JPH02179007A - Parabolic antenna - Google Patents

Abstract

PURPOSE:To attain the drive of the antenna to a desired azimuth angle and elevation angle with a small torque by providing plural planer antennas so that they are located on plural parabolic lines passing through the center of a reflecting mirror while being around the center. CONSTITUTION:A primary radiator 12 is provided to a focus of a rotary parabolic reflecting mirror 10, planer antennas 14a, 14b are provided respectively on parabolas in a vertical direction passing through the center of the reflecting plane of the mirror 10 at both sides around the center, and planer antennas 14c, 14d are provided respectively on parabolas in a horizontal direction passing through the center of the reflecting plane of the mirror 10 at both sides around the center. Lots of ground conductors 18 are provided to one side of the dielectric substance 16 of each antenna and lots of radiation elements 20 are provided on the other side. The elevating angle and the azimuth angle of a converter 24 connecting to each feeding point 22 are adjusted to an antenna corresponding to an intermediate frequency signal at a maximum level in each antenna.

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> Generally, in a moving object such as a ship or a vehicle,
In order to receive good radio waves from a fixed station, such as a broadcasting satellite, the azimuth and elevation angle of the antenna must be automatically adjusted so that the antenna always faces the broadcasting satellite, since ships and vehicles are moving. It is necessary to. 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 receiving radio waves or SHFHF, 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 with a

<Invention or problem to be solved> However, in the parabolic antenna as described above, a plurality of primary radiators must be placed near the focal position of the parabolic reflector, and there are physical restrictions on the placement position. There was a problem. Also, each primary radiator is connected to each converter provided correspondingly via a waveguide, or each primary radiator, each waveguide, and each converter is
Since they are generally mechanically coupled to parabolic reflectors, these coupled parabolic reflectors are 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 in 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 reflecting surface of the parabolic reflecting mirror so as to be located on a plurality of parabolas -L that pass through the center and intersect, respectively, with the center on either side, 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 be aligned with the above-mentioned reflective surface.

<Operation/Effect> According to the present invention, the planar antenna is provided with a plurality of planar antennas so as to be positioned on the 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, weighing only one weight, the weight of the attached parabolic reflector does not increase much, and is determined by comparing the output of each planar antenna. The parabolic antenna can be driven at the azimuth and elevation angles by 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. This phase lag can be canceled out 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.

Furthermore, when a planar antenna with a multilayer structure and a surface made of metal with slits is used, radiation of radio waves 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> The first example is shown in Figs. 1 and 2. This example is a satellite that is mounted on a moving body such as a ship or a vehicle and is transmitting from a broadcasting satellite that is a geostationary satellite. The present invention is applied to a parabolic antenna that is used to ensure good reception of broadcasts at all times.

In FIGS. 1 and 2, lO is the parabolic reflector 2
For example, it is a rotating parabolic reflector made of metal, and a primary radiator 12 is provided at its focal point.

Although not shown in FIG. 1, the primary radiator 12 transmits, for example, a 12 GHz band satellite broadcast signal to an IG via a waveguide.
It is connected to a BS converter that converts it into a first intermediate frequency signal in the H2 band. This BS converter is mechanically coupled to the parabolic reflector 10 by suitable supports.

In a vertical parabola passing through the center of the reflective surface of the parabolic reflection filo, planar antennas 14aJ4b are provided on both sides of the center. Similarly, in a horizontal parabola passing through the center of the reflecting surface of the parabolic reflector lO, there are planar antennas 14c, 1 on both sides of the center.
4d is provided. Each planar antenna 14a, 14
b, 14c, and I4d are those in which, for example, a ground conductor 18 made of metal foil is provided on one surface of a dielectric 16, and a number of crank-shaped radiating elements 20 are provided on the other surface.

The ground conductor 18 is attached so as to be located on the reflective surface side of the parabolic reflector 10. Note that since the parabolic reflector IO is made of metal, when this is used as the ground conductor 18, it is possible to omit providing the ground conductor 18 on the dielectric 16 side. Note that such planar antennas 14a, 14b,
Since the surfaces of the antennas 14c and 14d are attached to the reflecting surface of the parabolic reflector 10, the surfaces thereof are not flat but paraboloidal.
By designing the 14cJ4d radiating element 20 in a shape that corrects its curved surface and adjusting the feeding phase, it is possible to provide directivity equivalent to that of a flat surface. 2
2.22.22.22 is each planar antenna 14a, 1
4b% 14c and 14d are provided at the center side of the parabolic reflector 10, respectively, and these converters 24.24 and 24.24 are provided on the back side of the parabolic reflector 10 as shown in FIG. It is connected to the. These converters 24.24.24.24 are for example 12GH
, band satellite broadcasting signal into a first intermediate frequency signal of I GHz band, each of the planar antennas 14a, 14b,
Among the antennas 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 radiation mirror 10 so that satellite broadcasting can be received well, each of the planar antennas 14a, 14b,
The directivity of 14c and 14d is as shown in Fig. 2.
It is preferable that each of the planar antennas 14a, 1
This is possible by adjusting the phase of power feeding to the radiating elements 20 of 4b, 14c, and 14d. Furthermore, if each of the planar antennas 14a, 14b, 14c, and 14d is configured to occupy approximately 175 of the area along the reflective surface of the parabolic reflector lO, each converter 24, 24, 24
, z4 and the converter coupled to the primary radiator 12, each was able to provide good reception.

A second embodiment is shown in FIG. 3. In the first embodiment, the radio waves received by the primary radiator 12 are transmitted through planar antennas 14a, 14b, 14c, and 14d as shown in FIG. The radio wave B consists of a radio wave A that is reflected and incident on a portion where the planar antennas 14a, 14b, 14c% and 14d are provided, and a radio wave B that is incident on the portion where the planar antennas 14a, 14b, 14c% and 14d are provided. The phase is delayed. When each of the planar antennas 14a, 14b, 14c, and 14d occupies a relatively large proportion of the reflecting surface of the parabolic reflector IO, the above-mentioned phase delay may not be negligible. In such a case, the second
In the embodiment, the planar antennas 14a, I4b.

The parts to which 14c and 14d are attached protrude toward the primary radiator 12 side, and the planar antennas 14g, 14b, 14c,
14d so that the radio waves arrive faster than other parts, so that even if there is a phase delay in the dielectric 16, when the radio waves are incident on the primary radiator 12, they are different from those reflected in other parts. This is so that they are in the same phase. Note that dielectric 1
The dielectric constant of 6 (if 1 is 1.8 and the thickness is 1.5 mg +, the amount of protrusion is approximately 0.41- (h slope 1-1
/eoes), ε. is the dielectric constant of vacuum.

A third embodiment is shown in FIG. 4. In this embodiment, each planar antenna 141 has a multilayer structure. That is,
This planar antenna 141 has a ground conductor 181 on one surface of a dielectric 161, a radiating element 201 on the opposite surface, another dielectric 202, and a metal surface 203 on top of the ground conductor 181. Each radiating element 20 is placed on a metal surface 203.
A slit 204 is provided corresponding to 1. In this planar antenna 141, radiation occurs at each slit 204. Therefore, in order to align the m-phase with the portion where the planar antenna 141 is not provided, it is necessary to position the metal surface 203 or other portions of the parabolic reflector IO in a circular paraboloid shape. Therefore, in this embodiment, the portions of the parabolic reflector 10 to which the planar antennas 1 and 41 are attached are made to protrude to the side opposite to the primary radiation 312 than the other portions. Note that this protruding elm is located on the metal surface 2.
03 is selected so that it forms a paraboloid with the portion to which 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.

Furthermore, a slit 204 is provided on the surface of the parabolic reflector 10 at the mounting position of each planar antenna 141, and the slit 204 is inserted into the metal surface 2.
It may be used instead of 03. In this case, of course, there is no need for the part of the parabolic reflector where the planar antenna is attached to protrude to the side opposite to the primary radiator 12.

In each of the examples described above, a total of four planar antennas were installed in the upper F direction and in the left and right directions with the center in between. They may be installed so that they are located on both sides of the center on each parabola.Furthermore, if the number of each planar antenna is installed so that the center is on both sides of two or more parabolas that pass through the center, the number of planar antennas is the same as above. can be increased more than in the embodiment. Further, in each of the above embodiments, a rotating parabolic reflector is used as the parabolic reflector, but an offset parabolic reflector may also be used.Furthermore, the planar antenna may be other than the one shown in each of the above embodiments. Alternatively, various known microstrip planar antennas or the like may 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, and FIG. 2 is a cross-sectional view taken along line A-A in FIG.
Figure 3 is an end view corresponding to Figure 2 of the second embodiment;
The figure is a partially omitted longitudinal sectional view of the third embodiment. IO...parabolic reflector, 12...-primary radiator, 14a, 14b, 14e, 14d, 141---
--Planar antenna. 1st Group 3rd Figure 2 Seki 4th M

Claims (3)

[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 along the reflecting surface of the parabolic reflector, with the center sandwiched between the two. A parabolic antenna comprising a plurality of planar antennas positioned at . (2) The parabolic antenna according to claim 1, wherein a portion of the reflecting surface of the parabolic reflector to which each of the planar antennas is attached is made to protrude toward the primary radiator side more than other portions of the reflecting surface. parabolic antenna. (3) The parabolic antenna according to claim 1, wherein each of the planar antennas has a multilayer structure and is made of metal having slits on its surface, and is located on the same surface as the reflecting surface.