Wireless device

Abstract

The present invention provides a wireless device with which a communication range can be prevented from being reduced even in a case where a height of the device is limited. The wireless device includes an antenna device that is composed of a substrate including a substrate ground portion and an antenna element provided on the substrate, and a conductor formed in a lateral U shape. The conductor includes an upper portion and a lower portion that are disposed along a ground plane and are disposed above and below each other, and an intermediate portion that is disposed substantially perpendicularly to the ground plane between one end of the upper portion and one end of the lower portion. The conductor is disposed so that the upper portion, the lower portion, and the intermediate portion are close to an upper edge portion, a lower edge portion, and a side edge portion of the antenna device, respectively. The upper portion of the conductor is disposed in the vicinity of the antenna element, and the conductor functions as an antenna due to excitation of a current in the conductor when power is supplied to the antenna element.

Description

TECHNICAL FIELD

[0001] The present application relates to a wireless device. BACKGROUND

[0002] Patent Document 1 discloses a mounting body located near an antenna. The mounting body according to Patent Document 1 includes a conductor located near an antenna of a transmitter in a state adjacent to the transmitter. An induced current is generated in the conductor by a drive current of the antenna, and the induced current has a current component in a direction different from that of the drive current.

[0003] Further, Patent Document 2 discloses a wireless device including an antenna device for horizontal polarization. The antenna device for horizontal polarization includes a radiating conductor including two conductive plates facing each other with a predetermined gap obtained by bending, a ground conductor, and a feed element, the radiating conductor as a whole formed in a cylindrical shape extending in a vertical direction. The ground conductor is disposed in an inner space surrounded by the two conductive plates of the radiating conductor and is electrically grounded. The feed element is disposed in the inner space along an inner wall of the conductive plate in a top view and operates as an inverted L antenna when fed between one end portion thereof and the ground conductor, and feeds the radiating conductor by electromagnetic coupling.

[0004] REFERENCE LIST

[0005] PATENT DOCUMENT

[0006] Patent Document 1: International Patent Publication No. 2017 / 204132

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2013-131901 SUMMARY

[0008] TECHNICAL PROBLEM

[0009] In order to perform transmission / reception of radio waves between wireless devices, the polarizations of antennas must be matched. Therefore, in a case where the polarization of the antenna of the counterpart device is only vertical polarization, the antenna of the subject device needs to have vertical polarization. Here, in general, in order to achieve vertical polarization, a component of an antenna device perpendicular to a ground plane needs to have a certain length, and in order to increase vertical polarization, the height of the device must be increased. However, the height of the device is often limited by the installation conditions of the device and the like, and in such a case, vertical polarization can be small. This can cause a problem of a reduced communication range. The technology according to the above-described patent documents cannot solve the above-described problem.

[0010] An object of the present disclosure is to solve the above-described problem, and to provide a wireless device with which a reduction in a communication range can be prevented even in a case where the height of the device is limited.

[0011] Technical solutions to solve technical problems

[0012] The wireless device according to this disclosure includes: an antenna device comprising a substrate including a substrate ground portion and an antenna element disposed on the substrate; and a conductor formed in a transverse U-shape, wherein the conductor includes an upper portion and a lower portion disposed along a ground plane and disposed vertically to each other, and a middle portion disposed substantially perpendicular to the ground plane between one end of the upper portion and one end of the lower portion, the conductor being configured such that its upper portion, lower portion and middle portion are respectively close to the upper side portion, lower side portion and side portion of the antenna device, the upper portion of the conductor being disposed near the antenna element, and the conductor serving as an antenna due to the current induced in the conductor when power is supplied to the antenna element.

[0013] Beneficial effects of the present invention

[0014] According to this disclosure, a wireless device can be provided that prevents a reduction in communication range even when the height of the device is limited. Attached Figure Description

[0015] Figure 1 This diagram is used to describe the case where the antenna is a dipole antenna.

[0016] Figure 2 This diagram is used to describe the case where the antenna is a dipole antenna.

[0017] Figure 3 This diagram is used to describe the case where the antenna is a dipole antenna.

[0018] Figure 4 This diagram is used to describe the case where the antenna is a dipole antenna.

[0019] Figure 5 This is a diagram illustrating the wireless device according to the first comparative example.

[0020] Figure 6 This is a diagram illustrating an example of the flow of high-frequency current through the wireless device according to the first comparative example at a certain moment.

[0021] Figure 7 It shows the basis Figure 5 A diagram illustrating an example of the radiation pattern of the wireless device of the first comparative example in the direction of the ground plane.

[0022] Figure 8 This is a diagram showing the wireless device according to the second comparative example.

[0023] Figure 9 This is a diagram illustrating an example of the flow of high-frequency current through the wireless device according to the second comparative example at a certain moment.

[0024] Figure 10 It shows the basisFigure 8 A diagram illustrating an example of the radiation pattern of the wireless device of the second comparative example in the direction of the ground plane.

[0025] Figure 11 This is a diagram illustrating a wireless device according to a first example embodiment.

[0026] Figure 12 This is a diagram illustrating a wireless device according to a first example embodiment.

[0027] Figure 13 This is a diagram illustrating an example of the flow of high-frequency current through a wireless device according to a first exemplary embodiment at a certain moment.

[0028] Figure 14 It shows the basis Figure 11 and Figure 12 A diagram illustrating an example of the radiation pattern of the wireless device of the first exemplary embodiment in the direction of the ground plane.

[0029] Figure 15 It is a diagram in which the vertically polarized radiation pattern of the wireless device according to the second comparative example and the vertically polarized radiation pattern of the wireless device according to the first exemplary embodiment overlap with each other.

[0030] Figure 16 This is a diagram illustrating a wireless device according to a second example embodiment.

[0031] Figure 17 It shows the basis Figure 16 A diagram illustrating an example of the radiation pattern of the wireless device in the ground plane direction of the second example embodiment.

[0032] Figure 18 It is a diagram in which the vertically polarized radiation pattern of the wireless device according to the second comparative example and the vertically polarized radiation pattern of the wireless device according to the second exemplary embodiment overlap with each other.

[0033] Figure 19 This is a diagram illustrating a wireless device according to a third example embodiment.

[0034] Figure 20 It is a diagram in which the vertically polarized radiation pattern of the wireless device according to the third exemplary embodiment overlaps with the vertically polarized radiation pattern in the case of removing the conductor from the wireless device according to the third exemplary embodiment.

[0035] Figure 21 This is a diagram illustrating a wireless device according to a fourth example embodiment.

[0036] Figure 22is a diagram in which the radiation pattern for vertical polarization of the wireless device according to the fourth embodiment overlaps with the radiation pattern for vertical polarization in the case where the conductor is removed from the wireless device according to the fourth example embodiment. DETAILED DESCRIPTION

[0037] (Overview of Example Embodiments of the Present Disclosure)

[0038] Before describing example embodiments of the present disclosure, an overview of example embodiments of the present disclosure will be given. First, polarization of an antenna will be described.

[0039] Polarization is one of the characteristics of an antenna. A case where an electric field is confined to one plane is referred to as linear polarization. Further, in linear polarization, a case where an electric field is parallel to a ground plane is referred to as horizontal polarization, and a case where an electric field is perpendicular to a ground plane is referred to as vertical polarization. For example, when an antenna device is disposed parallel to a ground plane, the polarization of the antenna is horizontal polarization. When the antenna device is disposed perpendicular to a ground plane, the polarization of the antenna is vertical polarization.

[0040] Figures 1 to 4 is a diagram for describing a case where the antenna is a dipole antenna. Figure 1 shows a dipole antenna 2 disposed perpendicular to a ground plane 90. Figure 2 shows a dipole antenna 4 disposed parallel to a ground plane 90. Figure 3 is a diagram showing Figure 1 is a diagram showing an example of a radiation pattern in a ground plane direction (on the XY plane) of the dipole antenna 2 shown. Figure 4 is a diagram showing Figure 2 is a diagram showing an example of a radiation pattern in a ground plane direction (on the XY plane) of the dipole antenna 4 shown. In addition, the ground plane direction refers to a plane along the ground plane 90.

[0041] In Figure 3 , the radiation pattern for vertical polarization is indicated by a thick solid line (the thick solid line is also applied to the radiation pattern in other diagrams). Further, in Figure 4 , the radiation pattern for horizontal polarization is indicated by a thick dashed line (the thick dashed line is also applied to the radiation pattern in other diagrams). As Figure 3 indicated, in the case of a pure dipole antenna, the polarization of the dipole antenna 2 disposed perpendicular to the ground plane 90 is only vertical polarization. Further, as Figure 4 indicated, the polarization of the dipole antenna 2 disposed parallel to the ground plane 90 is only horizontal polarization. In addition, the resonant frequency of the antenna according to the present disclosure is 900 MHz. Therefore, Figure 3 and Figure 4 indicated show the results in the case where the resonant frequency of the antenna is 900 MHz, respectively. Further, the resonant frequency of the antenna is not limited to 900 MHz.

[0042] Next, comparative examples for the example embodiments of the present disclosure will be described.

[0043] Figure 5 is a diagram showing a wireless device 10 according to a first comparative example. The wireless device 10 according to the first comparative example includes a substrate 12, an antenna element 14 provided on the substrate 12, and a driving unit 18. Further, the substrate 12 and the antenna element 14 form an antenna device 16. The driving unit 18 supplies power to the antenna element 14. The substrate 12 includes a substrate ground (GND).

[0044] The antenna element 14 can be an antenna pattern drawn (printed) on the substrate 12, for example. The antenna element 14 is a reverse L-shaped antenna, for example. Thus, the antenna element 14 includes a horizontal portion 14a as a component parallel to the ground plane 90 and a vertical portion 14b as a component perpendicular to the ground plane 90. The antenna element 14 (antenna device 16) thus has a horizontal polarization and a vertical polarization.

[0045] Further, the substrate 12 of the wireless device 10 according to the first comparative example is formed so that a dimension Al in a direction parallel to the ground plane 90 is smaller than a dimension A2 in a direction perpendicular to the ground plane 90. That is, Al < A2 is true. Al is 60 mm and A2 is 100 mm, for example, but the dimensions of the substrate 12 are not limited thereto.

[0046] Figure 6 is a diagram showing an example of a flow of high-frequency current flowing through the wireless device 10 according to the first comparative example at a certain time. The antenna element 14 is provided on the substrate 12 including the substrate ground (GND), and thus, as shown by arrows A to D in Figure 6 , the high-frequency current flows not only through the antenna element 14 but also through the substrate 12 (GND). Thus, the antenna device 16 formed by the substrate 12 and the antenna element 14 functions as an antenna.

[0047] Figure 7 is a diagram showing an example of a radiation pattern in a horizontal plane direction (on the XY plane) of the wireless device 10 according to the first comparative example shown in Figure 5 . Here, the generation of the horizontal polarization and the vertical polarization is determined on the basis of the distribution of the high-frequency current on the antenna device 16, and generally depends on the length of the component parallel to the ground plane 90 and the length of the component perpendicular to the ground plane 90 of the entire antenna device 16 functioning as an antenna. With the wireless device 10 according to the first comparative example, the length of the component perpendicular to the ground plane 90 is large, and the length of the component parallel to the ground plane 90 is small, and thus, the vertical polarization is large, and the horizontal polarization is small.

[0048] Figure 8is a diagram showing a wireless device 20 according to a second comparative example. As with the wireless device 10 according to the first comparative example, the wireless device 20 according to the second comparative example includes a substrate 22, an antenna element 24 provided on the substrate 22, and a driving unit 28. Further, the substrate 22 and the antenna element 24 form an antenna device 26. The driving unit 28 supplies power to the antenna element 24. The substrate 22 includes a substrate ground (GND).

[0049] For example, as with the antenna element 14, the antenna element 24 can be an antenna pattern drawn (printed) on the substrate 22. For example, the antenna element 24 is an inverted L-shaped antenna. Thus, the antenna element 24 includes a horizontal portion 24a as a component parallel to the ground plane 90 and a vertical portion 24b as a component perpendicular to the ground plane 90. The antenna element 24 (and the antenna device 26) thus has horizontal polarization and vertical polarization.

[0050] The substrate 22 of the wireless device 20 according to the second comparative example is formed so that the dimensions of the substrate 12 of the wireless device 10 according to the first comparative example in the long side direction and the short side direction are switched. That is, the substrate 22 is formed so that the dimension LI in the direction parallel to the ground plane 90 is larger than the dimension L2 in the direction perpendicular to the ground plane 90. That is, LI > L2 is true. For example, LI is 100 mm and L2 is 60 mm, but the dimensions of the substrate 22 are not limited thereto.

[0051] Figure 9 is a diagram showing an example of the flow of high-frequency current flowing through the wireless device 20 according to the second comparative example at a certain time. As with the wireless device 10 according to the first comparative example, the antenna element 24 is provided on the substrate 22 including the substrate ground (GND), and thus, as shown by arrows A to D in Figure 9 , high-frequency current not only flows through the antenna element 24 but also flows through the substrate 22 (GND). Thus, the antenna device 26 formed by the substrate 22 and the antenna element 24 functions as an antenna.

[0052] Here, the frequency of the high-frequency current is assumed to be 900 MHz. As shown by arrows A and B, the high-frequency current flows through the antenna element 24 and flows in the short side direction (vertical direction) of the substrate 22. Further, as shown by arrows C and D, the high-frequency current flows through the portion facing the antenna element 24 (in the long side direction (horizontal direction) of the substrate 22).

[0053] The direction of the high-frequency current flowing through the antenna element 24 (shown by arrow A) is opposite to the direction of the high-frequency current flowing in the long side direction of the substrate 22 (shown by arrows C and D). Thus, some horizontal polarization waves caused by the high-frequency current flowing in the horizontal direction cancel each other out, and the remaining horizontal polarization waves that are not cancelled are radiated to the outside.

[0054] Furthermore, since the dimension of substrate 22 in the short side direction (vertical direction) is less than 1 / 4 of the wavelength of 900MHz, high-frequency current is difficult to flow in the short side direction. This is due to the high-frequency current in the vertical direction of antenna device 26 (current flows in the direction indicated by arrow B), in other words, due to vertical polarization (see description later). Figure 10 This reduces radiation. This is because, as will be explained later, in order to achieve resonance in the antenna, the antenna length needs to be approximately half the wavelength of the resonant frequency of the antenna (antenna element 24). With approximately one-quarter of the wavelength of the resonant frequency guaranteed by antenna element 24, the remaining one-quarter wavelength requires the substrate 22. Therefore, if the dimension of the substrate 22 in the short side direction (vertical direction) is less than one-quarter of the wavelength, the high-frequency current flows in the long side direction, which guarantees one-quarter of the wavelength. Thus, it is difficult for the high-frequency current to flow in the short side direction.

[0055] Figure 10 It shows the basis Figure 8 The diagram shows an example of the radiation pattern of the wireless device 20 of the second comparative example in the ground plane direction (on the XY plane). Compared with the wireless device 10 according to the first comparative example, the wireless device 20 according to the second comparative example has a shorter length in the direction perpendicular to the ground plane 90 (vertical direction), therefore, Figure 10 The vertical polarization in is less than Figure 5 Vertical polarization. Conversely, compared to the wireless device 10 according to the first comparative example, the wireless device 20 according to the second comparative example has a longer length in the direction parallel to the ground plane 90 (horizontal direction), therefore, Figure 10 The horizontal polarization in the middle is greater than Figure 5 Horizontal polarization. In this way, to obtain large horizontal polarization, the length of the antenna device's components parallel to the ground plane must be increased, and to obtain large vertical polarization, the length of the antenna device's components perpendicular to the ground plane must be increased.

[0056] In order to transmit / receive radio waves between wireless devices, the polarization of their antennas must be matched. In this case, if the antenna of the counterpart device is only vertically polarized, the antenna of the counterpart device must also be vertically polarized. As mentioned above, to achieve vertical polarization, components perpendicular to the ground plane in the antenna apparatus must be added; therefore, to obtain a large vertical polarization, the height of the wireless device must be increased. However, the height of the wireless device is often limited by factors such as installation conditions. In this situation, the vertical polarization may be reduced, potentially leading to a decrease in the communication range between the wireless devices.

[0057] In contrast, the wireless device according to the present disclosure includes an antenna device composed of a substrate including a substrate ground portion and an antenna element disposed on the substrate, and a conductor formed in a lateral U-shape. The conductor includes an upper portion and a lower portion disposed along the ground plane and above and below each other, respectively, and an intermediate portion disposed substantially perpendicular to the ground plane between one end of the upper portion and one end of the lower portion. The upper portion, the lower portion, and the intermediate portion of the conductor are disposed near the upper edge portion, the lower edge portion, and the side edge portion of the antenna device, respectively. The upper portion of the conductor is disposed near the antenna element, and the conductor functions as an antenna due to excitation of a current in the conductor when power is supplied to the antenna element.

[0058] In other words, the wireless device according to the present disclosure includes an antenna device composed of a substrate including a substrate ground portion and an antenna element disposed on the substrate, and a conductor formed in a lateral U-shape and disposed to partially surround the antenna device. One end portion of the conductor is disposed near the antenna element, and the conductor functions as an antenna due to excitation of a current in the conductor when power is supplied to the antenna element. Further, the conductor is disposed such that a center portion of the conductor is substantially perpendicular to the ground.

[0059] According to such a configuration, as described later, the wireless device according to the present disclosure can increase vertical polarization without increasing the height of the device. Therefore, with the wireless device according to the present disclosure, it is possible to prevent a reduction in communication range even in a case where the height of the device is limited.

[0060] (First Example Embodiment)

[0061] Example embodiments will be described below with reference to the accompanying drawings. The following description and drawings include omissions or appropriate simplifications for the sake of clarity. In addition, the same elements in the drawings are denoted by the same reference numerals, and redundant descriptions are omitted as necessary.

[0062] Figure 11 And Figure 12 is a diagram showing a wireless device 100 according to the first example embodiment. Figure 11 is a plan view of the wireless device 100 from the Y direction, and Figure 12 is a perspective view of the wireless device 100. As with the wireless device 20 shown in Figure 8 , the wireless device 100 includes a substrate 22, an antenna element 24 disposed on the substrate 22, and a driving unit 28. The substrate 22 and the antenna element 24 form an antenna device 26. The substrate 22 includes a substrate ground portion (GND). In addition, as with the wireless device 20 shown in Figure 8 , the substrate 22 is formed in such a manner that the dimension in the direction perpendicular to the ground plane 90 is smaller than the dimension in the direction parallel to the ground plane 90.

[0063] The wireless device 100 according to the first example embodiment also includes a conductor 110 formed in a lateral U-shape. The conductor 110 is disposed in the vicinity of the antenna device 26 but is not physically connected to the antenna device 26. Thus, the conductor 110 is a parasitic element to which the driving unit 28 does not directly supply power.

[0064] As shown in FIG. 1, the conductor 110 includes an upper portion 110a, a lower portion 110b, and an intermediate portion 110c. The upper portion 110a and the lower portion 110b are disposed along the ground plane 90 and are disposed above and below each other, respectively. The intermediate portion 110c is disposed substantially perpendicular to the ground plane 90, the intermediate portion 110c being located between one end P1 of the upper portion 110a and one end P2 of the lower portion 110b. Here, "substantially perpendicular" means that the elevation angle is within a range of 90 ± 45 degrees. Further, in the present specification, the term "perpendicular" alone does not mean that the elevation angle is exactly 90 degrees, but can mean that the elevation angle is within a range of 90 ± 45 degrees. Further, the upper portion 110a, the lower portion 110b, and the intermediate portion 110c are integrally formed, and the conductor 110 can be formed by bending an elongated conductor at P1 and P2. Figure 11 The conductor 110 is disposed such that the upper portion 110a thereof is along the upper edge portion 26a of the antenna device 26. Further, the conductor 110 is disposed such that the lower portion 110b thereof is along the lower edge portion 26b of the antenna device 26. Further, the conductor 110 is disposed such that the intermediate portion 110c thereof is along the side edge portion 26c of the antenna device 26. That is, the conductor 110 is disposed such that the upper portion 110a, the lower portion 110b, and the intermediate portion 110c thereof are close to the upper edge portion 26a, the lower edge portion 26b, and the side edge portion 26c of the antenna device 26, respectively. Here, a gap between the intermediate portion 110c and the side edge portion 26c is given as Lc. Further, the length of the intermediate portion 110c is desirably about the same as or greater than the length of the side edge portion 26c.

[0065] The upper portion 110a of the conductor 110 is disposed in the vicinity of the antenna element 24. The total length of the conductor 110 (the combined length of the upper portion 110a, the lower portion 110b, and the intermediate portion 110c) is desirably about the same as 1 / 2 of the wavelength of the resonant frequency. Thus, resonance can be achieved in the conductor 110 at the desired frequency. Further, the conductor 110 is desirably disposed in such a manner that the central portion of the conductor 110 is substantially perpendicular to the ground plane 90.

[0066]

[0067] ​The driving unit 28 is provided near the outer edge (side portion 26c) of the substrate 22, and the driving unit 28 supplies power to the antenna element 24. When power is supplied to the antenna element 24 by the driving unit 28, high-frequency current is excited in the conductor 110 provided near the antenna element 24. At this time, the conductor 110 resonates at a frequency of about 1 / 2 of the wavelength of the total length of the conductor 110, thereby functioning as an antenna. That is, when current is excited in the conductor 110 when power is supplied to the antenna element 24, the conductor 110 functions as an antenna.

[0068] Furthermore, in reality, when the influence of the conductor 110 being bent at P1 and P2, the influence applied due to the conductor 110 being adjacent to the substrate 22 (GND), and the like are taken into consideration, the total length of the conductor 110 must be shorter than 1 / 2 of the wavelength of the actual resonance frequency. The reason is as follows. In the case where the antenna is expressed as an RLC series equivalent circuit, when the antenna is close to the ground (GND), the antenna is made to have electrostatic capacity, and C (capacity) increases. In order to offset this influence, L (inductance) must be reduced, and L is adjusted to be small by making the total length shorter than 1 / 2 of the wavelength. Therefore, the total length of the conductor 110 must be shorter than 1 / 2 of the wavelength of the actual resonance frequency.

[0069] Furthermore, in the case where a dielectric body such as the housing of the wireless device 100 exists near the conductor 110, the total length of the conductor 110 must be further reduced. Furthermore, the strength of the high-frequency current excited in the conductor 110 depends on the high-frequency current flowing through the antenna element 24 (inverted L-shaped antenna). Therefore, the resonance frequency of the antenna element 24 and the resonance frequency of the conductor 110 must be matched.

[0070] Figure 13 is a drawing showing an example of the flow of high-frequency current flowing through the wireless device 100 according to the first example embodiment at a certain time. The frequency of the high-frequency current is assumed to be 900 MHz. As with the wireless device 20 of the second comparative example shown in Figure 9 As with the wireless device 20 of the second comparative example shown in Figure 13 , high-frequency current flows not only through the antenna element 24 but also through the substrate 22, as shown by arrows A to D in . Therefore, the antenna device 26 formed by the substrate 22 and the antenna element 24 functions as an antenna.

[0071] Figure 13 Furthermore, as shown in , high-frequency current is excited in the conductor 110 in the direction opposite to the high-frequency current flowing through the antenna element 24 and in the short side direction (vertical direction) of the substrate 22. Therefore, high-frequency current flows through the upper portion 110a of the conductor 110 in the direction shown by the dotted arrow H, high-frequency current flows through the middle portion 110c of the conductor 110 in the direction shown by the dotted arrow I, and high-frequency current flows through the lower portion 110b of the conductor 110 in the direction shown by the dotted arrow J.

[0072]

[0072] Here, for the high-frequency current excited in conductor 110, the direction of the high-frequency current flowing through the upper part 110a (indicated by arrow H) is opposite to the direction of the high-frequency current flowing through the lower part 110b (indicated by arrow J). Therefore, the polarization of the high-frequency currents flowing through these two parts cancels each other out. Thus, the upper part 110a and the lower part 110b contribute almost nothing to the polarization (horizontal polarization) radiation.

[0073] A high-frequency current flows through the middle portion 110c in the opposite direction (arrow I) to the direction of the high-frequency current flowing in the short-side direction (vertical direction) of the substrate 22. As described above, the high-frequency current flowing through the short-side direction (vertical direction) of the substrate 22 is relatively weak. Therefore, the polarization of the high-frequency current flowing through the middle portion 110c contributes to polarized (vertical) radiation without being largely canceled out. Now, the high-frequency current excited in the conductor 110, which has a total length of approximately half the wavelength of the desired frequency, is largely distributed in the center of the conductor 110, and not much near the tip. In this example embodiment, the shape of the conductor 110 is a transverse U-shape, so the center of the conductor 110 can be easily set to be substantially perpendicular to the ground plane 90. Therefore, vertical polarization can be increased.

[0074] As described above, in order to increase vertical polarization, it is important to strongly excite high-frequency current in the transverse U-shaped conductor 110. For this purpose, the electrical coupling with the antenna element 24 must be strengthened, therefore, the upper part 110a of the conductor 110 must be located near the antenna element 24.

[0075] Ideally, the middle portion 110c of conductor 110 is positioned as far away as possible from the side portion 26c of substrate 22. That is, the gap Lc between the middle portion 110c and the side portion 26c is greater than a predetermined length. In other words, Lc > Lth is true. Here, Lth is a predetermined length. For example, in the case of a frequency of 900MHz, a substrate 22 with a length of 100mm and a length of 60mm in the short side direction, Lth is 5mm. However, Lth is not limited to such a value. Furthermore, Lth can be appropriately set according to the frequency and size of substrate 22.

[0076] Furthermore, the reason why the middle portion 110c of the conductor 110 is ideally positioned as far away as possible from the side portion 26c of the substrate 22 is that the closer the middle portion 110c is to the substrate 22, the stronger the high-frequency current excited by the conductor 110 in the substrate 22. The direction of the high-frequency current excited by the conductor 110 in the substrate 22 is opposite to the direction of the high-frequency current flowing through the conductor 110. Therefore, when the middle portion 110c is close to the substrate 22 and the high-frequency current excited by the conductor 110 in the substrate 22 is strong, vertical polarization radiation is suppressed.

[0077] Figure 14is a graph showing an example of a radiation pattern in a horizontal plane direction (on the XY plane) of the wireless device 100 according to the first example embodiment shown in Figure 11 and Figure 12 is a graph showing an example of a radiation pattern in a horizontal plane direction (on the XY plane) of the wireless device 100 according to the first example embodiment shown in Figure 15 is a graph in which the radiation pattern for vertical polarization of the wireless device 20 according to the second comparative example and the radiation pattern for vertical polarization of the wireless device 100 according to the first example embodiment overlap each other. In Figure 15 , the radiation pattern for vertical polarization of the wireless device 20 according to the second comparative example (i.e., the radiation pattern for vertical polarization in Figure 10 ) is indicated by a thick dotted line, and the radiation pattern for vertical polarization of the wireless device 100 according to the first example embodiment is indicated by a thick solid line.

[0078] When comparing Figure 10 and Figure 14 , the radiation patterns for horizontal polarization in both are substantially the same. However, Figure 14 , the circle of the radiation pattern for vertical polarization in Figure 10 is larger than the circle of the radiation pattern for vertical polarization in Figure 15 . This is also clear in

[0079] In addition, as described above, in order to increase the vertical polarization of the conductor 110 formed in a lateral U-shape, the magnitude of the high-frequency current flowing through the middle portion 110c of the conductor 110 must be larger than the magnitude of the high-frequency current flowing in the vertical direction of the substrate 22. Furthermore, as described above, when the size of the substrate 22 in the vertical direction is reduced, the distribution of the component of the high-frequency current in the vertical direction becomes smaller. According to the simulation results, the effect of the wireless device 100 according to the present disclosure is ideally obtained by making the size of the substrate 22 in the vertical direction equal to or smaller than 1 / 3 of the wavelength of the resonant frequency of the antenna (antenna element 24). That is, when the size of the substrate 22 in the vertical direction is equal to or smaller than 1 / 3 of the wavelength of the resonant frequency, the high-frequency current flowing through the substrate 22 in the vertical direction can be reduced to the extent that the polarization of the high-frequency current flowing through the middle portion 110c is not substantially canceled out.

[0080] (Second Example Embodiment)

[0081] Next, a description will be given of a second example embodiment. The following description and drawings include omissions or appropriate simplifications for the sake of clarity. Furthermore, the same elements are denoted by the same reference numerals in the drawings, and redundant descriptions are omitted as necessary.

[0082] Figure 16 is a diagram showing a wireless device 200 according to a second example embodiment. Figure 16 is a perspective view of the wireless device 200. The wireless device 200 includes the antenna device 26 (the antenna element 24 and the substrate 22) and the conductor 210 formed in a lateral U-shape. Furthermore, although not shown, like in the first example embodiment, the wireless device 200 includes the drive unit 28 for supplying power to the antenna element 24. Figure 16 The illustrated antenna device 26 is substantially the same as Figure 12 the illustrated antenna device.

[0083] The conductor 210 includes an upper portion 210a, a lower portion 210b, and an intermediate portion 210c. The intermediate portion 210c is substantially the same as the intermediate portion 110c. The upper portion 210a is obtained by changing the shape of the upper portion 110a so that the tip end portion is closer to the substrate 22. In the same manner, the lower portion 210b is obtained by changing the shape of the lower portion 110b so that the tip end portion is closer to the substrate 22.

[0084] The dimensions of the conductor 210 and the positional relationship between the conductor 210 and the substrate 22 are substantially the same as in the case of the conductor 110 according to the first example embodiment. That is, the length of the conductor 210 is about 1 / 2 of the wavelength of the resonance frequency. Furthermore, the upper portion 210a and the lower portion 210b are disposed along the ground plane 90 and are disposed above and below each other. The intermediate portion 210c is disposed substantially perpendicular to the ground plane 90, the intermediate portion 210c being located between one end P1 of the upper portion 210a and one end P2 of the lower portion 210b. Furthermore, the conductor 210 is disposed so that its upper portion 210a is along the upper edge portion 26a of the antenna device 26. The conductor 210 is disposed so that its lower portion 210b is along the lower edge portion 26b of the antenna device 26. The conductor 210 is disposed so that its intermediate portion 210c is along the side edge portion 26c of the antenna device 26.

[0085] Figure 17 is a diagram showing an example of a radiation pattern in the horizontal plane direction (on the XY plane) of the wireless device 200 according to Figure 16 the second example embodiment. Furthermore, Figure 18 is a diagram in which the radiation pattern for vertical polarization of the wireless device 20 according to the second comparative example and the radiation pattern for vertical polarization of the wireless device 200 according to the second example embodiment overlap each other. In Figure 18 the diagram, the radiation pattern for vertical polarization of the wireless device 20 according to the second comparative example is indicated by a thick dotted line, and the radiation pattern for vertical polarization of the wireless device 200 according to the second example embodiment is indicated by a thick solid line.

[0086] When comparing Figure 10 andFigure 17 At this time, the radiation pattern for horizontal polarization in both is substantially the same as in the first example embodiment. However, Figure 17 the circle of the radiation pattern for vertical polarization in Figure 10 the circle of the radiation pattern for vertical polarization in Figure 18 This is also clear in

[0087] (Third Example Embodiment)

[0088] Next, a description will be given of a third example embodiment. The following description and drawings include omissions or appropriate simplifications for the sake of clarity. Furthermore, the same elements are denoted by the same reference numerals in the drawings, and redundant descriptions are omitted as necessary.

[0089] Figure 19 is a diagram showing a wireless device 300 according to the third example embodiment. Figure 19 is a plan view of the wireless device 200 from the Y direction. As Figure 16 indicated, the wireless device 300 includes the antenna device 26 (the antenna element 24 and the substrate 22), the driving unit 328, and the conductor 110 formed in a lateral U shape. Furthermore, the conductor 110 can be replaced with the conductor 210.

[0090] The driving unit 328 is disposed on the inner side of the substrate 22. The driving unit 328 is disposed on the upper edge portion 26a of the substrate 22. Furthermore, the tip of the antenna element 24 faces the outside of the antenna device 26. That is, in the third example embodiment, the power feeding position of the antenna element 24 is different from that in the first example embodiment.

[0091] Figure 20 is a diagram in which the radiation pattern for vertical polarization of the wireless device 300 according to the third example embodiment and the radiation pattern for vertical polarization in the case where the conductor 100 is removed from the wireless device 300 according to the third example embodiment are overlaid with each other. In Figure 20 , the radiation pattern for vertical polarization in the case where the conductor 110 is not included is indicated by a thick dotted line, and the radiation pattern for vertical polarization of the wireless device 300 according to the third example embodiment is indicated by a thick solid line.

[0092] As Figure 20As shown, the circle of the radiation pattern for the vertical polarization of the wireless device 300 according to the third example embodiment, or in other words, the circle of the radiation pattern for the vertical polarization in the case where the conductor 110 is included, is larger than the circle of the radiation pattern for the vertical polarization in the case where the conductor 110 is not included. That is, the vertical polarization of the wireless device 300 according to the third example embodiment is larger than the vertical polarization in the case where the conductor 110 is not included. Thus, with the wireless device 100 according to the third example embodiment, it is also possible to increase the vertical polarization radiation while preventing an increase in the height of the device. Thus, the antenna element 24 can take any form as long as a high-frequency current is excited in the conductor 110 formed in a lateral U-shape.

[0093] (Fourth Example Embodiment)

[0094] Next, a description will be given of a fourth example embodiment. The following description and drawings include omissions or appropriate simplifications for the sake of clarity. Furthermore, the same elements are denoted by the same reference numerals in the drawings, and redundant descriptions are omitted as necessary.

[0095] Figure 21 is a diagram showing a wireless device 400 according to the fourth example embodiment. Figure 21 is a perspective view of the wireless device 400. As Figure 21 shown, the wireless device 400 includes the antenna apparatus 26 (the antenna element 24 and the substrate 22) and a conductor 410 formed in a lateral U-shape. Furthermore, although not shown, like in the first example embodiment, the wireless device 400 includes the drive unit 28 for supplying power to the antenna element 24. Figure 21 The antenna apparatus 26 shown is substantially the same as the antenna apparatus 26 shown Figure 12 in FIG. 1.

[0096] The conductor 410 includes an upper portion 410a, a lower portion 410b, and an intermediate portion 410c. When viewed from the Y direction (the upward direction on the page), the conductor 410 is disposed so as to overlap the substrate 22 (the antenna apparatus 26).

[0097] In other aspects, the positional relationship of the conductor 410 to the substrate 22 and the size of the conductor 410 are substantially the same as in the case of the conductor 110 according to the first example embodiment. That is, the length of the conductor 410 is about 1 / 2 of the wavelength of the resonance frequency. Further, the upper portion 410a and the lower portion 410b are disposed along the ground plane 90 and are disposed above and below each other. The intermediate portion 410c is disposed substantially perpendicular to the ground plane 90, the intermediate portion 410c being located between one end PI of the upper portion 410a and one end P2 of the lower portion 410b. Further, the conductor 410 is disposed such that its upper portion 410a is along the upper edge portion 26a of the antenna device 26. The conductor 410 is disposed such that its lower portion 410b is along the lower edge portion 26b of the antenna device 26. The conductor 410 is disposed such that its intermediate portion 410c is along the side edge portion 26c of the antenna device 26.

[0098] Figure 22 is a graph in which the radiation pattern for vertical polarization of the wireless device 400 according to the fourth example embodiment overlaps with the radiation pattern for vertical polarization in the case where the conductor 410 is removed from the wireless device 400 according to the fourth example embodiment. In Figure 22 , the radiation pattern for vertical polarization in the case where the conductor 410 is not included is indicated by a thick dotted line, and the radiation pattern for vertical polarization of the wireless device 400 according to the fourth example embodiment is indicated by a thick solid line. In addition, the radiation pattern for vertical polarization in the case where the conductor 410 is not included is substantially the same as the radiation pattern for vertical polarization of the wireless device 20 according to the second comparative example.

[0099] As Figure 22 indicated, the circle of the radiation pattern for vertical polarization of the wireless device 400 according to the fourth example embodiment, or in other words, the circle of the radiation pattern for vertical polarization in the case where the conductor 410 is included, is larger than the circle of the radiation pattern for vertical polarization in the case where the conductor 410 is not included. That is, the vertical polarization of the wireless device 400 according to the fourth example embodiment is larger than the vertical polarization in the case where the conductor 410 is not included. Therefore, with the wireless device 400 according to the fourth example embodiment, it is also possible to increase the vertical polarization radiation while preventing an increase in the height of the device.

[0100] (Modified Type)

[0101] Further, the present application is not limited to the above-described example embodiments, and can be appropriately changed within the scope of the spirit of the present application. For example, in the above-described example embodiments, the antenna element 24 is a reverse L-shaped antenna, but the antenna element 24 is not limited to a reverse L-shaped antenna.

[0102] Moreover, in the example embodiment described above, it is assumed that the total length of the conductor formed in the lateral U-shape is about 1 / 2 of the wavelength of the resonance frequency, but such a configuration is not limiting. Resonance can be generated in the conductor even if the total length of the conductor formed in the lateral U-shape is about (1 / 2) x N (where N is an integer of 1 or more) of the wavelength. However, if N is 2 or more, the size of the conductor increases.

[0103] Moreover, in the example embodiment described above, the substrate 22 is formed so that the length in the horizontal direction is greater than the length in the vertical direction, but such a configuration is not limiting. On the other hand, by forming the substrate 22 so that the length in the horizontal direction is greater than the length in the vertical direction, not only the vertical polarization but also the horizontal polarization can be increased.

[0104] Thus far, the application of the present application has been described with reference to the example embodiments, but the application of the present application is not limited to the example embodiments described above. As for the configuration and details of the application of the present application, various modifications that can be understood by those skilled in the art can be made within the scope of the present application.

[0105] This application claims priority to Japanese Patent Application No. 2019-136946 filed on July 25, 2019, the entire contents of which are incorporated herein by reference.

[0106] List of Reference Signs

[0107] 22 substrate

[0108] 24 antenna element

[0109] 24a horizontal portion

[0110] 24b vertical portion

[0111] 26 antenna device

[0112] 26a upper edge portion

[0113] 26b lower edge portion

[0114] 26c side edge portion

[0115] 28 drive unit

[0116] 90 ground plane

[0117] 100 wireless device

[0118] 110 conductor

[0119] 110a upper portion

[0120] 110b lower portion

[0121] 110c middle portion

[0122] 200 wireless device

[0123] 210 conductor

[0124] 210a upper portion

[0125] 210b lower portion

[0126] 210c middle portion

[0127] 300 wireless device

[0128] 328 drive unit

[0129] 400 wireless device

[0130] 410 conductor

[0131] 410a upper portion

[0132] 410b lower portion

[0133] 410c middle portion

Claims

1. A wireless device, comprising: The antenna device comprises a substrate including a substrate ground portion and an antenna element disposed on the substrate. as well as The conductor is formed into a transverse U-shape, in which When the wireless device is positioned above the ground plane, which is the surface of the Earth, the conductor includes an upper portion and a lower portion disposed along the ground plane and positioned vertically relative to each other, and a middle portion disposed substantially perpendicular to the ground plane between one end of the upper portion and one end of the lower portion. The conductor is configured such that its upper portion, lower portion, and middle portion are close to the upper, lower, and side portions of the antenna device, respectively. The upper portion of the conductor is disposed near the antenna element, the length direction of the upper portion of the conductor is set to be along the length direction of the antenna element, and the conductor serves as an antenna because a current is induced in the conductor when power is supplied to the antenna element. The conductor is configured such that the gap between the middle portion of the conductor and the side portion of the antenna device is greater than the shortest interval between the upper portion of the conductor and the antenna element.

2. The wireless device according to claim 1, wherein, The conductor is configured such that its center is substantially perpendicular to the ground plane.

3. The wireless device according to claim 1 or 2, wherein, The substrate is formed such that its dimension in the direction perpendicular to the ground plane is smaller than its dimension in the direction parallel to the ground plane.

4. The wireless device according to claim 1, wherein, The size of the substrate in the direction perpendicular to the ground plane is equal to or less than 1 / 3 of the wavelength of the resonant frequency.

5. The wireless device according to claim 1, wherein, The conductor is arranged such that the gap between the middle portion of the conductor and the side portion of the antenna device is greater than a predetermined length.

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