Antenna device

Abstract

To provide an antenna device which can easily change the directivity of an antenna by a simple configuration.SOLUTION: An antenna device 10 for changing the directivity of electric waves, includes: a first substrate 100; and a power supply element 110 provided in the first substrate 100 and radiating electric waves by power supply. The antenna device 10 includes: a second substrate 200 located in a place away from the power supply element 110 in a radiation direction of an electric wave radiated from the power supply element and provided in parallel to a substrate flat surface of the first substrate 100; and a non-feeding element 210 provided in the second substrate 200 and operating as a waveguide unit.SELECTED DRAWING: Figure 1A

Description

[Technical field]

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

[0002] Conventionally, devices for changing the directivity of an antenna have been proposed. Patent Document 1 discloses an antenna device including a director, a reflector, and a radiator. The antenna device disclosed in Patent Document 1 switches between an arrangement in which a director, a radiator, and a reflector arranged in parallel at a predetermined interval show strong directivity to a 2.4 GHz signal, and an arrangement in which the antenna device functions as an omnidirectional antenna. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-26943 A Summary of the Invention [Problem to be solved by the invention]

[0004] The antenna device disclosed in Patent Document 1 uses a director and a reflector as parasitic elements. In general, the reflector needs to be set in a direction opposite to the direction in which the radio wave is to be emitted from the primary radiator. Therefore, the antenna device disclosed in Patent Document 1 needs to secure a space for installing the reflector.

[0005] The present invention has been made in consideration of the problems inherent in the conventional techniques, and an object of the present invention is to provide an antenna device that has a simple configuration and is capable of easily changing the antenna directivity. [Means for solving the problem]

[0006] An antenna device according to an embodiment of the present invention is an antenna device that changes the directivity of radio waves, and comprises a first substrate, a feed element provided on the first substrate that radiates radio waves when fed power, a second substrate located a predetermined distance away in the radiation direction of the radio waves radiated from the feed element and arranged parallel to the substrate plane of the first substrate, and a parasitic element provided on the second substrate that operates as a director. Effect of the Invention

[0007] According to the present invention, it is possible to provide an antenna device that has a simple configuration and is capable of easily changing the antenna directivity. [Brief description of the drawings]

[0008] [Figure 1A] 1 is a diagram showing a configuration of an antenna device according to an embodiment of the present invention; [Figure 1B] 1 is a diagram showing a configuration of an antenna device according to an embodiment of the present invention; [Figure 2A] 1 is a diagram showing a configuration of an antenna device according to an embodiment of the present invention; [Figure 2B] 1 is a diagram showing a configuration of an antenna device according to an embodiment of the present invention; [Diagram 3] 5A and 5B are diagrams for explaining a radiation pattern of the antenna device according to the embodiment. [Figure 4] 5A to 5C are diagrams for explaining the movement trajectory of the second substrate of the antenna device according to the present embodiment. [Diagram 5] 6A to 6C are diagrams for explaining radiation patterns when the position of the second substrate in the antenna device according to the present embodiment is changed. [Figure 6] 5A to 5C are diagrams illustrating directional gain in the maximum radiation direction for each position of the second substrate in the antenna device according to the present embodiment. [Figure 7] 13 is a diagram showing a configuration of an antenna device according to another embodiment. [Figure 8A] 13 is a diagram showing a configuration of an antenna device according to another embodiment. [Figure 8B]13 is a diagram showing a configuration of an antenna device according to another embodiment. [Figure 9] 13 is a diagram showing a configuration of an antenna device according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The antenna device 10 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the sake of explanation and may differ from the actual ratios. In addition, in the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0010] 1A is a diagram showing the configuration of an antenna device 10 according to this embodiment. The antenna device 10 according to this embodiment is a device for changing the directivity of radiated radio waves.

[0011] 1A, an antenna device 10 according to this embodiment includes a first substrate 100 and a feed element 110 that is provided on the first substrate 100 and emits radio waves when fed. The antenna device 10 also includes a second substrate 200 that is located a predetermined distance away in the radiation direction of the radio waves emitted from the feed element 110 and is provided parallel to the substrate plane of the first substrate 100. The antenna device 10 also includes a parasitic element 210 that is provided on the second substrate 200 and operates as a director.

[0012] In this embodiment, the first substrate 100 and the second substrate 200 are made of a printed circuit board, which is a dielectric substrate. In this embodiment, the feed element 110 has an electrical length that allows it to function as a half-wave dipole antenna at frequency f. Furthermore, the parasitic element 210 has an element length slightly shorter than that of the feed element 110 in the longitudinal direction, and functions as a director.

[0013] In the example shown in FIG. 1A, the longitudinal direction of the feed element 110 and the parasitic element 210 is defined as the X direction, and the lateral direction of the feed element 110 and the parasitic element 210 is defined as the Y axis direction. That is, the substrate plane of the first substrate 100 is formed on the XY plane in the example shown in FIG. 1A. Similarly, the substrate plane of the second substrate 200 is formed on the XY plane in the example shown in FIG. 1A. Also, the direction perpendicular to the XY plane is defined as the Z axis direction. That is, in the example shown in FIG. 1A, the first substrate 100 and the second substrate 200 are overlapped with a predetermined distance in the Z axis direction, and are provided at positions parallel to each other on the XY plane. The predetermined distance may be, for example, 0.159λ (see FIG. 1B).

[0014] 1A shows an example in which the length of the first substrate 100 in the longitudinal direction is 0.455λ, and the length of the second substrate 200 in the longitudinal direction is 0.45λ. Note that λ represents the wavelength in a vacuum for a radio wave of frequency f.

[0015] 1A, the second substrate 200 is shorter in the longitudinal direction by 0.005λ. The lengths of the first substrate 100 and the second substrate 200 in the lateral direction are both 0.15λ.

[0016] 1A shows an example in which the longitudinal length of feed element 110 is 0.305λ, and the longitudinal length of parasitic element 210 is 0.3λ. That is, in the example shown in FIG 1A, parasitic element 210 is (slightly) shorter in the longitudinal direction by 0.005λ.

[0017] Fig. 1B is a diagram showing the configuration of an antenna device 10 according to this embodiment. In the example shown in Fig. 1B, the antenna device 10 shown in Fig. 1A is shown as viewed from the side in the YZ plane. As shown in Fig. 1A, the distance between the feed element 110 and the parasitic element 210 of the antenna device 10 is 0.159λ.

[0018] The distance between the feed element 110 and the parasitic element 210 is generally considered to be about 0.25λ. In the configuration shown in Figures 1A and 1B, a dielectric substrate is used as the first substrate 100 and the second substrate 200, and therefore an example is shown in which the distance is 0.159λ, which is shorter than 0.25λ, due to the wavelength short-circuiting effect.

[0019] Fig. 2A is a diagram showing the configuration of an antenna device 10 according to this embodiment. As shown in Fig. 2A, in the antenna device 10 according to this embodiment, a first substrate 100 and a second substrate 200 are connected by a support arm 400. The antenna device 10 according to this embodiment changes the radiation direction determined by the feed element 110 and the parasitic element 210 by driving the support arm 400.

[0020] The driving of the support arm 400 is realized, for example, by providing a motor 500 for driving the support arm 400 on the side of the support arm 400 facing the first substrate 100 .

[0021] Fig. 2B is a diagram showing the configuration of the antenna device 10 according to this embodiment, and shows an example in which the support arm 400 is driven by the motor 500 to move the second substrate 200 in the Y-axis direction in the configuration shown in Fig. 2A. That is, as shown in Figs. 2A and 2B, the antenna device 10 according to this embodiment can change its directivity while maintaining the distance between the feed element 110 and the parasitic element 210.

[0022] Fig. 3 is a diagram for explaining the radiation pattern of the antenna device 10 according to this embodiment. In the example shown in Fig. 3, an example of the radiation pattern of the directional gain of the antenna device 10 modeled at a wavelength of frequency f=28 GHz in the configuration shown in Fig. 1A and Fig. 1B is shown. In the example shown in Fig. 3, the solid line shows the radiation pattern of the antenna when the second substrate 200 (substrate 2) is not included, and the dashed line shows the radiation pattern when the second substrate 200 (substrate 2) is included in the antenna device 10 according to this embodiment.

[0023] As shown in Fig. 3, the radiation pattern without the second substrate 200 is omnidirectional, but by disposing the second substrate 200 in the Z-axis direction as shown in Fig. 1B, the radiation pattern increases in the Z-axis direction. For example, in the example shown in Fig. 3, the gain in the Z-axis direction is 1.9 dB in the configuration without the second substrate 200, and 5.3 dB in the configuration with the second substrate 200, so the gain is greater in the configuration with the second substrate 200.

[0024] Fig. 4 is a diagram for explaining the movement trajectory of the second substrate 200 of the antenna device 10 according to this embodiment. In the example shown in Fig. 4, the angle from the negative direction of the Y axis to the Z axis direction is defined as angle θ.

[0025] Fig. 5 is a diagram for explaining the radiation pattern when the position of the second substrate 200 in the antenna device 10 according to this embodiment is changed. In the example shown in Fig. 5, the angle θ in Fig. 4 is 0, 30, 60, and 90 (deg.). As shown in Fig. 5, it can be seen that the maximum radiation direction of the radiation pattern changes in the same direction as the angle θ of the second substrate 200.

[0026] Fig. 6 is a diagram for explaining the directional gain in the maximum radiation direction for each position of the second substrate 200 in the antenna device 10 according to this embodiment. In the example shown in Fig. 6, the horizontal axis indicates the position of the second substrate 200, and the vertical axis indicates the directional gain in the maximum radiation direction. As shown in Fig. 6, it can be seen that changing the directivity by changing the position of the second substrate 200 does not have a significant effect on the directional gain. In other words, when the position of the second substrate 200 is changed, it is possible to appropriately change the directivity of the radio wave while maintaining the directional gain.

[0027] As described above, the antenna device 10 according to this embodiment is an antenna device 10 that changes the directivity of radio waves, and includes a first substrate 100 and a feed element 110 that is provided on the first substrate 100 and radiates radio waves when fed. The antenna device 10 also includes a second substrate 200 that is located a predetermined distance away in the radiation direction of the radio waves radiated from the feed element 110 and is provided parallel to the substrate plane of the first substrate 100. The antenna device 10 also includes a parasitic element 210 that is provided on the second substrate 200 and operates as a director.

[0028] As a result, the antenna device 10 can be realized as a device capable of easily changing the antenna directivity with a simple configuration.

[0029] Furthermore, the first substrate 100 and the second substrate 200 of the antenna device 10 may be connected by a support arm 400. The antenna device 10 may change the radiation direction determined by the feed element 110 and the parasitic element 210 by driving the support arm 400. This allows the antenna device 10 to change the directivity while maintaining the distance between the feed element 110 and the parasitic element 210.

[0030] Furthermore, the antenna device 10 may include a motor 500 for driving the support arm 400 on the first substrate 100 side of the support arm 400. This allows the antenna device 10 to change the directivity more accurately while maintaining the distance between the feed element 110 and the parasitic element 210.

[0031] (Other embodiments) Although the embodiments have been described in detail with reference to the drawings, the present embodiments are not limited to the contents described in the above embodiments. The components described above include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described above can be appropriately combined. Various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

[0032] In the above-mentioned embodiment, an example in which the parasitic element 210 is provided on one substrate is shown, but this configuration does not limit the configuration of the embodiment. FIG. 7 is a diagram showing the configuration of an antenna device 10 according to another embodiment. As shown in FIG. 7, the antenna device 10 includes a third substrate 300 that is located at a predetermined distance in the radiation direction of the radio wave radiated from the feed element 110 and is provided so as to be parallel to the substrate plane of the first substrate 100 and the substrate plane of the second substrate 200. The antenna device 10 shown in FIG. 7 further includes another parasitic element 310 that is provided on the third substrate 300 and operates as a director. The predetermined distance here may be, for example, 0.159λ, as in the example shown in FIG. 1B. This allows the antenna device 10 to have a higher directivity.

[0033] In the above embodiment, the support arm 400 is driven by the motor 500, and the second substrate 200 moves on a semicircle centered on the feed element 110. The support arm 400 and the form of movement of the second substrate 200 by the motor 500 do not limit the configuration of the embodiment. For example, the support arm 400 may be configured to move along a moving shaft 600 provided in the Y-axis direction while being extended and retracted by the motor 500. FIGS. 8A and 8B are diagrams showing the configuration of the antenna device 10 according to another embodiment. In the example shown in FIGS. 8A and 8B, the support arm 400 is configured to extend and retract in the longitudinal direction. This makes it possible to realize a more stable antenna device 10 in the movement of the second substrate 200. In addition, in the configuration shown in FIGS. 8A and 8B, the moving shaft 600 may be configured to rotate on the XY plane centered on the feed element 110. This allows antenna device 10 to place parasitic element 210 in the radiation direction of radio waves from feed element 110 at an appropriate position on the hemisphere.

[0034] In the above-described embodiment, the parasitic element 210 is provided on the planar second substrate 200. For example, as shown in FIG. 9, the second substrate 200 may be moved on the support jig 700 by winding the second substrate 200 with a winding mechanism 710. That is, in the configuration shown in FIG. 9, the second substrate 200 is arranged along the support jig 700. The support jig 700 is a semi-cylindrical jig located at a predetermined distance in the radiation direction of the radio wave emitted from the feed element 110. This allows the antenna device 10 to accurately set the position of the parasitic element 210 while stabilizing the position of the second substrate 200. The predetermined distance may be, for example, 0.159λ, as in the example shown in FIG. 1B.

[0035] The features of the antenna device 10 are described below.

[0036] The antenna device 10 according to the first aspect is an antenna device 10 that changes the directivity of radio waves, and includes a first substrate 100 and a feed element 110 that is provided on the first substrate 100 and radiates radio waves when fed. The antenna device 10 also includes a second substrate 200 that is located a predetermined distance away in the radiation direction of the radio waves radiated from the feed element 110 and is provided parallel to the substrate plane of the first substrate 100. The antenna device 10 also includes a parasitic element 210 that is provided on the second substrate 200 and operates as a director.

[0037] According to the above configuration, the antenna device 10 can realize a device that can easily change the antenna directivity with a simple configuration.

[0038] The first substrate 100 and the second substrate 200 of the antenna device 10 according to the second embodiment may be connected by a support arm 400. The antenna device 10 may change the radiation direction determined by the feed element 110 and the parasitic element 210 by driving the support arm 400.

[0039] According to the above configuration, the antenna device 10 can change the directivity while maintaining the distance between the feed element 110 and the parasitic element 210.

[0040] The antenna device 10 according to the third embodiment may include a motor 500 for driving the support arm 400 on the side of the support arm 400 facing the first substrate 100 .

[0041] According to the above configuration, the antenna device 10 can change the directivity more accurately while maintaining the distance between the feed element 110 and the parasitic element 210.

[0042] The support arm 400 of the antenna device 10 according to the fourth embodiment may be configured to be extendable and contractable in the longitudinal direction.

[0043] According to the above configuration, the antenna device 10 can be realized as a more stable antenna device 10 when the second substrate 200 moves.

[0044] The antenna device 10 according to the fifth aspect may include a third substrate 300 located in the radiation direction of the radio wave radiated from the feed element 110 and arranged parallel to the substrate plane of the first substrate 100 and the substrate plane of the second substrate 200. The antenna device 10 may further include another parasitic element 310 arranged on the third substrate 300 and operating as a director.

[0045] According to the above configuration, the antenna device 10 can further improve the directivity.

[0046] The antenna device 10 according to the sixth aspect is an antenna device 10 that changes the directivity of radio waves, and includes a first substrate 100 and a feed element 110 that is provided on the first substrate 100 and radiates radio waves when fed. The antenna device 10 also includes a semi-cylindrical support jig 700 that is located a predetermined distance away in the radiation direction of the radio waves radiated from the feed element 110. The antenna device 10 also includes a second substrate 200 that is disposed along the support jig 700, and a parasitic element 210 that is provided on the second substrate 200 and operates as a director.

[0047] According to the above configuration, the antenna device 10 can accurately set the position of the parasitic element 210 while stabilizing the position of the second substrate 200. [Explanation of symbols]

[0048] 10 Antenna device 100 First substrate 110 Power supply element 200 Second substrate 210, 310 Parasitic element 300 Third Board 400 Support Arm 410 Telescopic Support Arm 500 Motor 600 moving axis 700 Support jig 710 Winding mechanism

Claims

1. An antenna device that changes the directivity of radio waves, A first substrate; a power supply element provided on the first substrate and configured to radiate the radio wave when power is supplied; a second substrate located at a predetermined distance in the radiation direction of the radio wave radiated from the power supply element and provided so as to be parallel to a substrate plane of the first substrate; a parasitic element provided on the second substrate and operating as a director,

2. the first substrate and the second substrate are connected by a support arm; The antenna device according to claim 1 , wherein the radiation direction determined by the feed element and the parasitic element is changed by driving the support arm.

3. The antenna device according to claim 2 , further comprising a motor for driving the support arm, the motor being provided on a side of the support arm facing the first substrate.

4. The antenna apparatus according to claim 2 or 3, wherein the support arm is configured to extend and contract in a longitudinal direction.

5. a third substrate located at a predetermined distance in the radiation direction of the radio wave radiated from the power supply element and provided so as to be parallel to a substrate plane of the first substrate and a substrate plane of the second substrate; The antenna device according to claim 1 , further comprising: another parasitic element provided on the third substrate and operating as a director.

6. An antenna device that changes the directivity of radio waves, A first substrate; a power supply element provided on the first substrate and configured to radiate the radio wave when power is supplied; a semi-cylindrical support jig located at a predetermined distance in the radiation direction of the radio wave radiated from the power supply element; a second substrate disposed along the support jig; a parasitic element provided on the second substrate and operating as a director; An antenna device comprising:

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