JPS606124B2 - array antenna - Google Patents

Description

[Detailed Description of the Invention] This invention is constructed by arranging a plurality of element antennas,
The present invention also relates to an array antenna that employs a power feeding system in which each of the above-mentioned element antennas and a power distribution/synthesizer are connected by a feeding line.

In conventional array antennas of this type, one power distribution combiner was used to distribute and combine the power to each element antenna, so the power distribution ratio was fixed, and therefore the radiation characteristics of the array antenna were fixed. It was something like that.

That is, it has not been possible to use a single array antenna to vary radiation characteristics such as side lobes, gain, and beam width depending on the purpose. In order to eliminate these drawbacks, the present invention combines two or more power distribution combiners and switches.

FIG. 1 shows an embodiment of the present invention, in which 1 is an element antenna, 2 is a switch, 3 and 3a are feed lines, 4a and 4b are power dividers, 5a and 5b are feed lines, 6 is a switch, and 7 is a power divider. is the transmission source.

The power divider 4a is a 6 divider, and the power divider 4b is an 8 divider.
It is a distributor. Further, the power distribution ratio of the power divider 4a is uniform, and the power distribution ratio of the power divider 4b has a tapered distribution in order to keep sidelobes small. That is, the signal power output from the transmission source 7 enters the switch 6,
If the switch 6 is connected to the upper terminal in FIG.
Enter a.

Furthermore, assuming that the six switches 2 are all connected to the upper terminal in FIG. 1 is radiated into space. At this time, since the power distribution ratio of the power divider 4a is uniform, the excitation amplitudes of the six element antennas 1 are uniform, so that radiation with sharp directivity is performed. In addition, in FIG. 1, if all switches 2 and 6 are connected to the lower terminals in the figure, the signal power from the transmission source 7 will be
After entering the power divider 4b through the feeder line 5b, it is divided into eight parts, passes through the feeder line 3 and the switch 2, or the feeder line 3a, and is radiated into space from the eight element antennas 1.

The power distribution ratio of the power divider 4b is tapered to be larger at the center and smaller toward both ends.Therefore, the amplitude distribution of the eight element antennas is also tapered, resulting in a radiation pattern with a low sidelobe level. . In the example of FIG. 1, when using the power divider 4b, the power divider 4a
By using a larger number of elements than in the case of using the antenna, the decrease in the efficiency of the array antenna Sekiguchi due to the tapered amplitude distribution is offset by the increase in the directivity gain due to the increase in the length of the array antenna Sekiguchi.

The array antenna of the present invention, which can be used by switching such excitation distribution, is not only effective when used alone, but also highly effective when used as a primary radiator in a reflector antenna or lens antenna.

An embodiment in such a case will be explained using FIG. 2. In Fig. 2, reference numeral 8 is a reflector whose vertical cross-section (plane of the paper in Fig. 1) is a parabola, and the element antennas 1 are arranged opposite to it. It consists of

A variable phase shifter 9 and a switch 2 are connected to each element antenna 1, and two terminals of the switch 2 are connected to power dividers 10a and 10b, respectively. The two power dividers 10a and 10b are connected to a switch 6. As shown in FIG. 2, the power dividers 10a and 10b are both 5-way dividers, but the power divider 10a has a uniform power distribution ratio, and the power divider 10b has a high-level mountain-shaped power distribution in the center. It has a distribution ratio that is tapered. In addition, in FIG. 2, a variable phase shifter 9 is connected to each element antenna 1, so the phase distribution of the array antenna is controlled to scan the beam, which is a so-called phased array.
The reflector antenna in FIG. 2 shows a phased array feeding reflector antenna. Since the reflector antenna using the array antenna according to the present invention is configured as described above, for example, if each switch 2 and switch 6 are all connected to the power divider 10a side, the closed surface of the reflector 8 Since the above power distribution is relatively close to a uniform distribution, an antenna with high opening efficiency can be obtained, and beam scanning can be performed in the vertical plane while maintaining this high efficiency. Moreover, if each switch 2 and switch 6 are all connected to the power divider 10b side, the power distribution on the Sekiguchi surface becomes a mountain-shaped taper shape, thus realizing a reflector antenna with a low side rope. The conditions remain approximately the same across the beam scan in the vertical plane. That is, by using the configuration shown in FIG. 2, the reflector antenna can be used both as a high-efficiency type and as a low sidelobe type, which has great practical advantages.

Although the above explanation was about transmission, there is no harm in using it for reception as well.

Note that during reception, the power divider works as a power combiner.

In addition, as explained above, the number of element antennas, the number of switches 2, and the number of power dividers are not limited to those in the embodiment, and the distribution ratio of each power divider may be arbitrary depending on the purpose. It is clear from the above.Furthermore, the present invention can be carried out in exactly the same way even if the arrangement of element antennas is not limited to a linear arrangement, but a planar arrangement or a curved arrangement.In the embodiment shown in FIG. In the array antenna according to the present invention, the amplitude distribution can be varied in various ways by using a plurality of switches and a plurality of power distribution/synthesizers. When used as the primary radiator of a closed-surface antenna, and when used in radar or communication antennas, it can simultaneously satisfy various purposes required by the system.
It has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is a schematic diagram of a reflector antenna using an array antenna according to the present invention. In the figure, 1 is an element antenna, 2 and 6 are switches, 4a,
4b, 10a, 10b are power dividers, and 9 is a variable phase shifter. In the drawings, the same or corresponding parts are denoted by the same reference numerals. Multi-figure beard Z-diagram

Claims (1)

[Claims] 1. In an array antenna consisting of a plurality of element antennas and a power distribution/synthesizer that distributes power to each of the element antennas or combines the power from each of the element antennas, the plurality of power distribution/synthesizers are used. . An array antenna characterized in that all or some of the element antennas are provided with a switch, and the power distribution/synthesizer is selectively switched and used by the switch.