JP2649114B2 - Two-dimensional beam compression device for antenna pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional beam compression processing device for two-dimensionally compressing an antenna pattern in an antenna device of a monopulse feeding system.

[0002]

2. Description of the Related Art In general, one of the indices indicating the goodness of an antenna pattern such as a receiving antenna is a beam width. The smaller the beam width, the better the performance as an antenna pattern. However, the beam width and the size (length) of the antenna are inversely proportional to each other. When the beam width is reduced, the antenna size increases, and when the antenna size is reduced, the beam width increases. Would.

For example, in a radar antenna, if the degree of discrimination of an object, that is, the resolution is to be doubled, the beam width must be halved, and the size of the antenna is doubled. When the size is doubled, not only the area occupied by the antenna becomes large, but also various adverse effects such as an increase in antenna weight and an increase in the size of the antenna support structure are caused. Conversely, if the size of the antenna is reduced to half, the beam width is doubled, and the discrimination degree is reduced to half.

It is well known that the beam width and the size of the antenna have contradictory properties. In most practical antennas, the area occupied by the antenna is limited in most cases. Therefore, under such restrictions, a compromise is made at a certain beam width.

[0005] In order to partially solve such a problem, conventionally, a beam compression method for reducing a beam width by subtracting a difference signal pattern from a sum signal pattern of reception signals of the same two antennas of a monopulse feeding system is used. Methods are known. FIG. 6 is a diagram showing an antenna apparatus for performing such beam compression, wherein 101 and 101 are antennas of a monopulse feeding system having a length a and a center-to-center distance d, and 102 are reception signals of the two antennas 101 and 101, respectively. 103 is a detection circuit that detects the sum signal Σ and the difference signal Δ, and 104 is a subtraction circuit that subtracts the difference signal Δ from the sum signal Σ and outputs an antenna output signal. is there.

FIGS. 7 and 8 show a case where a horn antenna in which the antenna length a is set to about 25.7 times the wavelength of a received radio wave and the center-to-center distance d is equal to a in the antenna apparatus shown in FIG. It is a diagram showing the simulation results of,
The aperture distribution of the antenna is assumed to be uniform, and the electric field pattern (FIG. 7) and the power pattern (FIG. 8) normalized by the value when the angle is zero are shown. In these pattern diagrams, the dashed line indicates the sum signal 、, and the solid line indicates the output pattern, which indicates that the beam has been compressed.

[0007]

The above-mentioned conventional beam compression method uses only one antenna system composed of the same two antennas of the monopulse feeding system, and the beam width is only one-dimensionally. Cannot be compressed, and the discrimination ability is insufficient. That is, for example, assuming that a main beam pattern when no beam compression is performed is a pattern 201 as shown in FIG.
In this case, it is impossible to identify the five objects a, b, c, d, and e. When the beam is compressed one-dimensionally in the X direction, the compressed main beam pattern 202 becomes as shown in FIG. 9B, and the discrimination ability is improved as compared with the case where the beam compression is not performed, but still, There is a problem that the three objects a, c, and e cannot be identified, and the identification ability is insufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems in the conventional beam compression method. It is an object of the present invention to provide an antenna pattern two-dimensional beam compression apparatus which performs two-dimensional beam compression to improve discrimination ability. With the goal.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides the same two-pulse power supply system.
One of Ri Do from the antenna, a first antenna system arranged to match the first direction is the beam width to be compressed,
Ri Do the same two antennas of a monopulse power feed system,
An antenna means comprising a second antenna system arranged so that its central axis coincides with the central axis of the first antenna system and in a second direction orthogonal to the first direction ;
Means for scanning the antenna beam of the antenna means in directions other than the first and second directions , a first antenna system and a second
A received signal of each antenna of the second antenna system is converted into a signal obtained by inputting a received signal of each antenna of the antenna system and subtracting a difference signal thereof from a sum signal of the received signals of each antenna of the first antenna system. antenna in a sum signal by adding a signal obtained by subtracting those of the difference signal, a signal processing unit for outputting the sum signal as an output signal of the antenna means
This constitutes a two-dimensional beam compression device having a na pattern .

[0010] In the two-dimensional beam compression apparatus configured as described above, the signal processing section includes the first and second directions.
By subtracting the difference signal from the sum signal of the reception signals of the respective antennas of the first antenna system obtained by scanning other than the above, an output signal with a reduced beam width in the first direction is obtained. Similarly, except for the first and second directions
By subtracting the difference signal from the sum signal of the reception signals of the respective antennas of the second antenna system obtained by scanning in the above manner, an output signal with a reduced beam width in the second direction is obtained. By adding these output signals, a two-dimensional beam compressed antenna output signal in the first direction and the second direction is obtained. In the present invention,
And the antenna beam of the antenna means is connected to the first and second antennas.
Scan the antenna beam using a means to scan in directions other than
In the first or second direction,
When scanning the antenna beam of the antenna means, the second direction
Alternatively, beam compression in the first direction is not performed, and one-dimensional
Only beam compression is performed and two sets of antenna systems are used.
The meaning of the first and second directions.
The means for scanning other than to perform two-dimensional beam compression
Is an essential requirement.

[0011]

Next, an embodiment will be described. FIG. 1 is a diagram showing a schematic configuration of an antenna device for describing an embodiment of a two-dimensional beam compression device for an antenna pattern according to the present invention. In the figure, reference numerals 1a and 1a denote two receiving antennas of the same configuration of a monopulse feeding system, which use a horn antenna, an array antenna, or the like in a first direction (X direction).
To form a first antenna system. 1
Reference numerals b and 1b denote two receiving antennas of the same configuration in the same monopulse feeding system, which use a horn antenna, an array antenna, or the like, and are arranged in a second direction (Y direction) orthogonal to the first direction and have a second direction. Of the antenna system. So
Then, an antenna is provided by these first and second two antenna systems.
Antenna means, wherein the antenna means is provided in first and second directions.
It is configured to scan in other directions. 2a,
2b is a hybrid circuit, and the hybrid circuit 2a forms a sum signal Σ1 and a difference signal Δ1 of reception signals from the two antennas 1a, 1a of the first antenna system,
The hybrid circuit 2b includes a sum signal Σ2 and a difference signal Δ of reception signals from the two antennas 1b and 1b of the second antenna system.
2 is formed. 3a, 3a, 3b, 3b are detection circuits, and 4 is a signal processing unit, which is a signal obtained by subtracting the difference signal Δ1 from the sum signal Σ1 demodulated by the detection circuit and a signal obtained by subtracting the difference signal Δ2 from the sum signal Σ2. Are added and output.

When a radio wave arrives at the antenna device configured as described above, the hybrid circuit 2a that has received the received signal from the first antenna system generates a sum signal Σ1 corresponding to the sum signal pattern and a difference signal corresponding to the difference signal pattern. The signal Δ1 is output. Further, the hybrid circuit 2b to which the received signal from the second antenna system has been input receives the sum signal Σ2 corresponding to the sum signal pattern and the difference signal Δ2 corresponding to the difference signal pattern.
Is output. These outputs are output to detection circuits 3a, 3a, 3
b and 3b, the signal processing unit 4 performs signal processing for adding a signal obtained by subtracting the difference signal Δ1 from the sum signal Σ1 and a signal obtained by subtracting the difference signal Δ2 from the sum signal Σ2. Is obtained corresponding to the two-dimensionally compressed pattern.

FIG. 2 shows a first and second antenna systems using square horn antennas each having a size six times the wavelength of a received radio wave as antennas constituting the first antenna system and the second antenna system. FIG. 13 is a diagram showing a simulation result in a case where an antenna system in which the center-to-center distance between the two antennas constituting each is about 8.48 times the wavelength of the received radio wave is used. At this time, it is assumed that the aperture distribution of each antenna is uniform, and FIG. 2A shows a pattern obtained by adding the reception signals of four square horn antennas constituting each antenna system. (B) shows a pattern obtained by performing two-dimensional beam compression in the form of a contour map, and based on the value of the origin, -3, -6, -9, -12, -15,
The values of -18 and -21 are shown. From these patterns X
It can be seen that the beam width in the direction and the Y direction can be reduced to about half two-dimensionally.

When beam compression is performed two-dimensionally,
FIG. 3 is a schematic diagram similar to FIG. 9 showing how the degree of discrimination is improved. That is, when the beam is two-dimensionally compressed, the main beam becomes like the pattern 5, and it becomes possible to identify the objects a, b, c, d, and e, and it can be seen that the identification ability is further improved. .

Next, a specific configuration example of each antenna system of the antenna device is shown in FIG. In this configuration example, the rectangular horn antenna 11 is used for both the first antenna system and the second antenna system.
a, 11a, 11b, and 11b. The antennas 11a and 11a of the first antenna system are arranged in a first direction (X direction), and the antennas 1 and 2 of the second antenna system
1b and 11b are arranged in the second direction (Y direction) with their antenna central axes coincident with the central axis of the first antenna system. Note 12 Ri support der antenna system, first
And the antenna device is scanned in a direction other than the second direction.
That it has been in.

As the signal processing section, a general differential amplifier or an adder circuit can be used when processing is performed in an analog manner. A known technique such as means for performing subtraction and addition processing by a computer after conversion into a digital signal by a / D converter can be used. An example is shown in FIG.
In the figure, reference numerals 21, 22, 23, and 24 denote A / D converters for converting the analog sum signal Σ1, the difference signal Δ1, the sum signal 差 2, and the difference signal Δ2 demodulated by the detection circuit into digital signals, respectively. Numeral 25 denotes a computer which adds a sum signal Σ to a signal obtained by subtracting the difference signal Δ1 from the sum signal Σ1 converted to a digital signal.
It is configured to perform a process of adding a signal obtained by subtracting the difference signal Δ2 from 2.

[0017]

As described above with reference to the embodiments,
According to the present invention, scanning is performed in a direction other than the first and second directions by using a first antenna system arranged in a first direction and a second antenna system arranged in a second direction in a monopulse feeding system. Since a signal obtained by adding a signal obtained by subtracting the difference signal from the sum signal of the second antenna system to a signal obtained by subtracting the difference signal from the sum signal of the first antenna system obtained by performing The width can be two-dimensionally compressed to further improve the discriminating ability.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an antenna device for describing an embodiment of a two-dimensional beam compression device for an antenna pattern according to the present invention.

FIG. 2 is a diagram showing a combined pattern obtained by the antenna device shown in FIG.

FIG. 3 is a diagram showing a two-dimensional compressed main beam pattern for describing improvement of discrimination ability by two-dimensional beam compression.

FIG. 4 is a diagram showing a specific configuration example of an antenna system of an antenna device used for implementing the present invention.

FIG. 5 is a circuit configuration diagram showing a specific configuration example of a signal processing unit.

FIG. 6 is a schematic diagram showing a conventional monopulse power feeding type antenna device that performs one-dimensional beam compression.

7 is a diagram showing an electric field pattern of an output signal of the antenna device shown in FIG.

8 is a diagram showing a power pattern of an output signal of the antenna device shown in FIG.

FIG. 9 is an explanatory diagram for explaining the discrimination ability by a main beam.

[Explanation of symbols]

 1a Antenna of first antenna system 1b Antenna of second antenna system 2a, 2b Hybrid circuit 3a, 3b Detection circuit 4 Signal processing unit

Claims (1)

(57) [Claims] 1. A Ri Do the same two antennas of a monopulse power feed system, a first antenna system arranged to match the first direction is the beam width to be compressed, the same monopulse feeding system Ri Do from the two antennas, the central axis is coincident with the center axis of the first antenna system, formed by arranging to match the second direction and orthogonal to the first direction the
An antenna means arranged at a second antenna system, and means for scanning antenna beams of said antenna means in addition to the first and second directions, the first antenna system and the second antenna
The received signal of each antenna of the second antenna system is input to the signal obtained by subtracting the difference signal from the sum signal of the received signal of each antenna of the first antenna system. adding the signal obtained by subtracting those of the difference signal from the sum signal, the two-dimensional beam compression instrumentation of the antenna pattern, characterized in that the sum signal and a signal processing unit for outputting as the output signal of the antenna means
Place .