewed from the front in the direction of vehicle travel.

[0020] Alternatively, the first element and / or the second element can be bent so that their upper edges are opposite each other near the ridge of the radome.

[0021] Alternatively, the first element can be configured at an angle relative to the base plate, and the second element can be configured perpendicular to the base plate.

[0022] In addition, the second component can be positioned at the front or rear of the vehicle in the direction of travel, near the base plate, and fixed to the side of the vehicle where it is located.

[0023] In addition, the second element can be composed of a bow-shaped antenna with a cone shape extending from the ridge section toward the power supply section of the second element.

[0024] Furthermore, it may also include a coil connected between the first element and the power supply unit for the first element, which is adjusted to function as a resonant antenna for the third frequency band using the series circuit of the first element and the coil.

[0025] Alternatively, the first element may be disposed on one of the left and right sides of the vehicle's direction of travel, and also partially disposed on the other side of the vehicle's direction of travel.

[0026] Furthermore, the portion of the first element located on one side of the vehicle's direction of travel and the portion located on the other side are formed as a single unit on the edge side, such that the cross-sectional shape is mountain-shaped when viewed from the front in the direction of vehicle travel.

[0027] Alternatively, the second element can be placed at the position of the first element, which is not present and is also located on the other side of the vehicle's direction of travel.

[0028] Furthermore, it is also possible to have a coil connected between the first element and the power supply unit for the first element, which is adjusted to function as a resonant antenna for the third frequency band using the series circuit of the first element and the coil, and the coil is positioned below the position of the first element, which is also located in the other part of the left and right directions of the vehicle's travel direction.

[0029] The effects of the invention

[0030] The low-profile composite antenna device of the present invention has the advantage of miniaturization while ensuring antenna transmission and reception characteristics. Attached Figure Description

[0031] Figure 1 This is a schematic diagram illustrating the low-profile composite antenna device of the present invention.

[0032] Figure 2 This is a schematic front view illustrating another example of the relative configuration of the first and second elements of the low-profile composite antenna device of the present invention.

[0033] Figure 3 This is a schematic front view illustrating another example of the shape near the ridge portion of the first and second elements of the low-profile composite antenna device of the present invention.

[0034] Figure 4 This is a schematic side view illustrating an example of the shape of another side of the second element of the low-profile composite antenna device of the present invention.

[0035] Figure 5 This is a schematic top view illustrating another example of the configuration of the first and second elements of the low-profile composite antenna device of the present invention.

[0036] Figure 6 This is a schematic diagram illustrating another example of the first element of the low-profile composite antenna device of the present invention. Detailed Implementation

[0037] Hereinafter, embodiments for carrying out the present invention will be described together with the illustrated examples. Figure 1 This is a schematic diagram illustrating the low-profile composite antenna device of the present invention. Figure 1 (a) is a side view. Figure 1 (b) is a top view. Figure 1 (c) is the front view. Furthermore, to illustrate the interior of the low-profile composite antenna device, a partial sectional view is provided. As shown, the low-profile composite antenna device of the present invention includes a base plate 10, a circuit board 20, an antenna radome 30, a first element 40, and a second element 50. Furthermore, in Figure 1 (a) and Figure 1 In the example shown in (b), the left side of the attached diagram represents the direction of vehicle travel.

[0038] The base plate 10 is fixed to the vehicle. The base plate 10 is disposed in the vehicle with its longitudinal direction facing the direction of travel. Specifically, the base plate 10 can be a so-called resin base made of an insulator such as resin, or a so-called metal base made of a conductor such as metal. Alternatively, the base plate 10 can be a composite base of resin and metal. For example, threaded protrusions 11 are provided on the base plate 10. The threaded protrusions 11 are inserted into holes provided in the vehicle's roof panel, etc., and the base plate 10 is fixed to the roof panel by using nuts to clamp the roof panel from, for example, the vehicle interior. For example, power cables, signal cables, etc., connecting the vehicle interior and the antenna device pass through the threaded protrusions 11. Furthermore, the base plate 10 is constructed to be covered by the antenna radome 30, which will be discussed later.

[0039] The circuit board 20 is disposed on the base plate 10 and has a power supply section 21 for a first component and a power supply section 22 for a second component. Amplifier circuits, filter circuits, etc., are appropriately provided on the circuit board 20 to enable signal transmission and reception. Furthermore, the example shown in the figures illustrates an example where the power supply section 21 for the first component and the power supply section 22 for the second component are on a single circuit board 20; however, the present invention is not limited to this, and two circuit boards may be used, each with its own power supply section.

[0040] The radome 30 is fitted into the base plate 10. In the illustrated example, the radome 30 is used to define the shape of the low-profile composite antenna device. However, the low-profile composite antenna device of the present invention is not limited to this; for example, the radome 30 may also consist of an inner cover and an outer cover. That is, it may be a double cover. In this case, the inner cover is used to house the circuit board 20, the first element 40 (discussed later), and the second element 50, while the outer cover is used to define the shape. Figure 1As shown in (c), the radome 30 has a ridge portion 31 extending longitudinally toward the vehicle's direction of travel and side portions 32 extending from both sides of the ridge portion 31, and has a cross-sectional shape that is mountain-shaped when viewed from the front in the vehicle's direction of travel.

[0041] The first element 40 is housed within the radome 30. The first element 40 is a plate-shaped component connected to the first element power supply unit 21 of the circuit board 20 and functioning as an antenna for the first frequency band. The first element 40 is positioned on one side, left or right, in the vehicle's direction of travel. Specifically, as... Figure 1 As shown in (b), the first element 40 is positioned on the left side in the direction of vehicle travel. Additionally, as... Figure 1 As shown in (c), the first element 40 is arranged at an angle relative to the base plate 10 when viewed from the front in the vehicle's direction of travel. Specifically, the inclined surface extends outward and downward from the upper edge 41. Furthermore, the upper edge 41 of the first element 40 is located near the ridge portion 31.

[0042] The first element 40 is a so-called capacitive load antenna element. Specifically, the first frequency band refers to the AM frequency band. In the AM frequency band, the first element 40 functions as a capacitive antenna. As an example of such a capacitive load antenna element, the first element 40 is arranged with a gap in the height direction relative to the base plate 10, and is connected to the power supply unit 21 of the first element via the power supply line 25. By arranging the first element 40 in such an inclined manner, the antenna capacitance can be increased. Furthermore, the longitudinal direction of the first element 40 faces the vehicle's direction of travel. That is, the plate-like surface of the first element 40 faces the vehicle's direction of travel. The first element 40 can be appropriately fixed to the base plate by an insulating bracket or the like. Alternatively, it can be configured to be fixed to, for example, the inner side of the radome 30 without using a bracket or the like.

[0043] Alternatively, the length of the first element 40 can also correspond to the length of the first frequency band. In this case, the first frequency band can be, for example, a DTV band. In the DTV band, the first element 40 functions as a resonant antenna.

[0044] Furthermore, the second element 50 is also housed in the radome 30. The second element 50 is a plate-shaped component connected to the second element power supply unit 22 of the circuit board 20 and functioning as an antenna for a second frequency band different from the first frequency band. The second element 50 is positioned on the opposite side of the left-right axis in the vehicle's direction of travel. Specifically, as... Figure 1As shown in (b), the second element 50 is positioned on the right side in the vehicle's direction of travel. However, the invention is not limited to this; the first element 40 and the second element 50 may also be arranged with their positions reversed. Furthermore, the upper edge 51 of the second element 50 is positioned near the ridge portion 31 with a gap between it and the first element 40. The second element 50 is positioned opposite the first element 40 from the ridge portion 31 toward the base plate 10. This opposite arrangement means that the longitudinal direction of the first element 40 and the second element 50 are respectively aligned with the vehicle's direction of travel. That is, the plate-like surfaces of the first element 40 and the second element 50 only need to face the vehicle's direction of travel. Therefore, it is not necessary for the surfaces to be parallel to each other. The second element 50 can be appropriately fixed to the base plate by an insulating bracket or the like. Alternatively, it may be configured to be fixed to, for example, the inner side of the radome 30 without using a bracket or the like.

[0045] In addition, such as Figure 1 (a) and Figure 1 As shown in (b), an example is illustrated where the second element 50 is offset from the first element 40 in the forward direction of vehicle travel, but the invention is not limited thereto. The first element 40 and the second element 50 may also be arranged in a forward-aligned manner, or the first element 40 may be offset from the second element 50 in the forward direction.

[0046] The second element 50 can be, for example, a broadband antenna. Specifically, the second frequency band refers to the frequency band used by the TEL. Figure 1 In the example shown in (c), the second element 50 is bent into an S-shape when viewed from the front in the direction of vehicle travel. By bending the second element 50 in this way, it interacts with the first element 40, which is arranged at an angle. This allows the second element 50 to move away from the first element 40 from top to bottom and in a direction separating it from the first element 40, thus increasing the distance between the elements and extending the length of the second element 50. As a result, even in narrow spaces, the mutual interference with the first element 40 can be suppressed, while also enabling operation at lower frequency bands.

[0047] The side shape of the second element 50 is described in more detail below. (Refer to...) Figure 1 ,like Figure 1 As shown in (a), the second element 50 is composed of a bow-shaped antenna with a cone shape extending from the ridge portion 31 toward the power supply portion 22 for the second element. In the example shown, a member with an extended end shape is shown at the front side in the vehicle's direction of travel. By adopting such a shape, a wide bandwidth can be achieved. In addition, by adopting a curved shape without corners, unexpected resonances can be suppressed.

[0048] Moreover, such as Figure 1As shown in (c), the upper portions of the first element 40 and the second element 50 are configured in a Japanese "ハ" shape when viewed from the front in the direction of vehicle travel. Specifically, the portion of the first element 40 that is configured at an incline relative to the base plate 10 and the portion of the second element 50 opposite to it are configured in a Japanese "ハ" shape. In the example shown, the second element 50 is bent into an S-shape, so only at least the upper portion is formed in a Japanese "ハ" shape with the first element 40. However, the present invention is not limited to an S-shape, and the second element 50 may also be formed to extend vertically downward from the upper portion configured in a Japanese "ハ" shape.

[0049] In addition, such as Figure 1 As shown in (c), at least the upper portion of the first element 40 and at least the upper portion of the second element 50 are arranged along the side portion 32 of the radome 30. Thus, by arranging the first element 40 and the second element 50 along the side portion 32 of the radome 30, the mutual interference between the first element 40 and the second element 50 can be suppressed, while effectively utilizing the narrow space. Furthermore, the invention is not limited thereto, and either the first element 40 or the second element 50 may also be configured to be arranged along the side portion 32.

[0050] Among them, if refer to Figure 1 Near the ridge portion 31 of (c), the first element 40 and the second element 50 are bent so that their upper edges 41 and 51 face each other near the ridge portion 31 of the radome 30. That is, the capacitors are coupled at the upper edges 41 and 51. By arranging the upper edges 41 and 51 close together and facing each other near the ridge portion 31, the second element 50 is affected by the first element 40, resulting in an increased element length. That is, the element length for transmitting and receiving the desired TEL bandwidth can be shortened, so that even in a narrower space, an element with sufficient element length can be arranged. Furthermore, the influence of the second element 50 is less from the perspective of the first element 40.

[0051] Additionally, the example shown in the figure has a coil 60 connected between the first element 40 and the power supply unit 21 for the first element. The arrangement is such that the series circuit of the first element 40 and the coil 60 functions as a resonant antenna for the third frequency band. Specifically, the third frequency band refers to the FM band. For example, the inductance of the coil 60 is appropriately selected so that the series circuit of the first element 40 and the coil 60 functions as a resonant antenna in the FM band.

[0052] Furthermore, as shown in the figure, the coil 60 is arranged such that its axis is parallel to the base plate 10 and parallel to the longitudinal direction of the first element 40. With this arrangement, even if the length (number of turns) of the coil 60 changes, for example, depending on the vehicle type, the coil 60 remains laterally positioned. Therefore, changing the length only laterally does not alter the distance from the circuit board 20. Consequently, even if the length of the coil 60 is adjusted, the change in antenna reception characteristics is minimal. Moreover, the invention is not limited to this; the coil 60 may also be arranged in a direction orthogonal to the longitudinal direction of the first element 40 (vertical direction).

[0053] In addition, such as Figure 1 As shown in (b), the second element 50 is positioned opposite the first element 40 at the front side in the vehicle's direction of travel, and the coil 60 is positioned in the empty space at the rear side of the second element 50 in the vehicle's direction of travel. This effectively utilizes the empty space and reduces the influence of the coil 60 on the second element 50. Furthermore, as long as the influence of the coil 60 on the second element 50 can be reduced, the coil 60 can also be positioned relative to the first element 40 at any position, either at the front side or the center front / rear side in the vehicle's direction of travel.

[0054] In the low-profile composite antenna device of the present invention, the first element 40 and the second element 50 can be arranged to the left and right in the vehicle's direction of travel, thereby miniaturizing the antenna while ensuring its transmission and reception characteristics.

[0055] Furthermore, the configuration of the first element 40 and the second element 50 as viewed from the front in the direction of vehicle travel is not limited to the example shown in the figure above. Figure 2 This is a schematic front view illustrating another example of the relative arrangement of the first and second elements of the low-profile composite antenna device of the present invention. In the figure, the labels are... Figure 1 The same reference numerals denote the same objects. Furthermore, in the example drawings, primarily the first element 40 and the second element 50 are shown, and other components are omitted. Additionally, as mentioned above, the first element 40 and the second element 50 can be appropriately fixed to the base plate by an insulating bracket or the like. Furthermore, the first element 40 can be connected to the first element power supply section of the circuit board via a power supply line 25. Figure 1 In the example shown in (c), the first element 40 and the second element 50 are shown with their upper parts arranged in the shape of the Japanese character ハ. Figure 2 In the example shown, the first element 40 is configured at an angle relative to the base plate, while the second element 50 is configured perpendicular to the base plate. Thus, depending on the available space inside the radome 30, an element, such as the second element 50, can also be configured vertically.

[0056] Even with this configuration, because the first element 40 is arranged at an angle, the second element 50 moves away from the first element 40 from top to bottom and in a direction separating it from the first element 40. The mutual interference between the second element 50 and the first element 40 can be appropriately suppressed depending on the available space inside the radome 30. Alternatively, contrary to the example shown, the first element 40 can be arranged perpendicular to the base plate, while the second element 50 can be arranged at an angle relative to the base plate.

[0057] In addition, Figure 1 In (c), an example is shown in which the upper edge 41 of the first element 40 and the upper edge 51 of the second element are bent to face each other near the ridge portion 31 of the radome 30, but the present invention is not limited thereto. Figure 3 This is a schematic front view illustrating another example of the shape near the ridge portion of the first and second elements of the low-profile composite antenna device of the present invention. In the figure, the labels are... Figure 1 The same reference numerals in the accompanying drawings denote the same object. Furthermore, in the example drawings, element 40 (first element) and element 50 (second element) are primarily shown, while other components are omitted. Figure 3 In the example shown, the upper edge 41 of the first element 40 is bent towards the second element 50, while the upper edge 51 of the second element 50 is not bent towards the first element 40. The upper edge 41 of the first element 40 extends towards the second element 50 beyond the center of the left and right sides of the vehicle's direction of travel. Thus, only one of the upper edges 41 of the first element 40 and 51 of the second element 50 may be bent. Furthermore, in the example shown, an example is shown where the upper edge 41 of the first element 40 is bent and extends towards the second element 50, but the invention is not limited to this. For example, it is also possible to configure the second element 50 without bending the upper edge 41 of the first element 40, while bending the upper edge 51 of the second element 50 and extending towards the first element 40.

[0058] In addition, Figure 4 The image shows an example of the shape of the other side of the second element 50. Figure 4 This is a schematic side view illustrating an example of the shape of the other side of the second element of the low-profile composite antenna device of the present invention. Figure 4 (a) is another example. Figure 4 (b) is yet another example. In the figure, the labels and... Figure 1 The same reference numerals in the accompanying drawings denote the same object. Figure 1 In the example shown in (a), the shape is defined as extending forward at the end in the direction of vehicle travel. Figure 4In the example shown in (a), a bow-shaped antenna with extended ends is illustrated in the direction of vehicle travel. Various bow-shaped antennas can be configured according to the available space inside the radome 30 where the second element 50 is configured and the desired frequency band.

[0059] In addition, such as Figure 4 As shown in (b), the second element of the low-profile composite antenna device of the present invention can also be a general square shape. Figure 2 As shown, Figure 4 The example shown in (b) illustrates an example where the second element 50 is perpendicular to the base plate. Various element shapes can be applied depending on the desired frequency band and bandwidth.

[0060] Next, the arrangement of the first element 40 and the second element 50 will be explained in more detail. (Refer to...) Figure 1 , then Figure 1 As shown in (b), the second element 50 is positioned opposite the first element 40 on the front side in the vehicle's direction of travel. In cases where the second element 50 functions as a TEL (Transmission Electron) band element, the band is relatively high; therefore, it is preferable to position it in a stable contact location. In low-profile composite antenna devices for vehicles, the base plate 10 is fixed to the vehicle's roof using threaded protrusions 11. This fixed position on the vehicle becomes the most stable contact location. Therefore, the second element 50 is preferably positioned on the side of the base plate 10 fixed to the vehicle, closer to the front or rear of the vehicle in the direction of travel. Figure 1 In example (b), the threaded protrusion 11 is located on the front side of the first element 40 in the vehicle travel direction, and therefore the second element 50 is configured opposite to the first element 40 on the side of the front side in the vehicle travel direction.

[0061] However, the present invention is not limited thereto, and may also be as follows: Figure 5 The configuration is shown below. Figure 5 This is a schematic top view illustrating another example of the configuration of the first and second elements of the low-profile composite antenna device of the present invention. In the figure, the labels are... Figure 1 The parts of the same reference numerals in the accompanying drawings represent the same object. Figure 5 The example shown is a configuration in which the rear side of the base plate 10 in the vehicle's travel direction is also grounded relative to the vehicle's roof. In this case, the second element 50 can also be configured opposite the first element 40 to the first element 40 on its rear side in the vehicle's travel direction. This is because the rear side of the base plate 10 is grounded, thus, even the rear side becomes a stable grounding position.

[0062] Next, another example of the first element of the low-profile composite antenna device of the present invention will be described. Figure 6This is a schematic diagram illustrating another example of the first element of the low-profile composite antenna device of the present invention. Figure 6 (a) is a top view. Figure 6 (b) is a perspective view taken from the rear of the vehicle in the direction of travel. In the diagram, the labels are... Figure 1 The same reference numerals denote the same object. Furthermore, in the example drawings, primarily the first element 40 and the second element 50 are shown, while other components are omitted. As shown, the first element 40 is positioned on one side of the vehicle's direction of travel, and also partially positioned on the other side. Specifically, the first element 40 is positioned on the left side of the vehicle's direction of travel, and also partially positioned on the right side. That is, as shown with reference to reference numeral 40a, a portion of the first element 40 extends to the right side of the vehicle's direction of travel. Figure 6 As shown in (b), the portion of the first element 40 disposed on the left side in the vehicle's direction of travel and the portion 40a disposed on the right side are formed integrally on the ridge portion 31 side, resulting in a mountain-shaped cross-section when viewed from the front in the vehicle's direction of travel. In the low-profile composite antenna device of the present invention, by configuring the first element 40 such that a portion extends to the right side, the antenna capacitance of the first element 40 can be further increased.

[0063] And, as Figure 6 As shown, the second element 50 is positioned at the location of the first element 40a, which is not present in the right side of the vehicle's direction of travel. Therefore, by making various adjustments to the antenna capacitance and element length according to the priority of the antenna transmit / receive characteristics of each element, the first element 40 and the second element 50 can be efficiently and well configured in a narrow space.

[0064] Additionally, in the example where coil 60 is used to correspond to the third frequency band, such as... Figure 6 As shown in (b), the coil 60 can be positioned below the first element 40, which is formed integrally with the ridge portion 31 and has a mountain-shaped cross-section when viewed from the front in the vehicle's direction of travel. This reduces the influence of the coil 60 on the second element 50. Furthermore, as long as the influence of the coil 60 on the second element 50 can be reduced, the coil 60 can also be positioned relative to the first element 40 at any position, such as the front side or the front / rear center in the vehicle's direction of travel. In the example shown, an example is shown where the coil 60 is positioned in a direction orthogonal to the longitudinal direction of the first element 40 (vertical direction). However, the invention is not limited to this, and the coil can also be configured such that its axis is parallel to the base plate and parallel to the longitudinal direction of the first element.

[0065] Furthermore, the low-profile composite antenna device of the present invention is not limited to the examples shown in the figures above, and various modifications can be made without departing from the spirit of the present invention.

[0066] Explanation of reference numerals in the attached figures

[0067] 10. Base plate; 11. Threaded protrusion; 20. Circuit board; 21. Power supply section for the first component; 22. Power supply section for the second component; 25. Power supply line; 30. Antenna radome; 31. Ridge section; 32. Side section; 40. First component; 41. Top edge; 50. Second component; 51. Top edge; 60. Coil.

Claims

1. A low-profile composite antenna device, which is a low-profile composite antenna device for vehicles, characterized in that, This low-profile composite antenna device features: The base plate is fixed to the vehicle and its longitudinal direction faces the direction of the vehicle's travel. A circuit board disposed on the base plate has a power supply section for a first element and a power supply section for a second element; The radome, which fits into the base plate, has a ridge portion that faces the vehicle's direction of travel in the longitudinal direction and side portions that extend from both sides of the ridge portion. When viewed from the front in the direction of vehicle travel, the cross-sectional shape of the radome is mountain-shaped. A plate-shaped first element, housed within the radome, is positioned on one side (left or right) in the vehicle's direction of travel and is arranged at an angle relative to the base plate when viewed from the front in the vehicle's direction of travel. The upper edge of the first element is positioned near the ridge. This first element is connected to a first element on the circuit board via a power supply unit and functions as an antenna for the first frequency band. A plate-shaped second element, housed within the radome, is positioned on the opposite side of the vehicle's travel direction (left or right). The upper edge of this second element is positioned near the ridge section, spaced apart from the first element. The second element is positioned opposite the first element, extending from the ridge section towards the base plate. This second element is connected to the second element of the circuit board via a power supply unit and functions as an antenna for a second frequency band different from the first. The first element and / or the second element are bent such that the upper edge of the first element and the upper edge of the second element are close to each other near the ridge portion, so as to capacitively couple with each other.

2. The low-profile composite antenna device according to claim 1, characterized in that, The first and second elements are configured such that, when viewed from the front in the direction of vehicle travel, at least the upper part resembles the Japanese character "ハ".

3. The low-profile composite antenna device according to claim 1 or 2, characterized in that, At least the upper portion of the first element and / or the second element is arranged along the side portion of the radome.

4. The low-profile composite antenna device according to claim 1 or 2, characterized in that, The second element is bent into an S-shape when viewed from the front in the direction of vehicle travel.

5. The low-profile composite antenna device according to claim 1 or 2, characterized in that, The first element is configured to be inclined relative to the base plate, and the second element is configured to be perpendicular to the base plate.

6. The low-profile composite antenna device according to claim 1 or 2, characterized in that, The second element is positioned in the front or rear of the vehicle in the direction of travel, near the base plate, and fixed to the side of the vehicle where it is located.

7. The low-profile composite antenna device according to claim 1 or 2, characterized in that, The second element is composed of a bow-shaped antenna with a cone shape extending from the ridge portion toward the power supply portion of the second element.

8. The low-profile composite antenna device according to claim 1 or 2, characterized in that, The low-profile composite antenna device also includes a coil connected between the first element and the power supply unit for the first element. The coil is adjusted to function as a resonant antenna for the third frequency band by utilizing the series circuit of the first element and the coil.

9. The low-profile composite antenna device according to claim 1 or 2, characterized in that, The first element is disposed on one of the left and right sides of the vehicle's direction of travel, and is also disposed on a portion of the other side of the vehicle's direction of travel.

10. The low-profile composite antenna device according to claim 9, characterized in that, The portion of the first element located on one side of the vehicle's direction of travel and the portion located on the other side are formed as a single unit on the edge side, such that the cross-sectional shape is mountain-shaped when viewed from the front in the direction of vehicle travel.

11. The low-profile composite antenna device according to claim 9, characterized in that, The second element is positioned at the location of the first element, which is also located on the other side of the vehicle's direction of travel, either left or right.

12. The low-profile composite antenna device according to claim 10, characterized in that, This low-profile composite antenna device also includes a coil connected between the first element and the power supply unit for the first element. This coil is adjusted to function as a resonant antenna for the third frequency band by utilizing the series circuit between the first element and the coil. The coil is positioned below a first element that is integrally formed on the ridge side and has a mountain-shaped cross-section when viewed from the front in the direction of vehicle travel.

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