Antenna device

Abstract

To provide an antenna device capable of reducing the frequency at which a reflecting mirror should be rotated for changing a main radiation direction of the antenna device.SOLUTION: An antenna device includes: a primary radiator radiating or receiving an electromagnetic wave and having an electronically controllable main radiation direction; a reflecting mirror reflecting the electromagnetic wave; a rotation mechanism rotating the reflecting mirror; and a controller electronically controlling the main radiation direction and controlling the rotation of the reflecting mirror by the rotation mechanism.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses an antenna device. In this antenna device, a primary radiator irradiates radio waves onto multiple reflectors. The multiple reflectors reflect the irradiated radio waves. A rotary drive device has the multiple reflectors mounted thereon and rotates the horizontal plane. The multiple elements of the primary radiator form a phased array in which a beam is scanned in the elevation angle direction (paragraphs 0019, 0021 and 0023). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4622898 Summary of the Invention [Problem to be solved by the invention]

[0004] In the antenna device disclosed in Patent Document 1, when the beam is scanned in the azimuth direction, the multiple reflectors must be rotated in a horizontal plane, which increases the frequency with which the multiple reflectors are rotated in the horizontal plane.

[0005] In view of this problem, an aspect of the present disclosure has been made. An object of the present disclosure is to provide an antenna device that can reduce the frequency at which a reflector needs to be rotated in order to change a main radiation direction of the antenna device, for example. [Means for solving the problem]

[0006] An antenna device according to one embodiment of the present disclosure comprises a primary radiator that emits or receives electromagnetic waves and has an electronically controllable main radiation direction, a reflector that reflects the electromagnetic waves, a rotation mechanism that rotates the reflector, and a controller that electronically controls the main radiation direction and controls the rotation of the reflector by the rotation mechanism. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view illustrating an antenna device according to a first embodiment. [Diagram 2] 2 is a block diagram of a control system of the antenna device of the first embodiment. FIG. [Diagram 3] This is a top view diagram illustrating a primary radiator and a reflector provided in the antenna device of the first embodiment, the main radiation direction of the primary radiator, the main radiation direction of the antenna device, and the beam pattern of the main lobe of the electromagnetic wave radiated or received by the antenna device. [Figure 4] 1 is a side view illustrating a schematic diagram of a primary radiator and a reflector provided in an antenna device of a first embodiment, the main radiation direction of the primary radiator, the main radiation direction of the antenna device, and the beam pattern of the main lobe of an electromagnetic wave radiated or received by the primary radiator. [Diagram 5] 2 is a block diagram of a signal system of the antenna device according to the first embodiment. FIG. [Figure 6] 5 is a flowchart showing a flow of control of the directivity of the antenna device according to the first embodiment. [Figure 7] 1 is a top view illustrating a schematic diagram of a reflector provided in an antenna device of the first embodiment, and changes in the beam pattern of the main lobe of an electromagnetic wave radiated or received by the antenna device when the directivity of the antenna device is controlled. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0009] 1. First embodiment 1.1 Antenna device FIG. 1 is a perspective view that diagrammatically illustrates an antenna device according to a first embodiment.

[0010] FIG. 1 illustrates the coordinate axes of a three-dimensional Cartesian coordinate system defined in a space in which the antenna device 1 of the first embodiment is disposed. Any two axes selected from the X-axis, Y-axis, and Z-axis included in the coordinate axes are perpendicular to each other. The X-axis and Y-axis extend in the horizontal direction. The Z-axis extends in the vertical direction. Therefore, the XY plane including the X-axis and Y-axis is a horizontal plane. The XZ plane including the X-axis and Z-axis and the YZ plane including the Y-axis and Z-axis are vertical planes. However, the X-axis and Y-axis may extend in a direction other than the horizontal direction. The Z-axis may extend in a direction other than the vertical direction. The XY plane may be a plane other than a horizontal plane. The XZ plane and YZ plane may be a plane other than a vertical plane.

[0011] In the following, the directions parallel to the X-axis toward the positive and negative sides of the X-axis are referred to as the +X and -X directions, respectively. Additionally, the directions parallel to the Y-axis toward the positive and negative sides of the Y-axis are referred to as the +Y and -Y directions, respectively. Additionally, the directions parallel to the Z-axis toward the positive and negative sides of the Z-axis are referred to as the +Z and -Z directions, respectively.

[0012] In the following, the angle that a direction in a plane parallel to the XY plane makes with the +X direction is called the azimuth angle of that direction. Also, the angle that a direction tilted toward the +Z direction from a direction parallel to the XY plane makes with the XY plane is called the elevation angle of that direction.

[0013] The antenna device 1 emits or receives electromagnetic waves. The antenna device 1 can mechanically and electronically change the azimuth angle of the main radiation direction of the antenna device 1, and can electronically change the elevation angle of the main radiation direction.

[0014] As shown in FIG. 1, the antenna device 1 includes a primary radiator 11, a reflector 12, and a rotation mechanism 13.

[0015] The primary radiator 11 radiates or receives an electromagnetic wave.

[0016] The primary radiator 11 has a radiation surface 11s. The radiation surface 11s radiates or receives electromagnetic waves. The radiation surface 11s is parallel to the XY plane.

[0017] The primary radiator 11 is capable of electronically controlling a main radiation direction of the primary radiator 11. The primary radiator 11 is capable of controlling an azimuth angle and an elevation angle of the main radiation direction.

[0018] The reflector 12 reflects the electromagnetic waves radiated or received by the primary radiator 11 .

[0019] The reflector 12 has a reflecting surface 12s. The reflecting surface 12s reflects the electromagnetic wave radiated or received by the primary radiator 11. When viewed from the radiation surface 11s of the primary radiator 11, the reflecting surface 12s is located in a direction midway between a direction D1 parallel to the XY plane and the +Z direction. The reflecting surface 12s faces a direction midway between a direction D2 opposite to the direction D1 and the -Z direction. As a result, the reflecting surface 12s reflects the electromagnetic wave radiated by the primary radiator 11 to generate an electromagnetic wave traveling in the direction D2, and reflects the electromagnetic wave traveling in the direction D1 to generate an electromagnetic wave received by the primary radiator 11.

[0020] The position and shape of the reflecting surface 12s of the reflector 12 are determined so that when the main radiation direction of the primary radiator 11 changes in a first plane parallel to the XY plane, the main radiation direction of the antenna device 1 changes in the first plane. In addition, the position and shape of the reflecting surface 12s are determined so that the beam width of the electromagnetic field generated by the reflecting surface 12s reflecting the electromagnetic wave radiated by the primary radiator 11 is narrower than the beam width of the electromagnetic wave radiated by the primary radiator 11. This makes it possible to increase the gain of the antenna device 1.

[0021] The rotation mechanism 13 rotates the reflecting mirror 12. The primary radiator 11 is fixed. The rotation mechanism 13 may rotate the primary radiator 11.

[0022] The rotation mechanism 13 rotates the primary radiator 11 and the reflector 12 in a first plane parallel to the XY plane. As a result, the rotation mechanism 13 rotates the direction D2 in which the electromagnetic waves radiated by the antenna device 1 travel and the direction D1 in which the electromagnetic waves received by the antenna device 1 travel in the first plane. Since the XY plane is a horizontal plane, the first plane is also a horizontal plane. The rotation mechanism 13 rotates the primary radiator 11 and the radiation surface 11s around a rotation axis that passes through the center of the radiation surface 11s of the primary radiator 11 and is parallel to the Z axis.

[0023] As shown in FIG. 1, the rotation mechanism 13 includes a rotation table 21 .

[0024] The rotating base 21 has a disk-like shape. The rotating base 21 has a main surface 21s. A hole 21h is formed in the rotating base 21. The reflecting mirror 12 is fixed to the main surface 21s and disposed parallel to the main surface 21s. The primary radiator 11 is housed in the hole 21h.

[0025] 1.2 Control system FIG. 2 is a block diagram of a control system of the antenna device of the first embodiment.

[0026] As shown in FIG. 2, the antenna device 1 includes a primary radiator 11, a rotation mechanism 13, and a controller .

[0027] The controller 14 controls the primary radiator 11 and the rotation mechanism 13 .

[0028] The controller 14 electronically controls the main radiation direction of the primary radiator 11. Thus, the controller 14 can change the main radiation direction of the antenna device 1 by electronically changing the main radiation direction of the primary radiator 11 while keeping the position of the reflector 12 fixed. Thus, the situation in which the reflector 12 must be rotated is only when the main radiation direction of the antenna device 1 must be changed to a range outside the range that can be changed by electronically changing the main radiation direction of the primary radiator 11. Thus, the frequency at which the reflector 12 must be rotated to change the main radiation direction of the antenna device 1 can be reduced. This effect is particularly noticeable when the antenna device 1 is provided in a semi-fixed communication terminal such as a customer premises equipment (CPE). The controller 14 rotates the main radiation direction of the primary radiator 11 in a first plane parallel to the XY plane and in a second plane non-parallel to the first plane. Thus, the main radiation direction of the antenna device 1 can be changed in the first plane and the second plane. As described above, the first surface is a horizontal surface, and the second surface is a vertical surface that is perpendicular to the first surface.

[0029] The controller 14 controls the rotation of the reflecting mirror 12 by the rotation mechanism 13 .

[0030] 1.3 Control of directivity in the first plane Figure 3 is a top view diagrammatically illustrating the primary radiator and reflector provided in the antenna device of the first embodiment, the main radiation direction of the primary radiator, the main radiation direction of the antenna device, and the beam pattern of the main lobe of the electromagnetic wave radiated or received by the antenna device.

[0031] 3, when the controller 14 rotates the main radiation direction of the primary radiator 11 in the first plane, the controller 14 rotates the main radiation direction of the primary radiator 11 in a range R in which the main radiation direction of the primary radiator 11 is a direction toward the reflector 12. For this reason, the controller 14 changes the main radiation direction of the primary radiator 11, for example, between a plurality of different directions A11, A12, A13, A14, and A15 included in the range R. The plurality of directions A21, A22, A23, A24, and A25 in which electromagnetic waves travel, generated by reflecting the electromagnetic waves traveling in the plurality of directions A11, A12, A13, A14, and A15 by the reflecting surface 12s of the reflector 12, are different from each other. For this reason, the controller 14 changes the main radiation direction of the antenna device 1, for example, among a plurality of different directions A21, A22, A23, A24 and A25, and changes the beam pattern of the main lobe of the electromagnetic waves radiated or received by the antenna device 1, for example, among a plurality of different beam patterns BP21, BP22, BP23, BP24 and BP25.

[0032] 1.4 Control of directivity in the second plane Figure 4 is a side view illustrating a schematic diagram of a primary radiator and reflector provided in the antenna device of the first embodiment, the main radiation direction of the primary radiator, the main radiation direction of the antenna device, and the beam pattern of the main lobe of the electromagnetic wave radiated or received by the primary radiator.

[0033] As shown in Figure 4, when the controller 14 rotates the main radiation direction of the primary radiator 11 in the second plane, it rotates the main radiation direction of the primary radiator 11 between a first direction E11 toward the reflector 12 and a second direction E12 away from the reflector 12.

[0034] The electromagnetic wave traveling in the first direction E11 is reflected by the reflector 12. The electromagnetic wave generated by reflecting the electromagnetic wave traveling in the first direction E11 by the reflecting surface 12s of the reflector 12 travels in a direction E21 having a first elevation angle. Therefore, the first direction E11 is a direction in which the main radiation direction of the antenna device 1 is the direction E21 having the first elevation angle. The electromagnetic wave traveling in the direction E21 having the first elevation angle, which is radiated by the antenna device 1, is generated by reflecting the electromagnetic wave traveling in the first direction E11 by the reflecting surface 12s. Therefore, the first direction E11 is different from the main radiation direction of the antenna device 1. The first elevation angle is, for example, 0°. When the first elevation angle is 0°, the direction E21 having the first elevation angle is the horizontal direction.

[0035] The electromagnetic wave traveling in the second direction E12 is not reflected by the reflector. Therefore, the electromagnetic wave traveling in the second direction E12 travels directly in a direction E22 having a second elevation angle that is larger than the first elevation angle. Therefore, the second direction E12 is a direction in which the main radiation direction of the antenna device 1 is the direction E22 having the second elevation angle. The electromagnetic wave traveling in the direction E22 having the second elevation angle that is radiated by the antenna device 1 is the electromagnetic wave traveling in the second direction E12 itself. Therefore, the second direction E12 is the same as the main radiation direction of the antenna device 1.

[0036] The beam width of the electromagnetic wave traveling in the direction E21 having the first elevation angle becomes narrower than the beam width of the electromagnetic wave traveling in the first direction E11 because the electromagnetic wave traveling in the first direction E11 is reflected by the reflecting surface 12s of the reflector 12. For this reason, the gain of the antenna device 1 when the controller 14 sets the main radiation direction of the primary radiator 11 to the first direction E11 is higher than the gain of the antenna device 1 when the controller 14 sets the main radiation direction of the primary radiator 11 to the second direction E12.

[0037] The first direction E11 and the direction E21 having the first elevation angle are suitable when the distance from the antenna device 1 to the communication partner, such as a wireless base station, is long. This is because, when the distance is long, the elevation angle of the direction from the antenna device 1 to the communication partner becomes small and the direction approaches the horizontal direction. Also, when the distance is long, the amount of attenuation that the electromagnetic waves experience when propagating from the communication partner to the antenna device 1 becomes large, and the gain required of the antenna device 1 becomes high.

[0038] The second direction E12 and the direction E22 having the second elevation angle are suitable when the distance from the antenna device 1 to the communication partner, such as a wireless base station, is short. This is because, when the distance is short, the elevation angle of the direction from the antenna device 1 to the communication partner becomes large, and the direction approaches the vertical upward direction. Also, when the distance is short, the amount of attenuation that the electromagnetic waves undergo when propagating from the communication partner to the antenna device 1 becomes small, and the gain required for the antenna device 1 can be low.

[0039] The controller 14 includes a microcontroller, peripheral circuits, etc. The microcontroller includes a processor, memory, etc. The processor executes a control program stored in the memory to operate the microcontroller, peripheral circuits, etc. as the controller 14. All or part of the functions of the microcontroller may be implemented by a dedicated electronic circuit.

[0040] 1.5 Signal System FIG. 5 is a block diagram of a signal system of the antenna device of the first embodiment.

[0041] As shown in Fig. 5, the primary radiator 11 includes a plurality of antenna elements 31. Fig. 5 illustrates a case where the plurality of antenna elements 31 is 16 antenna elements. However, the plurality of antenna elements 31 may be 15 or less or 17 or more antenna elements.

[0042] The plurality of antenna elements 31 are arranged in a matrix to form a phased array. The method of arranging the plurality of antenna elements 31 may be changed.

[0043] As shown in FIG. 5, the antenna device 1 includes a controller 14 and a radio frequency integrated circuit (RFIC) 15.

[0044] The controller 14 generates a control signal. The RFIC 15 adjusts the phase of a radio frequency (RF) signal input to or input from the multiple antenna elements 31 according to the generated control signal, thereby adjusting the main radiation direction of the primary radiator 11.

[0045] The primary radiator 11 may include a plurality of antenna elements 31 having different main radiation directions. In this case, the RFIC 15 selects an antenna element 31 from the plurality of antenna elements 31 according to the generated control signal, and adjusts the main radiation direction of the primary radiator 11 by inputting an RF signal to the selected antenna element 31 or receiving an RF signal from the selected antenna element 31.

[0046] 1.6 Reflector As shown in FIG. 1, the reflecting surface 12s of the reflecting mirror 12 has a first surface 121, a second surface 122, and a third surface 123. The second surface 122, the first surface 121, and the third surface 123 are arranged in the described order in the direction D1 and in the direction D3 perpendicular to the Z axis. The first surface 121 and the second surface 122 are adjacent to each other. The first surface 121 and the third surface 123 are adjacent to each other. The second surface 122 is continuous from the first surface 121. The third surface 123 is continuous from the first surface 121.

[0047] Each surface 120 of the first surface 121, the second surface 122, and the third surface 123 is a concave curved surface. Therefore, the first surface 121, the second surface 122, or the third surface 123 reflects the electromagnetic wave radiated or received by the primary radiator 11, thereby narrowing the beam width of the electromagnetic wave radiated or received by the antenna device 1. This makes it possible to increase the gain of the antenna device 1.

[0048] The curvature of each surface 120 in a direction D4 perpendicular to the direction D1 and parallel to the Z axis is greater than the curvature of each surface 120 in the direction D3. For example, the curvature of each surface 120 in the direction D4 is greater than the curvature of each surface 120 in the direction D3. This allows the beam width in the first plane to be relatively wide, and the beam width in the second plane to be relatively narrow. This allows the gain of the antenna device 1 to be increased while facilitating the search for the azimuth angle in the direction from which the electromagnetic wave from the communication destination arrives.

[0049] Furthermore, by having the second surface 122 and the third surface 123 on both sides of the first surface 121 of the reflecting surface 12s of the reflecting mirror 12, the beam width in the first surface can be widened. This makes it easier to search for the azimuth angle of the direction in which the electromagnetic waves from the communication destination arrive. However, both or either of the second surface 122 and the third surface 123 may be omitted.

[0050] The curvature of the second surface 122 and the third surface 123 in the direction D3 is zero.

[0051] The curvature of the second surface 122 and the third surface 123 in the direction D4 may be the same as the curvature of the first surface 121 in the direction D4, or may be different from the curvature of the first surface 121 in the direction D4.

[0052] The radiation surface 11s is disposed so as to be shifted from the focal point of the curvature of the first surface 121 in the direction D3. As a result, when the main radiation direction of the primary radiator 11 changes in the first surface parallel to the XY plane, the main radiation direction of the antenna device 1 changes in the first surface.

[0053] The reflecting surface 12 may have a shape other than the above-mentioned shapes. For example, the reflecting surface 12 may be a paraboloid, a paraboloid of revolution, or the like. When the reflecting surface 12 is a paraboloid or a paraboloid of revolution, the radiation surface 11s is disposed so as to be shifted from the focal point of the paraboloid or the paraboloid of revolution. As a result, when the main radiation direction of the primary radiator 11 changes in a first plane parallel to the XY plane, the main radiation direction of the antenna device 1 changes in the first plane.

[0054] 1.7 Controlling the directivity of antenna devices Fig. 6 is a flowchart showing a flow of controlling the directivity of the antenna device of the first embodiment in a first plane. Fig. 7 is a top view showing a reflector provided in the antenna device of the first embodiment and a schematic diagram of changes in a beam pattern of a main lobe of an electromagnetic wave radiated or received by the antenna device when the directivity of the antenna device is controlled.

[0055] When the directivity of the antenna device 1 in the first plane is to be controlled, steps S11 and S12 shown in FIG. 6 are executed.

[0056] 7, the controller 14 electronically controls the main radiation direction of the primary radiator 11 while fixing the position of the reflector 12 at the first position P1 using the rotation mechanism 13, thereby scanning the main scanning direction of the antenna device 1. In this way, the controller 14 changes the beam pattern of the main lobe of the electromagnetic wave radiated or received by the antenna device 1, for example, among a plurality of beam patterns BP31, BP32, and BP33.

[0057] 7, in step S12 after step S11, the controller 14 causes the rotation mechanism 13 to rotate the reflector 12 so that the position of the reflector 12 changes from a first position P1 to a second position P2, thereby scanning the antenna device 1 in the main scanning direction. As a result, the controller 14 changes the beam pattern of the main lobe of the electromagnetic wave radiated by the antenna device 1 to, for example, beam patterns BP41, BP42, and BP43.

[0058] In this way, by having the rotating mechanism 13 rotate the reflector 12 to scan the main scanning direction of the antenna device 1, the frequency with which the rotating mechanism 13 rotates the reflector 12 can be reduced by prioritizing scanning the main scanning direction of the antenna device 1 by electronically controlling the main scanning direction of the primary radiator 11.

[0059] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that has the same action and effect, or a configuration that can achieve the same purpose. [Explanation of symbols]

[0060] 1 Antenna device, 11 Primary radiator, 11s Radiation surface, 12 Reflector, 12s Reflection surface, 120 Each surface, 121 First surface, 122 Second surface, 123 Third surface, 13 Rotation mechanism, 14 Controller, 15 Radio frequency integrated circuit (RFIC), 21 Rotation table, 21s Main surface, 21h Hole, 31 Antenna element, A11, A12, A13, A14, A15, A21, A22, A23, A24, A25 Direction, BP21, BP22, BP23, BP24, BP25, BP31, BP32, BP33, BP41, BP42, BP43 Beam pattern, D1, D2, D3, D4 Direction, E11 First direction, E12 Second direction, E21 Direction having a first elevation angle, E22 Direction with second elevation angle, P1 first position, P2 second position, R range.

Claims

1. a primary radiator for emitting or receiving electromagnetic waves and having an electronically controllable main radiation direction; A reflector that reflects the electromagnetic wave; A rotation mechanism that rotates the reflecting mirror; a controller that electronically controls the main radiation direction and controls the rotation of the reflector by the rotation mechanism; An antenna device comprising:

2. The rotation mechanism rotates the reflecting mirror within a first plane, The controller rotates the main radiation direction in the first plane.

2. The antenna device according to claim 1.

3. The first surface is a horizontal surface.

3. The antenna device according to claim 2.

4. The controller rotates the main radiation direction in the first plane within a range in which the main radiation direction is a direction toward the reflector.

4. The antenna device according to claim 2 or 3.

5. The controller rotates the main radiation direction in a second plane non-parallel to the first plane.

4. The antenna device according to claim 2 or 3.

6. The second surface is a vertical surface.

6. The antenna device according to claim 5.

7. The controller rotates the primary radiation direction in the second plane between a first direction toward the reflector and a second direction away from the reflector.

6. The antenna device according to claim 5.

8. the first direction is a direction in which a main radiation direction of the antenna device has a first elevation angle; The second direction is a direction in which a main radiation direction of the antenna device has a second elevation angle that is larger than the first elevation angle.

8. The antenna device according to claim 7.

9. the first direction is different from a main radiation direction of the antenna device, The second direction is the same as the main radiation direction of the antenna device.

9. The antenna device according to claim 8.

10. The controller scans the main radiation direction of the antenna device by electronically controlling the main radiation direction, and then scans the main radiation direction of the antenna device by rotating the reflector using the rotating mechanism.

4. An antenna device according to claim 1.

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