JPH0559601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a parabolic antenna, and particularly to a parabolic antenna suitable for detecting the arrival direction of radio waves.

<Prior art> In general, in order for a moving object such as a ship or vehicle to receive radio waves from a fixed station, such as a broadcasting satellite, it is necessary to always receive radio waves from a fixed station, such as a broadcasting satellite, because the ship or vehicle is moving. It is necessary to automatically adjust the azimuth and elevation angle of the antenna so that it points to the Similarly, when receiving radio waves from a moving object, such as an artificial satellite, at a fixed position, it is necessary to adjust the azimuth and elevation angle of the antenna so that the antenna always points toward the artificial satellite. . In this adjustment method, in addition to the main receiving antenna, multiple sub-antennas are used to detect the azimuth and elevation angle from which radio waves are arriving, and the elevation angle of the sub-antenna with the highest reception level is used. There is also a method of directing the main antenna in both directions and azimuth.

Conventionally, as an antenna used for such an adjustment method, when the received radio waves are in the SHF band or above, one primary radiator is installed as the main antenna at the focal position of the parabolic reflector, and multiple primary radiators are installed around it as sub antennas. There was a parabolic antenna equipped with a device.

<Problems to be Solved by the Invention> However, in the parabolic antenna as described above, a plurality of primary radiators must be placed near the focal point of the parabolic reflector, and there are physical restrictions on the placement positions. There was a problem. Also,
Each primary radiator is connected via a waveguide to each converter provided correspondingly, but each primary radiator, each waveguide, and each converter are generally mechanically connected to a parabolic reflector. Because they are combined, the combined parabolic reflector is heavy. Therefore, there is a problem in that a driving device that generates a large driving force must be used to adjust the azimuth and elevation angle of the parabolic reflector toward the direction in which the radio waves arrive.

An object of the present invention is to provide a parabolic antenna that solves each of the above-mentioned problems.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a parabolic reflector and a primary radiator provided at the focal point of the parabolic reflector, and uses these as a main antenna. , a plurality of planar antennas are provided along the reflective surface of the parabolic reflector so as to be positioned on a plurality of parabolas that pass through the center and intersect with each other, sandwiching the center, and these are used as sub-antennas.

Further, the reflecting surface portion of the parabolic reflector to which each planar antenna is attached may be made to protrude toward the primary radiator side more than the other reflecting surface portions.

Furthermore, each planar antenna may have a multilayer structure and be made of metal with slits on its surface, and the metal surface may coincide with the other reflecting surface portions.

<Operations/Effects> According to the present invention, the planar antenna is provided with a plurality of planar antennas so as to be located on a plurality of parabolas passing through the center of the reflecting mirror, with the center sandwiched between them. There are no restrictions and installation is relatively easy. Since each of the planar antennas attached to the parabolic reflector is very light in weight, the weight of the parabolic reflector to which they are attached does not increase significantly, and a comparison of the output of each planar antenna shows that The parabolic antenna can be driven to the azimuth and elevation angles determined by using a drive device with a small driving force.

In addition, if the part of the parabolic reflector to which the planar antenna is attached protrudes toward the primary radiator compared to other parts, the planar antenna will have a ground conductor on one dielectric surface and a radiating element on the other surface. It is possible to cancel out the phase delay that occurs when using a device equipped with . In other words, the radio wave that is reflected by the part of the parabolic reflector provided with the planar antenna and incident on the primary radiator passes through the dielectric material, is reflected by the part not provided with the planar antenna, and is incident on the primary radiator. However, by making the part of the parabolic reflector to which the planar antenna is attached protrude closer to the primary radiator than the other parts, this phase lag can be offset.

Furthermore, when a planar antenna with a multilayer structure and a metal surface with slits is used, radio wave radiation occurs on this metal surface. Therefore, by positioning this metal surface at the same position as the surface of the parabolic reflector that is not provided with a planar antenna, the phases can be aligned.

<Example> A first example is shown in FIGS. 1 and 2. In this embodiment, the present invention is applied to a parabolic antenna that is mounted on a moving body such as a ship or vehicle and is used to always receive satellite broadcasts transmitted from a broadcasting satellite, which is a geostationary satellite. It is something.

In FIGS. 1 and 2, 10 is a parabolic reflecting mirror, for example a rotating parabolic reflecting mirror made of metal,
A primary radiator 12 is provided at the focal point. Although not shown in the figure, the primary radiator 1
2 is a BS that converts, for example, a 12 GHz band satellite broadcast signal into a 1 GHz band first intermediate frequency signal via a waveguide.
connected to the converter. This BS converter can be installed using a parabolic reflector 10 with a suitable support.
mechanically coupled to.

In a vertical parabola passing through the center of the reflecting surface of the parabolic reflecting mirror 10, planar antennas 14a and 14b are provided on both sides of the center, respectively. Similarly, in a horizontal parabola passing through the center of the reflecting surface of the parabolic reflector 10, planar antennas 14c and 14d are provided on both sides of the center. Each planar antenna 14a, 14b, 14
c and 14d, for example, a ground conductor 18 made of metal foil is provided on one surface of a dielectric 16, and a large number of crank-shaped radiating elements 20 are provided on the other surface.
8 is attached so as to be located on the reflecting surface side of the parabolic reflecting mirror 10. Note that since the parabolic reflector 10 is made of metal, when it is used as the ground conductor 18, it is possible to omit providing the ground conductor 18 on the dielectric 16 side. Note that the surfaces of such planar antennas 14a, 14b, 14c, and 14d are not flat but parabolic because they are attached to the reflecting surface of the parabolic reflector 10. Antenna 14a, 14b, 1
By designing the radiating elements 20 of 4c and 14d in a shape that corrects their curved surfaces and adjusting the phase of feeding, it is possible to provide directivity equivalent to that of a flat surface. 22, 22, 22, 22 are feeding points of the respective planar antennas 14a, 14b, 14c, 14d, and are provided on the center side of the parabolic reflector 10, respectively, as shown in FIG. Converter 2 installed on the back side
4, 24, 24, 24. These converters 24, 24, 24, 24 are, for example,
This converts the 12 GHz band satellite broadcasting signal to the 1 GHz band first intermediate frequency signal, and each flat antenna 14
Among the planar antennas a, 14b, 14c, and 14d, the elevation angle and azimuth angle are adjusted toward the planar antenna corresponding to the first intermediate frequency signal having the highest level. In addition, when adjusting the azimuth angle and elevation angle of the parabolic reflector 10 so that satellite broadcasting can be received well, each of the planar antennas 14a, 14b, 14
The directivity of c and 14d is approximately as shown in Figure 2.
It is desirable to face outward by 5° to 10°. It is also possible to have such a directivity characteristic for each planar antenna 14.
This is possible by adjusting the phase of power feeding to the radiating elements 20 of a, 14b, 14c, and 14d. In addition, each planar antenna 14a, 14b, 14c, 1
4d occupies approximately 1/5 of the area along the reflective surface of the parabolic reflector 10, in the converter coupled to each converter 24, 24, 24, 24 and the primary radiator 12, Each received good reception.

A second embodiment is shown in FIG. In the first embodiment, the radio waves received by the primary radiator 12 are transmitted through planar antennas 14a, 14b, 14 as shown in FIG.
The radio waves A that are reflected and incident on the portions where antennas c and 14d are not provided and the planar antennas 14a and 14
It consists of a radio wave B that is reflected and incident at the portions where the electrodes b, 14c, and 14d are provided, and the phase of the radio wave B is delayed by the amount that it passes through the dielectric 16. If each of the planar antennas 14a, 14b, 14c, and 14d occupies a relatively large proportion of the reflecting surface of the parabolic reflector 10, the above-mentioned phase delay may not be negligible. The second embodiment corresponds to such a case, and the planar antenna 14
The parts to which a, 14b, 14c, and 14d are attached protrude toward the primary radiator 12 side, and the planar antenna 14
a, 14b, 14c, and 14d faster than the other parts, so that even if a phase delay occurs in the dielectric 16, when the radio waves are incident on the primary radiator 12, the radio waves will arrive at the other parts faster. This is so that the phase is the same as that of the radio waves reflected by the Note that dielectric 1
When the dielectric constant ε _s of 6 is 1.8 and the thickness is 1.5 mm,
The protruding amount h is approximately 0.4 mm (h≒t-t/√ _p
ε _s ). ε _p is a vacuum dielectric.

A third embodiment is shown in FIG. This example is
Each planar antenna 141 has a multilayer structure. That is, this planar antenna 141 has a ground conductor 181 provided on one surface of a dielectric 161, a radiating element 201 and another dielectric 202 provided on the opposite surface, and a metal surface 203 provided thereon. , a slit 204 is provided on this metal surface 203 so as to correspond to each radiating element 201. In this planar antenna 141, each slit 2
Radiation occurs at 04 respectively. Therefore, in order to align the phase with the portion where the planar antenna 141 is not provided, the metal surface 203 needs to be positioned in the same parabolic shape as the other portions of the parabolic reflector 10. Therefore, in this embodiment, the part of the parabolic reflector 10 to which the planar antenna 141 is attached is made to protrude more than the other parts to the side opposite to the primary radiator 12. Note that this amount of protrusion is selected so that the metal surface 203 forms the same paraboloid as the portion where the planar antenna 141 is not attached. Furthermore, similarly to the first embodiment, if the parabolic reflecting mirror 10 is made of metal, the ground conductor 181 may be omitted.

Further, a slit 204 is provided on the surface of the parabolic reflector 10 at the mounting position of each planar antenna 141,
This may be used instead of the metal surface 203. In this case, of course, it is not necessary to make the part of the parabolic reflector where the planar antenna is attached protrude to the side opposite to the primary radiator 12.

In each of the above embodiments, a total of four planar antennas were installed in the vertical and horizontal directions with the center in between. They may be provided so as to sandwich the center. Furthermore, the number of planar antennas can be increased compared to the above embodiments if they are mounted so as to be located on two or more parabolas passing through the center with the center sandwiched therebetween. Further, in each of the above embodiments, a rotating parabolic reflecting mirror is used as the parabolic reflecting mirror, but an offset parabolic reflecting mirror may also be used. In addition to the planar antennas shown in the above embodiments, various known microstrip planar antennas may also be used.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a first embodiment of a parabolic antenna according to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. The corresponding end view, FIG. 4, is a partially omitted longitudinal sectional view of the third embodiment. 10... Parabolic reflector, 12... Primary radiator, 14a, 14b, 14c, 14d, 141...
...Planar antenna.

Claims (1)

[Claims] 1. A parabolic reflector, a primary radiator provided at the focal point of the parabolic reflector, and a plurality of parabolas that intersect through the center of the parabolic reflector along the reflecting surface of the parabolic reflector. A parabolic antenna comprising: a plurality of planar antennas positioned across the center; 2. The parabolic antenna according to claim 1,
A parabolic antenna in which a reflective surface portion of the parabolic reflector to which each of the planar antennas is attached projects more toward the primary radiator than other reflective surface portions. 3. In the parabolic antenna according to claim 1,
A parabolic antenna in which each of the planar antennas has a multilayer structure and is made of metal with slits on its surface, and the surface thereof is located on the same plane as the reflecting surface.