JPS63268301A - Array antenna - Google Patents

Abstract

PURPOSE:To form a mono-pulse pattern with simple circuit constitution by providing a means having a variable attenuator between a combination input terminal of a power combiner and a distribution output terminal of a power two-distributer and controlling the attenuation of the variable attenuator. CONSTITUTION:A caption 1 shows antenna element arrays arranged on a circle and a caption SP3T2 is a switch to select eight antenna elements to be excited among 24 antenna elements. The signal is divided into two systems by the power two-distributer 3; one is directed to an output terminal 6 and the other is routed to an output terminal 7. The system directed to the output terminal 6 forms a sum pattern by the power combiner 5. A phase shifter 4(hereafter referred to as 0 deg./180 deg. phase shifter) varying a phase shift of 180 deg. inverts the phase of a signal through one side four elements and the remaining four elements of eight consecutive antenna element arrays selected by the switch SP3T2 among signals toward the output terminal 7. The signal passing through the 0 deg./180 deg. phase shifter forms a difference pattern by the power combiner 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an array antenna, and more particularly to a power combining section of an array antenna that forms a monopulse pattern.

Conventional technology Conventionally, in order to form a monopulver pattern, the power of an RF flaw signal from the right half and the RF flaw signal from the left half of an antenna aperture consisting of a plurality of antenna elements are separately combined, and a hybrid circuit is used to form a sum pattern. and formed a differential pattern.

In particular, when using different distributions as the excitation amplitude distributions for forming the sum pattern and the difference pattern,
Using a monopulse feed W circuit as shown in the figure, the excitation amplitude distribution was set to form a desired monopulse pattern.

Now, when this type of array antenna is used as an antenna for a radar device, an omnidirectional beam scanning function is often required. Alternatively, a method is used in which a phased play antenna base that performs electronic scanning over a range of more than 900 angles is installed with each tOo pointing in a different direction, and the beam is electrically scanned in all directions. .

Against these! To perform omnidirectional beam scanning electrically, the excitation aperture can be electrically scanned, such as a circular array antenna in which multiple antenna elements are arranged on the circumference, or a cylindrical array antenna in which multiple elements are arranged on the surface of a cylinder. A method has been proposed in which beam scanning is performed by switching. This method is superior to the above-mentioned mechanical rotation method in that the beam scanning period etc. can be controlled more freely, and compared to the above-mentioned planar array antenna method, the radiation pattern performance during beam scanning is less degraded. However, its importance has increased in recent years.

Problems to be Solved by the Invention In the conventional power combining method for monopulse pattern formation described above, it is necessary that the antenna element array and the input terminal of the power combining section correspond to each other in sequence.

Therefore, when scanning is performed by electrically switching the excitation aperture of a cylindrical array antenna, etc., by switching the transfer switch 9 as shown in FIG. A series switch circuit connected in a predetermined relationship, or as shown in Figure 3,
By switching the transfer switch t and the single-pole three-throw switch (hereinafter abbreviated as SP and ?T), the power combining section is created.

A switch matrix circuit or the like is required to connect the antenna elements within the excitation aperture in a predetermined relationship.

However, the series switch circuit shown in FIG. 4 has a drawback in that the power loss between the power combiner and the antenna element varies depending on the switching state of the switch.

For example, if we consider the case where three antenna elements are arranged on nine circles and t of them are excited as shown in Fig. 4, when the power loss of seven switches is ldB, the maximum power loss is 30dB.
There is a difference in the loss of B.

On the other hand, the switch size matrix circuit shown in FIG. 5 is required. For example, when the number of excited antenna elements is 136, approximately 1000 transfer switches and approximately 100
θ connection cables are required.

Therefore, the conventional method has disadvantages such as reduced unreliability due to complicated wiring and high assembly costs.

The present invention has been made in view of the above-mentioned conventional situation,
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel array antenna that makes it possible to eliminate the above-mentioned drawbacks inherent in the conventional technology.

Means for Solving the Problems In order to achieve the above object, an array antenna according to the present invention is a play antenna comprising a plurality of antenna elements and a power combining section, in which the power combining section combines the antenna elements from the plurality of antenna elements. Each input signal is connected to one wire for one day, and the same number of power distributors as P antenna probes are used.
For each of the power systems divided by the power dividers, one power combiner for combining multiple signals and one phase shift amount that is relatively 1 to 0 phase different are switched and set. It has the same number of phase shifters as the power splitter.

and the phase shifter is connected between at least one synthesis input terminal of the power combiner and the distribution output terminal of the electric waste distribution register; The array antenna includes a variable attenuator between a synthesis input terminal of the power combiner and a distribution output terminal of the power distribution device, and includes means for controlling an amount of attenuation of the variable attenuator. configured.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

In the following embodiments of the present invention, for convenience of explanation, a circular array antenna in which antenna elements are arranged on a circumference will be used.

FIG. 1 shows a schematic configuration of a first embodiment of the present invention, in which two antenna elements are arranged on the circumference in a solid circular array antenna, and three consecutive antenna elements are excited. FIG.

Referring to FIG. 1, the reference number / indicates a row of antenna elements arranged on the circumference, and C is SP, 7T,
This is a switch for selecting three antenna elements to be excited among μ antenna elements.

3 is a power divider, whereby the signal is .

It is divided into two systems: one for output terminal +6 and one for output terminal 7. The system going to the output end +6 forms a sum pattern by the power combiner j. DA is a phase shifter that switches the phase shift amount of /10° (hereinafter referred to as θ°/1WO6 phase shifter), and among the signals going to the output terminal, three consecutive antennas selected from 5pJT It is used to invert the phase of one side of the element array and the remaining one side of the element array.

The signal that has passed through the 0'/IgO' phase shifter is sent to the power combiner! A difference pattern is formed by

For example, when exciting the antenna elements loi-iot in FIG.
) - element tol-totr KW continues, o'/t
to' The phase shifter lI/~daza is used with g/~lIψ set to the phase shift amount o', and in~<<r set to the phase shift amount/10'. Next, when exciting antenna elements 10 to 109, SP and 7T are switched so that n-λt is connected to antenna element 101 and IC is connected to antenna element 109. It will be done. Furthermore, o0/lto° phase shifter Hiroshi/-'lt.

Dako~111 has a phase shift of 0', II/and 176~17g
is used by setting the phase shift amount ito°.

As can be seen from this embodiment, in the present invention, the input terminals of SP and 7T- do not need to match the arrangement of the antenna elements to be excited.

FIG. 2 is a schematic configuration diagram showing a first embodiment of the present invention, which is a further expansion of the circuit configuration shown in FIG.

Referring to FIG.
By weighting the excitation amplitude distribution over the aperture using , the radiation pattern is made to have a low siderope.

In each of the embodiments described above, a circular array antenna has been described, but the present invention can be similarly applied to a conformal array antenna, a planar array antenna, a cylindrical array antenna, etc. in which a plurality of elements are arranged on an arbitrary curved surface. Of course.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a power divider;
By configuring a power combining section using a phase shifter that switches a phase shift amount of /100 and a power combiner.

When scanning by switching the excitation aperture of the array antenna,
It is no longer necessary to sequentially correspond the excited antenna element array to the input terminal of the power combining section, and it is possible to form a monopulse pattern with a simple circuit configuration.

Furthermore, according to the present invention, by using an independently controllable variable attenuator, it is possible to weight the excitation amplitude and form a monopulse pattern with low side lobes.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention;
FIG. 1 is a block diagram showing a first embodiment of the present invention;
FIG. 3 is a diagram showing an example of a monopulse power supply circuit, FIG. 3 is a diagram showing an example of a series switch circuit, and FIG. 5 is a diagram showing an example of a switch matrix circuit. l...A row of antenna elements arranged on the circumference including a phase shifter,
(27~2g)...SP, 7T,,7...Power splitter. Hiro (dat-tIg)...Phase shifter that switches the amount of phase shift of itoo (0'/IgO' phase shifter), j...Power combiner, 6...Sum pattern output terminal, Ri... ...Difference pattern output terminal, Z...variable attenuator, q...transfer switch, /l, 10/~/koto...antenna element,
/U...Phase shifter,J...Power synthesis unit Patent applicant NEC Corporation Representative Patent attorney Yuta Kumagai 6: I: Ilgter: /8 force j Takako 7: Difference putter 〉Output n*+ 8: Possible t five-attenuator. Fig. 2 6: Japanese pattern output 7: manno (° ter 2, j shika tachi S+ 9: tiger; suffu 7-switch 51: power stand gtg13 Fig. 5

Claims (2)

[Claims] (1) In an array antenna having a plurality of antenna elements and a power combining section, the power combining section has the same number of antenna elements as the number of antenna elements for dividing signals input from the plurality of antenna elements into two systems, respectively. A two-power divider, two power combiners for combining a plurality of signals in each of the two systems divided by the two-power divider, and switching between two relatively 180° phase shift amounts. and the same number of phase shifters as the two power dividers set as the two power dividers, and the phase shifters are provided between the synthesis input terminal of at least one of the power combiners and the distribution output terminal of the two power dividers. An array antenna characterized by being connected. (2) A variable attenuator is provided between the synthesis input terminal of the power combiner and the distribution output terminal of the two-power divider, and means for individually controlling the amount of attenuation of the variable attenuator is provided. The array antenna according to claim (1) is further characterized.