Radio wave lens and antenna

Abstract

The purpose of the present invention is to provide a radio wave lens and an antenna with which it is possible to achieve both gain improvement and emission angle expansion. A radio wave lens (50) according to the present invention is provided with a structure in which a focusing lens (10) for focusing incident radio waves and a diverging lens (20) for diverging incident radio waves are stacked. An antenna (101) according to the present invention is provided with a structure in which a radiator (30) for beam-steering radio waves, the focusing lens (10) for focusing incident radio waves, and the diverging lens (20) for diverging incident radio waves are stacked.

Description

Lenses and antennas for radio waves

[0001] The present disclosure relates to a radio wave lens and an antenna.

[0002] Conventionally, there has been known an antenna comprising a radio wave deflecting element having a planar Luneburg lens structure including a plurality of laminated dielectric layers, and a radio wave source that radiates radio waves to the radio wave deflecting element (see, for example, Patent Document 1).

[0003] International Publication No. 2024 / 009865

[0004] A focusing lens, such as a flat Luneburg lens, focuses the incoming radio waves. This increases the peak antenna gain of the radio waves emitted from the focusing lens. However, this narrows the angle of emission of the radio waves, resulting in a narrower range of coverage.

[0005] The present disclosure provides a radio wave lens and antenna that can achieve both improved gain and a wider emission angle.

[0006] The radio wave lens of the first aspect has a structure in which a converging lens that converges incident radio waves and a diverging lens that diverges incident radio waves are stacked.

[0007] A radio wave lens of a second aspect is the radio wave lens of the first aspect, wherein the diverging lens may be a concave lens having a concave surface.

[0008] A radio wave lens of a third aspect is the radio wave lens of the second aspect, wherein the concave lens may be a spherical lens in which the concave surface is a spherical surface.

[0009] A fourth aspect of the radio wave lens is the radio wave lens of the second aspect, wherein the concave lens may be an aspherical lens in which the concave surface is aspherical.

[0010] A radio wave lens of a fifth aspect is the radio wave lens of the fourth aspect, wherein the concave surface may have a plurality of different radii of curvature.

[0011] A radio wave lens of a sixth aspect is the radio wave lens of the fourth aspect, wherein the concave surface may include an ellipsoidal surface.

[0012] A radio wave lens of a seventh aspect is the radio wave lens of the sixth aspect, wherein the concave surface may include a spherical surface or an aspherical surface and an ellipsoidal surface.

[0013] The radio wave lens of an eighth aspect is the radio wave lens of the fourth aspect, wherein the concave surface may include a straight line in a cross-sectional view.

[0014] A radio wave lens of a ninth aspect is the radio wave lens of any one of the first to eighth aspects, wherein the dielectric constant of the diverging lens may increase with increasing distance from the central axis of the diverging lens.

[0015] A radio wave lens of a tenth aspect is the radio wave lens of any one of the first to ninth aspects, wherein the dielectric constant of the focusing lens may decrease with increasing distance from the central axis of the focusing lens.

[0016] An eleventh aspect of the radio wave lens is the radio wave lens of any one of the first to tenth aspects, wherein the focusing lens may be a Luneburg lens.

[0017] The antenna of the twelfth aspect comprises a radiator for beam steering radio waves, and a structure in which a converging lens for converging the incident radio waves and a diverging lens for diverging the incident radio waves are stacked.

[0018] The antenna of a thirteenth aspect is the antenna of the twelfth aspect, wherein the diverging lens may be located between the radiator and the converging lens.

[0019] The antenna of a fourteenth aspect is the antenna of the thirteenth aspect, wherein the converging lens may be located between the radiator and the diverging lens.

[0020] According to the present disclosure, it is possible to achieve both an improvement in gain and an expansion of the output angle.

[0021] 1 is a diagram schematically showing an example of a cross-sectional configuration in the ZX plane of the antenna according to the first embodiment. FIG. 1 is a diagram schematically showing an example of a cross-sectional configuration in the ZX plane of a converging lens and a radiator. FIG. 2 is a diagram schematically showing an example of a cross-sectional configuration in the ZX plane of a diverging lens and a radiator. FIG. 3 is a diagram showing a first specific example of a cross-sectional configuration in the ZX plane of the antenna according to the first embodiment. FIG. 4 is a diagram showing a second specific example of a cross-sectional configuration in the ZX plane of the antenna according to the first embodiment. FIG. 5 is a diagram showing a fifth specific example of a cross-sectional configuration in the ZX plane of the antenna according to the first embodiment. FIG. 6 is a diagram showing a fifth specific example of the antenna according to the first embodiment in an XY plane view. FIG. 7 is a diagram showing the configuration of a radiator according to the fifth specific example of the first embodiment. FIG. 8 is a diagram showing another example of a cross-sectional configuration in the ZX plane of a planar Luneburg lens. FIG. 9 is a diagram showing an example of a simulation result of peak values ​​of beam gain when the beam steering angle is changed for five types of configurations. FIG. 10 is a diagram showing an example of a simulation result of beam emission angles when the beam steering angle is changed for five types of configurations. 1 is a diagram showing an example of a simulation result of a peak value of beam gain when the beam steering angle is changed for three types of configurations; FIG. 2 is a diagram showing an example of a simulation result of a beam output angle when the beam steering angle is changed for three types of configurations; FIG. 3 is a diagram showing an example of a simulation result of a peak value of beam gain when the beam steering angle is changed for two types of configurations; FIG. 4 is a diagram showing an example of a simulation result of a beam output angle when the beam steering angle is changed for two types of configurations;

[0022] Hereinafter, embodiments will be described with reference to the drawings. For ease of understanding, the scale of each part in the drawings may differ from the actual scale. Directions such as parallel, right angle, orthogonal, horizontal, vertical, up, down, left, right, and the like, as well as terms such as identical and equal, are permitted to be deviated to the extent that the operation and effect of the embodiments are not impaired.

[0023] The X-axis, Y-axis, and Z-axis directions represent directions parallel to the X-axis, Y-axis, and Z-axis, respectively. The X-axis, Y-axis, and Z-axis directions are perpendicular to one another. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X-axis and Y-axis directions, imaginary planes parallel to the Y-axis and Z-axis directions, and imaginary planes parallel to the Z-axis and X-axis directions, respectively.

[0024] FIG. 1 is a diagram schematically illustrating an example of a cross-sectional configuration of an antenna according to the first embodiment taken along the ZX plane. The antenna 101 shown in FIG. 1 transmits or receives radio waves in a predetermined frequency band included in the band of 0.3 GHz to 300 GHz. The predetermined frequency band includes the UHF (Ultra High Frequency) band of 0.3 GHz to 3 GHz, the SHF (Super High Frequency) band of 3 GHz to 30 GHz, and the EHF (Extremely High Frequency) band of 30 GHz to 300 GHz. For example, the antenna 101 emits radio waves in the 28 GHz band. The 28 GHz band is, for example, a band of 27.5 GHz to 29.5 GHz (i.e., 28.5 GHz ±1.0 MHz).

[0025] The antenna 101 is configured to be capable of transmitting or receiving radio waves corresponding to, for example, a fifth generation mobile communication system (so-called 5G), a wireless communication standard such as Bluetooth (registered trademark), or a wireless LAN (Local Area Network) standard such as IEEE 802.11ac. The antenna 101 may be configured to be capable of transmitting or receiving radio waves corresponding to standards other than these, or may be configured to be capable of transmitting or receiving radio waves at a plurality of different frequencies. The antenna 101 can be used, for example, as a wireless base station.

[0026] The antenna 101 is a lens antenna including a lens 50 and a radiator 30 .

[0027] The lens 50 is an example of a radio wave lens, and refracts and transmits incident radio waves. The lens 50 is a radio wave lens having a structure in which a converging lens 10 and a diverging lens 20 are stacked in the Z-axis direction.

[0028] The focusing lens 10 focuses incident radio waves. The focusing lens 10 has an incident surface 11 facing the negative Z-axis direction and an exit surface 12 facing the positive Z-axis direction. In this example, the normal directions of the incident surface 11 and the exit surface 12 are parallel to the Z-axis direction. The focusing lens 10 refracts the radio waves incident on the incident surface 11 and emits the radio waves from the exit surface 12.

[0029] The focusing lens 10 is, for example, a planar Luneburg lens including a plurality of laminated dielectric layers. However, the focusing lens 10 is not limited thereto and may be, for example, a spherical Luneburg lens including a plurality of laminated dielectric layers, or another type of lens such as a Fresnel lens. The focusing lens 10 may also be a convex lens having a convex exit surface 12 (convex surface). Examples of convex lenses include a biconvex lens, a plano-convex lens, and a convex meniscus lens.

[0030] The diverging lens 20 diverges the incident radio waves. The diverging lens 20 has an incident surface 21 facing the negative Z-axis direction and an exit surface 22 facing the positive Z-axis direction. In this example, the normal directions of the incident surface 21 and the exit surface 22 are parallel to the Z-axis direction. The diverging lens 20 refracts the radio waves incident on the incident surface 21 and emits the radio waves from the exit surface 22.

[0031] The diverging lens 20 is, for example, a concave lens having a concave incident surface 21 (concave surface), but other types of lenses may also be used. Examples of concave lenses include biconcave lenses, plano-concave lenses, and concave meniscus lenses. The concave lens may be a spherical lens in which the concave incident surface 21 (concave surface) is spherical, or an aspherical lens in which the concave incident surface 21 (concave surface) is aspherical.

[0032] 1 shows an example of a structure in which focusing lens 10 and diverging lens 20 are in contact with each other in the Z-axis direction, but focusing lens 10 and diverging lens 20 may be stacked in the Z-axis direction with a gap therebetween, or focusing lens 10 and diverging lens 20 may be stacked in the Z-axis direction with a dielectric layer such as an adhesive layer therebetween. In other words, exit surface 22 and entrance surface 11 may be in direct contact with each other, a gap may exist between exit surface 22 and entrance surface 11, or a dielectric layer such as an adhesive layer may exist between exit surface 22 and entrance surface 11. By bonding exit surface 22 and entrance surface 11 with an adhesive layer, focusing lens 10 and diverging lens 20 are fixed to each other.

[0033] The focusing lens 10 and the diverging lens 20 may be disk-shaped lenses when viewed in a plane in the Z-axis direction, but the outer shape of the lenses is not particularly limited. The lens 50 is a combination of the focusing lens 10 formed from one or more dielectric materials and the diverging lens 20 formed from one or more dielectric materials. However, the lens 50 (the combination of the focusing lens 10 and the diverging lens 20) may be formed from a single dielectric material.

[0034] The radiator 30 is a device that radiates radio waves in the above frequency band. The radio waves radiated from the radiator 30 pass through the lens 50. The radiator 30 has, for example, at least one array antenna. The array antenna has a plurality of radiating elements arranged in a plane. The radiator 30 beamsteers the radio waves radiated from one or more array antennas. The radiator 30 may be a device that includes an electronic circuit that controls beam steering of the radio waves radiated from one or more array antennas. The radiator 30 may be an antenna fed by a Butler matrix circuit.

[0035] 2 is a diagram showing an example of a cross-sectional configuration of a converging lens and a radiator in the ZX plane. Fig. 2 shows a configuration in which the diverging lens 20 is removed from the antenna 101 in Fig. 1. The incident angle θ ｉ The radio wave incident on the incident surface 11 is refracted by the focusing lens 10 and emerges from the exit surface 12 at a refraction angle (exit angle θ ｔ The focusing lens 10 focuses the radio waves incident on the incident surface 11 at an output angle θ ｔis the angle of incidence θ ｉ Narrower than (θ ｔ <θ ｉ ).

[0036] 3 is a diagram showing a schematic cross-sectional configuration of a diverging lens and a radiator in the ZX plane. Fig. 3 shows a configuration in which the converging lens 10 is removed from the antenna 101 in Fig. 1. The incident angle θ ｉ The radio wave incident on the incident surface 21 is refracted by the diverging lens 20 and emerges from the exit surface 22 at a refraction angle (exit angle θ ｔ The diverging lens 20 diverges the radio wave incident on the incident surface 21, and therefore emits the radio wave at an emission angle θ ｔ is the angle of incidence θ ｉ wider than (θ ｔ >θ ｉ ).

[0037] Here, in the configuration shown in FIG. ｔ <θ ｉ Therefore, in a plane perpendicular to the exit surface 12 or the XY plane, the peak value of the antenna gain of the radio wave emitted from the exit surface 12 becomes larger than that in the case where the focusing lens 10 is not provided. However, when the radiator 30 is ｂｉ (≒θ ｉ ), the beam steering angle θ of the radio wave (beam) emitted from the emission surface 12 ｂｔ (≒θ ｔ ) narrows. As a result, when the radiator 30 is turned at a beam steering angle θ ｂｉ Even if you change the setting, the range of the radio waves will be narrowed.

[0038] In contrast, the antenna 101 (FIG. 1) according to the first embodiment has a lens 50 having a structure in which a converging lens 10 and a diverging lens 20 are stacked. As a result, the incident angle θ ｉ The radio wave incident on the incident surface 21 has an incident angle θ ｉ A wider refraction angle θ ｔ After that, the radio wave incident on the incident surface 11 from the exit surface 22 is refracted at a refraction angle θ ｔ The output angle θ is narrower than ｔTherefore, the beam steering angle θ of the radio wave (beam) emitted from the emission surface 12 is ｂｔ (≒θ ｔ ) can be expanded compared to the configuration shown in Fig. 2. Furthermore, the peak value of the gain of the radio waves emitted from the emission surface 12 can be improved by the focusing lens 10 compared to the configuration shown in Fig. 3.

[0039] As described above, the lens 50 according to the first embodiment has a structure in which the converging lens 10 and the diverging lens 20 are stacked, and therefore it is possible to achieve both an improvement in gain and an expansion of the output angle.

[0040] In antenna 101 shown in Fig. 1, diverging lens 20 is located between radiator 30 and focusing lens 10. However, although not specifically shown, focusing lens 10 may also be located between radiator 30 and diverging lens 20. That is, the positions of focusing lens 10 and diverging lens 20 may be interchanged in the Z-axis direction. Even if the positions of focusing lens 10 and diverging lens 20 are interchanged in the Z-axis direction, both an improvement in gain and an expansion of the output angle can be achieved by using the same concept as above (the same applies to each specific example shown below).

[0041] Next, a more specific example of the antenna according to the first embodiment will be described.

[0042] Fig. 4 is a diagram showing a first specific example of the cross-sectional configuration of the antenna in the ZX plane according to the first embodiment. Antenna 101a shown in Fig. 4 is one specific example of the above-mentioned antenna 101. Lens 50 of antenna 101a has a structure in which converging lens 10, which is a planar Luneburg lens, and diverging lens 20, which is a spherical lens, are stacked.

[0043] 4, the focusing lens 10 is a planar Luneburg lens having a nested structure in which a plurality of dielectric layers L1 to L6 are nested from a central axis 40 toward the outer edge. The nested structure has a dielectric layer L1 at its center, and dielectric layers L2 to L6 are formed in order from the dielectric layer L1 toward the outer edge of the focusing lens 10. The dielectric constants of the dielectric layers L1 to L6 decrease stepwise from the dielectric layer L1 to the dielectric layer L6. The number of dielectric layers with sequentially different dielectric constants is not limited to six, and may be any other number.

[0044] The dielectric layers L1 to L6 may be made of various resins such as ABS (acrylonitrile butadiene styrene) resin or inorganic oxides such as alumina or quartz glass. r1 to r6 represent the radius of each of the dielectric layers L1 to L6. h1 to h6 represent the thickness of each of the dielectric layers L1 to L6 in the Z-axis direction. ε1 to ε6 represent the dielectric constant of each of the dielectric layers L1 to L6.

[0045] The manufacturing method of the focusing lens 10 is not particularly limited. For example, it can be manufactured by known methods such as injection molding, extrusion molding, and molding using a 3D printer. Among these, molding methods using a 3D printer are preferred because it is easy to finely adjust the infill rate of the focusing lens, thereby facilitating control of the relative dielectric constant. When manufacturing a focusing lens using a 3D printer, using a material with a relatively high relative dielectric constant increases the design freedom of the relative dielectric constant of the focusing lens. For example, the relative dielectric constant of the material is preferably 3 or more, more preferably 5 or more, and particularly preferably 7 or more. For example, alumina has a relatively high relative dielectric constant and a relatively low dielectric loss tangent, making it suitable as a material for the focusing lens.

[0046] The dielectric constant of the focusing lens 10 decreases with increasing distance from the central axis 40 of the focusing lens 10, thereby achieving the function of focusing radio waves.

[0047] 4, the diverging lens 20 is a spherical lens having a concave entrance surface 21 (concave surface) that is spherical. The entrance surface 21 has a constant radius of curvature R. The diverging lens 20 is a columnar member having a concave surface. The columnar material can be, for example, various resins such as ABS (acrylonitrile butadiene styrene) resin or inorganic oxides such as alumina or quartz glass.

[0048] The dielectric constant of diverging lens 20 increases with increasing distance from central axis 40 of diverging lens 20, thereby exhibiting a diverging function of radio waves. In the case of Figure 4, the columnar member with height h10 has a dielectric constant εr that is higher than the dielectric constant of the region (air) in the negative Z-axis direction with respect to incident surface 21, thereby exhibiting a diverging function of radio waves.

[0049] FIG. 5 is a diagram showing a second specific example of the cross-sectional configuration of the antenna according to the first embodiment in the ZX plane. Antenna 101b shown in FIG. 5 is a specific example of the antenna 101 described above. Lens 50 of antenna 101b has a structure in which focusing lens 10, which is a planar Luneburg lens, and diverging lens 20, which is an aspherical lens, are stacked. Focusing lens 10 in FIG. 5 may be the same as focusing lens 10 in FIG. 4. In the second specific example, the description above is used to cite the same configuration as the above specific example, and therefore a description thereof will be omitted.

[0050] 5, the diverging lens 20 is an aspheric lens having a concave entrance surface 21 with a plurality of different radii of curvature R1 and R2. The radius of curvature of the entrance surface 21 increases as it approaches the central axis 40. In this case, the radius of curvature R2 is larger than the radius of curvature R1. The entrance surface 21 may have three or more different radii of curvature.

[0051] FIG. 6 is a diagram showing a third specific example of the cross-sectional configuration of the antenna according to the first embodiment in the ZX plane. Antenna 101c shown in FIG. 6 is a specific example of the antenna 101 described above. Lens 50 of antenna 101c has a structure in which focusing lens 10, which is a planar Luneburg lens, and diverging lens 20, which is an aspherical lens, are stacked. Focusing lens 10 in FIG. 6 may be the same as focusing lens 10 in FIG. 4. In the third specific example, the description above is used to cite the same configuration as the above specific example, and therefore a description thereof will be omitted.

[0052] In Fig. 6, the diverging lens 20 is an aspherical lens having a concave entrance surface 21 that includes an ellipsoid. In the case of Fig. 6, the entrance surface 21 includes an aspherical surface having a plurality of different radii of curvature R1, R2 and an ellipsoid formed on the negative Z-axis direction side of the aspherical surface. The ellipsoid has a major axis Re and a minor axis Re1. The concave entrance surface 21 may be an ellipsoid only. The aspherical surface having a plurality of different radii of curvature R1, R2 may be replaced with a spherical surface having a single radius of curvature.

[0053] The concave entrance surface 21 of the aspherical lens is not limited to an ellipsoidal surface, but may be a surface including a curved surface (excluding a spherical surface) expressed by a polynomial. Specific examples of curved surfaces (excluding a spherical surface) expressed by a polynomial include a paraboloid, a hyperboloid, and a quartic surface.

[0054] Fig. 7 is a diagram showing a fourth specific example of the cross-sectional configuration in the ZX plane of the antenna according to the first embodiment. Antenna 101d shown in Fig. 7 is a specific example of the above-mentioned antenna 101. Lens 50 of antenna 101d has a structure in which a converging lens 10, which is a slim Luneburg lens, and a diverging lens 20, which is an aspherical lens, are stacked. In the fourth specific example, the description above is used, and therefore a description of the same configuration as the above specific example will be omitted.

[0055] 7, focusing lens 10 is a slim Luneburg lens having a nested structure in which a plurality of dielectric layers L1 to L6 are arranged in a nested manner, each curved from a central axis 40 toward an outer edge. The slim Luneburg lens may be applied to the focusing lenses 10 of the first to third other specific examples.

[0056] 7, the concave entrance surface 21 of the diverging lens 20 may include inner surfaces 21a and 21b that include a straight line in a cross section of the ZX plane. The inner surface 21b that forms part of the recess corresponds to a part of the side surface of a cone (the curved surface of a circular cone or the flat surface of a pyramid) with a height h11. The inner surface 21a that forms the recess corresponds to a part of the side surface of a truncated cone (the curved surface of a circular cone or the flat surface of a pyramid) with a lower surface b1 and an upper surface t1.

[0057] Fig. 8 is a diagram showing a fifth specific example of the cross-sectional configuration of the antenna according to the first embodiment in the ZX plane. Fig. 9 is a plan view of the antenna of the fifth specific example as seen in the XY plane. Antenna 101e shown in Figs. 8 and 9 is a specific example of the antenna 101 described above. Lens 50 of antenna 101e has a structure in which a converging lens 10, which is a Luneburg lens, and a diverging lens 20, which is an aspherical lens, are stacked. In the fifth specific example, the description above is used, and therefore a description of the same configuration as the above specific examples will be omitted.

[0058] 8 and 9, the focusing lens 10 is a slim Luneburg lens having a nested structure in which a plurality of dielectric layers L1 to L6 are arranged in a nested manner, each curved from a central axis 40 toward an outer edge. Each of the plurality of dielectric layers L1 to L6 has an ellipsoidal surface with its major axis in the X-axis direction. The slim Luneburg lens may be applied to the focusing lenses 10 of the first to fourth other specific examples.

[0059] As shown in Fig. 8, the diverging lens 20 may include a concave outer member 20a and an inner member 20b having different radii of curvature. The diverging lens 20 may include three or more concave members each having a different radii of curvature. The diverging lens 20 may also be applied to the diverging lenses 20 of the first to fourth other specific examples. Note that the description above is used to cite the same configurations as those of the above specific examples, and therefore a description thereof will be omitted.

[0060] 10 shows an example of a radiator 30 according to a fifth specific example. The radiator 30 is an array antenna composed of n (n≧2) subarrays 31_1, 31_2, ..., 31_n arranged in the X direction. Each subarray 31_1, 31_2, ..., 31_n is composed of m (m≧2) radiating elements 32 arranged in the Y direction. The radiating elements 32 in the same subarray radiate radio waves with the same amplitude and phase, but the radiating elements 32 in different subarrays radiate radio waves with different phases. Beam steering is controlled by adjusting the phase of the radio waves of each radiating element 32.

[0061] In the fifth specific example, the radiating elements 32 are preferably arranged and distributed approximately evenly in a plan view. Furthermore, the number n of radiating elements 32 arranged in the X-axis direction is preferably greater than the number m of radiating elements 32 arranged in the Y-axis direction (n>m). When the radiating elements 32 are arranged as described above, it becomes easier to achieve both an expansion of the beam steering angle of the radio waves (beam) emitted from the emission surface 12 and an improvement in gain.

[0062] Fig. 11 is a diagram showing another example of the cross-sectional configuration of a planar Luneburg lens in the ZX plane. The focusing lens 10 may be a planar Luneburg lens having the configuration shown in Fig. 11. The planar Luneburg lens shown in Fig. 11 has a structure that is axisymmetric with respect to the XY plane.

[0063] Next, the results of a simulation of gain improvement and output angle expansion will be described.

[0064] FIG. 12 shows the beam steering angle θ in the ZX plane including the central axis 40 for the five types of configurations. ｂｉ 13 shows an example of the results of simulating the peak gain value of the main lobe when the phase difference of each radiating element constituting the array antenna is changed so that the beam steering angle θ is 0°, 11°, 22°, 33°, and 44°. ｂｉ The outgoing angle θ of the main lobe when the phase difference of each radiating element constituting the array antenna is changed so thatｂｔ 12 and 13, when * is an arbitrary number, the first number represents an angle in the YZ plane including the central axis 40, and the second number represents an angle in the ZX plane including the central axis 40.

[0065] 12 and 13, antenna 100a shows a reference configuration (a configuration having only radiator 30) in which converging lens 10 and diverging lens 20 are removed from antenna 101a shown in Fig. 4. In Fig. 12 and 13, antenna 100b shows a comparative configuration (a configuration in which radiator 30 and converging lens 10 are combined) in which diverging lens 20 is removed from antenna 101a shown in Fig. 4. In Fig. 12 and 13, antennas 101a, 101b, and 101c show the embodiment of Fig. 4, the embodiment of Fig. 5, and the embodiment of Fig. 6, respectively.

[0066] 12 and 13, when comparing the antenna 100a and the antenna 100b, the antenna 100b has a higher gain than the antenna 100a (FIG. 12), but has a lower steering angle θ ｂｔ In contrast, the antennas 101a, 101b, and 101c have a higher gain than the antenna 100a (FIG. 12), and a smaller steering angle θ than the antenna 100b. ｂｔ Therefore, the antennas 101a, 101b, and 101c can achieve both an improvement in gain and an expansion of the emission angle.

[0067] In the simulations of Figures 12 and 13, the dielectric constants and dimensional conditions of the parts shown in Figure 4 are ε1 = 5, ε2 = 4, ε3 = 3, ε4 = 2.35, ε5 = 2, ε6 = 1.8, εr = 2.1, t = 3 mm, r1 = 11.4 mm, r2 = 23.8 mm, r3 = 31 mm, r4 = 36.6 mm, r5 = 42.45 mm, r6 = 50 mm, h1 = 4.56 mm, h2 = 9.52 mm, h3 = 12.4 mm, h4 = 14.64 mm, h5 = 16.98 mm, h6 = 20 mm, h10 = 16 mm, and R = 90 mm.

[0068] In the simulations of FIGS. 12 and 13, the dielectric constant and dimensional conditions of each part shown in FIG. 5 are the same as those of each part shown in FIG. 4, except that h10 = 15 mm, R1 = 30 mm, and R2 = 100 mm.

[0069] In the simulations of FIGS. 12 and 13, the dielectric constant and dimensional conditions of the parts shown in FIG. 6 are the same as those of the parts shown in FIG. 4, except that t=3.5 mm, h10=16 mm, R1=42 mm, R2=90 mm, Re=34 mm, and Re1=15 mm.

[0070] FIG. 14 shows the beam steering angle θ in the ZX plane including the central axis 40 for the three types of configurations. ｂｉ 15 shows an example of the results of simulating the peak gain value of the main lobe when the phase difference of each radiating element constituting the array antenna is changed so that the beam steering angle θ is 0°, 11°, 22°, 33°, and 44°. ｂｉ The outgoing angle θ of the main lobe when the phase difference of each radiating element constituting the array antenna is changed so that ｂｔ 14 and 15 , when * is an arbitrary number in “*°, *°”, the first number represents an angle in the YZ plane including the central axis 40, and the second number represents an angle in the ZX plane including the central axis 40.

[0071] 14 and 15, antenna 100a shows a reference configuration (a configuration having only radiator 30) in which converging lens 10 and diverging lens 20 are removed from antenna 101d shown in Fig. 7. In Fig. 14 and 15, antenna 100c shows a comparative configuration (a configuration in which radiator 30 and converging lens 10 are combined) in which diverging lens 20 is removed from antenna 101d shown in Fig. 7. In Fig. 14 and 15, antenna 101d shows the embodiment of Fig. 7.

[0072] 14 and 15, when comparing the antenna 100a and the antenna 100c, the antenna 100c has a higher gain than the antenna 100a (FIG. 14), but has a lower steering angle θ ｂｔ In contrast, the antenna 101d has a higher gain than the antenna 100a (FIG. 14) and a smaller steering angle θ than the antenna 100c. ｂｔ Therefore, the antenna 101d can achieve both an improved gain and a wider emission angle.

[0073] In the simulations of FIGS. 14 and 15 , the dielectric constants and dimensional conditions of the parts shown in FIG. 7 are as follows: ε1=5, ε2=4.4, ε3=4, ε4=3.5, ε5=3, ε6=2.2, εr=3, t=4 mm, r1=11.4 mm, r2=23.8 mm, r3=31 mm, r4=36.6 mm, r5=42.45 mm, r6=50 mm, h1=4.56 mm, h2=9.52 mm, h3=12.4 mm, h4=14.64 mm, h5=16.98 mm, h6=20 mm, h10=15.5 mm, h11=14 mm, b1=32 mm, and t1=19.6 mm.

[0074] FIG. 16 shows the beam steering angle θ in the ZX plane including the central axis 40 for the two types of configurations. ｂｉ 17 shows an example of the results of simulating the peak gain value of the main lobe when the phase difference of each radiating element constituting the array antenna is changed so that the beam steering angle θ is 0°, 22°, 44°, and 55° in the ZX plane including the central axis 40 for the same two types of configurations as in FIG. ｂｉ The outgoing angle θ of the main lobe when the phase difference of each radiating element constituting the array antenna is changed so that ｂｔ16 and 17 show an example of the results of simulating the above. In "*°, *°" shown in Fig. 16 and 17, if * is an arbitrary number, the first number represents an angle in the YZ plane including the central axis 40, and the second number represents an angle in the ZX plane including the central axis 40. Note that Fig. 16 and Fig. 17 show simulation results for horizontally polarized waves and vertically polarized waves, respectively.

[0075] 16 and 17, an antenna 100e shows a reference configuration (a configuration including only the radiator 30) in which the converging lens 10 and the diverging lens 20 are removed from the antenna 101e shown in Figures 8 and 9. In Figures 16 and 17, the antenna 101e shows the embodiment shown in Figures 8 and 9.

[0076] 16 and 17, when comparing the antenna 100e and the antenna 101e, the antenna 101e has a higher gain than the antenna 100e for both horizontally polarized waves and vertically polarized waves, and the gain is also improved when the steering angle θ ｂｔ Therefore, the antenna 101e can achieve both an improvement in gain and an expansion of the emission angle.

[0077] In the simulations of FIGS. 16 and 17, the dielectric constants and dimensional conditions of the parts shown in FIGS. 8 and 9 are ε1=7.5, ε2=6, ε3=5, ε4=4.1, ε5=2.5, ε6=2.3, εr=3.3, t=2.4 mm, r1a=17.1 mm, r1b=9.12 mm, r2a=35.7 mm, r2b=19.04 mm, r3a=17.1 mm, r3b=19.12 mm, r4a=17.1 mm, r5a=17.1 mm, r6a=17.1 mm, r7a=17.1 mm, r8a=17.1 mm, r9a=17.1 mm, r10a=17.1 mm, r11a=17.1 mm, r12a=17.1 mm, r13a=17.1 mm, r14a=17.1 mm, r15a=17.1 mm, r16a=17.1 mm, r17a=17.1 mm, r18a=17.1 mm, r19a=17.1 mm, r20a=17.1 mm, r21a=17.1 mm, r22a=17.1 mm, r23a=17.1 mm, r24a=17.1 mm, r25a=17.1 mm, r26a=17.1 mm, r27a=17.1 mm, r28a=17.1 mm, r29a=17.1 mm, r20a=17.1 mm, r21a=17.1 mm, r22a=17.1 mm, r23a = 46.5 mm, r3b = 24.8 mm, r4a = 54.9 mm, r4b = 29.28 mm, r5a = 63.75 mm, r5b = 34 mm, r6a = 75 mm, r6b = 40 mm, h1 = 2.85 mm, h2 = 5.95 mm, h3 = 7.75 mm, h4 = 9.5 mm, h5 = 10.6 mm, h6 = 12.5 mm, h10 = 20 mm.

[0078] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

[0079] This application claims priority based on Japanese Patent Application No. 2024-146613, filed on August 28, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0080] 10 Converging lens 11 Incident surface 12 Exit surface 20 Diverging lens 21 Incident surface 22 Exit surface 30 Radiator 40 Central axis 50 Lens 101, 101a, 101b, 101c, 101d Antenna

Claims

1. A radio wave lens that has a structure in which a converging lens that focuses incident radio waves and a diverging lens that diverges incident radio waves are stacked.

2. The radio wave lens according to claim 1, wherein the diverging lens is a concave lens having a concave surface.

3. The radio wave lens according to claim 2, wherein the concave lens is a spherical lens in which the concave surface is spherical.

4. The radio wave lens according to claim 2, wherein the concave lens is an aspherical lens in which the concave surface is aspherical.

5. The radio wave lens according to claim 4, wherein the concave surface has a plurality of different radii of curvature.

6. The radio wave lens according to claim 4, wherein the concave surface includes an ellipsoidal surface.

7. The radio wave lens according to claim 6, wherein the concave surface includes a spherical or aspherical surface and an ellipsoidal surface.

8. The radio wave lens according to claim 4, wherein the concave surface includes a straight line in a cross-sectional view.

9. The radio wave lens according to claim 1, wherein the dielectric constant of said diverging lens increases with increasing distance from the central axis of said diverging lens.

10. A radio wave lens according to any one of claims 1 to 9, wherein the dielectric constant of the focusing lens decreases with increasing distance from the central axis of the focusing lens.

11. A radio wave lens according to any one of claims 1 to 9, wherein the focusing lens is a Luneburg lens.

12. An antenna comprising a radiator for beam steering radio waves, a structure in which a converging lens for focusing the incident radio waves and a diverging lens for diverging the incident radio waves are stacked.

13. The antenna of claim 12, wherein the diverging lens is located between the radiator and the converging lens.

14. The antenna of claim 12, wherein the converging lens is located between the radiator and the diverging lens.

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