JP2000196345A - Antenna equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain antenna equipment with a beam scanning characteristic, which is mounted on a low-orbit satellite and is suitable for communication or the like with the earth by providing a rotationally symmetric dielectric lens formed by means of rotating the cross section of a convex lens shape and a planar array-antenna formed by means of radiation elements which are arranged in an angle range for looking through a dielectric lens from the focus of it. SOLUTION: Optical axis 16 of a dielectric lens 12 is set in a direction separated from a z-axis by a prescribed angle to obtain a beam scanning characteristic in a desired wide angle direction. Besides, the cross section of a convex lens shape for converting a cylindrical wave shape electric wave into a plane wave shape in the lens 12 is made to be the rationally symmetric shape which is formed by rotation around the z-axis. Most of the radiation elements are arranged comparatively in the neighborhood of the focus F to enable converting a cylindrical wave shape electric wave irradiated from a plane array 15 into a plane wave by the lens 12 within the angle range made by two straight lines for connecting the focus F of the lens 12 and both ends of the effective diameter of the lens 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device in which a dielectric lens and an array antenna are combined, and more particularly, to a wider angle than the zenith direction suitable for communication with the earth mounted on a low-orbit satellite. The present invention relates to an antenna device having a high beam scanning characteristic in a direction.

[0002]

2. Description of the Related Art FIG.
FIG. 4 is a cross-sectional view illustrating a configuration of a conventional planar array antenna device with a dielectric lens shown in 4-47109).
In the figure, 1 is a plane on which the radiating element is arranged (structural base), 2 is a plurality of radiating elements arranged on the plane 1,
3 is a planar array, 4 is a dielectric lens (a radio wave lens having a desired refractive index), 5 is a coordinate system, the z direction is the zenith direction, and 6 is
Is the separation angle θ from the zenith direction, and 7 is the opening diameter d of the planar array 3.
0 and 8 are aperture diameters d1 of the planar array 3 viewed from the θ2 direction,
Numeral 9 is an equivalent wave source aperture diameter d2 on the dielectric lens 3 as viewed from the direction θ2. A phase shifter or an amplifier is connected to the plurality of radiating elements 2, and the excitation amplitude and the excitation phase can be changed. The dielectric lens 4 has a rotationally symmetric structure with the z axis as a rotation axis, and covers the upper part of the planar array 3 in a hemispherical shape.

Next, the operation will be described. The plurality of radiating elements 2 on the plane 1 are excited so that their phases are substantially the same in the θ1 direction away from the zenith. The radio wave radiated from the plane array 3 in the θ1 direction is refracted by the dielectric lens 4 and forms a beam in the θ2 direction further away from the z-axis. Since the dielectric lens has a rotationally symmetric structure, it has symmetrical radiation characteristics in beam scanning in the circumferential direction.

The effect of the conventional planar array antenna device with a dielectric lens will be described. In the above-mentioned planar array antenna with a dielectric lens, without the dielectric lens 4,
A case where a beam is formed only in the planar array 3 in the θ2 direction is shown. In this case, the opening diameter d1 of the planar array 3 as viewed from the θ2 direction is the opening diameter d0 as viewed from the zenith direction (z-axis direction).
Since the size is smaller, a problem occurs that the gain is smaller than the zenith direction. The only way to increase the gain in the θ2 direction with the planar array 3 alone is to increase the aperture of the planar array 3, and there is a problem in that the size of the antenna and the number of radiating elements increase. However, when the dielectric lens 4 is used as described above, the planar array 3 is placed on the dielectric lens 4 in the θ1 direction.
Is regarded as a wave source, and the aperture diameter viewed from the θ2 direction is d2, which is larger than d1, so that the decrease in gain is smaller than when beam scanning is performed only with the planar array 3. That is, when the dielectric lens 4 is loaded, there is an effect that the same gain can be obtained at a wide angle with a smaller planar array and a smaller number of radiating elements as compared with the case of only the planar array. The purpose of this conventional antenna device is to suppress the fluctuation in gain in beam scanning from the zenith to the wide angle, and it is necessary to dispose a radiating element at a position relatively far from the focal point of the dielectric lens 4. . This is because the light condensing characteristic is improved when the lens is arranged near the focal point, and the gain is sharply increased in the optical axis direction of the lens.

[0005]

As described above, the conventional antenna device obtains the same gain at a wide angle with a smaller planar array and a smaller number of radiating elements than the case of only a planar array, and provides a wide range from the zenith to the wide angle. Has the effect of suppressing fluctuations in gain in beam scanning. However, it has a problem that it is not suitable for beam scanning in which the gain is increased at a wide angle and the gain is decreased in the zenith direction. For example, in low-orbit satellites that have been actively researched and put into practical use in recent years, the distance between the satellite and the earth's surface increases rapidly when the observation direction moves away from the axis connecting the satellite and the earth's center. That is, since the span loss increases, an antenna mounted on a low-orbit satellite is required to have a beam scanning characteristic in which the gain is higher at a wide angle than at the zenith.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to obtain a gain equal to or higher than that of a normal plane array in a wide angle direction with a smaller plane array aperture diameter and a smaller number of radiating elements. It is another object of the present invention to provide an antenna device having a beam scanning characteristic in which a gain at a wide angle is higher than that at a zenith direction as compared with a conventional array antenna with a radio lens.

Further, an antenna device in which a dielectric lens is thin and lightweight and low loss, an antenna device in which a module such as a phase shifter or an amplifier is easily disposed on the back of a radiating element, and a high degree of freedom in beam shaping at a wide angle. An object of the present invention is to provide an antenna device, an antenna device having a higher radiation level in the zenith direction, an antenna device having a smaller number of radiating elements and a simple structure, and an antenna device having reduced reflection from a dielectric lens.

[0008]

In order to achieve the above object, in the antenna device of the present invention, a cross section of a convex lens shape having an optical axis in a wide-angle direction separated by a predetermined angle from an axis in the zenith direction is described. A dielectric lens having a rotationally symmetrical shape formed by being rotated around an axis and having an opening in the zenith direction, and installed perpendicularly to the zenith direction axis inside the focal point of the dielectric lens; Is provided, and a planar array antenna formed from a plurality of radiating elements arranged substantially within the angle range that can see the dielectric lens from the focal point of the dielectric lens, for beam scanning with the planar array antenna, The gain in the wide angle direction is higher than the gain in the zenith direction.

In addition, a cross section of a convex lens shape having an optical axis in a wide angle direction separated by a predetermined angle from an axis in the zenith direction has a rotationally symmetric shape formed by rotating the section around the axis, and the zenith direction. A dielectric lens having a shape having an opening, and a bottom surface which is installed near the inside of the focal point of the dielectric lens and which is concave with respect to the opening which is rotationally symmetric with respect to the zenith direction axis and which faces the opening. A conformal array formed from a plurality of generally arranged radiating elements and a plurality of radiating elements generally arranged on the concave surface within an angular range from a focal point of the dielectric lens to a cross section of the convex lens shape corresponding to the focal point. An antenna, wherein the gain in the wide angle direction is higher than the gain in the zenith direction with respect to beam scanning by the conformal array antenna.

A cross section of a convex lens shape having an optical axis in a wide angle direction separated by a predetermined angle from an axis in the zenith direction is a rotationally symmetrical shape formed by rotating the section around the axis, and the zenith direction is defined. A dielectric lens having a shape having an opening, and a top which is installed inside the focal point of the dielectric lens and faces the opening which is convex with respect to the opening which is rotationally symmetric with respect to the axis in the zenith direction. A conformal array formed from a plurality of generally arranged radiating elements and a plurality of radiating elements generally arranged on the convex surface within an angular range from a focal point of the dielectric lens to a cross section of the convex lens shape corresponding to the focal point. An antenna, wherein the gain in the wide angle direction is higher than the gain in the zenith direction with respect to beam scanning by the conformal array antenna.

[0011] Further, provided in the opening connected to the dielectric lens, the thickness is smoothly and continuously changed following the opening end of the dielectric lens, and is perpendicular to the axis in the zenith direction. It is preferable to have a dielectric layer having the same dielectric constant as the above-mentioned dielectric lens on which a flat plate portion having a constant thickness is formed.

Further, a plurality of radiating elements at a portion facing the opening of the planar array antenna or the conformal array antenna are removed, and a plurality of radiating elements arranged at a position closer to the opening than the portion are removed. An array antenna comprising an element and installed near the opening may be provided.

A single radiating element in which a plurality of radiating elements facing the opening of the planar array antenna or the conformal array antenna are removed, and a radiating opening is arranged in the opening of the dielectric lens. May be provided.

Further, zoning can be applied to the dielectric lens to reduce its weight.

A matching layer is provided on the surface of the dielectric lens or the surfaces of the dielectric lens and the dielectric layer,
Reflection from a dielectric lens or the like can be reduced.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a cross-sectional view for explaining the structure of the antenna device according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view for explaining the structure of the antenna device as viewed from obliquely above. FIG. 3 is an explanatory diagram for explaining the beam scanning principle of the antenna device, and FIG. 4 is an explanatory diagram for explaining an envelope of a beam peak when the antenna device performs beam scanning. In FIG. 1, reference numeral 10 denotes a coordinate system, 11 denotes a separation angle θ from the z-axis of the coordinate system 10, 12 denotes a dielectric lens, 13 denotes a radiating element, 14 denotes a flat substrate on which the radiating element 13 is arranged, and 15 denotes a radiation. Reference numeral 16 denotes an optical axis of the dielectric lens 12, reference numeral 17 denotes a focal point F of the dielectric lens 12, and reference numeral 18 denotes an opening formed at the zenith of the dielectric lens 12. 3, reference numeral 19 denotes a beam in the direction of the optical axis 16, reference numeral 20 denotes a beam in a direction offset from the optical axis 16, reference numeral 21 denotes a beam in the zenith direction (z direction), and reference numeral 22 denotes a planar array 15.
Are emitted from the optical axis 16 and enter the dielectric lens 12 from the direction of the optical axis 16, and a cylindrical radio wave 23 forming a beam 19 is emitted from the planar array 15 and enters the dielectric lens 12 from a direction shifted from the optical axis 16. In addition, it is a cylindrical radio wave forming the beam 20. In FIG. 4, reference numeral 24 denotes an envelope of a beam peak when beam scanning is performed by the antenna device, and reference numeral 25 denotes a beam radiated from the antenna device. In FIGS. 1 to 4, the same or corresponding components are denoted by the same reference numerals.

Here, the optical axis 16 of the dielectric lens 12 is set at a predetermined angle away from the z axis so as to obtain a desired beam scanning characteristic in a wide angle direction. Further, the optical axis 16 of the dielectric lens 12 is included in a plane including the z axis, and the dielectric lens 12 rotates around the z axis the cross section of the convex lens that converts the cylindrical wave into a plane wave. It has a rotationally symmetrical shape formed. Note that the z-axis is perpendicular to the plane substrate 14. As shown in FIG. 1, in the plane including the z-axis, most of the radiating element 13 is a dielectric lens 1.
Within the angle range defined by two straight lines connecting the two focal points F and both ends of the effective diameter of the dielectric lens 12, the dielectric lens 12 converts the cylindrical wave radiated from the plane array 15 into a plane wave by the dielectric lens 12. Disposed relatively close to the dielectric lens 1
2 to form a sharper (focused) beam. Further, the planar array 15 is a phased array in which a phase shifter or the like is connected to the radiating element 12 so that the excitation phase can be changed. Note that a variable amplifier or the like may be connected to the radiating element 12 to form an active phased array that can change the excitation amplitude.

Next, the operation will be described with reference to FIG.
The operation of the antenna device at the time of transmission will be described below, but the antenna is reciprocal for transmission and reception, and has the same characteristics at the time of reception. First, when a beam is formed in the direction of the optical axis 16, a cylindrical wave-like radio wave 22 incident on the dielectric lens 12 from the direction of the optical axis 16 is radiated from the plane array 15. When the cylindrical radio wave 22 passes through the dielectric lens 12, the optical axis 1
It is converted into a plane wave radio wave traveling in six directions and forms a beam 19 in the direction of the optical axis 16. When a cylindrical radio wave 23 obliquely incident on the optical axis 16 is emitted from the planar array 15, a beam 20 is formed in a direction deviated from the optical axis 16 after passing through the dielectric lens 12, and performs beam scanning. be able to.

In the beam scanning in the vicinity of the zenith in the antenna device of this embodiment, since the planar array 15 is installed at a position distant from the opening 18,
A beam is formed by combining the direct radiation from the planar array 15 through and the radiation through the dielectric lens 12. At a wider angle, a beam is formed mainly by radiation from the dielectric lens 12 as described above.

Although the above description has been made in cross section, the antenna device of this embodiment has a structure in which the dielectric lens 12 and the planar array 15 are rotationally symmetric with respect to the z axis of the coordinate system 10. If the angle θ is the same, the beam scanning in the circumferential direction around the z-axis has symmetrical radiation characteristics, which is the same as described above.

In this embodiment, since the antenna aperture as viewed from a desired wide-angle direction is enlarged by the dielectric lens 12, a higher gain can be obtained at a wider angle than when only the planar array 15 is used. In addition, there is an advantage that a smaller planar array and a smaller number of radiating elements are required as compared with a case where the same gain is obtained only with a planar array. Further, since the radiating element 13 is arranged in the vicinity of the focal point F of the dielectric lens 12, focusing is achieved, so that the beam width at a wide angle is wider than that of the conventional lens-equipped array antenna as illustrated in FIG. A narrow, high-gain beam can be formed. Since the aperture 18 is provided in the zenith direction, the equivalent wave source aperture diameter is smaller than the wide angle direction, so that a beam having a lower gain than the wide angle direction is formed. When beam scanning is performed by the antenna device of this embodiment, the gain is high in the wide-angle direction and low in the zenith direction as shown by the envelope of the beam peak shown in FIG. Therefore, it is possible to obtain an antenna device which is mounted on a low-orbit satellite and has beam scanning characteristics suitable for performing communication with the earth.

Embodiment 2 FIG. FIG. 5 is a sectional view for illustrating the structure of the antenna device according to the second embodiment of the present invention. In the figure, 13a, 13b and 13c are radiating elements, 16a and 16b are optical axes, 30 is a generally frustoconical concave surface composed of side lines orthogonal to the optical axes 16a and 16b of the dielectric lens 12, and the radiating element 13c is the concave surface. Is a radiating element arranged on the bottom surface of the. 31 is a radiating element 13a, 13
b, a conformal array consisting of 13c and concave surface 30,
A transceiver module 32 is connected to each radiating element and includes a phase shifter, an amplifier, a filter, and the like. The same or corresponding components are denoted by the same reference numerals.

The operation of this embodiment is almost the same as that of the antenna device of the first embodiment, but has the following features. The radiation element 13a mainly emits radiation in the vicinity of the optical axis 16a.
Contributes. The radiating elements 13b and 13c play a role of suppressing side lobes other than near the optical axis 16a. Conversely, optical axis 1
The radiation element 13b mainly contributes to radiation in the vicinity of the direction 6b, and the radiation elements 13a and 13c play a role of suppressing side lobes other than in the vicinity of the optical axis 16b. The radiating element 13c mainly contributes to radiation in the vicinity of the zenith direction, and the radiating element 1
3a and 13b play a role of suppressing side lobes other than near the zenith direction.

In this embodiment, the radiating elements 13a and 13b can be arranged at a position closer to the focal point F as compared with the case where a flat array having the same size as the conformal array 31 is used. There is an advantage that a beam having a wide angle, a narrower beam width, and a higher gain can be formed. Also, since microstrip antennas and horn antennas generally used for radiating elements emit strong radiation in the front direction, the optical axes 16a, 16b
By arranging the radiating elements 13a and 13b provided on the concave surface of a generally frustoconical shape composed of side lines orthogonal to the above, strong radiation can be performed in the wide-angle direction. From this point as well, the antenna device of this embodiment can form a beam having a higher gain in a wide-angle direction than in the case of using a planar array.

In the case where the same gain as that in the case of using the planar array shown in the first embodiment is sufficient, the radiation element 1
Since the distance between 3a and 13b and the focal point F can be made approximately the same as when a planar array is used, the focal length of the dielectric lens 12 can be made longer. In this case, since the thickness of the dielectric lens 12 is reduced, there is an advantage that the weight of the dielectric lens 12 can be reduced. In addition, the thickness of the dielectric lens 12 is reduced, so that there is an advantage that the transmission loss in the dielectric lens can be reduced.

Further, since the rear surface of the conformal array 31 is widely opened as compared with the planar array, there is an advantage that the mounting of the module 32 becomes easier.

Embodiment 3 FIG. 6 is a sectional view illustrating the structure of the antenna device according to Embodiment 3 of the present invention. In the figure, 40 is the optical axis 16 of the dielectric lens 12.
The radiating element 13c, which is a generally frustoconical convex surface composed of side lines orthogonal to a and 16b, is a radiating element arranged on the top surface of the convex surface 40. 41 denotes radiating elements 13a, 13b, 13
This is a conformal array composed of c and the convex surface 40. The same or corresponding components are denoted by the same reference numerals.

The operation of this embodiment is the same as that of the second embodiment.
It is almost the same as the antenna device of FIG. In the antenna device of this embodiment, since the convex conformal array 41 is used, the dielectric lens 1 is compared with the first and second embodiments.
2 and the radiating element can be easily arranged near the opening 18. Therefore, the radiating elements 13a and 13 that can be arranged near the focal point F
The number of b increases. That is, since the number of radiating elements 13a and 13b can be increased, there is an advantage that the degree of freedom of beam shaping in the wide angle direction is increased, and the control of the side lobe level is facilitated.

The radiating element 13 is also located near the opening 18.
Since c can be arranged, there is an advantage that direct radiation from the opening becomes strong and the gain of the beam near the zenith direction can be increased.

The dielectric lens 12 can convert a cylindrical wave into a plane wave as long as its thickness is thickest near the optical axis and becomes thinner as the distance from the optical axis decreases. Therefore, in Embodiments 1 to 3, various shapes of the dielectric lens 12 can be considered. For example, both sides are convex, one side is flat and the other side is convex,
One surface is convex and the other surface is concave.

In the first to third embodiments, when radiation near the zenith is not important, the dielectric lens 12
It is not always necessary to provide the upper opening 18.

In the second and third embodiments, the concave and convex surfaces on which the radiating elements are arranged do not necessarily have to have a truncated conical shape, but a rotationally symmetric hemisphere, a conical surface, a polygonal truncated pyramid, and a polygonal pyramid. Any shape, such as a surface, may be used as long as it is suitable for beam scanning that is substantially rotationally symmetric in the circumferential direction.

Embodiment 4 FIG. FIG. 7 is a sectional view illustrating a dielectric lens portion of an antenna device according to a fourth embodiment of the present invention. In the figure, reference numeral 50 denotes an end of the dielectric lens 12 in contact with the opening 18, and reference numeral 51 denotes a dielectric layer which covers the upper opening of the dielectric lens 12 and is smoothly connected to the end of the dielectric lens 12. The same or corresponding components are denoted by the same reference numerals. The dielectric layer 51 is a dielectric lens 1
The portion other than the portion connected to 2 has a uniform thickness and no lens action, and is made of a material having the same dielectric constant as the dielectric lens 12.

In the case where an opening 18 having no dielectric is provided above the dielectric lens 12 as in the first to third embodiments,
Radio wave scattering occurs at the end 50 of the dielectric lens. This scattering has undesirable effects on the radiation pattern formation, such as a decrease in gain and an increase in side lobes. Therefore, as in this embodiment, a dielectric layer 51 having a uniform thickness connected to the dielectric lens 12 is provided so as to cover the opening 18 so that the thickness gradually changes at the end 50 of the dielectric lens. Thereby, the scattering of the radio wave is reduced, and the disturbance of the radiation pattern can be reduced.

Embodiment 5 FIG. FIG. 8 is a sectional view illustrating a configuration of an antenna device according to a fifth embodiment of the present invention. In the figure, reference numeral 60 denotes a flat array provided in the opening 18, and 61 denotes an electrical connection means for electrically connecting the flat array 60 to a transceiver. In addition, the same code | symbol shows the same or equivalent thing. The planar array 60 is supported with physical support means such as columns or the dielectric lens 12.

This embodiment is different from the antenna device shown in the third embodiment in that the truncated cone-shaped convex surface 40 is used.
The radiating element 13c provided at the upper part of FIG. With such a structure, the radiating element 13
The radiation from c is radiated directly to the space without being blocked by the dielectric lens 12. Therefore, the antenna device of this embodiment has an advantage that the gain of the beam near the zenith direction can be increased as compared with the first to third embodiments. It is to be noted that the same gain as in the first to third embodiments can be obtained even if the radiating element 13c is downsized.

Embodiment 6 FIG. FIG. 9 is a sectional view illustrating a configuration of an antenna device according to Embodiment 6 of the present invention. In the figure, 70 designates the antenna opening as the opening 18.
Horn antenna installed in In addition, the same code | symbol shows the same or equivalent thing.

Here, in the low earth orbit satellite communication which is an application example of the antenna device of the present invention, since the earth is divided by the coverage area of the same size, the coverage area viewed from the satellite has the largest zenith direction, It becomes smaller as the angle becomes wider. Therefore, a beam having a wide beam width is required near the zenith direction. In addition, since the coverage area looks large near the zenith direction, finer beam shaping is not required as in the wide angle direction. Therefore, in this embodiment, a beam having a wide beam width is formed in the vicinity of the zenith direction by using a horn antenna 70 which is a single radiating element having a radiating opening in the opening of the dielectric lens instead of a plurality of radiating elements. The configuration is such that: In the vicinity of the zenith, it is also possible to perform a certain amount of beam shaping by the contribution from the radiating elements 13a and 13b through the dielectric lens 12. In this embodiment, there is an advantage that radiation with little loss can be performed in the vicinity of the zenith direction because it is not blocked by the dielectric lens 12. Further, there is an advantage that the number of radiating elements can be reduced as compared with the sixth embodiment, and the structure is simplified since no array is used.

Embodiment 7 FIG. 10 is a sectional view illustrating a dielectric lens part according to a seventh embodiment of the present invention. In the figure, reference numeral 80 denotes a matching layer provided around the dielectric lens 12. The same or corresponding components are denoted by the same reference numerals.

Although there are various methods of forming the matching layer 80, for example, the refractive index of the dielectric lens 12 is set to n,
When the refractive index of the external medium is 1 (air or vacuum), √
A method of arranging a dielectric layer having a refractive index of n on the surface of the dielectric lens 12 with a thickness of １ ／ λg (λg: the wavelength of a radio wave used in the matching layer dielectric) is used.

When a radio wave enters a dielectric lens having no matching layer, reflection occurs on the surface of the dielectric lens. The reflected radio wave becomes loss or unnecessary radiation, and deteriorates the performance of the antenna device. This embodiment has an advantage that the reflection can be reduced by providing the matching layer 80 on the surface of the dielectric lens 12, and the performance deterioration of the antenna device can be reduced. This embodiment can be applied to the first to sixth embodiments.

Embodiment 8 FIG. FIG. 11 is a sectional view illustrating a dielectric lens part according to an eighth embodiment of the present invention. In the figure, 90 is the engraving of the dielectric lens, and 91 is the engraving width h. The same or corresponding components are denoted by the same reference numerals.

The provision of the engraving 90 on the dielectric lens 12 as shown in FIG. 11 is called zoning. Reference numeral 91 denotes an engraved width h. Assuming that the refractive index of the dielectric lens 12 is n and the wavelength of a radio wave used in free space is λ0, h = λ0 /
It is represented by (n-1). Even if zoning is applied,
The dielectric lens 12 has almost the same performance as before zoning.

In this embodiment, by zoning the dielectric lens 12, the thickness of the dielectric lens 12 can be reduced.
This has the advantage that the weight can be reduced without affecting the performance.
Further, there is an advantage that the loss of passing through the dielectric lens can be reduced by making the dielectric lens 12 thinner. This embodiment can be applied to the first to seventh embodiments.

[0045]

According to the antenna device of the first aspect of the present invention, the cross section of the convex lens shape having the optical axis in the wide-angle direction separated by a predetermined angle from the axis in the zenith direction is rotated around the axis. A formed rotationally symmetrical, and a dielectric lens having a shape with an opening in the zenith direction, and is installed perpendicular to the axis in the zenith direction inside the focal point of the dielectric lens,
A planar array antenna formed from a plurality of radiating elements arranged generally within an angle range in which the dielectric lens can be seen from the focal point of the dielectric lens. An antenna device with a beam scanning characteristic that can increase the gain in the wide angle direction mainly in the direction separated by a predetermined angle from the gain in the zenith direction and is suitable for communication with the earth mounted on low earth orbit satellites Obtainable.

Further, according to the antenna device of the second aspect of the present invention, the cross section of the convex lens shape whose optical axis is the wide angle direction separated by a predetermined angle from the axis in the zenith direction is rotated around the axis. A dielectric lens having a rotationally symmetrical shape and a shape having an opening in the zenith direction, and the dielectric lens is installed near the inside of the focal point of the dielectric lens and is rotationally symmetric with respect to the axis in the zenith direction. A plurality of radiating elements disposed generally at the bottom of the concave surface facing the opening and facing the opening, and the concave surface within an angle range that allows the cross section of the convex lens shape corresponding to the focal point of the dielectric lens to be viewed from the focal point of the dielectric lens. And a conformal array antenna formed from a plurality of radiating elements formed as described above, so that the radiating elements are smaller than when a flat array having a frontage of the same size as the conformal array is used. Ri focuses can be arranged at a position closer to the focal point of the dielectric lens can be formed with high beam gains a more beam width is narrow at the desired angle. Also, by using the above-mentioned conformal array antenna, the radiating element can be arranged without lowering the gain even if the focal length of the dielectric lens is increased, and the thickness of the dielectric lens is reduced. There is an advantage that the passage loss in the dielectric lens can be reduced. Further, since the rear surface of the conformal array antenna is widely opened, there is an advantage that the module can be easily mounted.

According to the antenna device of the third aspect of the present invention, the cross section of the convex lens shape whose optical axis is a wide angle direction separated by a predetermined angle from the axis in the zenith direction is rotated around the axis. A dielectric lens having a rotationally symmetrical shape and a shape having an opening in the zenith direction, and the opening provided inside the focal point of the dielectric lens and rotationally symmetric with respect to the axis in the zenith direction. A plurality of radiating elements generally arranged on a top portion facing the opening having a convex surface with respect to the portion and the convex surface within an angle range in which a section of the convex lens shape corresponding to the focal point of the dielectric lens is viewed from the focal point of the dielectric lens; And a conformal array antenna formed from a plurality of radiating elements, so that the angle range within which the cross section of the convex lens shape corresponding to the focal point of the dielectric lens can be seen from the focal point of the dielectric lens. Serial can be increased a plurality of radiating elements generally arranged on the convex surface, increases the flexibility of the beam shaping in the wide-angle direction, it has the advantage that control of the side lobe level is facilitated. Further, there is an advantage that the direct radiation from the opening becomes stronger and the gain of the beam near the zenith direction can be increased.

Furthermore, according to the antenna device of the fourth aspect of the present invention, the antenna device is provided in the opening connected to the dielectric lens, and the thickness thereof changes smoothly and continuously following the end of the opening of the dielectric lens. At the same time, since a dielectric layer having the same dielectric constant as the above-mentioned dielectric lens in which a flat plate portion having a constant thickness perpendicular to the axis in the zenith direction is provided, scattering of radio waves at the end of the dielectric lens is reduced, Disturbance of the radiation pattern can be reduced.

According to the antenna device of the fifth aspect of the present invention, the radiation from the array antenna installed near the opening is radiated directly to the space without being blocked by the dielectric lens, so that the radiation near the zenith direction can be obtained. This has the advantage that the beam gain can be increased.

Further, according to the antenna device of the sixth aspect of the present invention, since a single radiating element having a radiating opening disposed at the opening of the dielectric lens is used, the zenith is simplified with a simple structure using a horn antenna or the like. A beam beam with a wide beam width can be formed in the vicinity of the direction, an antenna device with a beam scanning characteristic in which the coverage area is the largest in the zenith direction and becomes smaller as the angle becomes wider, and it is suitable for characteristics required for low-Earth orbit satellite communication etc. There is an advantage that an antenna device can be obtained.

Further, according to the antenna device of the seventh aspect of the present invention, the dielectric lens can be made thin while the performance of the dielectric lens is almost maintained, so that the weight can be reduced and the passage loss can be reduced.

According to the antenna device of the eighth aspect of the present invention, since the matching layer is provided on the surface of the dielectric lens or on the surfaces of the dielectric lens and the dielectric layer, reflection by radio waves on the dielectric surface is achieved. There is an advantage that loss and unnecessary radiation can be reduced and performance degradation of the antenna device can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a structure of an antenna device according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating the structure of the antenna device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram for explaining a beam scanning principle of the antenna device according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram for explaining an envelope of a beam peak when beam scanning is performed by the antenna device according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a structure of an antenna device according to a second embodiment of the present invention.

FIG. 6 is a sectional view illustrating a structure of an antenna device according to a third embodiment of the present invention.

FIG. 7 is a sectional view illustrating a dielectric lens part of an antenna device according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view illustrating a configuration of an antenna device according to a fifth embodiment of the present invention.

FIG. 9 is a sectional view illustrating a configuration of an antenna device according to a sixth embodiment of the present invention.

FIG. 10 is a sectional view illustrating a dielectric lens part according to a seventh embodiment of the present invention.

FIG. 11 is a sectional view illustrating a dielectric lens part according to an eighth embodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating a configuration of a conventional planar array antenna device with a dielectric lens.

[Explanation of symbols]

Reference Signs List 1 plane (structural base), 2 radiating element, 3 plane array, 4 dielectric lens (radio wave lens having desired refractive index), 5 coordinate system, 6 angle of separation θ from zenith direction, 7 aperture diameter d0, 8 Aperture diameter d1, 9 Equivalent wave source aperture diameter d
2, 10 coordinate system, 11 Separation angle θ from z-axis, 12 Dielectric lens, 13, 13a, 13b, 13c Radiating element, 14 Flat substrate, 15 Flat array, 16, 16
a, 16b optical axis, 17 focal point F, 18 aperture, 19,
20, 21 beams, 22, 23 cylindrical radio waves, 2
4 envelope of beam peak, 25 beams, 30 truncated cone-shaped concave surface, 31 conformal array, 32 transceiver module, 40 truncated cone-shaped convex surface, 41 conformal array, 50 end, 51 dielectric layer, 60
Flat array, 61 electrical connection means, 70 horn antenna, 80 matching layer, 90 engraving, 91 engraving width h.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Yoshihiro Tahara 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Shuji Urasaki 2-2-2, Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Yoshihiko Konishi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5J020 AA02 BB01 BB11 BB12 BC04 BC13 DA03 DA04 DA10 5J021 AA05 AA09 AB06 BA03 CA03 DA01 DB03 FA32 GA02 GA08 HA01 HA03 HA05 HA07 JA07

Claims (8)

[Claims] 1. A rotationally symmetrical shape formed by rotating a cross section of a convex lens shape whose optical axis is a wide angle direction separated by a predetermined angle from an axis in the zenith direction around the axis, and in the zenith direction. A dielectric lens having a shape having an opening, and installed vertically to the axis in the zenith direction inside the focal point of the dielectric lens and substantially within an angle range in which the dielectric lens can be seen from the focal point of the dielectric lens. A planar array antenna formed from a plurality of radiating elements arranged, wherein the gain in the wide angle direction is higher than the gain in the zenith direction with respect to beam scanning by the planar array antenna. apparatus. 2. A rotationally symmetric shape formed by rotating a cross section of a convex lens shape having an optical axis in a wide angle direction separated by a predetermined angle from an axis in the zenith direction around the axis, and in the zenith direction. A dielectric lens having a shape having an opening, and a bottom surface which is installed near the inside of the focal point of the dielectric lens and which is concave with respect to the opening which is rotationally symmetric with respect to the zenith direction axis and which faces the opening. A conformal array formed from a plurality of generally arranged radiating elements and a plurality of radiating elements generally arranged on the concave surface within an angular range from a focal point of the dielectric lens to a cross section of the convex lens shape corresponding to the focal point. An antenna device, comprising: an antenna, wherein the gain in the wide angle direction is higher than the gain in the zenith direction with respect to beam scanning by the conformal array antenna. 3. A rotationally symmetrical shape formed by rotating a cross section of a convex lens shape whose optical axis is a wide angle direction separated by a predetermined angle from an axis in the zenith direction around the axis, and in the zenith direction. A dielectric lens having a shape having an opening, and a top which is installed inside the focal point of the dielectric lens and faces the opening which is convex with respect to the opening which is rotationally symmetric with respect to the axis in the zenith direction. A conformal array formed from a plurality of generally arranged radiating elements and a plurality of radiating elements generally arranged on the convex surface within an angular range from a focal point of the dielectric lens to a cross section of the convex lens shape corresponding to the focal point. An antenna device, comprising: an antenna, wherein the gain in the wide angle direction is higher than the gain in the zenith direction with respect to beam scanning by the conformal array antenna. 4. The antenna device according to claim 1, wherein said antenna device is provided in said opening in connection with said dielectric lens, and has a smooth and continuous thickness following the opening end of said dielectric lens. And a dielectric layer having the same dielectric constant as the dielectric lens in which a flat plate portion having a constant thickness perpendicular to the axis in the zenith direction is formed. 5. The antenna device according to claim 1, 2 or 3, wherein a plurality of radiating elements at a portion facing the opening of the planar array antenna or the conformal array antenna are removed, and the radiating element is removed from the portion. An antenna device comprising: a plurality of radiating elements disposed closer to the opening; and an array antenna disposed near the opening. 6. The antenna device according to claim 1, 2 or 3, wherein a plurality of radiating elements at a portion of the planar array antenna or the conformal array antenna facing the opening are removed and the dielectric lens is removed. An antenna device comprising a single radiating element in which a radiation opening is arranged at an opening of the antenna device. 7. The antenna device according to claim 1, wherein the dielectric lens is subjected to zoning. 8. The antenna device according to claim 1, wherein a matching layer is provided on a surface of the dielectric lens or a surface of the dielectric lens and the surface of the dielectric layer. Antenna device.