JPS5944106A - Electronic scanning antenna - Google Patents

Abstract

PURPOSE:To increase the adaptability of beam forming in the course of operation of an antenna and to eliminate the necessity of a high power resistive switch, by using plural variable power phase-shifters having both variable power distributing function and phase controlling function for an aerial feeding circuit. CONSTITUTION:A high frequency electric power supplied to the radiating section of an antenna through a mechanical rotary table is inputted into the input terminal 24 of a vertical feeding circuit 23 and distributed so that a prescribed amplitude and phase distribution are given to the longitudinal openings of an antenna, and then, outputted to (n) pieces of output terminals 23-1-23-n. The high frequency electric power from each output terminal is fed to radiant elements at logitudinal locations, through which radiant elements 20-1-20-n constituting the 1st radiant opening section 20 correspond to radiant elements 21-1- 21-n constituting the 2nd radiant opening section 21, through two-outputs variable power phase shifters 22-1-22-n. Then set phase differences of all the variable power phase shifters are set to values which correspond to a desired power ratio and the sum of set phases is set to a value which corresponds to a desired beam elevation, and thus, a prescribed antenna beam is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically scanned antenna, and more particularly to an electronically scanned antenna.
The present invention relates to an electronically controlled antenna that electronically controls the radiation levels, radiation angles, etc. of multiple beams within one radiation plane.

Conventionally, this type of electronic scanning antenna often has one antenna emission surface installed on a mechanical rotary table, which rotates in a horizontal plane at a constant speed while electronically scanning the beam in one vertical plane. It was something to do.

Therefore, when this antenna is used for radar, the data acquisition rate of the target is a constant value determined by the antenna rotation speed, and the number of hits is also an almost constant value determined by the rotation speed, so the data acquisition rate is reduced when the target turns. It has a drawback that it is difficult to adaptively increase the number of hits according to the characteristics of the input signal.

As a method to significantly improve this drawback, there is an antenna system that electronically scans the beam arbitrarily within two radiation planes at a predetermined elevation angle and azimuth, but the number of components such as a phase shifter is limited to electronics only in the elevation direction. Compared to scanning antennas, antennas have the drawbacks of being complex and expensive, such as being less reliable by the power of the square.

Next, as another example of the prior art, an antenna that is an intermediate system between the above two examples, in which a plurality of antenna radiation surfaces are installed on one rotary table, will be described with reference to FIG. In Figure 1, 1 and 5 are two antenna radiation surfaces, 2 and 6 are vertical feed circuits that feed each of the radiation surfaces, 3 and 7 are input terminals of each of the feed circuits, 4 and 8. 9 is an antenna beam formed on each radiation surface, and 9 is a high-power switching device.

Reference numeral 10 indicates an input terminal of the switching device, and reference numeral 11 indicates a rotary table.

According to the system shown in FIG. 1, the power applied to the input terminal 10 via the rotary table 11 is switched and transmitted to the input terminals 3 and 7 of the power supply circuit by the high-power switching device 9, and the antenna beam 4 Or form 8. Therefore, after detecting and moving inside a specific target using the antenna beam 4, when the antenna beam 8 is directed toward the target as the rotary table rotates, the power switch 9 is switched, and the antenna beam 8 By performing detection and measurement, it is possible to double the data acquisition rate for the above target.

However, this type of antenna requires two independent antenna radiators including a power feeding unit, making it large and expensive, and requires a high-power-resistant power switch to switch all the radar power at once. It had disadvantages such as being required.

The present invention eliminates the above drawbacks by using a plurality of variable power phase shifters in the antenna feed circuit, increases the flexibility of beamforming in antenna operation, reduces the number of components, and provides high durability. The present invention provides a simple, economical, and highly reliable electronic scanning antenna that does not require a power switch.

The electronic scanning antenna of the present invention has N in the first radiation plane.
N independent radiation apertures forming a book radiation beam;
a plurality of beam control means having both a variable power distribution function and a phase control function, the switching of the radiation beams within the first radiation plane regarding the N radiation beams, and the arbitrary radiation power ratio for each radiation beam; Radiation beam control including settings, etc. and radiation beam control including radiation beam scanning within a second radiation plane perpendicular to the first radiation plane in a predetermined reference direction regarding the N radiation beams are performed together. Further, the N independent radiation apertures forming N radiation beams in the first radiation surface have substantially the same radiation aperture surface due to the alternating arrangement of the radiating elements of each radiation aperture. In the case of sharing, in addition to switching the radiation beams within the first radiation plane regarding the N radiation beams, arbitrarily setting the radiation power ratio for each radiation beam, scanning the radiation beam by forming an overlap of the radiation beams, etc. and radiation beam control including radiation beam scanning in a second radiation plane orthogonal to the first radiation plane in a predetermined reference direction regarding the N beams.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a diagram showing an antenna radiating section on a rotary table in an embodiment of the present invention consisting of two antenna radiating openings.

In FIG. 2, 20 denotes the first radiation opening, 20-1 to 20-2.
0-n represents n radiating elements constituting the radiation surface 20,
21 is a second radiation aperture, 21-1 to 21-n are n radiating elements constituting the radiation aperture 21, and 22-1 to 21-n are n radiation elements constituting the radiation aperture 21;
22-0 are n two-output variable power phase shifters, 23 is a vertical plane feeding circuit, 231 to 23-n are n output terminals of the above vertical plane feeding circuit, and 24 is a power supply terminal. It shows. The present invention will be described assuming that this antenna is now in a transmitting state. The high frequency power supplied to the antenna radiator via the mechanical turntable is input to the input terminal 24 of the vertical feed circuit 23 . This high frequency power is distributed by the vertical feeder circuit 23 so as to give a predetermined amplitude/phase distribution to the antenna radiation section, and is output to n output terminals 23-1 to 23-n.

Next, the high frequency power from each output end is fed to a radiating element in a corresponding vertical position via a two-output variable power phase shifter. That is, taking the first element as an example, the power from the output terminal 23-1 of the vertical feeding circuit 23 is input to the two-output variable power phase shifter 22-i, and its output is input to the radiation aperture 20.
Power is supplied to the radiating element 20-1 for the radiating aperture 21, and to the radiating element 21-1 for the radiating aperture 21.

Fig. 3(a) shows an example of a two-output variable power phase shifter with two distributions of power from one person; in the figure, 30 is a 180° hybrid coupler, and 32 and 33 are two electronically controlled phase shifters. 31 is 90°
In the hybrid coupler, 34 is an input terminal, 37 and 38 are two output terminals, 35 is an error terminal, and 36 is a terminating resistor. In the above variable power phase shifter, the power input to the input terminal 34 passes through the 180° hybrid coupler 30 and
The phase shifters 32 and 33 are equally distributed, and again 90
. . . are synthesized in the hybrid 31, and outputs are obtained as a voltage EA at the output terminal 37 and as a voltage En at the output terminal 38 with respect to the matched load. At this time, EA, E
B represents the delay phase shift given by the phase shifters 32 and 33, respectively, by ψ1. Assuming ψ2, it is given by the following equation.

L Niben 3 EA = Eocos ("""knee")""(2"4
π) 4 EB= E, sin (!p2-X-!I!iit
)e−j (!22 +−F π)4 Therefore, the power ratio at the output terminal 37.38 is determined only by the difference in the set phase shift ψ2−ψ1, and the phase of each voltage is determined by the set phase. It is determined only by the sum ψ1 + ψ2.

From the above-mentioned operation of the variable power divider, the power supplied to the radiation aperture 20 is P□ with the set phase shift difference Δψ=ψ2−ψl of all the variable power dividers 22-1 to 22-n.

To make the power supplied to the radiation aperture 21 P2, set the phase shift sum Σ, = ψl + ψ2 of the father distributor to a value corresponding to the desired power ratio P 1 /P 2 to the desired beam elevation angle. If the value corresponding to θ is taken based on the principle of a phased array, the phase shift setting amount of the phase shifter in each variable power phase shifter 22-1 to 22-n is ψl=(Σ, -Δp)/ 2. ψ2=
It is uniquely determined as (Σ, +ΔP)/2. Therefore, if the directivity gains of the two radiation apertures 2° and 21 are set to 01102, and the above-mentioned predetermined amount of phase shift is set in the phase shifter, an antenna beam with a predetermined power ratio as shown in FIG. 4° (effective radiated power Pi Gl ) and 41 (effective radiated power P2G2) can be formed in a predetermined elevation angle direction θ. When radar operation is performed with a plurality of beams formed in a horizontal plane in this manner, the data acquisition rate can be improved by providing a means for removing uncertainty in the direction.

In particular, while keeping the phase shift difference Δ,=ψ2−ψ□ constant,
By changing the phase shifter Σ, = ψ1 + ψ2 according to the desired beam elevation angle, it is possible to scan the beam in the vertical plane without changing the power ratio of the two beams.

Further, in particular, if the phase shift difference Δ, = ψ2 - ψl is set to π/2, all the power appears at the output terminal 37 in FIG. 3, and the output at the output terminal 38 becomes 0. Also, phase shift difference Δ, = ψ2−ψ
When □ is set to 3π/2, the relationship of output power is exactly Δ, =
Contrary to the π/2 case, all power appears at output terminal 38. Assuming that the output end 37 of the above antenna is connected to the radiation surface 2o, and the output end 38 is connected to the radiation surface 21, the phase shift difference set value Δψ of the variable power phase shifters 22-1 to 22-n =
When ψ2-ψ1 is switched from π/2 to 3π/2, the antenna beam is instantaneously switched from the radiation surface 20 to the radiation surface 21. Therefore, as shown in FIG. 5, when a rotating router antenna forms a beam 40 using only the radiation surface 20 and performs electronic scanning in the elevation direction, it is possible to improve the data rate for a specific radar target 60. When necessary, at the moment when the antenna rotates and the beam formed when the radiation surface 21 is energized is directed in the direction of the radar target 60, the phase shift difference Δ,=ψ
By setting 2-ψ1 to 3π/2,
This makes it possible to detect the target twice during one rotation of the antenna, thereby improving the data rate.

Next, a second embodiment in which the above two antenna radiation surfaces are formed overlappingly will be described with reference to FIGS. 6 and 7. Figure 6 is 2
20-1 to 20-n are the element antennas constituting the radiation aperture 20, and 21-1 to 21-n are the radiation apertures. The element antenna constituting part 21 is shown, and it is shown that two radiation apertures are formed overlappingly on substantially the same aperture surface. FIG. 7 is a top plan view of the antenna shown in FIG. 6, in which two antenna radiating parts 20 and 21 are formed in almost the same aperture plane, and beams 40 and 41 corresponding to each radiating part are shown. This shows that the two beams are overlapped in the horizontal plane, separated by about the beam width. The operation will be described assuming that the antenna is in the transmitting state as in the first embodiment.

The power applied to the input terminal 24 of the vertical power supply circuit 23 is
Power is distributed to the input terminals of the two-output variable power phase shifters 22, which have the same number of radiating elements on the vertical plane, and each variable power phase shifter further distributes the antenna radiation on the two planes with a predetermined phase shift and power distribution ratio. Surfaces 20 and 21 are powered. In the same figure, the antenna radiation surface 2
The power supplied to the antenna beam 40 and the antenna radiation surface 2
1 form a beam 41, respectively.

In the antenna of this configuration, if the method shown in FIG. 3(a) is used as the two-output variable power phase shifter 22 as in the first embodiment, the phase shifter Σ of the two-output variable power phase shifter, =ψ1+ψ2
By controlling the electronic beam scanning in the vertical plane, and by controlling the phase shift difference Δ, = 92−ψ, the two beams 40 and 4
1 can be formed with any power ratio.

As a result, the two beams combined by the variable power phase shifter 22 are combined into one beam 42 oriented in a predetermined direction between the pointing directions of beams 40 and 41 according to their power ratio, and By controlling the phase shift difference of the output variable power phase shifter, it is possible to scan the beam in fine steps. Therefore, as shown in FIG. 8, when it is necessary to increase the number of hits to a specific target 61 in a radar using an antenna 50 rotating in a horizontal plane, the beam 40 in FIG. After irradiating, as shown in the figure (b), the beam is electronically scanned in the opposite direction to the rotating direction of the antenna to form a beam 42 in a predetermined direction, increasing the number of hits by increasing the irradiation time. be able to.

In the radiation aperture shown in Fig. 7, an example was shown in which 20 and 21 were slightly tilted in the horizontal plane, but even if the directions of the radiation surfaces are perfectly matched, by tilting the beam direction in the horizontal plane feeding circuit, You can get exactly the same behavior as above.

Furthermore, in the first and second embodiments, the antenna radiation surface is
Even when the number of planes is larger than that, basically the same operation as above can be ensured. In this case, as shown in Fig. 3(b) and below, as a variable power phase shifter with N output by one person,
As an example, (N-1) two-output variable power phase shifters 39 shown in FIG. Phase shift angle φ
1. By adjusting φ2, the power input from the input terminal is distributed to N outputs corresponding to the N output terminals, and the imaging width and phase shift of these outputs are controlled.

Further, in the above embodiment, the number of variable power phase shifters is the same as the number n of vertical elements in each radiation aperture, but as shown in FIG. A first vertical title circuit 52 is installed between the antenna and the variable power phase shifter to create a radiation aperture in which the number of antenna elements is reduced to m elements (m<n) without changing the antenna aperture. However, by connecting its input end to the second vertical power supply circuit 54 via m variable power phase shifters 53-1 to 53-m, the same operation as in the previous embodiment can be obtained.

Furthermore, the antenna of the present invention can be configured as a fixed type without being installed on a rotary table, or can be configured in such a manner that the first radiation surface and the second radiation surface are replaced with respect to the above embodiment, Effective operation can be obtained depending on the operating method of the system using this antenna.

As explained above, the present invention provides a plurality of variable power phase shifters between each element antenna and the vertical feed circuit in an eight-plane array antenna, thereby adapting beam forming to the operation of the antenna. In addition, the number of components including the variable phase shifter for radiation beam control is greatly reduced, a high-power-resistant power switch is not required, and the present invention is simple, economical, and highly reliable.

[Brief explanation of the drawing]

Figure 1 shows an example of a conventional beam switching antenna, Figure 2 shows an example of a conventional beam switching antenna.
The figure shows an embodiment of the electronic scanning antenna radiation section of the present invention.
FIG. 3 is a circuit diagram showing an example of a variable power phase shifter used in the present invention, FIG. 4 is a diagram showing an embodiment of beam forming by the aerial mK of the present invention, and FIG. 5 is a diagram showing beam switching by the aerial mK of the present invention. FIG. 6 is a diagram showing an embodiment of the radiation element arrangement of the antenna of the present invention; FIG. 7 is a diagram showing an embodiment of beam formation by the antenna of the present invention; FIG. This figure shows a beam scanning embodiment of the antenna of the present invention, and FIG. 9 is a diagram showing another embodiment of the antenna configuration of the present invention. 20.21...One antenna radiation surface, 20-1
~20-n, 21-1~21-n, 5
1-1 to 51-n...radiating element, 22-1 to 2
2-n, 53-1 to 53-m...Variable power phase shifter, 23,52゜54...Vertical surface feeding circuit, 2
3-1 to 23-n...N output terminals of the vertical plane feeding circuit, 24...Input terminal of the vertical plane feeding circuit, 30...18o0 hybrid coupler , 31
...90° hybrid coupler, 32.33.
...Electronically controlled phase shifter, 36... Terminating resistor, 39... Two output variable power phase shifter. ,-・, Agent Patent Attorney Yo Uchihara 1 , / // Figure 1 3γ ((1) Blade 3rd Evil (da) (“N
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(Antsuku U Saq figure

Claims (6)

[Claims] (1) comprising N independent radiation apertures that form N radiation beams in the first radiation surface, and a plurality of beam control means having a variable power distribution function and a phase control function; Radiation beam control including switching of radiation beams within the first radiation surface regarding the N radiation beams and arbitrary setting of a radiation power ratio for each radiation beam; and the first radiation surface regarding the N radiation beams. An electronic scanning antenna characterized in that radiation beam control including radiation beam scanning in a second radiation plane perpendicular to a predetermined reference direction is performed. (2) N radiation beams are formed in the first radiation surface, and the radiation elements of the radiation aperture corresponding to each of the N radiation beams are arranged substantially alternately, so that the radiation beams are substantially the same.
N independent radiation apertures sharing a radiation aperture surface, and a plurality of beam control means having a variable power distribution function and a phase control function; Radiation beam control including switching of radiation beams within a radiation plane, arbitrary setting of a radiation power ratio for each radiation beam, radiation beam scanning by forming an overlap of radiation beams, and the first method regarding the N radiation beams.
An electronic scanning antenna characterized in that radiation beam control including scanning of the radiation beam within a second radiation surface orthogonal to the radiation surface in a predetermined reference direction is performed. (3) An electronic scanning antenna according to claim 1 or 2, characterized in that the radiation aperture is rotated in a horizontal plane. (4) the first and second radiation surfaces correspond to a horizontal radiation surface and a vertical radiation surface, respectively, and each of the N independent radiation apertures forming the N beams is a vertical arrangement of radiation elements; The beam control device is configured to have M (M>1) input terminals, and the M beam control is applied to a group of N input terminals located at the same position in M sets of the N independent radiation apertures. A vertical feeding circuit having M output terminals is coupled to each input terminal of the M beam control means to supply power. Paragraph 1), Paragraph (2) or Paragraph (3)
Electronic scanning antenna as described in section. (5) the first and second radiation surfaces correspond to a vertical radiation surface and a horizontal radiation surface, respectively, and each of the N independent radiation apertures forming the N beams is a horizontal array of radiation elements; The beam control means is configured to have M (M>1) input terminals, and the M beam control means are connected to a group of N input terminals located at the same position in M sets of the N independent radiation apertures. , and a horizontal power supply circuit which outputs the M output terminals is coupled to each input terminal of the M beam control means to supply power. The electronic scanning antenna described in item 1), item (2), or item (3). (6) The beam control means includes a power divider that equally distributes input signals, and a pair of electronic variable phase shifters connected to each output terminal of the power divider and controlled by an external signal; A two-output variable power phase shifter having a pair of output terminals and a 90 degree hybrid coupling circuit that takes a pair of output symbols from the electronic variable phase shifter as input and outputs a pair of output signals; Corresponding to the radiation beam of the book (N
-1) are connected in series to form N output terminals corresponding to one input terminal. Section 2), Section (3)
), (4) or (5).