Antenna equipment

Abstract

We provide an antenna device capable of handling radio waves across a wide frequency band. [Solution] The antenna device 1 comprises a ground section 3, an antenna 2, and a parasitic element 30. The antenna 2 comprises an element 11 (main body) facing the ground section 3 and having an open end, and a feed section 12 extending from the element 11 in the direction of the ground section 3 and having a feed point 12A. The parasitic element 30 has a first end positioned at a distance from the open end of the element 11 and is used to adjust the impedance of the antenna 10.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an integrated antenna.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the integrated antenna disclosed in Patent Document 1, the first telephone antenna and the second telephone antenna each have a limited corresponding frequency band and are not capable of corresponding to wideband radio waves.

[0005] In view of the above problems, an example of the object of the present invention is to realize an antenna device capable of corresponding to radio waves in a wide frequency band.

Means for Solving the Problems

[0006] One aspect of the present invention is an antenna device including a ground portion, a main body portion facing the ground portion and having an open end portion, a feeding portion extending from the main body portion in the direction of the ground portion and having a feeding point, and a non-powered element for impedance adjustment of the antenna having a first end portion positioned at an interval from the open end portion.

[0007] According to one aspect of the present invention, an antenna device capable of corresponding to radio waves in a wide frequency band can be realized.

Brief Description of the Drawings

[0008] [Figure 1] This is a perspective view of the antenna device 1 of the first embodiment, viewed from (a) the left rear, (b) the right front, and (c) the right rear. [Figure 2] This is a schematic diagram of antenna 2, showing (a) the case where the length of antenna 20 is half the length of the radio wave in the corresponding frequency band and (b) the case where the length of antenna 20 is one-quarter the length of the radio wave in the corresponding frequency band. [Figure 3] This is a Smith chart showing the impedance characteristics of the antenna 10 in the case of (a) without the parasitic element 30 and (b) with the parasitic element 30. [Figure 4] This is a Smith chart showing the impedance characteristics of the antenna 10 when the powerless element 30 is absent. [Figure 5] This is a Smith chart showing the impedance characteristics of the antenna 10 when the unpowered element 30 is present. [Figure 6] This is a Smith chart showing the impedance characteristics of antenna 10 when a powerless element 30 is present and a capacitor is connected in series with antenna 10. [Figure 7] This graph shows the relationship between frequency and VSWR in antenna device 1. [Figure 8] (a) A diagram showing an example of the antenna device 1, and (b) a Smith chart showing the impedance characteristics of the antenna 10 when the distance between the parasitic element 30 and the antenna 10 is changed. [Figure 9] (a) A diagram showing an example of antenna device 1, and (b) a Smith chart showing the impedance characteristics of antenna 10 when the front-to-back length of the parasitic element 30 is changed. [Figure 10] (a) A diagram showing an example of antenna device 1, and (b) a Smith chart showing the impedance characteristics of antenna 10 when the front-to-back length of the parasitic element 30 is changed. [Figure 11] (a) A diagram showing an example of antenna device 1, and (b) A Smith chart showing the impedance characteristics of antenna 10 when the width of the parasitic element 30 is changed. [Figure 12] (a) A diagram showing an example of antenna device 1, and (b) A Smith chart showing the impedance characteristics of antenna 10 when the width of the parasitic element 30 is changed. [Figure 13] (a) A diagram showing an example of antenna device 1, and (b) A Smith chart showing the impedance characteristics of antenna 10. [Figure 14] (a) A diagram showing an example of antenna device 1, and (b) A Smith chart showing the impedance characteristics of antenna 10. [Figure 15] (a) A diagram showing an example of antenna device 1, and (b) A Smith chart showing the impedance characteristics of antenna 10. [Figure 16] This is an exploded perspective view of the antenna device 100 in the second embodiment. [Figure 17] This is a perspective view of the antenna device 100 in the second embodiment, showing (a) a view from the front left and (b) a view from the front right. [Modes for carrying out the invention]

[0009] The following matters become clear from this specification and the accompanying drawings:

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same or equivalent components, members, etc. shown in each drawing are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. ==First Embodiment== <<Overview of Antenna Device 1>> The outline of the antenna device 1 in this embodiment will be described with reference to Figures 1 and 2.

[0011] The antenna device 1 is a vehicle antenna device used in a vehicle (a vehicle with wheels) not shown in the figure. In the present embodiment, the antenna device 1 is mounted, for example, on the upper surface of the vehicle (including the roof and the back door), below the upper surface, or inside the instrument panel. However, the antenna device 1 may be located at a part of the vehicle other than inside the roof and the instrument panel, such as a spoiler or an overhead console of the vehicle. Further, the antenna device 1 may be an antenna device other than for vehicles.

[0012] The antenna device 1 includes an antenna 2, a ground portion 3, a parasitic element 30, a circuit board 50, and a holding member 60. The antenna 2 functions as two antennas each capable of corresponding to a different frequency band. These two antennas are hereinafter referred to as an antenna 10 and an antenna 20. In addition, the antenna 2 includes a feeding portion 12 (described later) that functions as a third antenna.

[0013] In the following description, as shown in FIG. 1, the direction from the ground portion 3 toward the antenna 2 is defined as the upward direction, and the opposite direction is defined as the downward direction. The direction in which the upper portion (a first extending portion 31 described later) of the parasitic element 30 extends toward a second extending portion 11B of an element 11 described later is defined as the forward direction, and the opposite direction is defined as the backward direction. Further, the direction orthogonal to the vertical direction and the front-rear direction is defined as the left-right direction.

[0014] As shown in FIG. 1, the front-rear direction may be referred to as the "X direction", the left-right direction may be referred to as the "Y direction", and the vertical direction may be referred to as the "Z direction". The backward direction may be referred to as the +X direction, the left direction may be referred to as the +Y direction, and the upward direction may be referred to as the +Z direction. Further, the left-right direction may be referred to as the "lateral direction" or the "width direction", and the vertical direction may be referred to as the "vertical direction" or the "height direction".

[0015] Regarding the definitions of the directions and the like described above, unless otherwise specified, they are common to other embodiments of this specification. <Ground portion 3> Ground section 3 functions as the ground for the antenna 2 and the parasitic element 30 of the antenna device 1. However, ground section 3 may also function as the ground for some of the antennas of antenna 2. For example, ground section 3 may function as the ground for antenna 10, and another ground section may function as the ground for antenna 20.

[0016] Furthermore, in this embodiment, the ground section 3 is formed as a single metal plate (sheet metal) as shown in Figure 1. However, the ground section 3 may be composed of multiple separate metal plates. For example, the ground section 3 may be configured such that the metal plate on which the antenna 10 is provided and another metal plate on which the antenna 20 is provided are electrically connected.

[0017] Furthermore, the ground section 3 may be formed in a form other than a plate, as long as it functions as the ground for the antenna of the antenna device 1. Also, the ground section 3 may be constructed by freely combining metal and non-metallic materials, as long as it functions as the ground for the antenna of the antenna device 1. For example, the ground section 3 may consist of a metal plate and a resin insulator. Alternatively, the ground section 3 may be composed of a single printed circuit board (PCB) on which a conductor pattern is formed.

[0018] Furthermore, as shown in Figure 1, the ground section 3 is formed of a roughly quadrilateral member when viewed in the vertical direction. In the following description, "roughly quadrilateral" or "rectangle" refers to a shape consisting of four sides, including, for example, a square or a rectangle, and for example, at least some of the corners may be cut diagonally to the sides, or at least some of the corners may include curves. In addition, in the shape of a "roughly quadrilateral" or "rectangle," some of the sides may be provided with notches (recesses) or protrusions (convex parts). <Antenna 10> Antenna 10 is a broadband antenna for mobile communications based on an inverted L antenna (see Figures 1 and 2). In this embodiment, antenna 10 supports radio waves in the 699MHz to 894MHz band (corresponding to the "first frequency band") for GSM, UMTS, and LTE. However, antenna 10 is not limited to this and may also support radio waves in some frequency bands (for example, only for 5G) among GSM, UMTS, LTE, and 5G.

[0019] Furthermore, antenna 10 may support radio waves in frequency bands other than those used for GSM, UMTS, and LTE. Antenna 10 may, for example, be an antenna that supports radio waves in frequency bands used for telematics, V2X (Vehicle to Everything: vehicle-to-vehicle communication, vehicle-to-infrastructure communication), Wi-Fi, Bluetooth, etc. Note that Wi-Fi and Bluetooth are registered trademarks.

[0020] The antenna 10 has an element 11 and a feed point 12. The element 11 is an element that resonates with the corresponding radio wave frequency band of the antenna 10 together with the feed point 12. As shown in Figure 1, the element 11 is connected to the upper end of the feed point 12.

[0021] Furthermore, "to be connected" is not limited to physical connection, but also includes "electrical connection." Electrical connection is not limited to connection with conductors, but also includes connection with electronic circuits, electronic components, etc.

[0022] Element 11 is a horizontally extending plate-shaped member that faces the ground portion 3 via a holding member 60 and has an L-shaped bend at its front when viewed from above. Element 11 has a first extension portion 11A and a second extension portion 11B.

[0023] The first extension portion 11A is a part that extends forward from the power supply portion 12. Furthermore, the first extension portion 11A is formed to face the ground portion 3 in the vertical direction.

[0024] The second extension portion 11B is a portion that extends to the right from the front of the first extension portion 11A. In this embodiment, the first extension portion 11A and the second extension portion 11B form a shape in which the element 11 is bent to the right when viewed from above. The end portion 11C of the second extension portion 11B forms an open end and, as shown in Figure 1, is spaced apart from the front end of the unpowered element 30 and faces it in the front-rear direction. Note that the term "end portion" does not mean a precise end as shown by the dotted line in Figure 1(a), but rather a certain area including the end portion.

[0025] The power supply unit 12 is a flat plate-shaped member formed to extend upward from the circuit board 50. A power supply point 12A, electrically connected to the circuit board 50, is provided at the lower end of the power supply unit 12.

[0026] The power supply section 12 forms a roughly semicircular shape, with an arc extending downward when viewed from left to right. Therefore, the upper end of the power supply section 12 is longer in the front-to-back direction (hereinafter sometimes referred to as width) than the lower end. Note that the shape of the power supply section 12 is not limited to a semicircular shape; it may be a polygon or other shape, and the length of the upper end of the power supply section 12 in the front-to-back direction may be longer than that of the lower end.

[0027] By increasing the length of the upper end of the power supply section 12 in the front-to-back direction (the width of the power supply section 12 when viewed in the left-to-right direction), the power supply section 12 functions as an antenna that corresponds to the 3.3 to 5 GHz frequency band (corresponding to the "second frequency band").

[0028] The length of the antenna 10, along its shape, from the feed point 12A to the end 11C, is approximately one-quarter of the wavelength of a radio wave in the 699MHz to 894MHz band (for example, the center frequency, 699MHz in the example in Figure 3) (indicated by the arrow with the number 1 in a circle in Figure 2). By making the length of the antenna 10 approximately one-quarter of the wavelength of the radio wave in the corresponding frequency band, the sensitivity of the antenna 10 in the corresponding frequency band can be improved.

[0029] <Antenna 20> Antenna 20 is a broadband antenna for mobile communications based on a folded monopole antenna (see Figures 1 and 2). In this embodiment, antenna 20, together with the feed unit 12, is compatible with radio waves in the 2GHz band (for example, 1710-2170MHz, corresponding to the "third frequency band"). However, antenna 20 is not limited to this and may be compatible with radio waves in some frequency bands within the 2GHz band.

[0030] Furthermore, antenna 20 may support radio waves in frequency bands for GSM, UMTS, LTE, and 5G. Antenna 20 may also be an antenna that supports radio waves in frequency bands used for telematics, V2X (Vehicle to Everything: vehicle-to-vehicle communication, vehicle-to-infrastructure communication), Wi-Fi, Bluetooth, etc. In addition, as described later, antenna 20 may support MIMO (Multiple-Input Multiple-Output) communication.

[0031] Antenna 20 has an element 21 and shares a feed point 12 with antenna 10.

[0032] Element 21 is a flat conductive member and is formed to extend rearward from the upper end of the power supply section 12. Element 21 has a first extended portion 21A and a second extended portion 21B.

[0033] The first extension 21A is a portion that extends horizontally and rearward from the upper end of the power supply section 12. The second extension 21B is a portion that extends downward from the rear end of the first extension 21A. The lower end of the second extension 21B is connected to the ground section 3 using a connector such as a screw, and is electrically connected to the ground section 3. Soldering or welding may be used to connect the second extension 21B to the ground section 3.

[0034] The length of the antenna 20 along its shape, from the feed point 12A to the connection point with the ground section 3, i.e., from the feed point 12A to the short-circuit terminal, is approximately half the wavelength of a 2GHz band radio wave (for example, the center frequency) (indicated by the arrow with the circled number 3 in Figure 2(a)). By making the length of the antenna 20 half the length of the radio wave in the corresponding frequency band, the sensitivity of the antenna 20 in the corresponding frequency band can be improved.

[0035] Furthermore, as shown in Figure 2(b), it is also possible to leave the end of the antenna 20 as an open end. In this case, by making the length of the antenna 20 approximately one-quarter of the wavelength of the radio wave in the corresponding frequency band (for example, the center frequency) (indicated by the arrow with the circled number 3 in Figure 2(b)), the sensitivity of the antenna 20 in the corresponding frequency band can be improved. Note that the wavelength of the corresponding frequency band indicated by the arrow with the circled number 1 in Figure 2(b) is the same as in Figure 2(a).

[0036] <Powerless element 30> The passive element 30 is a flat, conductive member that is mechanically and electrically connected to the ground portion 3 and has the function of adjusting the impedance of the antenna 10. The passive element 30 comprises a first extension portion 31 that extends in the front-rear direction and a second extension portion 32 that extends downward from the rear end of the first extension portion 31 (see Figures 1 and 2).

[0037] The first extension portion 31 is a portion formed in a substantially rectangular shape when viewed from above. The first extension portion 31 extends in the front-rear direction and faces the ground portion 3 in the vertical direction via the holding member 60. The distance (vertical height) of the first extension portion 31 from the ground portion 3 is shorter than the wavelength of the corresponding frequency band of the antenna 10 (699MHz to 894MHz), and is approximately equal to the distance of the first extension portion 11A, the second extension portion 11B, and the first extension portion 21A from the ground portion 3. As shown in Figure 1, the front end of the first extension portion 31 faces the end portion 11C in the front-rear direction.

[0038] Note that the distance of the first extension 31 from the ground portion 3 (D1 in Figure 2(a)) does not necessarily have to be equal to the distance of the first extension 11A and the second extension 11B from the ground portion 3 (D2 in Figure 2(a)). Therefore, the front end of the first extension 31 may be located below or above the end of the second extension 11B.

[0039] The second extension portion 32 is a rectangular section when viewed from the left and right, extending vertically to connect the rear end of the first extension portion 31 to the ground portion 3. The lower end of the second extension portion 32 is connected to the ground portion 3 using a connector such as a screw, and is also electrically connected to the ground portion 3. The length of the first extension portion 31 and the second extension portion 32 along their shapes, from the front end of the first extension portion 31 to the short-circuit end, is indicated by the arrow circle number 2 in Figures 2(a) and (b). Note that soldering or welding may be used to connect the second extension portion 32 to the ground portion 3.

[0040] Furthermore, the direction in which the first extension portion 11A, the second extension portion 11B, and the first extension portion 21A extend, as well as the direction in which the first extension portion 31 extends, are not limited to a direction parallel to the surface of the ground portion 3, but may also be a direction inclined at a predetermined angle from a direction parallel to the surface of the ground portion 3. The first extension portion 11A and the second extension portion 11B (element 11) and the first extension portion 21A correspond to the "main body portion" in this disclosure.

[0041] <Circuit board 50> The circuit board 50 is a rectangular component mounted on the upper surface of the ground section 3 and is electrically connected to the feed point 12A. The circuit board 50 is equipped with a capacitor (not shown) and is connected in series with antennas 10 and 20 via the feed point 12A. The capacitance of the capacitor is set appropriately according to the characteristics of antenna 10.

[0042] <Holding member 60> The holding member 60 is a member formed of an insulator such as resin, and has the function of supporting the antennas 10, 20 and the passive element 30. Specifically, the holding member 60 places the antennas 10, 20 and the passive element 30 on its upper surface and maintains the shape of the antennas 10, 20 and the passive element 30. The holding member 60 also supports the first extension portion 11A, the second extension portion 11B and the first extension portion 21A so that the distance from the ground portion 3 is constant.

[0043] Furthermore, the holding member 60 has two L-shaped locking portions 61 at the upper end on the plane facing the first extension portion 11A of the element 11 of the antenna 10 and the first extension portion 31 of the parasitic element 30, respectively. These locking portions 61 are inserted into the hole 11D of the first extension portion 11A of the element 11 of the antenna 10 and the hole 31A formed in the first extension portion 31 of the parasitic element 30, and the element 11 is held in place by sliding in the front-rear direction. In this way, the positioning of the element 11 of the antenna 10 and the parasitic element 30 with respect to the holding member 60 is made easy, and furthermore, the distance between the element 11(21) of the antenna 10(20) and the parasitic element 30 is kept constant, thereby maintaining stable antenna performance.

[0044] Alternatively, ribs may be provided near the edge of the holding member 60 to position the elements 11(21) and the passive element 30 of the antenna 10(20) relative to the holding member 60.

[0045] Of course, it is also possible to fix and hold the elements 11 (elements 21) of the antenna 10 (20) to the holding member 60 by integral molding, welding, or screw fastening, without providing such locking parts 61 or holes (notches). In that case, however, equipment for integral molding or welding and jigs for screw fastening would be required. On the other hand, when holding with locking parts 61 and holes (notches), such equipment and jigs are not required, which has the advantage of making assembly easier.

[0046] <Arrangement of the powerless element 30> As described below, the impedance characteristics of the antenna 10 are adjusted by the size or position of the parasitic element 30.

[0047] Figures 3(a) and 4 show the impedance characteristics of antenna 10 when the passive element 30 is absent. Figure 3(a) shows the impedance of antenna 10 normalized to 50 ohms as a dotted line graph on a Smith chart, with the start and end points of the graph being 600 MHz and 1000 MHz. Markers 1 and 2 on the graph correspond to the minimum value (699 MHz) and maximum value (894 MHz) of the frequency band that antenna 10 operates in. Figure 4 shows only the distribution in the frequency band that antenna 10 operates in as a solid line from Figure 3(a).

[0048] As shown in the figure, the impedance of antenna 10 is distributed along the equiresistance circle (shown as a solid line) on the Smith chart. In this embodiment, by installing a parasitic element 30, the impedance of antenna 10 is adjusted to be distributed above the real axis of the Smith chart. As will be described in detail later, in order to perform impedance matching and adjust to a constant impedance (e.g., 50 ohms) from 699 MHz to 894 MHz, it is preferable that the impedance falls on the upper half of the Smith chart.

[0049] Figures 3(b) and 5 show the impedance characteristics of the antenna 10 when the unpowered element 30 is installed. Figure 3(b) shows the impedance characteristics (dotted line) and the distribution of VSWR (Voltage Standing Wave Ratio) 3.5 (solid line). The range and normalization method of the impedance characteristics are the same as in Figure 3(a). Figure 5 shows only the distribution in the frequency band corresponding to the antenna 10 from Figure 3(b). As shown in the figure, the impedance of the antenna 10 is mostly distributed above the real axis of the Smith chart. Comparing Figure 4 and Figure 5, the shape of the impedance distribution changes and moves within or near the shaded area as shown by the dotted arrow in Figure 4. Also, the shape of the impedance distribution in Figure 3(b) differs from that in Figure 3(a), forming a large arc and staying within a certain range on the Smith chart.

[0050] Figure 6 is a Smith chart showing the impedance characteristics of antenna 10 when a 3.5pF capacitor is added in series with antenna 10 while the unpowered element 30 is present. The capacitance component of the impedance increases due to the capacitor, and as indicated by the "Series C" arrow in Figure 3(b), the impedance graph slides downward. As a result, as shown in Figures 3(b) and 6, the impedance is distributed in an arc shape around 1.0 (50Ω) on the real axis, with a VSWR of around 3.5, and remains within a certain range.

[0051] Furthermore, as shown in Figure 7, the VSWR of antenna 10 with a 3.5pF capacitor added is 3.5 or less in the frequency band of 699MHz to 894MHz. In this way, the parasitic element 30 contributes to adjusting the impedance characteristics of antenna 10, exhibiting good VSWR characteristics over a wide bandwidth. A pF capacitor is provided on the circuit board 50 shown in Figure 1(a), and a current contributing to the adjustment of the impedance characteristics of the antenna 10 is supplied via the feed point 12A in Figure 2.

[0052] As described above, the parasitic element 30 can adjust the impedance characteristics of the antenna 10 depending on its position and shape. Therefore, in order to make the impedance characteristics of the antenna 10 suitable for the design conditions, the parasitic element 30 can take on various shapes or positions other than those shown in Figure 1. The relationship between the position and shape of the parasitic element 30 and the impedance characteristics of the antenna 10 will be explained below.

[0053] (Distance between the unpowered element 30 and the antenna 10) As an example, the impedance characteristics of the antenna 10 can be adjusted by changing the distance between the passive element 30 and the antenna 10. Figure 8 shows the relationship between the configuration of the antenna 10 and the impedance of the antenna 10 (without capacitor connection) with respect to the distance between the front end of the first extension 31 and the end of the second extension 11B.

[0054] In the antenna 10 configuration of the antenna device 1 shown in Figure 8(a), the distance (d) between the front end of the first extension 31 and the end of the second extension 11B is changed in increments of 1 mm, ranging from 1 mm to 4 mm. The distance d is changed by shifting the passive element 30 forward or backward while maintaining its shape.

[0055] As shown in the Smith chart of Figure 8(b), it can be seen that the impedance distribution of antenna 10 changes by adjusting the interval d. When the interval d is widened, the parasitic capacitance between antenna 10 and the parasitic element 30 decreases, the inductor component increases, and it shifts upward on the Smith chart over a wide bandwidth. By changing the impedance distribution in this way, it is possible to distribute the impedance on the Smith chart so that it falls above the real axis, preferably within a certain range as shown in the shaded area of ​​Figure 4.

[0056] (Length of the unpowered element 30) Furthermore, as an example, the impedance characteristics of the antenna 10 can be adjusted by changing the length of the parasitic element 30. Figures 9(a) and 10(a) show the configuration indicating the length of the first extension 31 in the front-to-back direction, and the relationship between the length of the first extension 31 and the impedance of the antenna 10 (without capacitor connection). In Figures 9(a) and 10(a), the length L of the first extension 31 is changed in increments of 5 mm within the range of 47 mm to 82 mm. The distance between the front end of the first extension 31 and the end 11C was maintained at 1 mm. Note that in Figure 9(a), the length L of the first extension 31 of the parasitic element 30 in the front-to-back direction is longer than the length of the first extension 11A of the antenna 10 positioned opposite it, while in Figure 10(a), it is shorter than the length of the first extension 11A of the antenna 10 positioned opposite it.

[0057] As shown in the Smith charts of Figures 9(b) and 10(b), it can be seen that the impedance distribution of the antenna 10 changes by adjusting the length of the first extension 31 in the front-to-back direction. In this way, it is possible to distribute the impedance on the Smith chart so that it falls above the real axis, preferably within or near a certain range, as shown in the shaded area of ​​Figure 4.

[0058] (Width of the unpowered element 30) The impedance characteristics of the antenna 10 can also be adjusted by changing the width of the passive element 30. Figures 11(a) and 12(a) show the configuration of the width of the first extension 31 and the relationship between its width, i.e., its length in the left-right direction, and the impedance of the antenna 10 (without capacitor connection). In Figures 11(a) and 12(a), the width W of the first extension 31 is changed in increments of 5 mm within the range of 10 mm to 30 mm. The distance between the front end of the first extension 31 and the end 11C is 1 mm, and the length in the front-back direction is 67 mm. In Figure 11(a), the width W of the first extension 31 of the passive element 30 is narrower than the width of the first extension 31 shown in Figure 1, and in Figure 12(a), it is wider than the width of the first extension 31 shown in Figure 1.

[0059] As shown in the Smith charts of Figures 11(b) and 12(b), it can be seen that the impedance distribution of the antenna 10 changes by changing the width of the first extension 31. In this way, it is possible to distribute the impedance above the real axis on the Smith chart, preferably in the vicinity of or within a certain range, as shown in the shaded area of ​​Figure 4.

[0060] (Variations of the powerless element 30) Figures 13 to 15 show examples of the parasitic element 30 designed under the above considerations, illustrating the width and length of the first extension 31 and the distance from the end of the second extension 11B. In each of the examples shown in the figures, the impedance of the antenna 10 is generally distributed above the real axis of the Smith chart. Thus, it can be seen that there are various variations in the width and length of the first extension 31 and the distance from the end 11C, and that these contribute to impedance adjustment.

[0061] ==Second Embodiment== An antenna device 100 according to the second embodiment is shown in Figures 16 and 17.

[0062] The antenna device 100 comprises a ground section 103, antennas 102 (antennas 110 and 120), a passive element 130, a circuit board 150, a holding member (not shown) for holding the antennas 102, and a housing 101 that covers these members from above. The antenna device 100 also includes a flat patch antenna 170 (used in GNSS (Global Navigation Satellite System)) mounted on the circuit board 150, two bent rod-shaped Wi-Fi / Bluetooth antennas 140 (compatible with the 2.4 / 5GHz band), and two bent plate-shaped Sub6 antennas 175 (compatible with frequency bands below 6GHz). Note that the Wi-Fi / Bluetooth antennas 140 are not limited to a rod shape; they may also be formed by punching out plates or conductive plates, or by forming conductive patterns on a PCB. In addition, the antenna device 100 includes a rod-shaped V2X monopole antenna 180 extending upward from the circuit board 150, and a V2X antenna 190 having a parasitic element 192 and a radiating element 191.

[0063] The patch antenna 170, located on the circuit board 150, is positioned approximately in the center of the circuit board 150. The radiating elements 191 of the V2X monopole antenna 180 and the V2X antenna 190 are positioned on a line passing approximately through the center of the patch antenna 170 in the left-right direction, with the patch antenna 170 in between. Passive elements 192 are positioned at predetermined intervals on both sides of the radiating element 191 of the V2X antenna 190 in the front-rear direction. In Figure 16, a passive element is placed only on the V2X antenna 190 on the left side relative to the patch antenna 170, but a passive element may also be placed on the V2X monopole antenna 180 on the right side.

[0064] The V2X antenna 190 has a forward directional characteristic, while the V2X monopole antenna 180 has a rightward directional characteristic. The antenna device 100 can improve the gain of its leftward directivity, particularly by providing a powerless element 192 to the leftward-facing V2X antenna 190.

[0065] Each of the two Wi-Fi / Bluetooth antennas 140 is positioned on a line passing approximately through the center of the patch antenna 170, at a distance from the patch antenna 170 in the left-right direction. Furthermore, each of the two Wi-Fi / Bluetooth antennas 140 is positioned between the antenna 120 and the passive element 130 in the front-back direction, resulting in an arrangement that suppresses interference and allows for miniaturization.

[0066] The Patch Antenna 170 is applicable to satellite positioning system antennas capable of receiving circularly polarized signals using various feeding methods, such as two-point and four-point feeding. Any antenna capable of handling satellite wave signals is acceptable, including stacked antennas, multi-resonant antennas, and even those with added passive elements.

[0067] The antenna device 100 includes one antenna 110, one antenna 120, one parasitic element 130, and one holding member (not shown) on the left and one on the right. These members are arranged approximately symmetrically on the left and right sides. Below, the antennas 110, 120, and 130 arranged on the left side will be mainly described using Figure 17. The antennas 110, 120, and 130 arranged on the right side have the same configuration as those on the left side, so their description will be omitted.

[0068] The ground section 103 is a horizontally extending rectangular member and has the same function as the ground section 3. That is, the ground section 103 functions as the ground for the antennas 110 and 120 and the passive element 130 of the antenna device 100. Like the ground section 3, the ground section 103 functions as a common ground for the antennas 110 and 120. As shown in Figure 16, the ground section 103 is formed as a single metal plate (sheet metal). However, the ground section 103 may be composed of multiple separate metal plates.

[0069] Antenna 110 is a broadband antenna for mobile communications based on an inverted L antenna, with the same functions as antenna 10. Antenna 110 also has an element 111 and a feed point 112.

[0070] Element 111 is a horizontally extending plate-shaped member. Element 111 is formed to extend rearward from the power supply section 112 and faces the ground section 103 vertically. An open end 111C is formed at the rear end of element 111 and faces the unpowered element 130 in the front-rear direction.

[0071] The power supply section 112 is formed to extend upward from the upper surface of the circuit board 150. The power supply section 112 has a power supply point 112A that contacts the circuit board 150 at its lower end and is electrically connected to it. The upper end of the power supply section 112 (element 111 side) has a shape in which the width in the front-to-back direction is longer than that of the lower end (circuit board 150 side).

[0072] As shown by the arrow (circled number 1) in Figure 17(b), the length of the antenna 110 along its shape, from the feed point 112A to the end 111C, is equal to one-quarter of the wavelength of a radio wave in the 699MHz to 894MHz band. By making the length of the antenna 110 one-quarter of the wavelength of the corresponding frequency band, the sensitivity of the antenna 110 in the corresponding frequency band can be improved.

[0073] Antenna 120 is a broadband antenna for mobile communications based on a folded monopole antenna. Like antenna 20, antenna 120 supports radio waves in the 2GHz band (e.g., 1710-2170MHz). Antenna 120 may also support radio waves in frequency bands used for GSM, UMTS, LTE, and 5G. Antenna 120 may also be an antenna that supports radio waves in frequency bands used for telematics, V2X (Vehicle to Everything: vehicle-to-vehicle communication, vehicle-to-infrastructure communication), Wi-Fi, Bluetooth, etc.

[0074] Antenna 120 has an element 121 and shares a feed point 112 with antenna 110.

[0075] Element 121 is a flat conductive member and is formed to extend to the right from the upper end of the power supply section 112 (Figure 17(b)). Element 121 has a first extension section 121A and a second extension section 121B.

[0076] The first extension 121A is the portion that extends to the right from the upper end of the power supply section 112. The second extension 121B is the portion that extends downward from the right end of the first extension 121A. The lower end of the second extension 121B is mechanically and electrically connected to the ground section 103. The connection between the second extension 121B and the ground section 103 can be made using methods such as joining screws or other fasteners, or soldering or welding.

[0077] As shown by the arrow (circled number 3) in Figure 17(b), the electrical length of the antenna 120 along its shape, from the feed point 112A to the lower end of the second extension 121B, is approximately half a wavelength of a 2GHz band radio wave (for example, a radio wave at the center frequency). By making the electrical length of the antenna 120 half a wavelength of the radio wave in the corresponding frequency band, the sensitivity of the antenna 120 in the corresponding frequency band can be improved.

[0078] The passive element 130 is a flat conductive member mechanically and electrically connected to the ground portion 103, and, like the passive element 30, has the function of adjusting the impedance of the antenna 110 (Figure 17(a)). The passive element 130 includes a first extension portion 131 that extends in the left-right and front-back directions, and a second extension portion 132 that extends downward from the right end of the first extension portion 131.

[0079] The first extension portion 131 is a part formed to bend in an L-shape when viewed from above. The first extension portion 131 faces the ground portion 103 in the vertical direction. The height of the first extension portion 131 from the ground portion 103 is approximately equal to the height of the element 111 from the ground portion 103.

[0080] The first extension 131 extends to the left from the upper end of the second extension 132 and bends forward at its left end. The front end of the first extension 131 forms an open end and faces the end 111C of the element 111 with a gap between them.

[0081] The second extension portion 132 is a rectangular section when viewed in the front-to-back direction, extending vertically and connecting the right end of the first extension portion 131 to the ground portion 103. The lower end of the second extension portion 132 is mechanically and electrically connected to the ground portion 103 using connectors such as screws. The connection between the second extension portion 132 and the ground portion 103 can be achieved using methods such as joining with connectors such as screws, soldering, or welding.

[0082] The circuit board 150 is a rectangular component positioned above the ground section 103 and is electrically connected to the feed point 112A. The circuit board 150 is equipped with a capacitor (not shown) and is connected in series with antennas 110 and 120 via the feed point 112A.

[0083] In the configuration described above, as in the first embodiment, the impedance characteristics of the antenna 110 are adjusted by the length (indicated as arrow number 2 in Figure 17(a)), width, or distance from the antenna 10, which are in line with the shape of the parasitic element 130. As a result of designing the parasitic element 130 through such adjustments, the antenna 110 exhibits the desired impedance characteristics. In addition, the antenna 110 can exhibit good VSWR characteristics in the corresponding frequency band by being connected to the capacitor on the circuit board 150.

[0084] <Effects> In each of the above embodiments, the antenna devices 1 and 100 include ground sections 3 and 103, antennas 2 and 102, and parasitic elements 30 and 130. Antennas 2 and 102 have elements 11 and 111 (corresponding to the "main body") that face the ground sections 3 and 103 and have open ends, and feed sections 12 and 112 that extend from the elements 11 and 111 in the direction of the ground sections 3 and 103 and have feed points 12A and 112A. The parasitic elements 30 and 130 have first ends that are spaced apart from the open ends of the elements 11 and 111 and are used to adjust the impedance of antennas 10 and 110.

[0085] According to the above configuration, by providing the parasitic elements 30 and 130, the impedance characteristics of the antennas 10 and 110 can be adjusted, and the performance of the antennas 10 and 110 can be improved over a wide bandwidth.

[0086] In addition to the above configuration, the length from the feed points 12A and 112A through antennas 10 and 110 to the open end is the length corresponding to the frequency bands of antennas 10 and 110.

[0087] This configuration allows for good transmission and reception of radio waves within the corresponding frequency band.

[0088] In addition to the above configuration, the distance between elements 11 and 111 and ground sections 3 and 103 is shorter than the wavelength of the corresponding frequency band of antennas 10 and 110.

[0089] By configuring the antenna devices 1 and 100 as described above, their height can be reduced, thus miniaturizing them. The parasitic elements 30 and 130 contribute to this miniaturization. More specifically, as shown in Figures 3 and 7, the parasitic elements 30 and 130 adjust the impedance of the antennas 10 and 110, improving the VSWR characteristics over a wide bandwidth. Therefore, in the above embodiment, elements 11 and 111 are placed at a low position, achieving miniaturization of the entire device. As a result of this miniaturization, the antenna devices 1 and 100 can be placed in a narrow space.

[0090] In addition to the above configuration, the unpowered elements 30 and 130 are arranged to increase the inductance component of the impedance in the corresponding frequency band.

[0091] By configuring the system as described above, the impedance can be distributed upwards on the Smith chart, as shown in Figure 5, making impedance adjustment using elements such as capacitors (Figure 6) easier. If the impedance of the corresponding frequency band is located above the real axis on the Smith chart, the impedance distribution can be shifted downwards on the Smith chart by increasing the conductance component using a capacitor, making impedance adjustment easier.

[0092] In each of the above embodiments, capacitors that increase the capacitance component of the impedance in the corresponding frequency band are connected to antennas 10 and 110, thereby adjusting the impedance to fall within a certain range centered around 50Ω on the Smith chart (Figure 6). This makes it possible to obtain good VSWR characteristics.

[0093] The power supply section 12 has a wider width (front-to-back length) than the power supply point 12A at the connection point with the element 11. Therefore, it can support a frequency band higher than the corresponding frequency band and achieve high performance over a wide bandwidth.

[0094] Antennas 2 and 102 are equipped with second extensions 21B and 121B (corresponding to "connection parts") that connect the first extensions 21A and 121A (corresponding to the "main body") to the ground parts 3 and 103.

[0095] With this configuration, antennas 2 and 102 have the function of antennas 20 and 120, which correspond to frequency bands different from both the frequency bands of antennas 10 and 110 and the frequency band of the feed unit 12.

[0096] The vertical distance D2 (corresponding to the "first distance") from the ground portion 3 at the end of the second extension 11B is the same as the vertical distance D1 (corresponding to the "second distance") from the ground portion 3 at the front end of the first extension 31. Also, the vertical distance from the ground portion 103 at the front end of the element 111 is the same as the vertical distance from the ground portion 103 at the front end of the first extension 131.

[0097] By aligning the ends of elements 11, 111 and the ends of the opposing parasitic elements 130, 130 to the same height and making them flush, the antenna devices 1, 100 can be made lower in profile, i.e., their vertical height can be reduced, making them more compact. [Explanation of Symbols]

[0098] 1. 100 Antenna equipment 2,102 antenna 3, 103 Ground Section 12, 112 Power supply section 12A, 112A feed point 30, 130 unpowered elements 50 Circuit boards 60 Retaining member

Claims

1. The Ground Club and, An antenna having a main body portion facing the ground portion and having an open end portion that is open, and a feed portion extending from the main body portion in the direction of the ground portion and having a feed point, A parasitic element for adjusting the impedance of the antenna, having a first end positioned at a distance from the open end, An antenna device equipped with the following features.

2. The length from the feed point through the antenna to the open end is the length corresponding to the first frequency band. The antenna device according to claim 1.

3. The aforementioned length is, The wavelength of the first frequency band is approximately one-quarter of the wavelength of the first frequency band. The antenna device according to claim 2.

4. The antenna device according to claim 2 or 3, wherein the distance between the main body and the ground portion is shorter than the wavelength of the first frequency band.

5. The aforementioned unpowered element is Arranged to increase the inductance component of the impedance in the first frequency band, The antenna device according to any one of claims 2 to 4.

6. The antenna is further connected to a capacitor that increases the capacitance component of the impedance in the first frequency band, The antenna device according to any one of claims 2 to 5.

7. The aforementioned power supply unit is To accommodate a second frequency band higher than the first frequency band, the connection portion with the main body has a width greater than that of the power supply point portion. The antenna device according to any one of claims 2 to 6.

8. The aforementioned antenna is The device includes a connecting section that connects the main body and the ground section to correspond to a third frequency band that is different from both the first and second frequency bands. The antenna device according to claim 7.

9. In the vertical direction of the ground portion, the first distance from the first end to the ground portion is the same as the second distance from the open end to the ground portion. The antenna device according to any one of claims 1 to 8.

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