Antenna Device

Abstract

To provide an antenna device which allows a ground part to be more easily mounted on an antenna substrate while having desirable antenna characteristics of an antenna part.SOLUTION: An antenna element 30 of an antenna device 1 has an antenna part 31 which is disposed at a position away from a substrate surface 20a of an antenna substrate 20 by a predetermined length H in a first direction perpendicular to the substrate surface. The antenna element 30 further has a ground part 32 which is provided continuously with the antenna part 31 and is grounded to the antenna substrate 20. The ground part 32 has: a ground part body 321 which is provided continuously with the antenna part 31 on one side in the first direction; and a mounting part 322 which is provided continuously with the other side in the first direction of the ground part body 321 and is mounted on the antenna substrate 20. The mounting part 322 has a plurality of mounting pieces 3221 which are disposed at intervals along a second direction intersecting the first direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] As a conventional technique of this kind, the one disclosed in Patent Document 1 has been proposed. Patent Document 1 discloses an antenna device including an antenna element (a planar inverted-F antenna).

[0003] In Patent Document 1, the antenna element has an antenna section (a plate-shaped radiation conductor) arranged opposite an antenna substrate (a plate-shaped ground conductor). The antenna element further has a ground section (a plate-shaped short-circuit section) that connects one end of the antenna section to the antenna substrate, and a plate-shaped power supply section that extends from the antenna section toward the antenna substrate and supplies power to the antenna section. With the ground section mounted on the antenna substrate, power is supplied from the power supply section to the antenna section, causing the antenna section to function as an antenna of a desired frequency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-004678 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the connection of the ground portion to the antenna board is generally performed by soldering (solder mounting) the tip of the ground portion to the antenna board.

[0006] In addition, as in the above-mentioned conventional technology, in an antenna element in which the antenna portion functions as an antenna for a desired frequency, the ground portion may need to have a certain width in order to ensure the desired frequency band. If the ground portion is made to have a certain width in order to ensure the desired frequency band, heat tends to diffuse throughout the entire antenna element.

[0007] Therefore, if the grounding portion has a certain width and is mounted on the antenna board by soldering, the heat of the solder may diffuse over a wide area of ​​the antenna element, which may result in a long time being required to mount the grounding portion on the antenna board.

[0008] As described above, in the conventional technology, it was difficult to shorten the time required to mount the ground part on the antenna board while providing a certain width for the ground part in order to secure the desired frequency band, i.e., it was difficult to easily mount the ground part on the antenna board while maintaining the desired antenna characteristics of the antenna part.

[0009] The present invention has been made in consideration of the problems inherent in the conventional technology, and an object of the present invention is to provide an antenna device that can more easily mount a grounding portion on an antenna substrate while providing desired antenna characteristics for the antenna portion. [Means for solving the problem]

[0010] An antenna device according to one embodiment of the present invention comprises an antenna substrate and an antenna element connected to the antenna substrate, the antenna element comprising: an antenna section arranged parallel to the substrate surface of the antenna substrate at a position spaced a predetermined distance in a first direction perpendicular to the substrate surface of the antenna substrate; a grounding section connected to the antenna section and grounded to the antenna substrate; and a power supply section connected to the antenna section for supplying power to the antenna section, the grounding section comprising: a grounding section main body connected to the antenna section on one side of the first direction; and a mounting section connected to the other side of the grounding section main body in the first direction and mounted on the antenna substrate, the mounting section comprising a plurality of mounting pieces spaced apart along a second direction intersecting the first direction. Effect of the Invention

[0011] According to the present invention, it is possible to provide an antenna device in which the antenna characteristics of the antenna section are set to desired antenna characteristics, while the mounting of the ground section on the antenna board can be more easily performed. [Brief description of the drawings]

[0012] [Figure 1] 1 is an exploded perspective view illustrating an example of an antenna device according to an embodiment. [Diagram 2] 1 is a perspective view illustrating an example of an antenna device according to an embodiment. [Diagram 3] 2 is a perspective view showing an example of an antenna element included in an antenna device according to an embodiment. FIG. [Figure 4] 11 is a perspective view showing another example of an antenna element included in the antenna device according to the embodiment. FIG. [Diagram 5] 13 is a graph showing the frequency characteristics of the voltage standing wave ratio when the slit vertical width is kept constant and the slit horizontal length is changed, and is a graph showing the frequency characteristics of the voltage standing wave ratio in the 800 MHz band. [Figure 6]13 is a graph showing the frequency characteristics of the voltage standing wave ratio when the slit vertical width is changed while the slit horizontal length is kept constant, and is a graph showing the frequency characteristics of the voltage standing wave ratio in the 800 MHz band. [Figure 7] 13 is a graph showing the frequency characteristics of the voltage standing wave ratio when the slit vertical width is kept constant and the slit horizontal length is changed, and is a graph showing the frequency characteristics of the voltage standing wave ratio in the 2 GHz band. [Figure 8] 13 is a graph showing the frequency characteristics of the voltage standing wave ratio when the slit vertical width is changed while the slit horizontal length is kept constant, and is a graph showing the frequency characteristics of the voltage standing wave ratio in the 2 GHz band. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the antenna device according to the present embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0014] In the following, an in-vehicle antenna device installed in a vehicle is exemplified as the antenna device, and the description will be given by defining the longitudinal direction of the antenna device as the X direction, the lateral direction as the Y direction, and the thickness direction as the Z direction. In addition, the description will be given by defining the up-down direction of the antenna device in a state where the antenna device is disposed so that the circuit board (antenna board) is located at the bottom and the antenna unit is located at the top, with the thickness direction (Z direction) coinciding with the up-down direction.

[0015] The vehicle-mounted antenna device (antenna device) 1 of this embodiment can be a device that, for example, notifies a call center outside the vehicle of the vehicle's condition and location information when an abnormality occurs in the vehicle, and also enables an emergency call to be made with the call center.

[0016] 1 and 2, in this embodiment, the in-vehicle antenna device 1 includes a circuit board (antenna board) 20 and an antenna element 30 connected to the circuit board 20. The antenna device 1 also includes a housing 10 in which the circuit board 20 and the pair of antenna elements 30 are housed.

[0017] Furthermore, in this embodiment, a pair of second antenna elements 50, five pole antennas 60, one GPS antenna 70, and one amplifier circuit section 80 are housed inside the housing 10.

[0018] The housing 10 has a generally rectangular parallelepiped shape and includes a resin upper case (first case) 11 and a metal lower case (second case) 12. The upper case 11 includes a generally rectangular plate-shaped top wall 111 and a peripheral wall 112 extending downward from the outer periphery of the top wall 111, while the lower case 12 includes a generally rectangular plate-shaped bottom wall 121 and a peripheral wall 122 extending upward from the outer periphery of the bottom wall 121.

[0019] Then, by fixing the upper case 11 and the lower case 12, a housing 10 having a space formed therein is formed. In this embodiment, the peripheral wall 112 of the upper case 11 has a lower end 1121 formed only on the inner periphery side, and the peripheral wall 122 of the lower case 12 has an upper end 1221 formed only on the outer periphery side. In this way, when the upper case 11 and the lower case 12 are fixed, the lower end 1121 of the peripheral wall 112 of the upper case 11 is fitted into the upper end 1221 of the peripheral wall 122 of the lower case 12.

[0020] Furthermore, in this embodiment, the upper case 11 and the lower case 12 are fixed to each other using screws 91. Specifically, a fixing portion 113 that is fixed to the outer periphery of the top wall 111 of the upper case 11 by the screws 91 is formed. In this embodiment, the fixing portion 113 is formed by an accommodating recess 1131 that accommodates the screw 91 and an insertion hole 1132 that is formed at the lower end of the accommodating recess 1131 so as to penetrate in the Z direction (up-down direction: first direction).

[0021] Meanwhile, a screw recess 1222 is formed in a position facing the insertion hole 1132 on the outer peripheral edge of the bottom wall 121 of the lower case 12. Then, the screw 91 is inserted into the insertion hole 1132 and screwed into the screw recess 1222, so that the upper case 11 and the lower case 12 are fixed together by the screw 91.

[0022] Furthermore, when the upper case 11 and the lower case 12 are fixed together to form the housing 10, the circuit board 20 to which the components such as the antenna element 30 are electrically connected is accommodated inside the housing 10. In this embodiment, the circuit board 20 is accommodated inside the housing 10 with the components such as the antenna element 30 positioned on the upper side. In this embodiment, the pair of antenna elements 30, the pair of second antenna elements 50, the five pole antennas 60, the one GPS antenna 70, and the one amplifier circuit section 80 correspond to the components such as the antenna element 30.

[0023] Furthermore, in this embodiment, an insertion hole 21 is formed in the circuit board 20 at a position facing the insertion hole 1132 and the screw fixing recess 1222. When the upper case 11 and the lower case 12 are fixed with the screws 91, the circuit board 20 is also fixed with the screws 91. This makes it possible to prevent the circuit board 20 from moving relative to the housing 10 inside the housing 10.

[0024] The circuit board 20 has a substantially rectangular plate shape, and components such as the antenna element 30 are electrically connected to a surface (substrate surface) 20a of the circuit board 20. Note that an electrolytic capacitor or the like can also be mounted on the circuit board 20 depending on the application of the in-vehicle antenna device 1.

[0025] The antenna element 30 has an antenna portion 31 and functions as a plate-shaped inverted F antenna. In this embodiment, the antenna portion 31 is arranged parallel to the surface 20a of the circuit board 20 at a position separated by a predetermined length H in the first direction (vertical direction: Z direction). Specifically, a portion extending in the first direction (vertical direction: Z direction) is provided on the periphery of the antenna portion 31, and this portion extending in the first direction (vertical direction: Z direction) is fixed (mounted) to the circuit board 20 by solder. In this way, the antenna portion 31 is arranged parallel to the surface 20a of the circuit board 20 at a position separated by a predetermined length H in the first direction (vertical direction: Z direction).

[0026] Furthermore, in this embodiment, the portion extending in the first direction (vertical direction: Z direction) is electrically connected to the circuit board 20, thereby allowing this portion to function as the ground portion 32 and the power supply portion 33. Specifically, the portion extending in the X direction and the Z direction is electrically connected to the ground pattern of the circuit board 20, thereby allowing this portion to function as the ground portion 32. Moreover, the portion extending in the Y direction and the Z direction is electrically connected to the power supply pattern of the circuit board 20, thereby allowing this portion to function as the power supply portion 33.

[0027] Thus, in this embodiment, the antenna element 30 has the antenna portion 31, the ground portion 32 connected to the antenna portion 31 and electrically connected to the circuit board 20, and the power supply portion 33 connected to the antenna portion 31 and electrically connected to the circuit board 20. In other words, the antenna element 30 includes the antenna portion 31, the ground portion 32 connected to the antenna portion 31 and grounded to the circuit board 20, and the power supply portion 33 connected to the antenna portion 31 and supplying power to the antenna portion 31.

[0028] Furthermore, a substantially L-shaped slit 34 is formed in the antenna unit 31, dividing the antenna unit 31 into a plurality of regions. The plurality of regions are made to function as antenna elements with different frequency bands. In this manner, the in-vehicle antenna device 1 is made capable of communication in a plurality of frequency bands. In this embodiment, the antenna unit 31 includes a first antenna element 311 that resonates in the 800 MHz band and a second antenna element 312 that resonates in the 2 GHz band.

[0029] The antenna element 30 having such a shape can be formed, for example, by punching out a single metal plate by press working or bending it at a substantially right angle.

[0030] Furthermore, in this embodiment, the antenna device 1 includes a pair of antenna elements 30, and the pair of antenna elements 30 are arranged so as to be symmetrical with respect to a line extending in the Y direction.

[0031] The pair of antenna elements 30 thus arranged can be used, for example, as a TEL antenna for realizing communication with a call center (network server) that provides an emergency call service through a mobile phone communication network.

[0032] When a pair of antenna elements 30 are used as a TEL antenna, the predetermined length H indicating the distance between the antenna unit 31 and the circuit board 20 can be determined, for example, by the following method. That is, it can be determined by optimizing the length based on the relationship between the wavelength of the frequency band corresponding to each antenna element and the surrounding parts that affect each antenna element.

[0033] In this embodiment, the holder 40 is disposed between the circuit board 20 and the antenna portion 31, and the holder 40 maintains the distance between the antenna portion 31 and the surface 20a of the circuit board 20 at a predetermined length H. The holder 40 is made of an electrically insulating resin so that the influence on the antenna characteristics of the antenna portion 31 is relatively small. In this case, it is preferable to form the holder 40 using a resin material with a low dielectric constant or a resin material with a low dielectric loss tangent.

[0034] 1 and 2, the holder 40 has a main body 41 that is elongated in a first direction (vertical direction: Z direction) perpendicular to the board surface 20a of the circuit board 20. By using a columnar holder 40 that is elongated in the first direction (vertical direction: Z direction) in this manner, it is possible to minimize the influence of the holder 40 on the antenna characteristics of the antenna device 1. The shape of the holder 40 does not need to be cylindrical, and can be various types of shapes, such as a rectangular column shape.

[0035] A fitting protrusion 42 having a smaller diameter than the main body 41 is formed at the upper end of the main body 41 so as to protrude upward. A fitting hole 31a into which the fitting protrusion 42 is fitted is formed in the antenna part 31. By fitting the fitting protrusion 42 of the holder 40 into this fitting hole 31a, it is possible to prevent the antenna part 31 from moving on the XY plane perpendicular to the up-down direction (from being misaligned in the horizontal direction).

[0036] Furthermore, in this embodiment, when the antenna element 30 is housed in the housing 10, the tip surface of the fitting protrusion 42 penetrates the fitting hole 31a and abuts against the inner surface of the upper case 11. That is, the antenna unit 31 is sandwiched between the holder 40 and the upper case 11. This makes it possible to prevent the antenna unit 31 from moving in the vertical direction (being displaced in the vertical direction) due to vibration or the like.

[0037] In this way, by making it possible to suppress movement on the XY plane and movement in the up and down directions, the configuration of the antenna device 1 is made to be capable of withstanding vibrations when mounted on a vehicle.

[0038] At the lower end of the main body 41, a fitting protrusion (not shown) having a smaller diameter than the main body 41 is formed so as to protrude downward, and an insertion hole (not shown) into which the fitting protrusion is fitted is formed in the circuit board 20. Then, with the fitting protrusion fitted into the insertion hole, the holder 40 is fixed to the circuit board 20 by, for example, fixing with a plastic screw.

[0039] Furthermore, in this embodiment, a circular protrusion 1111 protruding downward is provided at a portion of the top wall 111 of the upper case 11 that abuts against the tip surface of the fitting protrusion 42. The lower surface (the inner surface of the upper case 11) of this circular protrusion 1111 abuts against the tip surface of the fitting protrusion 42. In this manner, a gap is formed between the top wall 111 and a portion of the antenna section 31 where the holder 40 is not disposed, and this gap makes it possible to minimize the effect of the top wall 111 on the antenna characteristics of the antenna device 1.

[0040] Furthermore, in this embodiment, the holders 40 are arranged on the periphery of the antenna unit 31. Specifically, the three holders 40 are arranged spaced apart from each other along the periphery of each antenna unit 31. At this time, the three holders 40 hold the portions of the antenna unit 31 that are relatively easily displaced in the vertical direction. That is, the fitting protrusions 42 of the three holders 40 are fitted into the portions of the antenna unit 31 that are relatively easily displaced in the vertical direction.

[0041] This makes it possible to more reliably suppress the vertical displacement of the antenna portion 31, while minimizing the effect of the holder 40 on the antenna characteristics of the antenna device 1. This makes it possible to more reliably suppress the deterioration of the antenna characteristics of the antenna device 1.

[0042] The pair of second antenna elements 50 may be antennas (plate-shaped inverted-F antennas) for receiving wavelengths in a high frequency band different from the 800 MHz band or the 2 GHz band, for example. The pair of second antenna elements 50 are also electrically connected (mounted by soldering) to the circuit board 20. In this embodiment, the pair of second antenna elements 50 are also arranged on the circuit board 20 so as to be line-symmetrical with respect to a straight line extending in the Y direction.

[0043] Furthermore, the five pole antennas 60 can be antennas for receiving wavelengths in a high frequency band different from those of the antenna element 30 and the second antenna element 50. The five pole antennas 60 are also electrically connected (mounted by soldering) to the circuit board 20.

[0044] The GPS antenna 70 is an antenna for receiving signals with time information from a plurality of positioning satellites, and this GPS antenna 70 is also electrically connected (mounted by soldering) to the circuit board 20. By using such a GPS antenna 70, it is possible to calculate the position, speed, and direction, and to acquire the time with high accuracy, and it becomes possible to measure the current position of the vehicle on the ground.

[0045] Furthermore, the amplifier circuit section 80 has a function of amplifying the signal received by the GPS antenna 70, and this amplifier circuit section 80 is also electrically connected to the circuit board 20 (mounted by soldering).

[0046] Such an in-vehicle antenna device (antenna device) 1 is used by mounting it on a ground plate (not shown) of, for example, 500 mm x 500 mm. Specifically, the in-vehicle antenna device 1 is mounted on the ground plate, and power is fed from the power feeder 33 to the antenna unit 31 with the grounding unit 32 mounted on the circuit board 20, so that the antenna unit 31 functions as an antenna that resonates in two bands, 800 MHz band and 2 GHz band. At this time, the amplifier circuit unit 80 is driven while the second antenna element 50, the pole antenna 60, and the GPS antenna 70 each function as an antenna of a desired frequency.

[0047] This allows the vehicle-mounted antenna device (antenna device) 1 to function as a composite antenna device that combines a plurality of antennas corresponding to different communication means.

[0048] In this embodiment, the portion that is connected to the first antenna element 311 that resonates in the 800 MHz band so as to extend in the X direction and Z direction and is electrically connected to the circuit board 20 is defined as the ground portion 32 of the antenna element 30.

[0049] At this time, in order to make the first antenna element 311 resonate in a desired frequency band (800 MHz band), it is necessary to make the width (length in the X direction) of the grounding part 32 connected to the first antenna element 311 at least a certain size. In this embodiment, the grounding part 32 has a width from the inner end in the X direction of the antenna part 31 to the vicinity of the slit 34, and the shape of the grounding part 32 is a rectangle that is wide in the X direction when viewed along the Y direction.

[0050] In this way, by providing the ground portion 32 that is wide in the X direction, it is possible to set the frequency band that acts on the antenna portion 31 to the desired frequency band (800 MHz band). However, if the ground portion 32 is wide in the X direction, when the antenna element 30 is mounted on the circuit board 20 by soldering, the solder heat may diffuse over a wide area of ​​the antenna element 30, which may increase the time required to mount the ground portion 32 on the circuit board 20.

[0051] On the other hand, if the width (length in the X direction) of the grounding portion 32 is reduced in order to shorten the time required to mount the grounding portion 32 on the circuit board 20, the first antenna element 311 cannot be resonated in the desired frequency band (800 MHz band).

[0052] In this way, simply forming grounding portion 32 wide and mounting the lower end of grounding portion 32 to circuit board 20 by soldering it made it difficult to obtain the desired antenna characteristics of antenna portion 31 while also making it easy to mount grounding portion 32 on circuit board 20.

[0053] Therefore, in this embodiment, the antenna characteristics of the antenna section 31 are set to desired antenna characteristics, while the mounting of the ground section 32 on the circuit board 20 can be made easier.

[0054] Specifically, the grounding portion 32 includes a grounding portion main body 321 connected to the antenna portion 31 on one side in the first direction (upper side in the vertical direction), and a mounting portion 322 connected to the other side in the first direction of the grounding portion main body 321 (lower side in the vertical direction) and mounted on the circuit board 20.

[0055] The mounting portion 322 is shaped like a three-pronged branch. That is, the mounting portion 322 is provided with three (a plurality of) mounting pieces 3221 spaced apart along a second direction (longitudinal direction of the antenna device: X direction) intersecting the first direction. In this embodiment, the three mounting pieces 3221 are connected to the lower end of the grounding portion main body 321 while being spaced apart in the X direction at a predetermined pitch. Furthermore, in this embodiment, the three mounting pieces 3221 are formed at both ends in the X direction and at the center in the X direction, so that the grounding portion 32 has a symmetrical shape when viewed along the Y direction.

[0056] Each of the three mounting pieces 3221 is fixed to the circuit board 20 by soldering, so that the grounding portion 32 is mounted on the circuit board 20. That is, each of the multiple mounting pieces 3221 that are connected to the lower end of the grounding portion main body 321 and spaced apart along the X direction is mounted on the circuit board (antenna board) 20.

[0057] This makes it possible to prevent the heat of the solder from diffusing throughout the antenna element 30 when mounting the ground portion 32 on the circuit board 20 by soldering, thereby shortening the time required to mount the ground portion 32 on the circuit board 20. This makes it easier to mount the ground portion 32 on the circuit board (antenna board) 20.

[0058] At this time, the three mounting pieces 3221 connected to the lower end of the grounding portion main body 321 are mounted on the circuit board 20, so it is possible to minimize the effect on the antenna characteristics of the antenna portion 31 (particularly, the first antenna element 311) caused by the change in the shape of the grounding portion 32. In other words, it is possible to minimize the deterioration of the antenna characteristics of the antenna portion 31 (particularly, the first antenna element 311).

[0059] Therefore, with the antenna device 1 according to this embodiment, it becomes possible to more easily mount the ground portion 32 on the circuit board 20 while providing the antenna portion 31 with desired antenna characteristics.

[0060] Furthermore, by forming the three mounting pieces 3221 at both ends and the center in the X direction, and making the shape of the grounding portion 32 symmetrical when viewed along the Y direction, it becomes possible to mount the lower end of the grounding portion 32 to the circuit board 20 more firmly and in a balanced manner.

[0061] The shape of each of the pair of antenna elements 30 does not have to be the shape shown in Fig. 3, and may be various shapes. For example, the shape of each of the pair of antenna elements 30 may be the shape shown in Fig. 4.

[0062] 4, the grounding portion 32 also includes a grounding portion main body 321 connected to the antenna portion 31 on the upper side in the vertical direction, and a mounting portion 322 connected to the lower side in the vertical direction of the grounding portion main body 321 and mounted on the circuit board 20. The mounting portion 322 has a three-pronged shape.

[0063] Here, in the antenna element 30 shown in FIG. 4, a narrow portion 3211 is formed in a part of the ground portion main body 321 in the first direction (up-down direction: Z direction), where the length in the second direction (longitudinal direction of the antenna device: X direction) is shortened.

[0064] This prevents the heat of the solder from being transferred to the antenna portion 31 when mounting the ground portion 32 on the circuit board 20 by soldering, thereby enabling the time required to mount the ground portion 32 on the circuit board 20 to be further shortened.

[0065] In this embodiment, a narrow portion 3211 is formed by forming a slit 3212 extending in a second direction (longitudinal direction of the antenna device: X direction) in a part of the first direction (vertical direction: Z direction) in the ground portion main body 321.

[0066] Specifically, slits 3212 that open outward in the X direction and have a substantially rectangular shape when viewed along the Y direction are formed on both sides in the X direction at the substantially central portion in the up-down direction of the grounding portion main body 321, thereby forming a narrow portion 3211 at the central portion in the X direction. In this way, the shape of the grounding portion 32 in the antenna element 30 shown in Fig. 4 is also made to be symmetrical when viewed along the Y direction.

[0067] In this way, by forming a slit 3212 in the grounding portion main body 321 so as to form a narrow portion 3211 in a portion of the grounding portion main body 321 in the vertical direction, it becomes possible to suppress the diffusion of the solder heat throughout the entire antenna element 30.

[0068] However, forming the slits 3212 in the grounding portion main body 321 affects the antenna characteristics of the antenna portion 31. This can be confirmed from the measurement results of the VSWR characteristics shown in Figs.

[0069] 5 to 8 are graphs showing frequency characteristics of the voltage standing wave ratio (VSWR) of the in-vehicle antenna device 1. FIG.

[0070] Specifically, Figure 5 shows the measurement results of the VSWR characteristics in the 800 MHz band when no slits are provided, when the vertical width of each slit 3212 on the left and right sides is fixed at 2 mm, and when the horizontal lengths are 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm.

[0071] FIG. 6 also shows the measurement results of the VSWR characteristics in the 800 MHz band when no slits are provided, when the horizontal length of each slit 3212 on the left and right sides is fixed at 4 mm, and when the vertical width is set to 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm.

[0072] FIG. 7 also shows the measurement results of the VSWR characteristics in the 2 GHz band when no slits are provided, when the vertical width of each slit 3212 on the left and right sides is fixed at 2 mm, and when the horizontal lengths are 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm.

[0073] FIG. 8 also shows the measurement results of the VSWR characteristics in the 2 GHz band when no slits are provided, when the horizontal length of each slit 3212 on the left and right sides is fixed at 4 mm, and when the vertical width is set to 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm.

[0074] 5 and 6, it can be seen that the antenna performance of the first antenna element 311 that resonates in the 800 MHz band varies depending on the size of the slit 3212 formed in the grounding portion main body 321. On the other hand, the graphs shown in Fig. 7 and 8 show that the antenna performance of the second antenna element 312 that resonates in the 2 GHz band remains almost unchanged even if the size of the slit 3212 formed in the grounding portion main body 321 is changed. From this, it can be seen that in this embodiment, the grounding portion 32 mainly acts in the 800 MHz band and hardly acts in the 2 GHz band.

[0075] 5 and 6, it can be confirmed that the resonance of first antenna element 311 becomes lower frequency when the vertical width or horizontal length of slit 3212 is increased. It is considered that such a phenomenon (the resonance of first antenna element 311 becomes lower frequency) occurs because the length of the outflow path through slit 3212 appears longer when slit 3212 of grounding portion 32 is increased in size.

[0076] Therefore, when forming a slit 3212 in the grounding portion main body 321 as in the antenna element 30 shown in Figure 4, it is preferable to adjust the size of the slit 3212 within a range that allows the first antenna element 311 to resonate in the desired frequency band.

[0077] For example, when the resonant frequency of first antenna element 311 without a slit is within a desired frequency band, it is preferable to adjust the size of slit 3212 within a range that does not affect the frequency characteristics. In other words, it is preferable to adjust the size of slit 3212 so that the resonant frequency of first antenna element 311 falls within a desired frequency band.

[0078] In addition, if the resonant frequency of the first antenna element 311 without the slit is higher than the desired frequency band, it is possible to adjust the resonant frequency of the first antenna element 311 to a lower frequency by providing the slit 3212.

[0079] This makes it possible to suppress the diffusion of heat caused by soldering performed when connecting the antenna element 30 to the circuit board 20 without degrading the antenna characteristics of the antenna section 31 (particularly the first antenna element 311).

[0080] 4, the narrow portion 3211 is formed by forming the slit 3212 extending in the X direction in a part of the vertical direction of the ground portion main body 321. In this way, it becomes possible to adjust the antenna characteristics of the antenna portion 31 and adjust the time required for solder mounting simply by adjusting the size (vertical width or horizontal length) of the slit 3212. In other words, it becomes easier to adjust the antenna characteristics of the antenna portion 31 and the time required for solder mounting of the ground portion 32 to the circuit board 20. As a result, it becomes easier to manufacture the antenna device 1 that can shorten the time required for mounting the ground portion 32 to the circuit board (antenna board) 20 while maintaining the desired antenna characteristics of the antenna portion.

[0081] [Actions and Effects] The characteristic configurations of the antenna devices shown in the above embodiment and its modified examples and the effects obtained thereby will be described below.

[0082] The antenna device 1 shown in the above embodiment and its modified example includes a circuit board (antenna board) 20 and an antenna element 30 connected to the circuit board 20.

[0083] Here, the antenna element 30 includes an antenna section 31 arranged parallel to the board surface 20a of the circuit board 20 at a position separated by a predetermined length H in a first direction (vertical direction: Z direction) that is a direction perpendicular to the board surface 20a of the circuit board 20. The antenna element 30 further includes a grounding section 32 connected to the antenna section 31 and grounded to the circuit board 20, and a power supply section 33 connected to the antenna section 31 and supplying power to the antenna section 31.

[0084] In addition, the grounding portion 32 includes a grounding portion main body 321 connected to the antenna portion 31 on one side in the first direction (upper side in the vertical direction), and a mounting portion 322 connected to the other side in the first direction of the grounding portion main body 321 (lower side in the vertical direction) and mounted on the circuit board 20.

[0085] The mounting portion 322 includes a plurality of mounting pieces 3221 that are spaced apart along a second direction (the longitudinal direction of the antenna device: the X direction) that intersects with the first direction.

[0086] In this manner, in the antenna device 1 shown in the above embodiment and its modified example, a plurality of mounting pieces 3221 are connected to the other side of the grounding portion main body 321 in the first direction and spaced apart along the second direction, and are mounted on the circuit board (antenna board) 20.

[0087] This prevents the heat of the solder from diffusing throughout the antenna element 30 when mounting the ground portion 32 on the circuit board 20 by soldering, thereby shortening the time required to mount the ground portion 32 on the circuit board 20. As a result, mounting the ground portion 32 on the circuit board (antenna board) 20 can be performed more easily.

[0088] At this time, since the multiple mounting pieces 3221 connected to the other side in the first direction of the grounding portion main body 321 are mounted on the circuit board 20, it is possible to minimize the effect on the antenna characteristics of the antenna portion 31 caused by the change in the shape of the grounding portion 32. In other words, it is possible to minimize the deterioration of the antenna characteristics of the antenna portion 31.

[0089] In this way, the antenna device 1 shown in the above embodiment and its modified example makes it possible to more easily mount the grounding portion 32 on the circuit board 20 while maintaining the desired antenna characteristics of the antenna portion 31.

[0090] Furthermore, a narrow portion 3211 may be formed in a part of the ground portion main body 321 in the first direction (vertical direction: Z direction) so that the length in the second direction (longitudinal direction of the antenna device: X direction) is shortened.

[0091] This more reliably prevents the heat of the solder from diffusing throughout the antenna element 30 when mounting the grounding portion 32 on the circuit board 20 by soldering, thereby making it possible to further shorten the time required to mount the grounding portion 32 on the circuit board 20.

[0092] In addition, the narrow portion 3211 may be formed by forming a slit 3212 extending in the second direction (longitudinal direction of the antenna device: X direction) in a part of the first direction (vertical direction: Z direction) in the ground portion main body 321.

[0093] In this way, it becomes possible to adjust the antenna characteristics of the antenna section 31 and the time required for solder mounting simply by adjusting the size (length and width) of the slit 3212. In other words, it becomes easier to adjust the antenna characteristics of the antenna section 31 and the time required for solder mounting of the ground section 32 to the circuit board 20. As a result, it becomes easier to manufacture the antenna device 1 that can shorten the time required for mounting the ground section 32 to the circuit board (antenna board) 20 while maintaining the desired antenna characteristics of the antenna section.

[0094] [others] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment.

[0095] For example, it is possible to appropriately combine the configurations described in the above embodiment and its modified examples.

[0096] In the above embodiment and its modified example, a composite antenna device in which multiple antennas corresponding to different communication means are combined is exemplified as the antenna device 1. However, the antenna device 1 does not need to be a composite antenna device, and the present invention can be applied to various antenna devices. For example, the present invention can be applied to an antenna device in which only a pair of antenna elements 30 are connected to the circuit board 20.

[0097] In addition, in the modified example of the above embodiment, an example was given of a slit 3212 in the ground contact portion main body 321 that has an approximately rectangular shape when viewed along the Y direction, but this is not limited to this, and it is possible to provide slits of various shapes, such as triangular or semicircular, in the ground contact portion main body 321.

[0098] In addition, in the modified example of the above embodiment, the slits 3212 are formed on both sides of the ground contact portion main body 321 in the X direction, but it is also possible to provide a slit on only one side of the ground contact portion main body 321 in the X direction.

[0099] In the modified example of the above embodiment, the slit 3212 opening in the X direction is formed in the grounding portion main body 321, but it is also possible to form a slit opening in the Z direction in the grounding portion main body 321. For example, it is also possible to provide a slit that opens on the other side in the Z direction (the lower side in the vertical direction) and is elongated in the Z direction up to the middle of the grounding portion main body 321 (such as the center in the vertical direction). This also makes it possible to form a narrow portion 3211 whose length in the second direction (longitudinal direction of the antenna device: X direction) is shortened in a part of the first direction (vertical direction: Z direction) in the grounding portion main body 321.

[0100] It is also possible to form slits in the grounding portion main body 321 that appropriately combine the shapes described above, and it is also possible to form multiple slits of different shapes in the grounding portion main body 321 (form multiple types of slits in the grounding portion main body 321).

[0101] The present invention can also be applied to antenna devices other than vehicle-mounted antenna devices installed in vehicles. For example, the present invention can be applied to antenna devices mounted on moving objects such as aircraft and ships, and can also be applied to antenna devices mounted on equipment that is not a means of movement.

[0102] In addition, the power supply section, antenna element, and other detailed specifications (shape, size, layout, etc.) can also be changed as appropriate. [Explanation of symbols]

[0103] 1 Vehicle-mounted antenna device (antenna device) 20 Circuit board (antenna board) 20a Surface (substrate surface) 30 Antenna Element 31 Antenna section 32 Grounding part 321 Grounding part body 3211 Narrow area 3212 Slit 322 Mounting section 3221 Mounting piece 33 Power supply unit H given length

Claims

[Claim 1] An antenna board; an antenna element connected to the antenna substrate; Equipped with The antenna element comprises: an antenna portion disposed in parallel to a substrate surface of the antenna substrate at a position spaced a predetermined distance from the substrate surface in a first direction perpendicular to the substrate surface of the antenna substrate; a grounding portion connected to the antenna portion and grounded to the antenna substrate; a power supply unit connected to the antenna unit and supplying power to the antenna unit; It is equipped with the ground portion includes a ground portion main body connected to the antenna portion at one side in the first direction, and a mounting portion connected to the other side in the first direction of the ground portion main body and mounted on the antenna substrate, the mounting portion includes a plurality of mounting pieces spaced apart along a second direction intersecting the first direction, A narrow portion having a length in the second direction is formed by forming a slit extending in the second direction in a part of the grounding portion body in the first direction. Antenna device.

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