JPH06132718A - Plane antenna for sng - Google Patents

Abstract

PURPOSE:To set a side robe to be the lowest as against the direction of the static orbit of a satellite and to keep the side robe in the static orbit within the allowable value of CCIR. CONSTITUTION:Respective radiation elements 4 are inclined in a phi direction by '-5 degrees' with the intersection point of the diagonals of the respective radiation elements as a center, and the plane of polarization in the plane antenna for SNG 1 is inclined in the phi direction by '-5 degrees' so as to set the side robe at phi=55 degrees becomes less than 30dB.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is an S for communicating with a satellite.
Related to the NG plane antenna, the polarization is adjusted so that the side lobes are low in the orbital direction of the satellite.
The present invention relates to a plane antenna for NG.

SUMMARY OF THE INVENTION The present invention relates to a configuration of a plane antenna, in which each radiating element constituting the plane antenna is arranged in a rotated state and polarized waves are matched with each other, whereby a side lobe with respect to a geostationary orbit direction of a satellite is obtained. The present invention relates to a planar antenna for SNG that can reduce

[0003]

2. Description of the Related Art As a planar antenna in which radiating elements such as microstrip patches are arranged on a plane, various antennas have been developed in the past.

FIG. 3 is a front view showing an example of a planar antenna in which such a radiating element is arranged on a plane.

A planar antenna 101 shown in this figure has a plate-shaped dielectric substrate 102 and a dielectric substrate 10.
2 and a plurality of radiating elements 104 formed by etching the metal foil 103 that is attached to the back surface of the planar antenna 101 and serves as a ground plane of the planar antenna 101, and the metal foil that is attached to the surface of the dielectric substrate 102. A power supply line 105 connected to the radiating element 104 by one-point power supply is provided, and when a transmission signal is supplied, it is guided to each radiating element 104 via the power supply line 105 to emit a radio wave. When a radio wave is incident, it is converted into a reception signal by each radiating element 104 and is output via the power supply line 105.

In this case, in this planar antenna 101,
Since each side of each radiating element 104 is arranged so as to be parallel to the X-axis and the Y-axis, and the bottom side (left side in the drawing) of each radiating element 104 is connected to the power supply line 105, A radio wave having a plane of polarization parallel to the X axis (a radio wave of vertical polarization) is transmitted and received.

[0007]

By the way, when such a plane antenna is used as a plane antenna for SNG, the following conditions must be satisfied.

That is, since the polarization of the satellite is determined for each channel of the satellite, when the plane antenna having the structure shown in FIG. 3 is used as the plane antenna for SNG, the plane of polarization of the satellite and the plane of polarization of the plane antenna for SNG are used. Since it is necessary to match with, the polarization plane of this SNG flat antenna,
The entire plane antenna for SNG must be rotated so that the plane of polarization of the satellite coincides.

In this case, when the planar antenna is small, there is no problem, but in an antenna having a large array structure such as a planar antenna for SNG, the vertical and horizontal directions are 6 respectively.
Since it is 0 cm or more, it is difficult to rotate the entire antenna.

Further, in the SNG antenna, CCIR is used.
The sidelobe level is defined by (for example, Recommendation 524), and especially in the geostationary satellite orbit, the sidelobe level must be within the allowable value.

In this case, when the geostationary satellite to be transmitted / received from Tokyo, for example, the geostationary satellite orbit of JC-SAT1 is seen, it becomes a band extending in the direction of φ '= 60 degrees as shown by the diagonal lines in FIG. CCIR side lobe in orbit
Must be within the allowable value of.

Therefore, in order to lower the side lobe of the planar antenna 101, it is necessary to take a measure such as tapering the excitation. Even with this, the planar antenna 101 shown in FIG. Thus, when φ is 60 ° and the plane of polarization is φ = 0 °, the side lobe is 25 dB.
Cannot be less than Therefore, when the entire antenna is rotated to match the polarization direction of the antenna with the polarization direction of the satellite, the side lobe of the antenna may exceed the allowable value in the direction of φ ′ = 60 degrees.

In view of the above circumstances, the present invention can achieve the lowest side lobe in the geostationary orbit direction of the satellite,
Thus, it is an object of the present invention to provide a planar antenna for SNG which can keep the side lobe in the geostationary orbit within the allowable value of CCIR.

[0014]

In order to achieve the above object, the present invention relates to an SNG plane antenna constituted by arranging a plurality of radiating elements on a plane, in which a radiation pattern corresponding to a geostationary orbit of a satellite is provided. It is characterized in that each radiating element is arranged so as to be inclined in the direction of the lowest side lobe.

[0015]

In the above structure, by arranging each radiating element in a direction in which the radiation pattern corresponding to the geostationary orbit of the satellite has the lowest sidelobe, the sidelobe with respect to the geostationary orbit of the satellite is lowered, Keeps the side lobe in the geosynchronous orbit within the allowable value of CCIR.

[0016]

1 is a front view showing an embodiment of a planar antenna for SNG according to the present invention.

The planar antenna 1 for SNG shown in this figure is
A dielectric substrate 2 formed in a plate shape, a metal foil 3 attached to the back surface of the dielectric substrate 2 and serving as a ground surface of the SNG planar antenna 1, and an outer surface of the dielectric substrate 2 were attached. It is provided with a plurality of rectangular radiating elements 4 formed by etching a metal foil and a feeding line 5 connected to each radiating element 4 by one-point feeding, and when a transmission signal is supplied, This is guided to each radiating element 4 via the power feeding line 5 to emit a radio wave, and when the radio wave is incident, each radiating element 4 converts this into a reception signal and outputs it via the power feeding line 5. To do.

In this case, each of the radiating elements 4 is "-5" in the φ direction around the intersection of the diagonal lines of the radiating elements 4.
It is arranged so as to be inclined by "" and is connected to each feeder line 5 in this state, whereby the polarization plane of the SNG antenna 1 is inclined by "-5 degrees" in the φ direction.

As a result, in the plane antenna 1 for SNG, the side lobe could be reduced to 30 dB or less when the directivity characteristic was calculated in the plane of φ = 55 degrees as shown in FIG.

Since the actual orbit of the geostationary satellite is inclined by 60 degrees in the φ direction with respect to the plane of polarization, this S
When the plane of φ = 55 degrees overlaps the orbit with the plane of polarization of the NG plane antenna 1 aligned with the plane of polarization of the satellite (that is, φ = φ ′), the sidelobe level in the direction of the geostationary satellite orbit is within the allowable value. Can be put in.

As described above, in this embodiment, each radiating element 4 is centered on the intersection of the diagonal lines of each radiating element 4.
Is tilted by “−5 degrees” in the φ direction to tilt the polarization plane of the SNG planar antenna 1 by “−5 degrees” in the φ direction so that the side lobe at φ = 55 degrees is 30 dB or less. Therefore, the side lobes can be the lowest with respect to the direction of the geostationary orbit of the satellite, which allows the side lobes in the geosynchronous orbit to be within the CCIR allowable value.

Further, in the above-mentioned embodiment, each radiating element 4 is tilted by "-5 degrees" in the φ direction, but it may be set at another angle.

In this case, as a procedure for obtaining the optimum rotation angle of each radiating element 4, first, the array factor of the SNG planar antenna 1 is calculated for all (θ, φ), and the lowest side lobe among them is calculated. Then, the polarization plane of the antenna, that is, the rotation angle of each radiating element 4 may be determined so that the φ plane becomes a stationary orbital plane.

Further, although the radiating element 4 has a rectangular shape in the above-described embodiments, it may have another shape such as a circular shape.

Further, in the above-mentioned embodiment, the number of the radiating elements 4 is set to eight in order to simplify the description, but in the case of a normal SNG plane antenna, it is generally one.
The multi-element array uses radiating elements of 000 elements or more.

In this case, as the array of each of these radiating elements, in addition to the square array shown in FIG. 1, each radiating element is sub-arrayed in units of several, and each of these sub-arrays is fixed in a specific direction by a fixed amount. You may make it arrange | position and it may shift.

[0027]

As described above, according to the present invention, the side lobes in the geostationary orbit direction of the satellite can be set to the lowest, so that the side lobes in the geostationary orbit fall within the CCIR allowable value. Can fit.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a planar antenna for SNG according to the present invention.

FIG. 2 is a table showing an example of radiation directivity characteristics of the SNG plane antenna shown in FIG.

FIG. 3 is a front view showing an example of a conventionally known planar antenna.

FIG. 4 is a schematic diagram showing a geostationary orbit of JC-SAT1 viewed from Tokyo.

5 is a table showing an example of radiation directivity characteristics when the flat antenna having the structure shown in FIG. 3 is used as a flat antenna for SNG.

[Explanation of symbols]

 1 Planar antenna for SNG 2 Dielectric substrate 3 Metal foil 4 Radiating element 5 Feed line

Claims (1)

[Claims] 1. In a planar antenna for SNG configured by arranging a plurality of radiating elements on a plane, the radiating elements are arranged so as to be inclined in a direction in which a radiation pattern corresponding to a geostationary orbit of a satellite has a lowest side lobe. A planar antenna for SNG characterized by the following.