Antenna device

Abstract

The antenna device is an antenna device disposed on a first surface, a second surface parallel to the first surface, and a third surface connecting the first surface and the second surface and perpendicular to the first surface and the second surface, and includes: a first antenna disposed on the first surface and the third surface; a second antenna disposed on the second surface; and a ground line disposed on the first surface. The first antenna has: a first power supply point disposed on the first surface; a conductive first element disposed on the first surface and extending from the first power supply point to the third surface; and a conductive second element disposed on the third surface and extending along the first surface from an end of the first element. The second antenna has: a second power supply point disposed spaced apart from the first power supply point in a direction parallel to the first surface and the second surface; and a conductive antenna element extending from the second power supply point. The ground line has: a ground point grounded; and a conductive ground line element connected to the ground point, including a portion extending along the first antenna and capacitively coupled to the first antenna.

Description

Technical Field

[0001] The present disclosure relates to an antenna device. Background Art

[0002] In the past, an antenna device corresponding to multiple frequency bands has been known (for example, refer to Patent Document 1). The antenna device disclosed in Patent Document 1 includes: a first antenna element connected to a first power supply unit; a second antenna element that resonates in a frequency band different from that of the first antenna element and is connected to a second power supply unit; and a ground line that is selectively connected to two different reactance elements via a switch. In the antenna device described in Patent Document 1, the antenna efficiency in each frequency band is improved by switching the reactance value of the reactance element connected to the ground line.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: JP-A-2011-120071 Summary of the Invention

[0006] The present disclosure provides an antenna device including two antennas, which can achieve miniaturization while ensuring isolation between the two antennas.

[0007] The antenna device according to one aspect of the present disclosure is disposed on a first surface, a second surface parallel to the first surface, and a third surface connecting the first surface and the second surface and perpendicular to the first surface and the second surface. The antenna device includes: a first antenna disposed on the first surface and the third surface; a second antenna disposed on the second surface; and a ground line disposed on the first surface. The first antenna has: a first power supply point disposed on the first surface; a conductive first element disposed on the first surface and extending from the first power supply point to the third surface; and a conductive second element disposed on the third surface and extending along the first surface from an end of the first element. The second antenna has: a second power supply point disposed in a direction parallel to the first surface and the second surface and isolated from the first power supply point; and a conductive antenna element extending from the second power supply point. The ground line has: a ground connection point grounded; and a conductive ground line element connected to the ground connection point, including a portion extending along the first antenna and capacitively coupled to the first antenna.

[0008] According to the present disclosure, an antenna device including two antennas can be provided, which can achieve miniaturization while ensuring isolation between the two antennas. Brief Description of the Drawings

[0009] Figure 1It is a schematic diagram showing the overall structure of the antenna device according to Embodiment 1.

[0010] Figure 2 It is a schematic diagram of the first surface of the antenna device according to Embodiment 1 as viewed from above.

[0011] Figure 3 It is a schematic diagram of the second surface of the antenna device according to Embodiment 1 as viewed from above.

[0012] Figure 4 It is a schematic diagram of the third surface of the antenna device according to Embodiment 1 as viewed from above.

[0013] Figure 5 It is a schematic diagram for explaining the loop antenna formed in Embodiment 1.

[0014] Figure 6 It is a graph showing the simulation results of the passing characteristics of the antenna device according to the comparative example.

[0015] Figure 7 It is a graph showing the simulation results of the passing characteristics of the antenna device according to Embodiment 1.

[0016] Figure 8 It is a graph showing the simulation results of the antenna efficiency of the antenna device according to the comparative example.

[0017] Figure 9 It is a graph showing the simulation results of the antenna efficiency of the antenna device according to Embodiment 1.

[0018] Figure 10 It is a schematic diagram showing the appearance of the communication terminal according to Embodiment 2.

[0019] Figure 11 It is a schematic diagram showing the overall structure of the antenna device according to Embodiment 2.

[0020] Figure 12 It is a schematic diagram of the first surface of the antenna device according to Embodiment 2 as viewed from above.

[0021] Figure 13 It is a schematic diagram of the second surface of the antenna device according to Embodiment 2 as viewed from above.

[0022] Figure 14 It is a schematic diagram of the third surface of the antenna device according to Embodiment 2 as viewed from above. Detailed Embodiments

[0023] The following specifically describes the embodiments with reference to the accompanying drawings.

[0024] In addition, the embodiments described below all show general or specific examples. The numerical values, shapes, materials, constituent elements, arrangement positions of the constituent elements, connection forms, steps, order of steps, etc. shown in the following embodiments are examples, and the gist thereof is not intended to limit the present disclosure.

[0025] In addition, each figure is a schematic diagram and is not necessarily strictly illustrated. In addition, in each figure, the same reference numerals are assigned to the same constituent members.

[0026] (Embodiment 1)

[0027] An antenna device according to Embodiment 1 will be described.

[0028] [1-1. Overall Structure]

[0029] First, Figures 1 to 4 will be used to describe the overall structure of the antenna device according to Embodiment 1. Figure 1 is a schematic diagram showing the overall structure of the antenna device 1 according to the present embodiment. In Figure 1 a perspective view of the antenna device 1 as viewed from the first surface P1 side is shown. Figure 2 , Figure 3 and Figure 4 are schematic diagrams of the first surface P1, the second surface P2, and the third surface P3 of the antenna device 1 according to the present embodiment as viewed from above, respectively.

[0030] The antenna device 1 is a wireless communication device that transmits and receives signals in a first frequency band and a second frequency band. The first frequency band and the second frequency band are not particularly limited. In the present embodiment, the first frequency band is a frequency band that includes the second frequency band. Specifically, the first frequency band is a frequency band of 1.2 GHz or higher and 6 GHz or lower, and the second frequency band is a frequency band of 2.4 GHz or higher and 6 GHz or lower. As Figure 1 shows, the antenna device 1 is disposed on a ground member 50 that is a conductive member serving as a ground. The ground member 50 is not particularly limited and is, for example, a frame of a terminal on which the antenna device 1 is disposed. The ground member 50 is formed of a conductive metal such as magnesium, for example.

[0031] As Figure 1As shown, the antenna device 1 is disposed on the first surface P1, the second surface P2, and the third surface P3. The second surface P2 is a surface parallel to the first surface P1. The third surface P3 is a surface that connects the first surface P1 and the second surface P2 and is perpendicular to the first surface P1 and the second surface P2. Here, the description of "parallel" not only refers to a completely parallel state, but also refers to a substantially parallel state. Specifically, a state where the inclination is 10° or less from the state where one surface is completely parallel to another surface is also referred to as "parallel". In addition, the description of "perpendicular" not only refers to a completely perpendicular state, but also refers to a substantially perpendicular state. Specifically, a state where the inclination is 10° or less from the state where one surface is completely perpendicular to another surface is also referred to as "perpendicular".

[0032] The antenna device 1 includes a first antenna 10, a second antenna 20, and a ground line 30. The antenna device 1 is disposed, for example, on an insulating substrate (not shown) having a first surface P1, a second surface P2, and a third surface P3. As the insulating substrate, for example, a flexible printed circuit (FPC) substrate or the like can be used. In addition, when using a flexible insulating substrate such as a flexible printed circuit substrate, the insulating substrate can also be disposed on a holder formed of an insulating material such as resin. Thereby, the shape of the insulating substrate can be stabilized.

[0033] The first antenna 10 is an antenna that resonates in the first frequency band. The first antenna 10 is disposed across the first surface P1 and the third surface P3 as shown in Figure 1 , Figure 2 and Figure 4 . The first antenna 10 has a first power supply point 14, a first element 11, and a second element 12. The electrical length of the first antenna 10, that is, the electrical length of the element formed by combining the first element 11 and the second element 12, is approximately 1 / 8 of the wavelength corresponding to the first frequency band. In the present embodiment, the electrical length of the first antenna 10 is 31.25 mm, which is 1 / 8 of the wavelength of 250 mm corresponding to 1.2 GHz. In addition, the wavelength includes the effective wavelength (the wavelength considering the wavelength shortening caused by the dielectric around the antenna element). The first antenna 10 can be used, for example, as an antenna for a wide-area data communication network based on wireless communication such as a communication network for mobile phones.

[0034] As shown in Figure 1 and Figure 2 , the first power supply point 14 is a power supply point disposed on the first surface P1 and is supplied with a signal in the first frequency band. Specifically, a signal in the first frequency band is supplied to the first power supply point 14 through a coaxial cable, a power supply pin, or the like. When using a coaxial cable, the inner conductor of the coaxial cable is connected to the first power supply point 14, and the outer conductor of the coaxial cable is connected to the ground member 50.

[0035] As Figure 1 and Figure 2 shown, the first element 11 is a conductive element disposed on the first surface P1 and extending from the first power supply point 14 to the third surface P3. In the present embodiment, the first element 11 extends from the first power supply point 14 in a direction perpendicular to the third surface P3.

[0036] As Figure 1 , Figure 2 and Figure 4 shown, the second element 12 is a conductive element disposed on the third surface P3 and extending along the first surface P1 from the end of the first element 11 (i.e., the end of the first element 11 far from the first power supply point 14). In the present embodiment, the second element 12 has a long strip shape extending from the end of the first element 11 in a direction parallel to the first surface P1.

[0037] The second antenna 20 is an antenna that resonates in the second frequency band. As Figure 1 and Figure 3 shown, the second antenna 20 is disposed on the second surface P2. The second antenna 20 has a second power supply point 24 and an antenna element 21. The electrical length of the second antenna 20 is approximately 1 / 4 of the wavelength corresponding to the second frequency band. In the present embodiment, the electrical length of the second antenna 20 is 31.25 mm, which is 1 / 4 of the wavelength 125 mm corresponding to 2.4 GHz. The second antenna 20 can be used, for example, as an antenna that resonates in the 2.4 GHz band and the 5 GHz band for a wireless LAN (Local Area Network).

[0038] The second power supply point 24 is a power supply point disposed on the second surface P2 and supplied with a signal in the second frequency band. The second power supply point 24 is disposed isolated from the first power supply point 14 in a direction parallel to the first surface P1 and the second surface P2. Specifically, the second power supply point 24 is supplied with a signal in the second frequency band through a coaxial cable, a power supply pin, etc. In the case of using a coaxial cable, the inner conductor of the coaxial cable is connected to the second power supply point 24, and the outer conductor of the coaxial cable is connected to the ground member 50. The second power supply point 24 can be disposed at a position as far as possible from the first power supply point 14. Thereby, the interference between the signal supplied to the first power supply point 14 and the signal supplied to the second power supply point 24 can be reduced. In the present embodiment, the second power supply point 24 is disposed isolated from the first power supply point 14 in a direction parallel to the first surface P1 and the second surface P2 (i.e., the X-axis direction).

[0039] In addition, the distance between the first surface P1 and the second surface P2 is 1 / 10 or less of the wavelength corresponding to the resonance frequency band of the first antenna 10.

[0040] As Figure 1 andFigure 3 As shown, the antenna element 21 is a conductive element disposed on the second surface P2 and extending from the second power supply point 24. In the present embodiment, the antenna element 21 has an L-shaped configuration. Specifically, the antenna element 21 has a portion extending from the second power supply point 24 in a direction intersecting the third surface P3, and a portion extending along the third surface P3 from the end of that portion remote from the second power supply point 24. In the present embodiment, the portion of the antenna element 21 that extends from the second power supply point 24 in a direction intersecting the third surface P3 extends from the second power supply point 24 in a direction perpendicular to the third surface P3.

[0041] The ground line 30 is a grounded conductive element, as Figure 1 and Figure 2 shown, disposed on the first surface P1. The ground line 30 has a ground connection point 34 and a ground line element 31.

[0042] The ground connection point 34 is a point grounded by connection to a ground member 50.

[0043] The ground line element 31 is a conductive element connected to the ground connection point 34, including a portion extending along the first antenna 10 and capacitively coupled to the first antenna 10. In the present embodiment, the ground line element 31 has an L-shaped configuration. Specifically, the ground line element 31 has a portion extending from the ground connection point 34 in a direction intersecting the third surface P3, and a portion extending along the third surface P3 from the end of that portion remote from the ground connection point 34. In the present embodiment, the portion of the ground line element 31 that extends from the ground connection point 34 in a direction intersecting the third surface P3 extends from the ground connection point 34 in a direction perpendicular to the third surface P3.

[0044] At least a part of the portion of the ground line element 31 that extends along the third surface P3 extends along the second element 12 of the first antenna 10. Thereby, the ground line element 31 is capacitively coupled to the first antenna 10. More specifically, at least a part of the portion of the ground line element 31 that extends along the third surface P3 extends along a portion including the open end of the second element 12 of the first antenna 10. Here, around the open end of the second element 12, the electric field intensity corresponding to the signal of the first frequency band becomes high. Therefore, by the ground line element 31 extending along such a portion including the open end of the second element 12, the ground line element 31 can be reliably capacitively coupled to the second element 12.

[0045] In addition, since the ground line element 31 and the second element 12 of the first antenna 10 are strongly capacitively coupled at a short distance, the capacitive coupling between the second antenna 20 disposed slightly away from the ground on a different second surface P2 and the first antenna 10 becomes weak.

[0046] In addition, the distance between the portion of the ground line element 31 extending along the second element 12 and the second element 12 is 1 / 100 or less of the wavelength corresponding to the resonance band of the first antenna 10. Thus, the ground line element 31 can be reliably capacitively coupled to the first antenna 10. Here, since the ground line 30 is connected to the ground member 50, the first antenna 10, the ground member 50, and the ground line 30 form a loop antenna. Here, Figure 5 is used to illustrate this loop antenna.

[0047] Figure 5 is a schematic diagram for illustrating the loop antenna formed in the antenna device 1 according to the present embodiment. As Figure 5 indicated by the dotted arrow in the figure, in the antenna device 1 according to the present embodiment, the first antenna 10, the ground line 30, and the ground member 50 form a loop antenna. By setting the electrical length of this loop antenna to an electrical length that resonates at the resonance band (i.e., the first band) of the first antenna 10, the antenna efficiency at the resonance band of the first antenna 10 can be improved. In the present embodiment, the electrical length of the above loop antenna is about 3 / 8 of the wavelength corresponding to the resonance band of the first antenna 10. More specifically, the electrical length of the above loop antenna is 93.75 mm, which is 3 / 8 of 250 mm, the wavelength corresponding to 1.2 GHz.

[0048] In addition, in the portion of the ground line element 31 extending along the second element 12, the direction from the end of the ground line element 31 close to the ground point 34 toward the open end of the ground line element 31 and the direction in the second element 12 from the end connected to the first element 11 toward the open end of the second element 12 are opposite directions. Here, the open end of the ground line element 31 is the end of the ground line element 31 away from the ground point, and the open end of the second element 12 is the end of the second element 12 away from the first element 11.

[0049] The electrical length of the ground line element 31 is not particularly limited. In the present embodiment, it is about 1 / 4 of the wavelength corresponding to the second band. More specifically, the electrical length of the ground line element 31 is 31.25 mm, which is 1 / 4 of 125 mm, the wavelength corresponding to 2.4 GHz.

[0050] In the present embodiment, the ground line 30 is disposed at a position facing the second antenna 20. In addition, the ground line element 31 includes a portion extending along the extending direction of the antenna element 21 of the second antenna 20. Specifically, the ground line element 31 includes: a portion extending in a direction intersecting the third plane P3; and a portion extending along the third plane P3.

[0051] Each of the first element 11 and the second element 12 of the first antenna 10, the antenna element 21 of the second antenna 20, and the ground element 31 of the ground line 30 is formed, for example, using a metal such as Cu, Al, Au, or an alloy containing multiple metals. In addition, each element can use, for example, printed wiring arranged on an insulating substrate. Additionally, the structure of each of these elements is not limited thereto. As each of these elements, for example, a rod-shaped, plate-shaped, or sheet-shaped conductive member can also be used. Furthermore, the manufacturing method of each element is not particularly limited and can be formed from a metal plate or by plating, vapor deposition, LDS (Laser Direct Structuring), etc.

[0052] [1-2. Function and Effect]

[0053] Next, the function and effect of the antenna device 1 according to the present embodiment will be described. First, the structural effect of the antenna device 1 according to the present embodiment will be described. As Figure 1 shown, etc., in the antenna device 1 according to the present embodiment, by three-dimensionally arranging each antenna and the ground line 30 dispersedly on the first surface P1, the second surface P2, and the third surface P3, miniaturization can be achieved compared to the case where each antenna and the ground line 30 are arranged on a plane. In the present embodiment, the shortest distance between the first antenna 10 and the second antenna 20 can be made close to about 1 / 20 of the wavelength corresponding to the second frequency band. When the 2.4 GHz frequency band is used as the second frequency band, the shortest distance between the first antenna 10 and the second antenna 20 can be set to about 6 mm.

[0054] In addition, in the antenna device 1 according to the present embodiment, by arranging a part of the first antenna 10 on the third surface P3, it is possible to avoid structural interference between the first antenna 10 and the ground line 30 arranged on the first surface P1 while ensuring the electrical length of the first antenna 10. In addition, by arranging the second antenna 20 on the second surface P2, it is possible to avoid structural interference between the second antenna 20 and the first antenna 10 and the ground line 30 while ensuring the electrical length of the second antenna 20.

[0055] Next, regarding the isolation characteristics between the first antenna 10 and the second antenna 20 of the antenna device 1 according to the present embodiment, while comparing with a comparative example, Figure 6 and Figure 7 will be used to explain. Figure 6 and Figure 7 are charts showing the simulation results of the passing characteristics of the comparative example and the antenna device according to the present embodiment, respectively. In Figure 6 and Figure 7 , the vertical axis represents the passing characteristics, and the horizontal axis represents the frequency. Figure 6 andFigure 7 The passing characteristic shown is an index indicating the proportion of the signal applied to the first antenna 10 that passes through the second antenna 20. That is, the lower the passing characteristic, the better the isolation characteristic.

[0056] The antenna device of the comparative example is different from the antenna device 1 according to the present embodiment in that it does not have the ground line 30, and is the same in other respects.

[0057] In Figure 6 In the antenna device according to the comparative example shown, in the 2.4 GHz band which is the resonance band of both the first antenna 10 and the second antenna 20, the passing characteristic is on the order of -8 dB to -9 dB. In the antenna device according to the comparative example, the first antenna 10 and the second antenna 20 share a grounding member 50 that functions as a ground, and the distance between these two antennas is small. Along with this, the electromagnetic waves resonating in these two antennas are coupled via the grounding member 50. Therefore, sufficient isolation between these two antennas cannot be ensured.

[0058] In contrast, in Figure 7 In the antenna device 1 according to the present embodiment shown, the passing characteristic is on the order of -17 dB to -19 dB. That is, compared with the antenna device of the comparative example, the antenna device 1 according to the present embodiment has improved isolation characteristics in the 2.4 GHz band. The degree of isolation characteristics required in a wireless communication device depends on the specifications of each device, and generally a passing characteristic of -10 dB or less is required. According to the antenna device 1 according to the present embodiment, such general requirements for isolation characteristics can be satisfied.

[0059] The improvement in the isolation characteristics in the antenna device 1 according to the present embodiment is due to the ground line 30 affecting the radiation directivity of the first antenna 10 and the second antenna 20. Specifically, the positional relationship between the ground line 30 and the first antenna 10 and the second antenna 20 is different from each other. Therefore, the ground line 30 brings different effects to the radiation directivity of the first antenna 10 and the second antenna 20 respectively. Along with this, the similarity of the radiation directivity of the first antenna 10 and the second antenna 20 is reduced. Therefore, it is speculated that since the coupling efficiency between the first antenna 10 and the second antenna 20 is reduced, the isolation characteristics between the first antenna 10 and the second antenna 20 are improved.

[0060] Next, regarding the antenna efficiencies of the first antenna 10 and the second antenna 20 of the antenna device 1 according to the present embodiment, while comparing with the above comparative example, use Figure 8 And Figure 9 To explain. Figure 8 And Figure 9 Are respectively charts showing the simulation results of the antenna efficiencies of the antenna device according to the comparative example and the present embodiment. Figure 8and Figure 9 The solid line and the dotted curve shown respectively represent the antenna efficiencies of the first antenna 10 and the second antenna 20. In Figure 8 and Figure 9 , the vertical axis represents the antenna efficiency and the horizontal axis represents the frequency. Figure 8 and Figure 9 The antenna efficiency shown refers to the ratio of the radiated power to the power supplied to the antenna.

[0061] As Figure 8 and Figure 9 shown, in the 1.2 GHz frequency band, the antenna efficiency of the first antenna 10 according to the comparative example is about -5 dB. In contrast, in the antenna device 1 according to the present embodiment, the antenna efficiency of the first antenna 10 is about -1.6 dB. This is because the resonance frequency of the first antenna is reduced from 1.5 GHz to 1.2 GHz, and the first antenna 10 according to the present embodiment is a loop antenna formed by the ground line 30 and the grounding member 50 to resonate in the 1.2 GHz frequency band.

[0062] That is, in the present embodiment, since not only the isolation between the first antenna 10 and the second antenna 20 is improved, but also such a loop antenna is formed, the low-frequency operation of the first antenna (i.e., the miniaturization of the antenna) can be achieved. Thus, in the antenna device 1 according to the present embodiment, the antenna efficiency of the first antenna 10 in the 1.2 GHz frequency band can be improved compared to the antenna device according to the comparative example.

[0063] In addition, as Figure 8 and Figure 9 shown, in the 2.4 GHz frequency band, the antenna efficiency of the second antenna 20 according to the comparative example is about -3.5 dB. In contrast, in the antenna device 1 according to the present embodiment, the antenna efficiency of the second antenna 20 is about -1.5 dB. Thus, in the antenna device 1 according to the present embodiment, the antenna efficiency of the second antenna 20 in the 2.4 GHz frequency band is improved compared to the antenna device according to the comparative example. This is presumably due to the following reason: Since the electrical length of the ground line 30 according to the present embodiment is about 1 / 4 of the wavelength corresponding to the 2.4 GHz frequency band as the second frequency band, the signal in the 2.4 GHz frequency band resonates in the ground line 30. That is, in the present embodiment, it is presumed that not only the second antenna 20 but also the ground line 30 contributes to the radiation of the signal in the 2.4 GHz frequency band.

[0064] As described above, according to the present embodiment, an antenna device can be provided. The antenna device 1 includes the first antenna 10 and the second antenna 20, and can be miniaturized while ensuring the isolation between these antennas. Further, according to the present embodiment, the antenna efficiency of each antenna of the antenna device 1 can also be improved. Thus, in the present embodiment, the antenna efficiency of each antenna can be improved while ensuring the isolation between the two antennas.

[0065] In addition, in the present embodiment, since the ground line 30 is disposed at a position opposite to the second antenna 20, the second power supply point 24 and the ground connection point 34 are close to each other, and the coupling efficiency between the second antenna 20 and the ground line 30 can be improved. Therefore, the radiation efficiency in the 2.4 GHz frequency band from the ground line 30 can be improved. Further, since the ground line 30 includes a portion extending along the direction in which the antenna element 21 of the second antenna 20 extends, it can be disposed in a limited space, and the antenna can be miniaturized.

[0066] (Embodiment 2)

[0067] An antenna device according to Embodiment 2 and a communication terminal including the antenna device will be described. The antenna device according to the present embodiment is different from the antenna device 1 according to Embodiment 1 mainly in that the first antenna and the second antenna each include a short circuit line. The following will use Figures 10 to 14 to describe the antenna device and the communication terminal according to the present embodiment, but a part of the description of the structure common to the antenna device 1 according to Embodiment 1 will be omitted.

[0068] Figure 10 is a schematic diagram showing the appearance of the communication terminal 102 according to the present embodiment. The communication terminal 102 according to the present embodiment is a terminal that performs wireless communication. As Figure 10 shown, it includes an antenna device 101. The communication terminal 102 further includes a display unit 190 and a housing 192. The communication terminal 102 is, for example, a tablet-type terminal.

[0069] The display unit 190 is a monitor that displays images in the communication terminal 102. As the display unit 190, for example, a liquid crystal display panel, an organic EL (Electro-Luminescence) display panel, or the like can be used.

[0070] The housing 192 is a housing that houses the antenna device 101 and other circuits and components included in the communication terminal 102. At least the periphery of the antenna device 101 in the housing 192 is formed of an insulating material such as resin. Thus, electromagnetic waves radiated from the antenna device 101 can be radiated to the outside of the housing 192, and electromagnetic waves incident from the outside can pass through the housing 192 and then propagate to the antenna device 101.

[0071] The antenna device 101 is a wireless communication device that transmits and receives signals in the first band and the second band, similar to the antenna device 1 as described in Embodiment 1. As Figure 10 shown, the antenna device 101 is disposed inside the housing 192. Hereinafter, Figures 11 to 14 will be used to describe the antenna device 101 according to this embodiment. Figure 11 is a schematic diagram showing the overall structure of the antenna device 101 according to this embodiment. In Figure 11 a perspective view of the antenna device 101 as viewed from the first surface P1 side is shown. Figure 12 、 Figure 13 and Figure 14 are schematic diagrams of the first surface P1, the second surface P2, and the third surface P3 of the antenna device 101 according to this embodiment, respectively, as viewed from above. In Figures 11 to 14 a state in which the housing 192 of the communication terminal 102 is removed is shown. As Figure 11 shown, the antenna device 101 is disposed on the ground member 150.

[0072] The ground member 150 is a grounded conductive member. In this embodiment, the ground member 150 is a member that functions as a frame of the communication terminal 102. The antenna device 101 is disposed and connected in a recess formed on the outer edge of the ground member 150. The ground member 150 is formed of a conductive material. The ground member 150 is formed of, for example, magnesium or the like.

[0073] As Figure 11 shown, the antenna device 101 according to this embodiment is disposed on the first surface P1, the second surface P2 parallel to the first surface P1, and the third surface P3 that connects the first surface P1 and the second surface P2 and is perpendicular to the first surface P1 and the second surface P2, and includes a first antenna 110, a second antenna 120, and a ground wire 130. The antenna device 101 is disposed, for example, on an insulating substrate (not shown) having the first surface P1, the second surface P2, and the third surface P3. In addition, in this embodiment, the first surface P1 is a surface disposed at a position closer to the back side of the display unit 190 in the communication terminal 102 than the display unit 190 (i.e., the back surface of the communication terminal 102). Further, the second surface P2 is a surface disposed at a position closer to the display unit 190 than the back side of the display unit 190 in the communication terminal 102 (i.e., the back surface of the communication terminal 102).

[0074] The first antenna 110 is an antenna disposed on the first surface P1 and the third surface P3, and as Figure 12 shown, has a first power supply point 114, a first element 111, a second element 112, a first short-circuit element 113, a first slit 115, and a first ground element 116.

[0075] The first power supply point 114 is a point to which a signal of the first frequency band is supplied. The first power supply point 114 has the same structure as the first power supply point 14 according to Embodiment 1.

[0076] The first element 111 is, as Figure 12 shown, a conductive element that is disposed on the first surface P1 and extends from the first power supply point 114 to the third surface P3. In the present embodiment, the first element 111 has a rectangular flat plate shape.

[0077] The second element 112 is, as Figure 12 well as Figure 14 shown, a conductive element that is disposed on the third surface P3 and extends along the first surface P1 from the end of the first element 111. In the present embodiment, the second element 112 has a rectangular flat plate shape. A first short - circuit element 113 is connected to the end of the second element 112 that is far from the first element 111.

[0078] The first short - circuit element 113 is a conductive element that shorts the first antenna 110 and the ground member 150. In the present embodiment, the first short - circuit element 113 is disposed on the first surface P1 and the third surface P3, and connects the end of the second element 112 that is far from the first element 111 and the first ground element 116. The first short - circuit element 113 shorts the second element 112 of the first antenna 110 and the ground member 150 via the first ground element 116. The first short - circuit element 113 is disposed along the first element 111 and the second element 112. A first slit 115 is disposed between the first short - circuit element 113 and the first element 111 and the second element 112. As Figure 12 shown, the first short - circuit element 113 has a long - strip - shaped portion disposed along the first element 111 on the first surface P1. Further, as Figure 14 shown, the first short - circuit element 113 has an L - shaped portion disposed along the second element 112 on the third surface P3.

[0079] The first slit 115 is, as Figure 12 well as Figure 14 shown, a slit that separates the first element 111 and the second element 112 of the first antenna 110 and the first short - circuit element 113.

[0080] The first ground element 116 is an element connected to the ground member 150. The first short - circuit element 113 is connected to the first ground element 116. The connection method of the first ground element 116 to the ground member 150 is not particularly limited. In the present embodiment, the first ground element 116 is connected to and fixed to the ground member 150 by being clamped between a conductive screw 118 screwed into a screw hole provided in the ground member 150 and the ground member 150.

[0081] The second antenna 120 is an antenna disposed on the second surface P2. As Figure 13 shown, it has a second power supply point 124, an antenna element 121, a second shorting element 123, a second slit 125, and a second ground element 126.

[0082] The second power supply point 124 is a point to which a signal of the second frequency band is supplied. The second power supply point 124 has the same structure as the second power supply point 24 according to Embodiment 1.

[0083] The antenna element 121, as Figure 13 shown, is a conductive element disposed on the second surface P2 and extending from the second power supply point 124. In the present embodiment, the antenna element 121 extends along the third surface P3 from the second power supply point 124. The antenna element 121 has a rectangular flat plate shape. A second shorting element 123 is connected to the end of the antenna element 121 that is far from the second power supply point 124.

[0084] The second shorting element 123 is a conductive element that shorts the second antenna 120 and the ground member 150. In the present embodiment, the second shorting element 123 is disposed on the second surface P2 and connects the end of the antenna element 121 that is far from the second power supply point 124 and the second ground element 126. The second shorting element 123 shorts the antenna element 121 of the second antenna 120 and the ground member 150 via the second ground element 126. The second shorting element 123 is disposed along the antenna element 121. A second slit 125 is disposed between the second shorting element 123 and the antenna element 121. As Figure 13 shown, the second shorting element 123 has a long strip-shaped portion disposed along the antenna element 121 on the second surface P2.

[0085] The second slit 125, as Figure 13 shown, is a slit that separates the antenna element 121 of the second antenna 120 and the second shorting element 123.

[0086] The second ground element 126 is an element connected to the ground member 150. The second shorting element 123 is connected to the second ground element 126. The connection manner of the second ground element 126 to the ground member 150 is not particularly limited. In the present embodiment, the second ground element 126 is connected to and fixed to the ground member 150 by being clamped by a conductive screw 128 screwed into a screw hole provided in the ground member 150 and the ground member 150.

[0087] The ground wire 130 is a conductive element grounded and, as Figure 11 shown, is disposed on the first surface P1. The ground wire 130, as Figure 12 shown, has a ground connection point 134 and a ground wire element 131.

[0088] The ground point 134 is a point grounded by being connected to a ground member 150.

[0089] The ground line element 131 is a conductive element that is connected to the ground point 134, includes a portion extending along the first antenna 110, and is capacitively coupled to the first antenna 110. In the present embodiment, the ground line element 131 has an L-shaped configuration. Specifically, the ground line element 131 has: a portion extending from the ground point 134 in a direction intersecting the third plane P3; and a portion extending along the third plane P3 from the end of that portion remote from the ground point 134. In the present embodiment, the portion of the ground line element 131 that extends from the ground point 134 in a direction intersecting the third plane P3 extends from the ground point 134 in a direction perpendicular to the third plane P3.

[0090] At least a part of the portion of the ground line element 131 that extends along the third plane P3 extends along the second element 112 of the first antenna 110. Thereby, the ground line element 131 is capacitively coupled to the first antenna 110. More specifically, at least a part of the portion of the ground line element 131 that extends along the third plane P3 extends along a portion including the open end of the second element 112 of the first antenna 110. Thereby, the ground line element 131 can be reliably capacitively coupled to the second element 112.

[0091] In addition, the distance between the portion of the ground line element 131 that extends along the second element 112 and the second element 112 is 1 / 100 or less of the wavelength corresponding to the resonance band of the first antenna 110. Thereby, the ground line element 131 can be reliably capacitively coupled to the first antenna 110. Here, since the ground line 130 is connected to the ground member 150, the first antenna 110, the ground member 150, and the ground line 130 form a loop antenna.

[0092] In the present embodiment, the ground line 130 is disposed at a position facing the second antenna 120. In addition, the ground line element 131 includes a portion extending along the direction in which the antenna element 121 of the second antenna 120 extends. Specifically, the ground line element 131 includes a portion extending along the third plane P3.

[0093] The connection manner of the ground line 130 to the ground member 150 is not particularly limited. In the present embodiment, the ground line 130 is connected to and fixed to the ground member 150 by being clamped by a conductive screw 138 screwed into a screw hole provided in the ground member 150 and the ground member 150.

[0094] In the antenna device 101 according to this embodiment, the same functions and effects as those of the antenna device 1 according to Embodiment 1 can also be achieved. In addition, in the communication terminal 102 according to this embodiment, since the antenna device 101 is provided, the same effects as those of the antenna device 101 can be achieved.

[0095] (Modifications, etc.)

[0096] The present disclosure has been described based on the above-described embodiments, but the present disclosure is not limited to the above-described embodiments. As long as the gist of the present disclosure is not deviated from, the solutions obtained by implementing various modifications conceived by those skilled in the art to the above-described embodiments can also be included in the scope of the present disclosure.

[0097] For example, in the above-described embodiments, the ground line is only arranged on the first surface P1, but the ground line can also be arranged on the third surface P3.

[0098] In addition, the shapes of the respective elements included in the antenna devices according to the above-described embodiments are not limited to the shapes illustrated in the above-described embodiments. The shapes of the respective elements can be an ellipse or the like, and can also be curved.

[0099] In addition, a meandering structure can be adopted for a part of the respective elements of the antenna devices according to the above-described embodiments.

[0100] In addition, in the above-described Embodiment 2, an example in which the antenna device 101 is applied to a flat-type terminal has been described, but the antenna devices according to the above-described embodiments can also be applied to other than flat-type terminals. For example, the antenna devices according to the above-described embodiments can also be applied to other communication terminals such as a notebook-type PC (Personal Computer) and a smart phone.

[0101] In addition, the modes realized by arbitrarily combining the constituent elements and functions in the respective embodiments within the scope not departing from the gist of the present disclosure are also included in the present disclosure.

[0102] Industrial Applicability

[0103] As an antenna device having two antennas and capable of achieving miniaturization while ensuring isolation between the two antennas, the antenna device of the present disclosure can be used, for example, in communication terminals such as flat-type terminals, notebook-type PCs, and smart phones.

[0104] Description of Reference Numerals

[0105] 1, 101 Antenna device

[0106] 10, 110 First antenna

[0107] 11, 111 First element

[0108] 12, 112 Second Element

[0109] 14, 114 First Power Supply Point

[0110] 20, 120 Second Antenna

[0111] 21, 121 Antenna Element

[0112] 24, 124 Second Power Supply Point

[0113] 30, 130 Ground Wire

[0114] 31, 131 Ground Wire Element

[0115] 34, 134 Grounding Point

[0116] 50, 150 Grounding Member

[0117] 102 Communication Terminal

[0118] 113 First Short - Circuit Element

[0119] 115 First Slit

[0120] 116 First Grounding Element

[0121] 118, 128, 138 Screw

[0122] 123 Second Short - Circuit Element

[0123] 125 Second Slit

[0124] 126 Second Grounding Element

[0125] 190 Display Unit

[0126] 192 Housing

[0127] P1 First Surface

[0128] P2 Second Surface

[0129] P3 Third Surface

Claims

1. An antenna device is disposed on a first surface, a second surface parallel to the first surface, and a third surface connecting the first surface and the second surface and perpendicular to the first surface and the second surface. The antenna device includes: A first antenna disposed on the first surface and the third surface; A second antenna disposed on the second surface; and A ground line disposed on the first surface. The first antenna has: A first power supply point disposed on the first surface; A conductive first element disposed on the first surface, extending from the first power supply point to the third surface; A conductive second element disposed on the third surface, extending along the first surface from an end of the first element. The second antenna has: A second power supply point disposed on the second surface isolated from the first power supply point; and A conductive antenna element extending from the second power supply point. The ground line has: A ground connection point grounded; and A conductive ground line element connected to the ground connection point, including a portion extending along the first antenna and capacitively coupled to the first antenna. The portion of the ground line element extending along the first antenna includes a portion extending along a portion including an open end of the second element. The ground connection point is connected to a grounded ground member, and the first antenna, the ground line element, and the ground member form a loop antenna.

2. The antenna device according to claim 1, wherein The distance between the portion of the ground line element extending along the second element and the second element is 1 / 100 or less of the wavelength corresponding to the resonance band of the first antenna.

3. The antenna device according to claim 2, wherein The electrical length of the loop antenna is 3 / 8 of the wavelength corresponding to the resonance band of the first antenna.

4. The antenna device according to any one of claims 1 to 3, wherein The ground line is disposed at a position facing the second antenna.

5. The antenna device according to any one of claims 1 to 3, wherein The electrical length of the ground line element is 1 / 4 of the wavelength corresponding to the resonance band of the second antenna.

6. The antenna device according to any one of claims 1 to 3, wherein In the portion of the ground line element extending along the portion including the open end of the second element, the direction from the end of the ground line element closer to the ground connection point to the open end of the ground line element and the direction from the end connected to the first element to the open end of the second element are opposite directions.

7. The antenna device according to any one of claims 1 to 3, wherein The distance between the first surface and the second surface is 1 / 10 or less of the wavelength corresponding to the resonance band of the first antenna.

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