JPH0582119U - Dual frequency antenna device - Google Patents

Abstract

(57) [Abstract] [Purpose] In the aperture antenna for dual frequency, the structure of the primary radiator is simplified and the antenna characteristics are highly efficient.
The purpose is to obtain low sidelobe characteristics. [Configuration] Each primary radiator corresponding to two frequencies,
The primary radiator placed at the focus of the parabola forming the back surface of the sub-reflector and the focus of the hyperbola forming the surface of the sub-reflector are placed horizontally, and the primary radiator placed at the focus of the parabola forming the back surface of the sub-reflector, and A primary radiator placed at the focal point of the hyperbola forming the subreflector surface is excited with horizontal polarization. Further, horizontal grids are formed on the front and back surfaces of the sub-reflecting mirror to transmit vertical polarized waves and reflect horizontal polarized waves. Further, the main reflecting mirror is formed with a diagonal 45 ° grid, and has a characteristic of changing only the polarization of the radio wave from the primary radiator placed at the focal point of the subreflecting mirror by 90 °. [Effect] Since the primary radiators are separately arranged, the structure of the primary radiators is simplified. In addition, since there is no blocking of the sub-reflector, high efficiency and low sidelobe antenna performance can be obtained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dual frequency antenna device including a main reflecting mirror, a sub reflecting mirror, and two primary radiators used in the microwave band.

[0002]

[Prior Art]

 FIG. 5 is an example of a cross-sectional view of a conventional dual frequency antenna device. In the figure, 1 is a primary radiator, 2 is a sub-reflecting mirror, 3 is a main reflecting mirror, 4 is a rotational symmetry axis, and 5 is an aperture plane. FIG. 6 shows an example of a primary radiator of a conventional dual frequency antenna device. In the figure, 1a and 1b are primary radiators of different frequency bands, and 15 is a sub-reflector focal point.

Next, the operation will be described. In any cross section including the axis of rotational symmetry 4, the main reflector 3 is usually a parabola and the sub-reflector 2 is a hyperbola or an ellipse. Spherical waves emitted from the two primary radiators 1a and 1b arranged on the focal point of a hyperbola or an ellipse are reflected by the sub-reflecting mirror 2 and the main reflecting mirror 3 in this order, and are radiated as plane waves in the direction of the aperture surface 5. ..

[0004]

[Problems to be solved by the device]

 Since the conventional dual frequency antenna device is configured as described above, in order to place the two primary radiators at the focal point of the sub-reflecting mirror, the primary radiators corresponding to two frequencies must be integrated. Since the structure becomes complicated and the distance between the outer primary radiators must be increased, the beam width of the primary radiator becomes small and the spillover becomes large, which lowers the antenna efficiency. In addition, the side lobe of the radiation pattern of the primary radiator enters the main reflecting mirror, which raises the problem that the side lobe rises.

The present invention has been made in order to solve the above-mentioned problems, and simplifies the structure of the primary radiator to provide a dual-frequency antenna device having high efficiency and low sidelobe characteristics at two frequencies. The purpose is to get.

[0006]

[Means for Solving the Problems]

 In the dual-frequency antenna device according to the present invention, one of the primary radiators is placed at the focal point of the parabola forming the back surface of the sub-reflector and excited by horizontal polarization, and the other primary radiator is placed on the surface of the sub-reflector. It is placed at the focal point of the constituent hyperbola and excited by horizontally polarized waves, and horizontal grids are placed on the front and back surfaces of the sub-reflector, and on the main reflector whose cross section including the axis of rotational symmetry is a parabola. It is arranged with a diagonal 45 ° grid.

Further, one of the primary radiators is arranged at the focal point of a parabola forming the back surface of the sub-reflector and excited by vertically polarized waves, and the other primary radiator is set to the hyperbolic focal point forming the surface of the sub-reflector mirror. They are arranged and excited by vertical polarization, and vertical grids are arranged on the front and back surfaces of the sub-reflecting mirror, and an arbitrary cross section including the axis of rotational symmetry is a parabolic main reflecting mirror with an angle of 45 °. The grid is arranged.

Further, one of the primary radiators is arranged at the focal point of a parabola forming the back surface of the sub-reflecting mirror and excited by horizontal polarization, and the other primary radiator is set at the focal point of an ellipse forming the surface of the sub-reflecting mirror. In addition to arranging and exciting with horizontal polarization, a horizontal grid is arranged on the front and back sides of the sub-reflecting mirror, and a diagonal 45 ° grid is arranged on the main reflecting mirror whose arbitrary cross section including the axis of rotational symmetry is a parabola. It was done.

Further, one of the primary radiators is placed at the focal point of a parabola forming the back surface of the sub-reflector and excited by vertically polarized waves, and the other primary radiator is placed at the focus of an ellipse forming the surface of the sub-reflector. In addition to arranging and exciting with vertical polarization, a vertical grid is arranged on the front and back surfaces of the sub-reflecting mirror, and a diagonal 45 ° grid is arranged on the main reflecting mirror whose section including the axis of rotational symmetry is a parabola. It was done.

[0010]

In the dual frequency antenna device according to the present invention, one of the primary radiators is arranged at the focal point of a parabola forming the back surface of the sub-reflector and excited by horizontal polarization, and the other primary radiator is sub-reflector. It is placed at the focal point of the hyperbola forming the surface and excited by horizontal polarization, and horizontal grids are placed on the front and back sides of the sub-reflector, and the main reflector with a parabola on any section including the axis of rotational symmetry. Since a 45 ° diagonal grid is placed on the top, the primary radiators can be placed separately on the axis of rotational symmetry, which simplifies the structure of the primary radiator, and also provides a highly efficient and low sidelobe antenna. The characteristics can be obtained.

[0011]

【Example】

 Example 1. FIG. 1 is a diagram showing an embodiment of the present invention, in which 1b is a primary radiator which is placed at the focal point of a parabola forming the back surface 2b of the sub-reflector and excited by horizontal polarization, and 1a is the surface of the sub-reflector. 2a is a primary radiator placed at the focal point of a hyperbola and excited by horizontal polarization, 6 is an oblique 45 ° grid placed on the main reflecting mirror 3, and 7 is placed on the front and back sides of the sub-reflecting mirror. It is a horizontal grid.

FIG. 2 is a cross-sectional view of the main reflecting mirror, and FIG. 3 is a diagram showing reflection of radio waves by the main reflecting mirror. In the figure, 8 is a conductor plate of the main reflector, 9 is an incident radio wave, 10 is a component orthogonal to the grid of the incident radio wave, 11 is a component parallel to the grid of the incident radio wave, and 12 is orthogonal to the grid of the reflected radio wave. The component, 13 is a component parallel to the grid of reflected radio waves, and 14 is the reflected radio waves. A radio wave that is horizontally polarized and incident on the main reflecting mirror is divided into a component that is orthogonal to the grid 6 and a component that is orthogonal to the component. The component parallel to the grid 6 is reflected by the grid 6 and the phase changes by 180 degrees. On the other hand, the component orthogonal to the grid 6 is transmitted and reflected by the conductor plate 8 of the main reflecting mirror. At this time, if the distance d between the grid 6 and the conductor plate 8 is determined by the following equation, when the radio wave reflected by the conductor plate 8 reaches the grid surface, the phase thereof becomes the same phase as the incident radio wave. d = λa / 4 (1)

In the above formula (1), λa is the wavelength of the radio wave radiated from the primary radiator 1a.

Therefore, the radio wave reflected by the conductor plate 8 is combined with the radio wave reflected by the grid surface 6 to change the polarization by 90 degrees, and is radiated as a vertically polarized plane wave.

FIG. 4 is a view showing a sectional view of the sub-reflecting mirror. In the figure, 2a is a hyperbola forming the subreflector surface, 2b is a parabola forming the backside of the subreflector, 15 is an incident radio wave having a polarization parallel to the grid, and 16 is a polarization orthogonal to the grid. The incident radio wave, 17 is a reflected radio wave having a polarization parallel to the grid, and 18 is a transmitted wave having a polarization orthogonal to the grid.

Next, the operation will be described. Since the spherical wave radiated from the primary radiator 1a is excited by the horizontally polarized wave, it is reflected by the surface 2a of the sub-reflecting mirror having the horizontal grid 7 and blown onto the main reflecting mirror 3.

The horizontally polarized radio wave blown to the main reflecting mirror 3 is reflected as a vertically polarized reflected radio wave on the mirror surface having the oblique 45 ° grid 6.

The radio wave converted into the vertically polarized wave reaches the sub-reflecting mirror 2, but the horizontal grid 7 on the sub-reflecting mirror 2 is transmitted and becomes a plane wave and is radiated in the direction of the aperture plane.

On the other hand, since the spherical wave radiated from the primary radiator 1b is excited by the horizontally polarized wave, it is reflected by the subreflecting mirror back surface 2b having the horizontal grid 7 and becomes a plane wave in the direction of the opening surface. Is emitted.

Example 2. In the above-mentioned embodiment, one of the primary radiators is arranged at the focal point of the parabola forming the back surface of the sub-reflector and excited by horizontal polarization, and the other primary radiator constitutes the surface of the sub-reflector. It is placed at the focal point of the hyperbola and excited by horizontal polarization, and horizontal grids are placed on the front and back surfaces of the sub-reflector, so that any section including the axis of rotational symmetry is on the main reflector with a parabola. The case where a 45 ° diagonal grid is arranged has been described. One of the primary radiators is placed at the focal point of the parabola forming the back surface of the sub-reflector and excited by vertical polarization, and the other primary radiator is arranged as the sub-reflector. It is placed at the focal point of the hyperbola forming the surface and excited by vertical polarization, and vertical grids are placed on the front and back surfaces of the sub-reflector, and on the main reflector whose cross section including the axis of rotational symmetry is a parabola. When a diagonal 45 ° grid is placed Even with the same effect.

Example 3. Also, one of the primary radiators is placed at the focal point of the parabola forming the back surface of the sub-reflector and excited by horizontal polarization, and the other primary radiator is placed at the focal point of the elliptical line forming the surface of the sub-reflector. In addition to excitation with horizontal polarization, horizontal grids are placed on the front and back surfaces of the sub-reflector, and a 45 ° diagonal grid is placed on the main reflector whose cross section, including the axis of rotational symmetry, is a parabola. The same effect can be obtained also in the case.

Example 4. Also, one of the primary radiators is placed at the focal point of the parabola forming the back surface of the sub-reflector and excited by vertically polarized waves, and the other primary radiator is placed at the focal point of the elliptical line forming the surface of the sub-reflector. When a vertical grid is placed on the front and back surfaces of the sub-reflector, and a 45 ° diagonal grid is placed on the main reflector whose section including the axis of rotational symmetry is a parabola. Also has the same effect.

[0023]

[Effect of the device]

 As described above, according to this invention, one of the primary radiators is placed at the focal point of the parabola forming the back surface of the sub-reflector and excited by horizontal polarization, and the other primary radiator is placed on the surface of the sub-reflector. It is placed at the focal point of the hyperbola to be excited by horizontal polarization, and horizontal grids are placed on the front and back surfaces of the sub-reflector, and an arbitrary cross section including the axis of rotational symmetry is oblique on the main reflector with a parabola. Since it has been constructed by arranging a grid of °, it has the effects of simplifying the structure of the primary radiator and obtaining high efficiency and low sidelobe characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a main reflecting mirror according to the present invention.

FIG. 3 is a diagram showing reflection of radio waves on a 45 ° grid on a main reflecting mirror according to the present invention.

FIG. 4 is a sectional view of a sub-reflecting mirror according to the present invention.

FIG. 5 is a cross-sectional view showing a conventional dual frequency antenna.

FIG. 6 is a diagram showing a primary radiator of a conventional dual-frequency antenna.

[Explanation of symbols]

 1 Primary radiator 2 Sub-reflecting mirror 3 Main reflecting mirror 4 Rotational symmetry axis 5 Aperture surface 6 45 ° grid 7 Horizontal grid 8 Conductor plate 9 Incident radio wave 10 Component orthogonal to the incident radio wave grid 11 Component parallel to the incident radio wave grid 12 Component orthogonal to the grid of reflected radio waves 13 Component parallel to the grid of reflected radio waves 14 Reflected radio wave 15 Incident radio wave with polarization parallel to the grid 16 Incident radio wave with polarization orthogonal to the grid 17 Polarization parallel to grid Reflected radio wave with 18 Transmitted radio wave with polarization orthogonal to the grid

Claims (1)

[Scope of utility model registration request] 1. A main reflecting mirror having a parabola in an arbitrary cross section including a rotational symmetry axis, and a hyperbola (or an ellipse) in which a main reflecting mirror side having an arbitrary cross section including a rotational symmetry axis coincides with one focus of the parabola. ) And the other is a parabolic subreflector, the primary radiator placed at the focal point of the parabola forming the subreflector, and the primary radiator placed at the hyperbolic focus of the subreflector. In the antenna device, the primary radiator placed at the focal point of the hyperbola (or ellipse) forming the sub-reflector is excited by horizontal polarization (or vertical polarization), and the other primary radiator is excited by vertical polarization ( Or a horizontally polarized wave), a 45 ° diagonal grid is arranged on the main reflecting mirror, and a horizontal grid (or vertical) is arranged on the front and back surfaces of the sub-reflecting mirror. ..