Lens, antenna device, communication device and mobile body

Abstract

To provide a lens adopted for an antenna device with a simple structure that a communication quality deterioration and a communication interruption are hardly generated in the case where it is adopted to a communication between mobile bodies.SOLUTION: A lens comprises a lens main body of a dielectric body, including a penetration hole in which a horizontal inner surface non-directional antenna is arranged, and includes a convex-like outer curvature of a rotation symmetry to a circumference of a center shaft of the penetration hole, and formed by a whole or a part of a peripheral direction of the rotation symmetry. An inner surface faced to the penetration hole of the lens main body is separated from the center shaft of the penetration hole by λ / 2π or more, and a distance of a separation may be not equal to a focal distance F in a radial direction of the lens main body. The outer curvature surface of the lens main body may be an aspherical surface that is determined on the basis of a relative dielectric constant of the dielectric body, a distance from the focal distance in the radial direction of the lens main body, and an end edge from a shaft direction center of the inner surface of the lens main body. The focal distance F in the radial direction of the lens main body may be a double of λ / 2π (λ is a wavelength of an electric wave). In the lens main body, a reflection member may be arranged in a partial omission part one part of the peripheral direction of the rotational symmetry is omitted.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a lens suitable for vehicle-to-vehicle communication using radio waves such as microwaves, millimeter waves, and submillimeter waves, as well as an antenna device, a communication device, and a mobile object that include the lens. [Background technology]

[0002] Conventionally, communication devices having antenna devices that can be mounted on moving bodies such as vehicles for performing inter-vehicle communication, such as inter-vehicle communication, have been known. For example, Patent Document 1 discloses a communication device that is mounted on a first moving body (vehicle) that can move along a moving path, and that performs inter-vehicle communication (inter-vehicle communication) with another second moving body (vehicle) as the first moving body moves along the moving path. This communication device forms a directional beam toward the second moving body using a directional antenna, and starts tracking the directional beam toward the second moving body when the second moving body moves out of the range of the directional beam and communication disconnection is predicted, thereby enabling inter-vehicle communication to be continued even when changing lanes on the moving path, turning right or left at an intersection, driving around a curve, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-113227 Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional communication device for performing communication between mobile bodies such as inter-vehicle communication, there is a demand for an antenna device with a simple configuration that is less susceptible to deterioration in communication quality or interruption of communication when applied to inter-mobile communication. [Means for solving the problem]

[0005] A lens according to one aspect of the present invention is a lens for microwave, millimeter wave, or submillimeter wave radio waves. This lens includes a dielectric lens body having a through hole in which an omnidirectional antenna in a horizontal plane is disposed, the lens body being made of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric about the central axis of the through hole, in the entire circumferential direction or in part.

[0006] In the lens, the inner surface of the lens body facing the through hole may be spaced apart from the central axis of the through hole by λ / 2π or more (λ: wavelength of radio waves), and the distance of the space may be equal to a focal length F in the radial direction of the lens body. Here, the radial direction of the lens body is a direction along the radius or diameter of the lens body that passes through the center of the lens body and is perpendicular to the central axis.

[0007] In any of the above lenses, the outer curved surface of the lens body has a dielectric constant ε r The lens may have an aspherical surface determined based on a focal length F in the radial direction of the lens body and a distance R from the center to the edge of the inner surface of the lens body in the direction along the rotation axis.

[0008] In any of the lenses described above, a focal length F in the radial direction of the lens body may be an integer multiple of λ / 2 (λ: wavelength of radio waves).

[0009] In any of the lenses described above, the lens body may have a shape in which a portion of the rotationally symmetric body is missing in the circumferential direction, and a reflective member that reflects the radio waves may be disposed in the missing portion in the circumferential direction of the lens body.

[0010] In any of the lenses described above, the rotationally symmetric body may have a shape with one rotational symmetry about the central axis of the through hole. The rotationally symmetric body may have a plurality (n) rotational symmetry shapes about the central axis of the through hole. The rotationally symmetric body may have rotationally symmetric shapes formed discretely at predetermined angles (at predetermined angle steps) about the central axis of the through hole. For example, the rotationally symmetric body may have a two- or three-degree rotational symmetry shape formed discretely at 180 degrees or 120 degrees about the central axis of the through hole. The rotationally symmetric body may have a 36-, 18-, or 21-degree rotational symmetry shape formed discretely at 10 degrees, 20 degrees, or 30 degrees about the central axis of the through hole.

[0011] An antenna device according to another aspect of the present invention includes any one of the lenses described above and an antenna that is omnidirectional in a horizontal plane and is disposed in a through-hole of the lens.

[0012] A communication device according to yet another aspect of the present invention includes the antenna device described above and a wireless communication unit connected to the antenna of the antenna device.

[0013] A mobile body according to still another aspect of the present invention includes the communication device and performs inter-mobile body communication with another mobile body located at least one of in front and behind in the direction of movement.

[0014] In the mobile body, the antenna device may have a directional beam with a beam width of 150 degrees or more and 180 degrees or less in mobile-to-mobile communication with the other mobile body.

[0015] The mobile body may include a plurality of the antenna devices at least on either the front or rear side in the direction of movement of the mobile body, and the same radio wave may be transmitted or received via the plurality of antenna devices. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an antenna device with a simple configuration that is less likely to cause deterioration in communication quality or interruption of communication when applied to mobile communication. [Brief explanation of the drawings]

[0017] [Figure 1] 1(a) is a diagram showing an example of the directivity characteristic in the horizontal plane of a dipole antenna applicable to the antenna device according to the embodiment, and FIG. 1(b) is a diagram showing an example of the directivity characteristic in the vertical plane of the same dipole antenna. [Figure 2] FIG. 2 is a diagram showing an example of the horizontal plane directivity characteristic of a half-wave dipole antenna. [Figure 3] FIG. 3 is a front view showing an example of an antenna device in which a half-wave dipole antenna and a single aspherical lens are combined. [Figure 4] FIG. 4 is a diagram showing an example of the directivity characteristic in the horizontal plane of the antenna device of FIG. [Figure 5] 5(a) and 5(b) are diagrams illustrating the problems that arise when a plurality of vehicles, each equipped with an antenna device having beam directivity, travel while performing inter-vehicle communication. [Figure 6] FIG. 6 is a diagram showing the positional relationship between an aspherical lens as a basic shape element used to design the shape of a lens that constitutes the antenna device of the embodiment and a half-wave dipole antenna. [Figure 7] Fig. 7(a) is a perspective view of the lens of the first embodiment as seen obliquely from the side, and Fig. 7(b) is a perspective view of the lens of the first embodiment as seen obliquely from above. [Figure 8] FIG. 8 is a diagram showing an example of the directivity characteristic in the horizontal plane of the lens of the first embodiment. [Figure 9] FIG. 9 is a perspective view of the lens of the second embodiment as seen obliquely from above. [Figure 10] FIG. 10 is a diagram showing an example of the directivity characteristic in the horizontal plane of the lens of the second embodiment. [Figure 11] FIG. 11 is a perspective view of the lens of the third embodiment as seen obliquely from above. [Figure 12] FIG. 12 is a diagram showing an example of the directivity characteristic in the horizontal plane of the lens of the third embodiment. [Figure 13]FIG. 13 is a perspective view of the lens of the fourth embodiment as seen obliquely from above. [Figure 14] FIG. 14 is a diagram showing an example of the directivity characteristic in the horizontal plane of the lens of the fourth embodiment. [Figure 15] Fig. 15(a) is a plan view of a lens of the fifth embodiment, Fig. 15(b) is a perspective view of an antenna device having the lens of the fifth embodiment as seen obliquely from the front, and Fig. 15(c) is a perspective view of an antenna device having the lens of the fifth embodiment as seen obliquely from the left side. [Figure 16] Fig. 16(a) is a plan view of the lens of the sixth embodiment, Fig. 16(b) is a perspective view showing the front and plan of the lens of the sixth embodiment, and Fig. 16(c) is a perspective view of an antenna device having the lens of the sixth embodiment as seen obliquely from below. [Figure 17] FIG. 17 is a diagram showing an example of how the antenna device according to the embodiment is attached to a vehicle. [Figure 18] FIG. 18 is a front view of the lens of the seventh embodiment. [Figure 19] FIG. 19 is a rear view of the lens of the seventh embodiment. [Figure 20] FIG. 20 is a left side view of the lens of the seventh embodiment. [Figure 21] FIG. 21 is a right side view of the lens of the seventh embodiment. [Figure 22] FIG. 22 is a plan view of the lens of the seventh embodiment. [Figure 23] FIG. 23 is a bottom view of the lens of the seventh embodiment. [Figure 24] FIG. 24 is a front view of the lens of the eighth embodiment. [Figure 25] FIG. 25 is a rear view of the lens of the eighth embodiment. [Figure 26] FIG. 26 is a left side view of the lens of the eighth embodiment. [Figure 27] FIG. 27 is a right side view of the lens of the eighth embodiment. [Figure 28] FIG. 28 is a plan view of the lens of the eighth embodiment. [Figure 29]FIG. 29 is a bottom view of the lens of the eighth embodiment. [Figure 30] FIG. 30 is a front view of the lens of the ninth embodiment. [Figure 31] FIG. 31 is a rear view of the lens of the ninth embodiment. [Figure 32] FIG. 32 is a left side view of the lens of the ninth embodiment. [Figure 33] FIG. 33 is a right side view of the lens of the ninth embodiment. [Figure 34] FIG. 34 is a plan view of the lens of the ninth embodiment. [Figure 35] FIG. 35 is a bottom view of the lens of the ninth embodiment. [Figure 36] FIG. 36 is a front view of the lens of the tenth embodiment. [Figure 37] FIG. 37 is a rear view of the lens of the tenth embodiment. [Figure 38] FIG. 38 is a left side view of the lens of the tenth embodiment. [Figure 39] FIG. 39 is a right side view of the lens of the tenth embodiment. [Figure 40] FIG. 40 is a plan view of the lens of the tenth embodiment. [Figure 41] FIG. 41 is a bottom view of the lens of the tenth embodiment. [Figure 42] FIG. 42 is a front view of the lens of the eleventh embodiment. [Figure 43] FIG. 43 is a rear view of the lens of the eleventh embodiment. [Figure 44] FIG. 44 is a left side view of the lens of the eleventh embodiment. [Figure 45] FIG. 45 is a right side view of the lens of the eleventh embodiment. [Figure 46] FIG. 46 is a plan view of the lens of the eleventh embodiment. [Figure 47] FIG. 47 is a bottom view of the lens of the eleventh embodiment. [Figure 48] FIG. 48 is a front view of the lens of the twelfth embodiment. [Figure 49]FIG. 49 is a rear view of the lens of the twelfth embodiment. [Figure 50] FIG. 50 is a left side view of the lens of the twelfth embodiment. [Figure 51] FIG. 51 is a right side view of the lens of the twelfth embodiment. [Figure 52] FIG. 52 is a plan view of the lens of the twelfth embodiment. [Figure 53] FIG. 53 is a bottom view of the lens of the twelfth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiments described herein include an antenna device suitable for microwave, millimeter wave, and submillimeter wave radio waves, a communication device including the antenna device and a wireless communication unit, and a mobile body including the communication device. The antenna device according to the embodiments includes a lens for microwave, millimeter wave, or submillimeter wave radio waves. The lens has a through hole in which an omnidirectional antenna in a horizontal plane is disposed, and a dielectric lens body formed of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis of the through hole, which extends in all or part of the circumferential direction. This allows for a simple antenna device that is less susceptible to communication quality degradation and communication interruptions when applied to mobile-to-mobile communications using microwave, millimeter wave, or submillimeter wave radio waves. In particular, the antenna device according to the embodiments is suitable for vehicle-to-vehicle communications using fifth-generation or later-generation mobile communications.

[0019] In this embodiment, the mobile object is a vehicle traveling on a road, which is a ground travel route. However, there are no particular restrictions on the type of mobile object or the type of travel route. For example, the vehicle may be an automobile, truck, bus, motorcycle, etc. The vehicle may be an automatic driving vehicle or a manually driven vehicle without an automatic driving function. Furthermore, the mobile object to be subjected to collision possibility determination may be a ground vehicle, or may be an aircraft or other mobile object capable of flying along a travel route in the air at a predetermined altitude. Furthermore, the mobile object may be an underground mobile object traveling along an underground travel route, a surface mobile object such as a ship traveling along a waterway (e.g., on the sea), or an underwater mobile object such as a submersible robot traveling along an underwater travel route (e.g., underwater).

[0020] The vehicle of this embodiment may be an electric vehicle, a fuel cell vehicle, or a hybrid vehicle having both an internal combustion engine and an electric motor. Furthermore, if the vehicle has multiple seats for occupants or passengers, the front-row and left-most seat may not be the driver's seat. That is, the vehicle may be a vehicle in which only the front-row and right-most seat is the driver's seat, or an autonomous vehicle that does not have a driver's seat at all.

[0021] Furthermore, the configuration and communication method of the mobile communication network in this embodiment are not limited to those conforming to a specific generation standard, and may be those conforming to, for example, LTE, LTE-Advanced, fifth generation, or later generation standards.

[0022] FIG. 1(a) is a diagram showing an example of a horizontal plane directivity characteristic 100H of a dipole antenna applicable to the antenna device according to the embodiment, and FIG. 1(b) is a diagram showing an example of a vertical plane directivity characteristic 100V of the same dipole antenna. FIG. 2 is a diagram showing an example of a horizontal plane directivity characteristic 100H of a half-wavelength dipole antenna. The horizontal plane directivity characteristic in FIG. 2 was obtained by computer-based electromagnetic field simulation using the finite difference time domain (FDTD) method. Ideally, an antenna for mobile communications, such as vehicle-to-vehicle communications, should have directivity in the vertical plane as shown in FIG. 1(b) and be completely omnidirectional in the horizontal plane as shown in FIGS. 1(a) and 2. Such directivity is similar to the characteristics of a collinear antenna.

[0023] FIG. 3 is a front view showing an example of an antenna device 100′ that combines a half-wavelength dipole antenna 10′ with a single aspherical lens 20. FIG. 4 is a diagram showing an example of a horizontal-plane directivity characteristic 101H of the antenna device 100′ of FIG. 3. Note that the black (single color) in FIG. 3 indicates the color of the background (the same applies to FIGS. 6, 7(a), 7(b), 9, 11, and 13 described below). The aspherical lens 20 of FIG. 3 is a dielectric lens made of a dielectric material such as fluororesin (e.g., Teflon (registered trademark)), and can be used to increase the gain of the antenna directivity (in the illustrated example, the gain is increased from approximately 2.5 dBi to approximately 6 dBi) or to change the beam direction, as shown in the downward beam-like horizontal-plane directivity characteristic 101H of FIG. 4.

[0024] 5(a) and 5(b) are diagrams illustrating the issues that arise when multiple vehicles (mobile bodies) 41, 42, each equipped with an antenna device having beam directivity, travel while communicating between vehicles. In Fig. 5, the leading vehicle 41 is equipped with an antenna device having a rearward-facing in-horizontal plane directivity characteristic 141HR and a sideward-facing in-horizontal plane directivity characteristic 141HS based on the direction of travel. The following vehicle 42 is equipped with an antenna device having a forward-facing in-horizontal plane directivity characteristic 141HF based on the direction behind travel.

[0025] On the straight road (travel route) shown in Figure 5(a), vehicle-to-vehicle communication can be carried out with the rearward-facing horizontal plane directional characteristic 141HR of the preceding vehicle 41 and the forward-facing horizontal plane directional characteristic 141HF of the following vehicle 42 almost facing each other, making it less likely that communication quality will deteriorate or connection will be interrupted.

[0026] However, on the curved road (travel route) shown in Figure 5(b), the rearward horizontal plane directional characteristic 141HR and the sideward horizontal plane directional characteristic 141HS of the leading vehicle 41 and the forward horizontal plane directional characteristic 141HF of the following vehicle 42 do not face each other, which may result in a deterioration in communication quality or a disconnection of the inter-vehicle communication. In particular, when traveling around a curve while performing inter-vehicle communication with a large inter-vehicle distance, if the gain decreases due to a null in the antenna's horizontal plane directional characteristic, the communication quality may easily deteriorate or a disconnection may occur.

[0027] One possible solution to the degradation in communication quality and connection interruptions is beam tracking, as described in the aforementioned Patent Document 1, but this requires a device to control the beam. Furthermore, a co-linear antenna can be considered to increase antenna gain while achieving horizontal omnidirectionality, but achieving a high gain of 10 dBi requires a large number of element stages. For this reason, for example, a series-type co-linear antenna can accumulate wavelength errors of several millimeters, making it impossible to achieve the desired gain. Furthermore, a parallel-type co-linear antenna requires a distribution structure for parallel feeding and a support structure for vertical placement, resulting in a complex structure and difficult manufacturing.

[0028] Therefore, in this embodiment, as exemplified below, by combining a horizontal plane non-directional (omni) antenna with a lens having a predetermined shape described below, an antenna device 100 with a simple configuration is provided that is less likely to cause communication quality degradation or communication interruptions when applied to vehicle-to-vehicle communication (mobile-to-mobile communication).

[0029] 6 is a diagram showing the positional relationship between an aspherical lens 20 as a basic shape element used in designing the shape of a lens constituting the antenna device of the embodiment, and an omnidirectional antenna 10 in a horizontal plane. The lenses of the embodiments exemplified below can be designed using, for example, the shape of the aspherical lens 20 shown in FIG. 6 as a basic shape element.

[0030] The aspherical lens 20 is made of a fluororesin such as PTFE (polytetrafluoroethylene) (for example, a material having a relative dielectric constant ε r The aspherical lens 20 is made of a dielectric material (Teflon (registered trademark)) with a refractive index of 2.1 and has an antenna-facing surface 201 on the antenna side and an outwardly curved surface 202. In FIG. 6, when the wavelength of the target radio wave is λ, the distance between the antenna-facing surface 201 of the aspherical lens 20 and the horizontally omnidirectional antenna 10 is equal to the focal length F (=λ / 2) of the aspherical lens 20. Furthermore, the radius (lens radius) R of the circular outer periphery of the aspherical lens 20, the antenna-facing surface 201, is equal to 5λ / 2. This radius (lens radius) R corresponds to the distance from the center to the edge of the inner surface facing the through hole in the lens body of the final lens, along the rotation axis.

[0031] Although the illustrated antenna-facing surface 201 is flat, it may be curved. Furthermore, the illustrated curved surface 202 is aspherical, but it may be a portion of a sphere. Furthermore, the horizontal-plane omnidirectional antenna 10 in FIG. 6 is a half-wave dipole antenna, but any antenna having horizontal-plane omnidirectional characteristics need not be a half-wave dipole antenna.

[0032] An integrated structure is obtained by rotating the aspherical lens 20 continuously or in predetermined angular steps around the position of the horizontal omnidirectional antenna 10 in Fig. 6, and the surface of the integrated structure has a disk-shaped lens shape consisting of a rotationally symmetric body. This lens has a through hole in which the horizontal omnidirectional antenna 10 is placed, and is provided with a lens body consisting of all or part of the circumferential direction of a rotationally symmetric body having a rotationally symmetric convex outer curved surface around the central axis of the through hole (the radiation center of the antenna).

[0033] The lens may be spaced λ / 2π or more from the radiation center of the horizontal plane omnidirectional (omni) antenna 10, with this distance being the focal length F of the lens. That is, in the lens, the inner surface facing the through hole of the lens body may be spaced λ / 2π or more from the central axis of the through hole, with this distance being equal to the focal length F in the radial direction of the lens body. By combining lenses having such shapes, horizontal omnidirectionality with high antenna gain can be obtained with the lenses alone, and deterioration of communication quality and occurrence of connection interruptions can be suppressed.

[0034] The outer curved surface of the lens may also be an aspheric surface that is determined by design using a ray tracing method based on the relative permittivity εr, focal length F, and lens radius R of the basic shape element (see FIG. 6). The outer curved surface of the lens, which is an aspheric surface determined in this way, can correct deviations in the focal position of the lens (spherical aberration).

[0035] Furthermore, the focal length F may be set to an integer multiple of λ / 2 so that the reflected wave and direct wave when entering the lens are in phase. This makes it possible to effectively utilize the power of the reflected wave when entering the lens and improve the antenna gain.

[0036] The lens body may have an arc-like shape consisting of a portion of the circumference of a rotationally symmetric body obtained by rotating aspherical lens 20 around the position of horizontal-plane omnidirectional antenna 10 in Fig. 6, and a portion of the circumference of the rotationally symmetric body (a partially missing portion of the lens body) may be replaced with a reflective member that reflects the target radio waves. This makes it possible to suppress unwanted radiation and, as described above, to effectively utilize power and improve antenna gain.

[0037] FIG. 7(a) is a perspective view of the lens 21 of the first embodiment, viewed from a diagonal side position, and FIG. 7(b) is a perspective view of the lens 21 of the first embodiment, viewed from a diagonal top position. FIGS. 7(a) and 7(b) show examples of the lens 21 formed based on an integrated structure (a 36-degree rotationally symmetric body) obtained by rotating an aspherical lens 20, serving as a basic form element, around a central axis Z0 in the Z-axis direction, which passes through the position of the horizontal-plane omnidirectional antenna 10 in FIG. 6, in steps of a predetermined angle (10 degrees in the example of FIG. 7). The surface of this integrated structure gives the lens 21 a disk-like shape consisting of the entire rotationally symmetric body. The lens 21 has a through-hole 210 in which the horizontal-plane omnidirectional antenna 10 is disposed, and includes a lens body 211 consisting of the entire circumferential direction of a rotationally symmetric body having a rotationally symmetric convex outer curved surface around the central axis Z0 of the through-hole 210 (the antenna radiation center).

[0038] Lens 21 can be formed by a three-dimensional printer using a dielectric material such as fluororesin (e.g., Teflon (registered trademark)) such as PTFE (polytetrafluoroethylene). Lenses in other embodiments described below can be formed in a similar manner. Note that the material of lens 21 may be a dielectric material other than fluororesin, as long as it has a predetermined relative dielectric constant and transmittance for the target radio waves (the same applies to lenses in other embodiments described below).

[0039] Fig. 8 is a diagram showing an example of the horizontal plane directivity characteristic of the lens 21 of the first embodiment. As shown in Fig. 8, by combining the horizontal plane omnidirectional antenna 10 with the lens 21 shown in Fig. 7(a) and Fig. 7(b), it is possible to provide the horizontal plane omnidirectional antenna device 100 with a high antenna gain (10 dBi in the illustrated example).

[0040] The shape of the lens 21 in Figures 7(a) and 7(b) and the antenna directivity characteristics in Figure 8 can be obtained, for example, by computer-based electromagnetic field simulation using the FDTD (Finite Difference Time Domain) method. The same applies to the lenses of other embodiments described below.

[0041] FIG. 9 is a perspective view of the lens 22 of the second embodiment, viewed obliquely from above. FIG. 9 shows an example of the lens 22 formed based on an integrated structure (a portion of a circumferential body of 36 rotations) obtained by rotating the aspherical lens 20 five-sixths of a revolution (300 degrees) in steps of a predetermined angle (10 degrees in the example of FIG. 9 ) around the central axis Z0 in the Z-axis direction, which passes through the position of the horizontal-plane omnidirectional antenna 10 in FIG. 6 . The surface of this integrated structure gives the disk-shaped lens 22 a shape consisting of a portion of a rotationally symmetric body. The lens 22 has a through-hole 220 in which the horizontal-plane omnidirectional antenna 10 is disposed, and includes a lens body 221 consisting of a portion of a rotationally symmetric body in the circumferential direction, having a rotationally symmetric convex outer curved surface around the central axis Z0 of the through-hole 220 (the antenna radiation center). In addition, an arc-shaped reflector 222 is provided as a reflecting member at a position on the inner surface of the lens body 221 within an angular range of 1 / 6 of the circumference (360 degrees) where the aspherical lens 20 is not rotated (a partially missing portion of the lens body).

[0042] Fig. 10 is a diagram showing an example of the horizontal plane directivity characteristic of the lens 22 of the second embodiment. As shown in Fig. 10, by combining the horizontal plane omnidirectional antenna 10, the lens 22 of Fig. 9, and the arc-shaped reflector 222 as a reflecting member, it is possible to provide the horizontal plane omnidirectional antenna device 100 with a high antenna gain (10 dBi to 13.5 dBi in the illustrated example).

[0043] Fig. 11 is a perspective view of the lens 23 of the third embodiment, viewed obliquely from above. Fig. 11 shows an example of the lens 23 formed based on an integrated structure obtained by continuously rotating the aspherical lens 20 one revolution (360 degrees) around the central axis Z0 in the Z-axis direction, which passes through the position of the horizontal-plane omnidirectional antenna 10 in Fig. 6. The surface of this integrated structure provides the disk-shaped lens 23, which is made up of the entire rotationally symmetric body. The lens 23 has a through-hole 220 in which the horizontal-plane omnidirectional antenna 10 is disposed, and includes a lens body 231 made up of the entire circumferential direction of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis Z0 of the through-hole 230 (the antenna radiation center).

[0044] Fig. 12 is a diagram showing an example of the horizontal plane directivity characteristics of the lens 23 of the third embodiment. As shown in Fig. 12, by combining the horizontal plane omnidirectional antenna 10 with the lens 22 of Fig. 11, it is possible to provide the horizontal plane omnidirectional antenna device 100 with a high antenna gain (10 dBi in the illustrated example).

[0045] FIG. 13 is a perspective view of the lens 24 of the fourth embodiment, viewed obliquely from above. FIG. 13 shows an example of the lens 24 formed based on an integrated structure obtained by continuously rotating the aspherical lens 20 five-sixths of a revolution (300 degrees) around a central axis Z0 in the Z-axis direction, which passes through the position of the horizontal-plane omnidirectional antenna 10 in FIG. 6 . The surface of this integrated structure provides the disk-shaped lens 24, which is a part of a rotationally symmetric body. The lens 24 has a through-hole 240 in which the horizontal-plane omnidirectional antenna 10 is disposed, and includes a lens body 241 formed of a part of a rotationally symmetric body in the circumferential direction, having a rotationally symmetric convex outer curved surface around the central axis Z0 of the through-hole 240 (the antenna radiation center). Furthermore, an arc-shaped reflector 242 is provided as a reflective member on the inner peripheral surface of the lens body 241, at a position within an angular range of one-sixth of a revolution (360 degrees) where the aspherical lens 20 is not rotated.

[0046] Fig. 14 is a diagram showing an example of the horizontal plane directivity characteristic of the lens 24 of the fourth embodiment. As shown in Fig. 14, by combining the horizontal plane omnidirectional antenna 10, the lens 22 of Fig. 13, and an arc-shaped reflector 242 as a reflecting member, it is possible to provide the horizontal plane omnidirectional antenna device 100 with a high antenna gain (10 dBi to 13.5 dBi in the illustrated example).

[0047] FIG. 15(a) is a plan view of a lens 25 according to a fifth embodiment. FIG. 15(a) shows an example of a lens 25 formed based on an integrated structure (a portion of a rotationally symmetric body in the circumferential direction) obtained by rotating an aspherical lens 20 one-third of a circle (120 degrees) in steps of a predetermined angle (30 degrees in the example of FIG. 15) around a central axis Z0 in the Z-axis direction, which passes through the position of the horizontal-plane omnidirectional antenna 10 in FIG. 6, with the focal length F being long and the antenna-facing surface 201 spaced from the antenna radiation center. The surface of this integrated structure provides the arc-shaped lens 25 formed from a portion of a rotationally symmetric body. The lens 25 has a through-hole 250 in which the horizontal-plane omnidirectional antenna 10 is disposed, and includes a lens body 251 formed from a portion of a rotationally symmetric body in the circumferential direction, with a rotationally symmetric convex outer curved surface around the central axis Z0 of the through-hole 250 (the antenna radiation center).

[0048] Fig. 15(b) is a perspective view of the antenna device 100 having the lens 25 of the fifth embodiment, viewed obliquely from the front. Fig. 15(c) is a perspective view of the antenna device 100 having the lens 25 of the fifth embodiment, viewed obliquely from the left side. As shown in Figs. 15(b) and 15(c), the lens 25 has a through-hole 250 that provides a relatively large antenna installation space, making it possible to easily install a large-sized antenna unit 11 having an antenna that is omnidirectional in the horizontal plane.

[0049] FIG. 16(a) is a plan view of a lens 26 according to a sixth embodiment. FIG. 16(b) is a perspective view showing the front and top views of the lens 26 according to the sixth embodiment. FIGS. 16(a) and 16(b) show an example of a lens 26 formed based on an integrated structure obtained by continuously rotating an aspherical lens 20 around a central axis Z0 in the Z-axis direction, which passes through the position of the horizontal-plane omnidirectional antenna 10 in FIG. 6, with the focal length F being long and the antenna-facing surface 201 spaced apart from the antenna radiation center. The surface of this integrated structure forms the annular shape of the lens 26, which is made up of the entire rotationally symmetric body. The lens 26 has a through-hole 260 in which the horizontal-plane omnidirectional antenna 10 is disposed, and includes a lens body 261 made up of the entire circumferential direction of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis Z0 of the through-hole 260 (the antenna radiation center).

[0050] Fig. 16(c) is a perspective view of the antenna device 100 having the lens 26 of the sixth embodiment, viewed obliquely from below. As shown in Fig. 16(c), the lens 26 has a through-hole 260 that provides a relatively large antenna installation space, so that a large-sized antenna unit 11 having an antenna that is omnidirectional in the horizontal plane can be easily installed.

[0051] FIG. 17 is a diagram showing an example of how the antenna device 100 of the embodiment is attached to a vehicle 40. In the example of FIG. 17, an outer frame 402 located on a side of a windshield 401 of a vehicle (large vehicle) serving as a moving body has a stay member 403 for attaching an auxiliary mirror, and the antenna device 100 is attached to the stay member 403. In FIG. 17, a plurality of (e.g., two sets of) antenna devices 100 may be attached to the stay member 403 to obtain an antenna diversity effect in inter-vehicle communication. Furthermore, a moving body such as a vehicle equipped with the antenna device 100 of the embodiment and a communication device having a wireless communication unit may perform inter-vehicle communication with another moving body such as a vehicle located at least one way in front of or behind the moving body in the direction of movement. The antenna device of the moving body may have a directional beam with a beam width of 150 degrees or more and 180 degrees or less in the horizontal plane in inter-vehicle communication with another moving body. In addition, a moving body such as a vehicle may be provided with multiple antenna devices at least in front of or behind the moving direction of the moving body, and may transmit or receive the same radio waves via the multiple antenna devices, for example, to obtain a diversity effect.

[0052] 18 to 23 are respectively a front view, a rear view, a left side view, a right side view, a plan view, and a bottom view of the lens of the seventh embodiment. Note that the black (single color) in each of the lenses in Figs. 18 to 23 is the background color. Also, the shading shown on the surface of the lens in Figs. 18 to 23 is intended to identify the three-dimensional shape.

[0053] 18 to 23 are lenses formed based on an integrated structure (part of a 12-rotationally symmetric body) obtained by rotating an aspherical lens 20 (see FIG. 6) as a basic shape element through one-third of a circle (120 degrees) in 30-degree steps around the central axis in the Z-axis direction. This lens has a through-hole in which an omnidirectional antenna in a horizontal plane is placed, and is provided with an arc-shaped lens body consisting of a circumferential part of a rotationally symmetric body having a rotationally symmetric convex outer curved surface around the central axis of the through-hole (the radiation center of the antenna).

[0054] 24 to 29 are respectively a front view, a rear view, a left side view, a right side view, a plan view, and a bottom view of the lens of the eighth embodiment. Note that the black (single color) in all of Figs. 24 to 29 is the background color. Also, the shading shown on the surface of the lens in Figs. 24 to 29 is intended to identify the three-dimensional shape.

[0055] 24 to 29 are lenses formed based on an integrated structure (part of a 12-rotationally symmetric body) obtained by rotating an aspherical lens 20 (see FIG. 6) as a basic shape element through one-third of a circle (120 degrees) in 30-degree steps around the central axis in the Z-axis direction. This lens has a through-hole in which an omnidirectional antenna in a horizontal plane is placed, and includes an arc-shaped lens body consisting of a part of the circumferential direction of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis of the through-hole (the radiation center of the antenna), and an upper disk installed on the top surface of the lens body.

[0056] 30 to 35 are respectively a front view, a rear view, a left side view, a right side view, a plan view, and a bottom view of the lens of the ninth embodiment. Note that black (single color) in all of Figs. 30 to 35 is the background color. Also, the shading shown on the surface of the lens in Figs. 30 to 35 is intended to identify the three-dimensional shape.

[0057] 30 to 35 are lenses formed based on an integrated structure (a portion of a rotationally symmetric body 36 in the circumferential direction) obtained by rotating an aspherical lens 20 (see FIG. 6) as a basic form element through one-third of a circle (120 degrees) in 10-degree steps around the central axis in the Z-axis direction. This lens has a through-hole in which an omnidirectional antenna in a horizontal plane is disposed, and includes an arc-shaped lens body consisting of a portion of a rotationally symmetric body in the circumferential direction having a convex outer curved surface that is rotationally symmetric around the central axis of the through-hole (the radiation center of the antenna).

[0058] 36 to 41 are respectively a front view, a rear view, a left side view, a right side view, a plan view, and a bottom view of the lens of the tenth embodiment. Note that the black (single color) in all of Figs. 36 to 41 is the background color. Also, the shading shown on the surface of the lens in Figs. 36 to 41 is intended to identify the three-dimensional shape.

[0059] 36 to 41 are lenses formed based on an integrated structure (a portion of the circumference of a rotationally symmetric body) obtained by rotating aspherical lens 20 (see FIG. 6) as a basic form element through one-third of a circle (120 degrees) in 10-degree steps around the central axis in the Z-axis direction. This lens has a through-hole in which an omnidirectional antenna in a horizontal plane is disposed, and includes an arc-shaped lens body consisting of a portion of the circumference of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis of the through-hole (the radiation center of the antenna), and an upper disk installed on the top surface of the lens body.

[0060] 42 to 47 are respectively a front view, a rear view, a left side view, a right side view, a plan view, and a bottom view of the lens of the eleventh embodiment. Note that the black (single color) in all of Figs. 42 to 47 is the background color. Also, the shading shown on the lens surface in Figs. 42 to 47 is intended to identify the three-dimensional shape.

[0061] 42 to 47 are lenses formed based on an integrated structure (a portion of the circumferential direction of a rotationally symmetric body (continuously rotating body)) obtained by continuously rotating an aspherical lens 20 (see FIG. 6) as a basic shape element through one-third of a revolution (120 degrees) around the central axis in the Z-axis direction. This lens has a through-hole in which an omnidirectional antenna in a horizontal plane is disposed, and is provided with an arc-shaped lens body consisting of a portion of the circumferential direction of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis of the through-hole (the radiation center of the antenna).

[0062] 48 to 53 are respectively a front view, a rear view, a left side view, a right side view, a plan view, and a bottom view of the lens of the twelfth embodiment. Note that the black (single color) in all of Figs. 48 to 53 is the background color. Also, the shading shown on the surface of the lens in Figs. 48 to 53 is intended to identify the three-dimensional shape.

[0063] 48 to 53 are lenses formed based on an integrated structure (a portion of the circumference of a rotationally symmetric body (continuously rotating body)) obtained by continuously rotating an aspherical lens 20 (see FIG. 6) as a basic shape element through one-third of a revolution (120 degrees) around the central axis in the Z-axis direction. This lens has a through-hole in which an omnidirectional antenna in a horizontal plane is disposed, and is equipped with an arc-shaped lens body consisting of a portion of the circumference of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around the central axis of the through-hole (the radiation center of the antenna), and an upper disk installed on the top surface of the lens body.

[0064] As described above, according to this embodiment, it is possible to provide the antenna device 100 having a simple configuration that is less likely to cause deterioration in communication quality or communication interruption when applied to communication between mobile objects such as vehicle-to-vehicle communication.

[0065] Furthermore, the present invention can provide mobile communications such as vehicle-to-vehicle communications that are less susceptible to degradation in communication quality and interruptions over the long term, thereby contributing to the achievement of Goal 9 of the Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation."

[0066] Moreover, the description of the embodiments disclosed herein is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. [Explanation of symbols]

[0067] 10: Antenna 11: Antenna unit 20: Aspherical lens 21~26: Lens 40: Vehicle 100: Antenna device 201: Antenna facing surface 202: Curved surface 210: Through hole 211: Lens body 220: Through hole 221: Lens body 222:Reflector 230: Through hole 231: Lens body 240:Through hole 241: Lens body 242:Reflector 250:Through hole 251: Lens body 260:Through hole 261: Lens body 401: Windshield 402: Outer frame 403: Stay member

Claims

1. A lens for microwave, millimeter wave or submillimeter wave radio waves, a dielectric lens body having a through hole in which an omnidirectional antenna in a horizontal plane is disposed, the lens body being made of a dielectric material and consisting of a whole or a part in the circumferential direction of a rotationally symmetric body having a convex outer curved surface that is rotationally symmetric around a central axis of the through hole; The rotationally symmetric basic shape of the rotationally symmetric body has an antenna-facing surface facing the through hole of the lens body and an outward curved surface, the distance between the antenna-facing surface and the central axis of the through hole is equal to the focal length F in the radial direction of the lens body, and the distance R from the center to the edge of the antenna-facing surface in the direction along the central axis is 5λ / 2 (λ: wavelength). lens.

2. 2. The lens of claim 1, an inner surface of the lens body facing the through hole is spaced apart from a central axis of the through hole by λ / 2π (λ: wavelength of radio waves) or more; The separation distance is equal to the radial focal length F of the lens body. lens.

3. 2. The lens of claim 1, The outer curved surface of the lens body has a relative dielectric constant ε ｒ , an aspheric surface determined based on a focal length F in the radial direction of the lens body and a distance R from the center to the edge of the inner surface of the lens body in the direction along the central axis, lens.

4. 2. The lens of claim 1, A lens in which the focal length F in the radial direction of the lens body is an integer multiple of λ / 2 (λ: wavelength of radio waves).

5. 2. The lens of claim 1, The lens body has a shape in which a part of the rotationally symmetric body in the circumferential direction is missing. lens.

6. In the lens of claim 1, A reflective member that reflects the radio waves is disposed in a missing portion in which a part of the lens body in the circumferential direction is missing. lens.

7. 2. The lens of claim 1, The rotationally symmetric body has a shape of single rotation symmetry around the central axis of the through hole or a shape of multiple (n) rotation symmetry around the central axis of the through hole. lens.

8. An antenna device comprising: a lens according to any one of claims 1 to 7; and an antenna that is omnidirectional in a horizontal plane and is disposed in a through-hole of the lens.

9. the antenna device of claim 8; a wireless communication unit connected to the antenna of the antenna device; A communication device comprising:

10. A mobile body comprising the communication device of claim 9, for performing inter-mobile communication with another mobile body located at least one of in front and behind in the direction of movement.

11. The moving body according to claim 10, the antenna device has a directional beam with a beam width of 150 degrees or more and 180 degrees or less in mobile-to-mobile communication with the other mobile body, Mobile object.

12. The moving body according to claim 10, a plurality of the antenna devices are provided at least one of a front and a rear in a moving direction of the moving body; The same radio wave is transmitted or received via the plurality of antenna devices. Mobile object.

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