JPS6017163B2 - double beam scanning antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reflector antenna capable of independently scanning a plurality of radiation beams.

For satellite-mounted antennas, one antenna can achieve 4/4
It may be required to share many frequency bands, such as the target Hz band, the 20/3 ratio band, or to scan the radiation beam to change the coverage area as needed.

In order to perform beam scanning with a reflector antenna, there is a method of mechanically moving a reflector, a sub-reflector, or a primary radiator, as well as a method of using an array antenna capable of beam scanning as a primary radiator.

Although the former is electrically simple, the beam scanning speed is limited by the moving speed of the reflector and primary radiator, so it is not suitable for high-speed beam scanning antennas. Furthermore, when moving the primary radiator, a rotary joint or a flexible waveguide is required somewhere between the primary radiator and the feed circuit or the connection between the feed circuit and the feed circuit in order to absorb this movement. On the other hand, in the method of beam scanning using an array antenna as the primary radiator, if the amplitude of each element of the array antenna is electrically limited, there are no moving parts, which simplifies the mechanical configuration and increases the beam scanning speed. can also be done at high speed. FIG. 1 is a diagram showing a conventional technique. Here, 1 is the main reflector, 2 is the sub-reflector, 3 is the array antenna, and 4, 4', 4'' are the radiation beams when the array antenna is excited with a --like phase.
6 is the equal phase plane at that time, 5, 5', 5'' is the radiation beam when exciting the array antenna with a linear phase distribution, 7 is the equal & phase plane at that time, 8 is the two reflecting mirrors. focus,
9 is the mirror axis (hereinafter referred to as the x-axis), and 10 is the spinal cord passing through the focal point and perpendicular to the x-axis (hereinafter referred to as the y-axis). Next, the principle of operation of this antenna will be briefly explained with reference to FIG. It is assumed that each element of the array antenna 3 is arranged along a direction parallel to the y-axis.

Now, if all elements are excited in the same phase, the equi-phase plane of the radial wave is 6, which is parallel to the y-axis, and the radiation beam is x
4 parallel to the axis. Radiation beam 4 is transmitted through parabolic sub-reflector 2
It is reflected by 4', and 4' is the parabolic main reflector 1
It is reflected by 4^ parallel to the x-axis. On the other hand, when the array antenna 3 is excited with a linear phase distribution, the equal phase plane of the reflected wave becomes 7 and the radiation beam becomes 5 perpendicular to 7. The radiation beam 5 is reflected by the sub-reflector 2 to become 5', and further reflected by the main reflector 1 to become the radiation beam 5'' having a certain inclination with respect to the x-axis. The direction of the radiation beam can be changed by controlling the phase distribution of antenna 1. However, in a reflector antenna whose primary radiator is an array antenna, the feeding system becomes complicated and at the same time a phase shifter is required. Because of limitations in frequency characteristics, etc., it has been difficult to use many frequency bands simultaneously with one array antenna.

A possible method of sharing frequencies with one reflector antenna is to use one main reflector and multiple primary radiators, but an array antenna used as the primary radiator of a reflector antenna is usually Because they are larger than the horn antennas used in reflector antennas, it was impossible to use multiple antennas in the same location.

In order to eliminate these drawbacks, the present invention uses the main reflecting mirror or the main reflecting mirror and the sub-reflecting mirror in common, and arranges multiple array antennas dedicated to each frequency band at different positions as primary radiators. Each array antenna with an appropriate phase distribution emits radio waves of one of the shared frequencies, and radio waves of other frequencies are reflected on the array surface, and radio waves of multiple frequencies are simultaneously emitted by the sub-reflector. Alternatively, the present invention provides a multi-beam scanning antenna that independently scans radio waves in a plurality of frequency bands by making them incident on the main reflecting mirror with appropriate equal phase planes. The present invention will be explained in detail below using the drawings.

FIG. 2 shows an embodiment of the present invention, in which 1 is a main reflector, 2 is a sub-reflector, 3', 3'' are array antennas, 4, 4', 4
r is the radiation beam, 6 is the equiphase front of the radiation beam 4, 5,5
', 5'', 5 are other radiation beams, 7 is the equiphase plane of the radiation beam 5, 8 is the focal point of the main reflector and sub-reflector, 9 is the mirror axis of the two reflectors (hereinafter referred to as the x axis). ), 10 passes through the focal point ×
an axis perpendicular to the axis (hereinafter referred to as the y-axis), 11 and 11' are the radiating elements of the array antenna, 12 and 12' are the phase shifters, 13,
13' is an oscillator, 14 and 14' are radiation elements of other array antennas, 15 and 15' are phase shifters, and 16 and 16' are oscillators. Further, FIG. 3 is an enlarged view of the array antenna portion of FIG. 2. Next, the operating principle of this antenna will be explained.

The array antenna 3' (second primary radiator array) has an element arrangement surface that mirrors the mirror axis, but the phase shifter 12,
By adjusting 12', the direction of the radiation beam can be changed. Now, the radiation beam of array antenna 3' is 4,
Assuming that its equiphase front is 5, it is reflected by the sub-reflector 2 and then reflected again by the main reflector 1, resulting in a radiation beam 4'' parallel to the mirror axis 9.As explained in FIG. The array antenna 3 is adjusted by adjusting the amount of phase shift of the phase shifters 12 and 12'.
', e.g. radiation beam 5.
If the radiation beam is radiated in the direction of
' (second primary radiator array) as shown in Figure 2, and the radiation beam emitted from this is 5''
shall be. The direction of the radiation beam radiated from the array antenna 3'' can be freely changed by adjusting the amount of phase shift of the phase shifters 15, 15'.
The radio waves radiated from the array antenna 3' are reflected by the element arrangement surface of the array antenna 3' to become a radiation beam 5, and are reflected by the sub-reflector 2 and the main reflector 1, respectively, to become a radiation beam 5''.At this time, the radiation of the array antenna 3'' By changing the beam direction appropriately, the angle of incidence on the array antenna 3' changes, so
The direction of the reflected wave 5 also changes. As a result, the directions of 5' and 5'' also change, making beam scanning possible.Here, multiple array antennas with the same configuration as 3' are placed in an appropriate arrangement, and each array antenna emits radio waves of different frequencies. By exciting the beam, each frequency beam can be scanned independently.Furthermore, if there are two array antennas, if each array antenna emits radio waves with different polarizations, each polarization can be scanned independently. Beam scanning is possible.Figure 3 is an enlarged view of the array antenna part in Figure 2, showing an example of the specific structure of the array antenna.It is an element antenna!
1.11' and 14, 14' are both made of rectangular waveguides. Now, 1 1, 1 1' is 2 Hz
An element antenna consisting of a band waveguide, 14,14'
Assuming that is an element antenna consisting of a waveguide for 4G households,
In the 40Hz band, the element antennas 1 1, 1 1' operate as a grating with sufficiently narrow spacing relative to the wavelength, so
Radio waves incident on this are reflected. element antenna 14,
The frequency of the radio waves radiated from 14' is the element antenna 11.
, 11', if the size of the waveguides 11, 11' is selected so that the cutoff frequency of the waveguides of the element antennas 11, 11' is lower than the cutoff frequency of the waveguides of the element antennas 11, 11', even if the frequency approaches the frequency of the radio waves radiated from the element antennas 11, 11'. The radio waves radiated from the antenna elements 14 and 14' are similarly reflected by the element antennas 11 and 11' and proceed toward the sub-reflector 2. Therefore, the frequencies of each array antenna may be close to each other to some extent. On the other hand, when beam scanning is performed independently using polarized waves, an element antenna for the array antenna 3' that reflects the polarized radio waves radiated from the array antenna 3'' may be used.An element antenna used in the above array antenna Now, not only waveguides but also dipoles, slots, or printed antennas may be used.
The figure shows another embodiment of the present invention, where 8 is the focal point of the reflecting mirror, 8
' is the phase center of the array antenna when the radiation beam of the array antenna is tilted.

The operating principle will be briefly explained below. The radiation direction of the radio waves radiated from the array antenna 3' can be arbitrarily changed by the phase shifter 12. Now, if the radiation direction is 4' and the phase center of the array antenna at that time coincides with the focal point 8, then after being reflected by the main reflector 1, the radiation beam 4 parallel to the x-axis
It becomes ＾. If the radiation beam direction is changed to 5' and the equivalent phase center is changed to 8' by appropriately determining the amount of phase shift of the phase shifter 12, the radiation beam from the main reflecting mirror 1 becomes 5''. The radiation direction of the radio waves radiated from the array antenna 3' can be changed to 4r or 5^ by adjusting the phase shift amount of the phase shifter 12. On the other hand, the radio waves radiated from the array antenna 3r ``'' is reflected by the element arrangement surface of the array antenna 3' and becomes 5', and further reflected by the main reflecting mirror 1 and becomes 5''.At this time, the radiation direction of the radiation beam 5'' from the array antenna 3'' is changed. For example, the direction 5' of reflection by the array antenna 3' changes, and as a result, the direction 5'' of radiation from the main reflecting mirror 1 also changes. Since the phase shifters 12 and 15 of the array antennas 3' and 3'' can be adjusted independently, the radiation direction of the radio waves radiated from each array antenna can be changed independently. The configuration example is the same as that shown in FIG.
As explained above, in the present invention, the main reflector or the main reflector and the sub-reflector are shared, only the primary radiator is a reflector antenna consisting of a plurality of array antennas, and each array antenna is separated. Because each device is arranged in such a way that it operates only in its own dedicated frequency band,
Not only can the entire antenna be made smaller, but the feeding circuit of the array antenna is also less complex than when scanning a radiation beam at a single frequency, and radiation beams at multiple frequency bands can be scanned simultaneously and independently. There are advantages that can be achieved.

Also, if the phase shifter of the array antenna is electrically controlled,
High-speed beam scanning is possible. For example, if the antenna of the present invention is used as a satellite-mounted antenna that shares the microwave band and the sub-millimeter wave band, the radiation beams of the microwave band and the sub-millimeter wave band can be scanned independently. Diverse and flexible lines that take advantage of each frequency band and take into consideration radio wave environmental conditions, such as using microwaves in rainy areas and sub-millimeter wave bands in sunny areas that require large capacity. Settings are now possible.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of a subordinate array antenna feeding reflector antenna, Fig. 2 is a schematic side view of an embodiment of the present invention, Fig. 3 is an enlarged view of the array antenna portion of Fig. 2, and Fig. 4 1 is a schematic side view showing another embodiment of the present invention. 1...Main reflecting mirror, 2...Sub reflecting mirror, 3, 3', 3r...
Array antenna, 4, 4', 4r...Radiation beam when array antenna is excited with uniform phase, 5, 5', 5
'', 5... Radiation beam when the array antenna is excited with a linear phase distribution, 6... Radiation beam 4
7, 7'... Equiphase plane of radiation beam 5 and 5 rivers, 8... Focus of main reflector and sub-reflector, 8'... Equivalent phase of array antenna Center, 9...
... Mirror axis (x-axis) of the main reflecting mirror and the sub-reflecting mirror, 10
・・・・・・axis passing through the focal point and perpendicular to the mirror axis (y-axis), 11
, 11', 14, 14'... element antenna of array antenna, 12, 12', 15, 15'... phase shifter, 13,
13', 16, 16'... Oscillator. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A first primary radiator array consisting of a reflecting mirror consisting of at least one quadratic curved surface and a plurality of radiating elements connected to adjustment means capable of adjusting the amplitude and phase of electromagnetic waves at its aperture. In the reflector antenna equipped with the above-mentioned 1.
A second primary radiator array consisting of a plurality of radiating elements is connected to a radio wave path between the secondary radiator array and the reflecting mirror, and an adjusting means capable of adjusting the amplitude and phase of the electromagnetic waves at the aperture surface. at least one, wherein electromagnetic waves from the first primary radiator array are reflected by the second primary radiator array and directed toward the reflector; the direction of the beam emitted from the array and the first
the direction of the beams emitted from said second primary radiator array and reflected by said second primary radiator array, said adjusting means being connected to said primary radiator array as the source of said respective beam; A multi-beam scanning antenna characterized in that it is configured so that scanning can be controlled independently of each other.