JP2608412B2 - Omni-directional antenna in horizontal plane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Regarding an omnidirectional antenna in a horizontal plane for communicating between a central station and a number of stator stations or mobile stations, controlling directivity in a vertical plane, For the purpose of enabling automatic tracking, etc., the main reflecting mirror whose radiation surface is a conical rotating paraboloid or a rotating surface obtained by correcting the conical paraboloid, and reflects radio waves to the reflecting surface of the main reflecting mirror Control means for controlling the directivity in the vertical plane by moving the relative position between the main reflector and the primary radiation system in the vertical direction in the omnidirectional antenna in the horizontal plane comprising the primary radiation system arranged as described above. Was provided.

[Industrial applications]

The present invention relates to an omnidirectional antenna in a horizontal plane for performing communication between a central station and a number of stator stations or mobile stations.

In a system for communicating between a central station and a number of stator stations scattered around the mobile station or mobile stations moving around the central station, instead of providing the central station with an antenna corresponding to the local station, It is preferable to provide one omnidirectional antenna in the horizontal plane.

[Conventional technology]

As an omnidirectional antenna in a horizontal plane, for example,
An antenna disclosed in JP-A-53-65045 is known. This antenna is composed of a reflector having a conical rotating paraboloid, a conical primary radiator, and a circular waveguide, and a rotation center axis forming a paraboloid of revolution, and a primary radiator. Radio waves emitted from the primary radiator are aligned with the central axis, are reflected by the reflector and are reflected in the horizontal direction, and become omnidirectional in the horizontal plane.

A biconical antenna is also an omnidirectional antenna in a horizontal plane, and an antenna obtained by stacking dipole antennas and slot antennas is also an omnidirectional antenna in a horizontal plane.

[Problems to be solved by the invention]

When using a frequency of several GHz or more to perform communication between the central station and a large number of stator stations scattered around the central station or with a large number of mobile stations moving around the central station, a half wavelength Dipole antennas are impractical because of their short wavelength and correspondingly small dimensions. Therefore, in general, an aperture antenna will be used.

However, since the biconical antenna is a radiation antenna without a reflector, it is difficult to interface the excitation source and the antenna system in a high frequency band, and it is difficult to control the directivity in the vertical plane. There are drawbacks. In the antenna disclosed in the above publication, the primary radiator is excited in the fundamental mode (TE ₁₁ mode) of the circular waveguide, and is reflected by the reflecting mirror and radiated in the horizontal direction. The generated radio waves have different polarization planes corresponding to the radiation directions in the horizontal plane. Therefore, in the mobile station, since the plane of polarization changes in accordance with the position of movement, it becomes difficult to design a receiving antenna.

If the mobile station moves on a fixed horizontal plane with respect to the central station, the directivity of the antenna in the vertical plane may remain constant, but the relative position of the central station and the mobile station in the vertical direction changes. When the mobile station moves on such an uneven surface, it is desirable to control the directivity of the antenna in the vertical plane to perform tracking control so that reception can be performed at a predetermined S / N ratio.

However, as described above, it is difficult to control the directivity of the biconical antenna in the vertical plane. Also, in the antenna disclosed in the above-mentioned publication, the directivity in the vertical plane could not be changed.

Also, there is known an antenna in which a plurality of dipole antennas or slot antennas are stacked in the vertical direction and the directivity in the vertical plane is controlled by adjusting the respective excitation phases, but the feeding circuit is complicated and large. There is a disadvantage that it becomes.

An object of the present invention is to control directivity in a vertical plane to enable automatic tracking and the like.

[Means for solving the problem]

The omnidirectional antenna in a horizontal plane according to the present invention can control directivity in a vertical plane, and will be described with reference to FIG.

A main reflecting mirror 1 having a conical rotating paraboloid or a rotating surface obtained by correcting the conical rotating paraboloid as a reflecting surface, and a primary radiating system 2 arranged to radiate radio waves to the reflecting surface of the main reflecting mirror 1 In the horizontal omnidirectional antenna, the relative position between the main reflecting mirror 1 and the primary radiating system 2 is moved in the vertical direction to maintain the same phase plane at the opening surface of the main reflecting mirror 1 in a straight line. In this state, control means 3 for controlling the directivity in the vertical plane is provided.

[Action]

The radio wave radiated from the primary radiation system 2 is reflected by the main reflecting mirror 1 and radiated in the horizontal direction with no directivity. In that case, TM ₀₁ mode or the primary radiation system 2 is excited by the TE ₀₁ mode, it is from main reflector 1 emitted as vertical polarization or horizontal polarization.

Then, the relative position between the main reflecting mirror 1 and the primary radiation system 2 is moved by the control means 3 in the vertical direction. For example, when the phase center a of the primary radiation system 2 coincides with the focal point of the main reflecting mirror 1 When the equi-phase plane at the opening surface of the main reflecting mirror 1 is linear and vertical, the directivity in the vertical plane is horizontal, and the primary radiation system 2 is controlled by the control means 3 as shown by a dotted line. When the phase center is moved from a to a 'by moving the phase center in the vertical direction, the isophase surface at the opening surface of the main reflecting mirror 1 is tilted by θ while maintaining the linearity. Thus, the in-plane directivity is upward by θ from the horizontal direction. That is, by controlling the relative position between the main reflecting mirror 1 and the primary radiation system 2, the directivity in the vertical plane can be controlled. Therefore, the control is performed such that the directivity is not directional in the horizontal plane and the maximum sensitivity is always obtained. By controlling the means 3 to control the directivity in the vertical plane, the function of automatic tracking can be realized.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a sectional view of the first embodiment of the present invention, in which 11 is a main reflecting mirror having a substantially conical rotating paraboloid or a corrected rotating surface as a reflecting surface, and 12 is a primary radiation mirror. , 13 is a telescopic waveguide, 14 is a mode converter, 15 is a rack, 16 is a motor, 17 is a pinion, 18 and 19 are sliding bearings, 20 and 21 are support columns, 22 is glass and fiber reinforced plastic A dielectric support cylinder having a certain degree of mechanical strength, such as 23, is an upper plate.

The main reflector 11 corresponds to the main reflector 1 in FIG. 1, the primary radiator 12 corresponds to the primary radiation system 2, and the telescopic waveguide section 13,
Rack 15, motor 16, pinion 17, sliding bearing 18,1
9 and the like correspond to the control means 3.

The main reflector 11 is supported on a support column 21 by a dielectric support cylinder 22 and is protected so that raindrops and the like do not enter the primary radiator 12. A conical opening of the primary radiator 12 is arranged to face the reflection surface of the main reflection mirror 11 so as to radiate radio waves, and a configuration for controlling a relative position between the main reflection mirror 11 and the primary radiator 12 is: The case where the primary radiator 12 is moved is shown. The primary radiator 12 is supported by supporting columns 21 so that the primary radiators 12 can be moved vertically by sliding bearings 18 and 19.
The mode conversion unit 14 supported in the inside and fixed in the support column 20
The primary radiator 12 movably supported in the support column 21 in the vertical direction is connected to the primary radiator 12 by a telescopic waveguide 13.

The motor 16 has a structure with a speed reducer and a brake, and is provided with an encoder and the like capable of detecting a moving amount. Since the pinion 17 and the rack 15 are engaged with each other, by driving the motor 16, the primary The radiator 12 can be moved vertically. That is, the relative position between the phase center of the primary radiator 12 and the focal point of the main reflecting mirror 11 can be controlled in the vertical direction.

The mode converter 14, the conversion and the primary radiator 12 from the rectangular waveguide mode to circular waveguide mode, and performs the mode conversion to excited in TM ₀₁ mode or TE ₀₁ mode. For example, when excited primary radiator 12 in TM ₀₁ mode, since the radial center of the field of TM ₀₁ mode is coincident with the center of the main reflecting mirror 11 is radiated in the horizontal direction as a vertical polarization. When the primary radiator 12 is excited in the TE ₀₁ mode, TE ₀₁
Since the center of the concentric electric field of the mode coincides with the center of the main reflecting mirror 11, the mode is radiated in the horizontal direction as a horizontally polarized wave. That is, in the horizontal plane, the polarization plane is constant in any direction, and the receiving antenna can be easily formed.

Although the above-described embodiment shows a case where the primary radiator 12 is provided so as to be movable, the primary radiator 12 is fixed, the main reflecting mirror 11 is supported so as to be movable in the vertical direction, and the It is also possible to adopt a configuration in which the movement is performed. In that case, the telescopic waveguide section 13 can be omitted.

FIG. 3 is a diagram for explaining the operation of the first embodiment of the present invention.
When the phase center a of the primary radiator 12 is present at the focal point of the main reflecting mirror 11, when the directivity in the vertical plane is horizontal, that is, when the equal phase plane of the aperture plane is vertical, the primary radiator 12 is When the primary radiator 12 is moved l 'in the opposite direction to the main reflector 11 side, the directivity in the vertical plane is shifted θ' when the primary radiator 12 is moved toward the main reflector 11 by l. Move.

In this case, the linear equal phase surface of the opening surface of the main reflecting mirror 11 is also inclined by θ or θ ′. The decrease in antenna gain due to the inclination of the angle θ of this linear equiphase plane is (1-cos
θ), but since the inclination angle θ or θ ′ of the above-mentioned equiphase surface is small, it can be considered that 1−cos θ ≒ 0. That is, without reducing the antenna gain, the main reflector 11
By controlling the relative position between the mirror and the primary reflector 12 in the vertical direction, the directivity in the vertical plane can be controlled.

The opening diameter of the primary radiator 12 having a conical opening is set to 2.
Excited in TM ₀₁ mode as 67λ (λ = wavelength), the main reflector
When the focal length of 11 is 15λ, and the opening W of the main reflector 11 is 25λ, + when the primary radiator 12 is moved to the main reflector 11 side, and when the primary radiator 12 is moved to the opposite side to the main reflector 11 −, The moving distance is shown on the horizontal axis in units of wavelength λ, the vertical axis is the deviation angle [degree] of the directivity in the vertical plane, the upward deviation angle is +, and the downward deviation angle is FIG. 4 shows the relationship between the moving distance and the shift angle as-. For example, when the primary radiator 12 is moved toward the main reflecting mirror 11 by 8λ, the directivity in the vertical plane shifts upward by about 3.8 degrees. Also, move the primary radiator 12 to the opposite side of the main reflector 11 8
When moved by λ, the directivity in the vertical plane shifts downward by about 3 degrees.

In the 50 GHz band, since the wavelength λ is 6 mm, the above-mentioned 8λ is 48 mm, and the primary radiator 12 is moved by 48 mm toward the main reflecting mirror 11.
When moved, the vertical in-plane directivity shifts upward by about 3.8 degrees, and when the primary radiator 12 is moved 48 mm away from the main reflector 11, the vertical in-plane directivity shifts downward by about 3 degrees. Move.

FIG. 5 shows a case where the main reflector 11 and the primary reflector 12 having the above dimensions are used, and the phase center a of the primary radiator 12 is located at the focal point of the main reflector 11, and the horizontal direction is 0 degree. Is shown in the vertical plane. In this case, the maximum gain was about 18 dB.

FIG. 6 shows the directivity in the vertical plane when the primary radiator 12 is moved by 6λ toward the main reflecting mirror 11, and is shifted from the horizontal direction by about 2.6 degrees upward. FIG. 7 shows that the primary radiator 12 is
It shows the directivity in the vertical plane when it is moved 6λ to the side opposite to 1, and is shifted about 2.3 degrees downward from the horizontal direction.

As described above, by driving the motor 16 and moving the primary radiator 12 with respect to the main reflecting mirror 11, the horizontal plane is omnidirectional, and the directivity in the vertical plane can be controlled. It is also easy to perform control so as to obtain a vertical in-plane directivity that is a sensitivity. Therefore, the automatic tracking function can be easily realized. Since the relationship between the relative position of the main reflector 11 and the primary radiator 12 and the directivity in the vertical plane can be known in advance, the relative position where the desired directivity in the vertical plane can be obtained by detecting the amount of movement. It is also possible.

FIG. 8 is a sectional view of a second embodiment of the present invention, in which 31 is an annular main reflecting mirror having a paraboloid of revolution or a rotating surface obtained by correcting the paraboloid as a reflecting surface, and 32 is a conical shaped reflecting mirror. Primary radiator having an aperture, 33 is a hyperboloid or spheroidal subreflector, 34
Is a screw, 35 is a fixed nut, 36 is a telescopic waveguide, 37 is a mode converter, 38 is a gear, 39 is an antenna base, 40 is a motor, 41 is a reducer, 42 is a pinion, and 43 is a dielectric. It is a support cylinder.

The primary radiator 32 and the sub-reflector 33 constitute the primary radiation system 2 in FIG. 1, and include a motor 40, a speed reducer 41, and a pinion.
The control means 3 shown in FIG. 1 is constituted by the gear 42, the gear 38, the telescopic waveguide section 36, the screw 34, the fixing nut 35 and the like. In this embodiment, the main reflecting mirror 31 and the sub-reflecting mirror 33 are
This shows a case where the primary radiator 32 is provided so as to be movable in the vertical direction while fixing the relative position of the primary radiator 32 and protecting it from penetration of raindrops and the like. However, it is also possible to fix the primary radiator 32 and movably provide one or both of the sub-reflector 33 and the main reflector 31.

By the mode converter 37 is converted from rectangular waveguide mode to circular waveguide mode, further, it is converted into a TM ₀₁ mode or TE ₀₁ mode, telescopic waveguide portion 36 the primary radiator 32 through a is excited, The radio wave radiated from the primary radiator 32 is reflected by a sub-reflector 33 having a hyperboloid of revolution or an ellipsoid of revolution and is incident on a main reflector 31, and is reflected by the main reflector 31 to form a dielectric support cylinder. The light passes through 43 and is radiated omnidirectionally in the horizontal direction.

When the motor 40 is driven, a pinion is
The pinion 42 rotates, and the gear 38 is rotated by the pinion 42. The rotation of the gear 38 causes the screw 34 to rotate inside the fixed nut 35, so that the primary radiator 32 moves in the vertical direction according to the rotation direction. Therefore, the relative position of the primary radiator 32 with respect to the main reflecting mirror 31 changes, and the directivity in the vertical plane is controlled. Also in this embodiment, means for detecting the amount of movement can be provided, and control can be performed so that desired characteristics can be obtained from the relationship between the amount of movement and directivity in the vertical plane.

FIG. 9 is a diagram for explaining the operation of the second embodiment of the present invention.
Sub-reflection mirror 33 whose reflection surface is a hyperboloid of revolution (solid line convex mirror)
Alternatively, one focal point a1 of the sub-reflecting mirror 33 'having a spheroidal (dotted concave mirror) and the main reflecting mirror 31 having a paraboloid of revolution as a reflecting surface
When the other focal point a2 coincides with the phase center of the primary radiator 32, a reference state is set, and any one of the main reflecting mirror 31, the primary radiator 32, and the sub-reflectors 33, 33 'is used. By controlling one or more of them so that they can move in the vertical direction, the relative position of the main reflecting mirror 31 and the primary radiating system consisting of the primary radiator 32 and the sub-reflecting mirrors 33 and 33 'is controlled, This controls the in-plane directivity.

When the sub-reflector 33 having a hyperboloid of revolution is used, in the reference state, the spherical wavefront radiated from the center position of the primary radiator 32 corresponding to the focal point a2 of the sub-reflector 33 is reflected by the sub-reflector 33. The reflected wave is incident on the main reflecting mirror 31 as a spherical wave radiated from the focal point a1 of the sub-reflecting mirror 33, and
Since a1 is the focal point of the main reflecting mirror 31, it is radiated in the horizontal direction as a plane wave whose phase coincides with the aperture surface.

When the sub-reflector 33 'having a spheroid is used, the primary radiator corresponding to the focal point a2 of the sub-reflector 33' in the reference state
The spherical wave radiated from the phase center of 32 is reflected by the sub-reflecting mirror 33 'and concentrated at the focal point a1, and is incident on the main reflecting mirror 31 as a spherical wave radiated from the focal point a1, and the main reflecting mirror 31 And is radiated in the horizontal direction as a plane wave whose phase coincides with the aperture surface.

In the case where the directivity in the vertical plane in the above-described reference state has the characteristic of being maximum in the horizontal direction, only the primary radiator 32 is provided so as to be movable, and the primary radiator 32 is vertically moved toward the sub-reflector 33 side. , The directivity in the vertical plane becomes upward with respect to the horizontal direction. When the primary radiator 32 is moved in the vertical direction to the side opposite to the sub-reflector 33, the directivity in the vertical plane becomes downward with respect to the horizontal direction.

Similarly, by moving the main reflecting mirror 31 or the sub-reflecting mirror 33 in the vertical direction, the directivity in the vertical plane can be controlled upward or downward with respect to the horizontal direction. Therefore, the main reflector 31 and the primary radiator 3 are set so that the reception sensitivity is maximized.
Automatic tracking can be performed by moving one or more of the two or the sub-reflector 33 in the vertical direction. Also, a means for detecting the amount of movement is provided, and the correspondence between the relative position of the main reflecting mirror 31 and the primary radiation system and the directivity in the vertical plane is known, so that the desired directivity in the vertical plane can be obtained. In addition, the movement of the relative position can be controlled.

FIG. 10 is a sectional view of a third embodiment of the present invention, in which 51 is a conical main reflecting mirror having a paraboloid of revolution or a rotating surface obtained by correcting the paraboloid, and 52 is a horizontal reflecting mirror. Biconical antenna with aperture, 53 is a hyperboloid or spheroidal sub-reflector, 54 is a screw, 55 is a gear, 56 is a motor, 57 is a reducer, 58 is a pinion, 59 is an antenna base, 60 is a dielectric It is a supporting cone of the body.

The biconical antenna 52 corresponds to the primary radiator in each of the above-described embodiments, and the biconical antenna 52
The primary radiation system 2 in FIG. 1 is constituted by the sub-reflection mirror 53 and the control means 3 in FIG. 1 is constituted by a screw 54, a gear 55, a pinion 58, a motor 56, a speed reducer 57 and the like. Make up. In this case, the biconical antenna 52 and the sub-reflector 53
In the configuration in which both the biconical antenna 52 and the biconical antenna 52 can move in the vertical direction, the waveguide fixed to the antenna base 59 and the biconical antenna 52 In the same manner as in the above-described embodiments, a telescopic waveguide section is provided. When a rectangular waveguide is fixed to the antenna base 59, the circular waveguide mode is switched from the rectangular waveguide mode. A mode conversion unit for converting to a waveguide mode is provided. Further, the main reflecting mirror 51 can be provided so as to be movable in the vertical direction.

The supporting cone 60 supports the main reflecting mirror 51 and protects the raindrops and the like from entering the inside thereof. It is of course possible to adopt a cylindrical shape as in the above-described embodiments. It is.

The radio wave radiated in the horizontal direction from the biconical antenna 52 is reflected by the sub-reflecting mirror 53 and is incident on the main reflecting mirror 51, is reflected in the horizontal direction by the main reflecting mirror 51, and passes through the supporting conical cylinder 60. Radiated. When the motor 56 is driven to rotate the pinion 58 via the speed reducer 57 and the gear 55 is rotated by the pinion 58, the screw 54 can move the biconical antenna 52 in the vertical direction.
Thereby, the relative position between the primary radiation system and the main reflecting mirror 51 is controlled, and the directivity in the vertical plane is controlled.

FIG. 11 is an explanatory diagram of the operation of the third embodiment of the present invention.
A primary radiation system 61 is constituted by a biconical antenna 52 as a primary radiator and a sub-reflector 53, and a phase center of the biconical antenna 52 is provided at one focal point b2 of the sub-reflector 53 of a hyperboloid of revolution or a spheroid. And when the focus of the main reflecting mirror 51 is matched to the other focal point b1, a reference state is established. With respect to this reference state, the main reflecting mirror 51 and the biconical antenna
Either the mirror 52 or the sub-reflector 53 can be provided so as to be movable in the vertical direction, or the primary radiation system 61 can be provided so as to be movable in the vertical direction.

In the reference state, the spherical wave radiated from the phase center of the biconical antenna 52 is reflected by the sub-reflecting mirror 53 and enters the main reflecting mirror 51. At this time, since the spherical wave is incident from the focal point b1 of the main reflecting mirror 51, it is radiated in the horizontal direction as a plane wave whose phase coincides with the opening surface of the main reflecting mirror 51.

Then, assuming that the vertical in-plane directivity has a characteristic that is maximum in the horizontal direction. For example, when the primary radiation system 61 is moved in the vertical direction toward the main reflecting mirror 51, the vertical in-plane directivity is upward with respect to the horizontal direction. Becomes When the primary radiation system 61 is moved in the opposite direction, the directivity in the vertical plane becomes downward with respect to the horizontal direction.

FIG. 12 is an explanatory diagram of the directivity in the vertical plane. As shown in FIG. 12 (a), when the directivity in the vertical plane in the reference state has the maximum characteristic in the horizontal direction, By controlling the relative position to the radiation system, α
Alternatively, a directivity of α 'can be obtained. Also, as shown in (b), one or both of the main reflecting mirror and the sub-reflecting mirror are set in shape, an inclination angle, etc., and in the reference state, for example, only an angle γ with respect to the horizontal direction. When the directivity is downward, by controlling the relative position between the main reflecting mirror and the primary radiation system, the angle .gamma.
Alternatively, the directivity may be β ′.

Control means for controlling the relative position between the main reflecting mirror and the primary radiation system is as follows:
It is configured to have a movement amount that can obtain a desired shift angle,
As described above, a shift angle of several degrees can be obtained by the movement amount for several wavelengths. As such a control means, a mechanism other than the above-mentioned embodiment can be adopted.

〔The invention's effect〕

As described above, the present invention relates to a primary radiation system 2 including a sub-reflector and the like, and a main reflector 1 having a conical rotation paraboloid or a rotation surface obtained by correcting the conical paraboloid. A control means 3 for controlling the directivity in the vertical plane by moving the relative position in the vertical direction is provided.
In the vertical plane, the directivity is controlled according to the position on the receiving side and the like, and the function of automatic tracking can be easily realized.

Therefore, in a system that communicates with a plurality of mobile stations moving around the central station or the fixed stations scattered around the central station by a microwave or the like, it is possible to control the system so as to have the optimum directivity. Therefore, efficient communication can be performed.

[Brief description of the drawings]

FIG. 1 is a view for explaining the principle of the present invention, FIG. 2 is a sectional view of the first embodiment of the present invention, FIG. 3 is an explanatory diagram of the operation of the first embodiment of the present invention, and FIG. FIG. 5, FIG. 6, and FIG. 7 are directivity curves in a vertical plane, and FIG.
FIG. 9 is a sectional view of the second embodiment of the present invention, FIG. 9 is an explanatory view of the operation of the second embodiment of the present invention, FIG. 10 is a sectional view of the third embodiment of the present invention, FIG. FIG. 12 is an explanatory diagram of the operation of the third embodiment of the present invention, and FIGS. 12 (a) and (b) are explanatory diagrams of directivity in a vertical plane. 1,11,31,51 are main reflectors, 2 is a primary radiation system, 3 is control means, 12,32 is a primary radiator, 33,53 sub-reflectors, 13,36 are telescopic waveguide sections, 37 is a mode converter, and 16 and 40 are motors.

Claims (1)

(57) [Claims] 1. A main reflector (1) having a conical paraboloid of revolution or a rotation surface obtained by correcting the conical paraboloid, and a radio wave is reflected by the reflection surface of the main reflector (1). In a horizontal omnidirectional antenna comprising a primary radiating system (2) disposed in a horizontal plane, a relative position between the main reflecting mirror (1) and the primary radiating system (2) is moved in a vertical direction, and A control means (3) for controlling directivity in a vertical plane while maintaining an equal phase plane in an opening surface of a main reflecting mirror (1) in a straight line is provided. antenna.