JPS62132403A - Method and apparatus for generating a differential beam in a first direction with omnidirectional sidelobes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to antennas, and more particularly to beam forming networks for antennas.

[Prior art]

In the aircraft collision avoidance system, the position of the aircraft is
, requires a sum pattern and a difference pattern to measure within a sector of 5 degrees. Aircraft interrogated within a sector receive P1 and P3 pulses. Those P
The amplitude of the 1 pulse and the P3 pulse is greater than the amplitude of the P2 pulse that occurs between the P1 pulse and the P3 pulse. The amplitude of the P2 pulse is attenuated in the desired interval using a difference pattern with zero pointing to the desired interval. The amplitude of the P2 pulse exceeds the width of the P1 and P3 pulses outside the desired interrogated sector in all other directions.

Figure 4 attached to U.S. Patent No. 4,425,567,
9 and 10 disclose beamforming circuitry for forming sum and difference patterns with omnidirectional side lobes.

FIG. 7 of the appendix of U.S. Pat. No. 4,316,192 discloses a beamforming network for generating sum and difference patterns. Its beamforming network is Butler (
Butler) matrices into a circular array. In FIG. 2 of this patent, the difference pattern formed by the beamforming network of FIG. 7 is formed by subtracting the sum pattern from the omnidirectional pattern and has omnidirectional side lobes.

Proc, IEEE, November 1968, 201
[A Matrix Fed Circular Array Continuous φ Scanning (A Matrix Fed C1r
cular Array for Continuous
Shelgu (Scanning) J.
eg) describes a Butler matrix provided with an electronically scanned circular play.

It would therefore be desirable to have a simpler beamforming network that provides a differential pattern in one direction and an omnidirectional pattern in the other direction.

Furthermore, rather than forming a difference pattern in one direction and adding the difference pattern and a sum pattern rotated by 180 degrees, it is also desirable to form omnidirectional patterns in other directions.

[Summary of the invention]

In accordance with the present invention, the method includes the step of generating a difference beam having maximum attenuation in a first direction and a second direction that are approximately 180 degrees apart in a predetermined plane of radiation, and generating a sum beam having a predetermined amplitude. and a step of reducing the maximum attenuation in the second direction by generating it in the second direction.
The first difference beam with omnidirectional side ropes in the other direction
A method for generating in the direction of and a device for carrying out this method are obtained.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

'First, refer to Figure 1. When the signal generated by beamforming network 1° is coupled to an antenna element, a difference beam is generated from the antenna element in a first direction, the difference beam having omnidirectional side lobes in the other direction. Beamforming network 1o can also generate a sum beam. Beamforming circuitry 10 can receive microwave energy via line 814 to generate a sum beam pattern and microwave energy via line 16 to generate a difference beam with omnidirectional side lobes. Can receive. The pin 14 is coupled to a first input terminal of a vibe 1) rad circuit 18. When microwave energy is applied to line 14, hybrid circuit 1B functions to provide an in-phase output to lines 19 and 20 with an amplitude attenuation of -3 dB. ilj 19 is coupled to output terminal 23 via directional coupler 22. Line 20 is hybrid circuit 2
4 is coupled to the first input terminal of 4. Hybrid circuit 2
4 receives microwave energy from line 20 and is in phase;
It functions to provide an output on line 25.26 that is attenuated by -3 dB. Lines 25.26 are output terminals 37.38
are respectively coupled to. Line 20 is also coupled via a directional coupler 28 . The directional coupler 28 transfers a portion of the signal of a predetermined amplitude, such as -10.5 dB, on line 20 to line 29.
It functions to combine with. Directional coupler 28 can break line 29 terminated with resistor 30 . The line 29 is coupled to a first input terminal of the hybrid circuit 32. Hybrid circuit 32 functions to receive microwave energy via line 29 and provide an output on line 33,34. Its output is in-phase and attenuated by -3 dB. Lines 33.34 are output terminals 35.36
is combined with

The directional coupler 22 is i! Il! A predetermined amount (such as -6,9 dB) of microwave energy on le f+! Combined with 40. One end of the wire 4° of the directional coupler 22 can be terminated with a resistor 41. The other end of line 40 is coupled to a first input terminal of hybrid circuit 42 . Hybrid circuit 42 receives microwave energy on line 40 and outputs an in-phase, -3 dB attenuated output on line 43.44.
It functions to give to. Lines 43 and 44 are output terminals 45
．． 46 respectively.

Line 16 is coupled to directional coupler 48 . This directional coupler 48 connects (-15) of the microwave energy on line 16.
, 7 dB) to line 49. One end of the directional coupler 480 line 49 is terminated by a resistor 50, and the other end is coupled to the second input terminal of the hybrid circuit 1B.

Hybrid circuit 18 splits the microwave energy on line 49 into lines 19 and 20. The microwave energy applied to line 19 is in phase with the microwave energy on line 49 and attenuated by -3 dB, while the microwave energy applied to line 20 is 180 degrees out of phase with the microwave energy on line 49. Different degrees, -3dB
It is attenuated only by The line 16 is the directional coupler 5
2.54 is also coupled to the second input terminal of the hybrid circuit 24. Directional coupler 52 couples a portion (such as -11,3an) of the microwave energy on line 16 to line 53. Line 53 is hybrid circuit 32
is coupled to a second input terminal of. Hybrid circuit 32
divides the microwave energy on line 53 into lines 33 and 34÷ and gives it. The microwave energy applied to line 34 is in phase with the microwave energy on line 53 and attenuated by -3 dB, and the microwave energy applied to line 34 is in phase with the microwave energy on line 53.
180 degrees different phase from the microwave energy above, -
It is attenuated by 3 dB. One end of the output line 53 of the directional coupler 52 is terminated by a resistor 55, and one end of the output line 5T of the directional coupler 54 is terminated by a resistor 56. Directional coupler 54 functions to provide a portion (such as -7.4 dB) of the microwave energy on line 16 to the output terminal of hybrid circuit 42 . Hybrid circuit 42 splits the microwave energy on line 57 into lines 43 and 44. The microwave energy applied to line 43 is in phase with the microwave energy on line 57 and attenuated by -3 dB, and the microwave energy applied to line 44 is 180 degrees out of phase with the microwave energy on line 57. It is attenuated by −3 dB.

The hybrid circuits 18, 24, 42, and 32 can be constructed from nine folded magic tees, for example. FIG. 7 shows a specific example of a hybrid circuit 18 made up of light-reflecting magic T's. In this hybrid circuit 18, a first input terminal such as the hybrid circuit 180 line 14 corresponds to a Σλ input terminal. A second input terminal, such as line 49, corresponds to the Δλ input terminal of the folded magic T. A first output terminal such as line 19 of the hybrid circuit 18 corresponds to the E' output terminal of the folding magic T and is connected to the hybrid circuit 180.
A second output terminal, such as line 20, corresponds to the ΔI output terminal of the Magic T. The input signal to the folding magic T02 input terminal appears as a -3 dB attenuated output with a phase delay of 190 degrees at the E' output terminal and the ΔI output terminal. The input signal to the Δλ input terminal of the light-reflecting magic T is delayed by 190 degrees in phase to the Σ' output terminal, and is -3 dB.
It appears as an attenuated output, with a phase delay of 1270 degrees at the Δ' output terminal, and appears as a -3 dB attenuated output. The phase delay of -270 degrees is given by the length of the reflected light of the magic T. The Folded Magic T is smaller than the traditional circular 1.5 wavelength diameter rat race from which it originates. Reflective light magic T is 90
90 degree design wavelength line length 135 from Σ port to Σ' port, 90 degree line length 137 from Σ' port to Δ port, 2
70 degree line length 138 from Δ port to Δ' port, 90
It can be constructed by providing a degree line length 139 on the printed circuit board 136 from the Δ' port to the Σ port.

Reference is now made to FIG. 2, where a block diagram of beamforming network 10 is shown. Beamforming network 10 includes phase shifter 6
3-69 and Butler matrix 62 to circular antenna array 60. Beam forming network 10
Output terminals 23, 37° 45.35, 36, 46.38
are coupled to phase shifter input terminals 63-690, respectively, via lines 70-76, respectively. The output terminals of phase shifters 63-69 are coupled to respective input terminals of Butler matrix 62 via lines 77-83, respectively. The eighth input terminal of Butler matrix 62 is terminated by resistor 85 via [84. The output terminals of Butler matrix 62 are coupled to antenna elements 101-108 of circular antenna array 60 via lines 91-98, respectively. The antenna elements 101 to 108 are centered at 1
30, the diameter indicated by arrow 99 is 26.67 cm.
(10,5 inches) spaced evenly around a circle. Butler matrix 62 connects the input signal on Hrr~84 suitable for a linear antenna to circular antenna array 60.
Convert it to an appropriate signal and give it the same antenna pattern.

The orientation of the sum and difference patterns of beamforming network 10 can be changed by steering electronics 110. The steering electronics receives digital steering command inputs via 1Is111 and outputs via Is111.
Published in v112. As used herein, the terms sum pattern, difference pattern, sum beam, and difference beam refer to antenna patterns suitable for use in monopulse radar direction finding.

An antenna pattern is radiated outward from circular antenna array 60. standard! if LH is circular antenna array 6
The reed passes through the center 130 in the plane of 0. The reference line 132 also lies within the plane of the circular antenna array 60 and forms an angle φ with respect to the reference line 131, as indicated by an arrow 133. The position of the reference line 131 can be considered to be 0 degrees. Therefore, angle φ represents the radiation angle from circular antenna array 60.

Next, the operation of the beam forming network 10 will be explained.

When microwave energy is coupled through line 14 to the sum terminal, the microwave energy is coupled to output terminals 23, 37, 45° as microwave energy with amplitude and phase as shown in Table 1. 35.36, 46.3
distributed to 8.

Table 1 Sum pattern strength terminal to phase shifter Mode Amplitude (dB) Phase (button 23
0 -4.002 0.037 -1
-6.426 0.045 -2 -12.9
21 0.035 -3 -16.521
0.036 +3 -16.521
0.046 +2 -12.921 0.0
38 +1 -6.426 0.0 Phase shifter 6
The antenna pattern radiated by circular antenna array 60 using the values shown in Table 1 is shown in FIG. 3 after being suitably phase shifted by 3 to 69. Phase shifter 63-6
9. Due to the phase shift performed, the circular antenna array 6o
Nyoshi Radiation Saji: To, Ma'14 Type-Ki-1z, S1-~R) Urushimu T Uchita -F -F -2. Nohe 1 table can be changed. The phases shown in Table 1 are suitable for coupling to linear antenna arrays that are equally spaced across the radiation direction. In Figure 3, the vertical axis represents power (dB), and the horizontal axis represents polar angle (polar angle).
gle) ([). Curve 114 represents the sum beam and curves 115-118 represent the side rope patterns.

When microwave energy is coupled into line 49, it becomes microwave energy having an amplitude and phase as shown in Table 1 and is output to microwave output terminals 23, 37, 45, 35, 36° 46. Appears in .38. The antenna pattern radiated from the circular antenna array 60 using the values shown in Table 1 is shown in FIG. 4 after being appropriately phase shifted by the phase shifters 63-69.

Table 2: Beam Filling Intensity and Equipment Terminals Mode Amplitude (an) Phase (23 0 -
4.002 0q) -1 t, A
9Rin45 -2 -12.921
035 -3 -16.521
18036 +3 -16.5
21 18046 +2 -12
．． 921 038 +1 -
6.426 180 In Figure 4, the vertical axis represents power (dB) and the horizontal axis represents polar angle (button). 1 to the second input terminal of hybrid circuit 18. As shown in FIG. Curve 1 appears on the right side of the diagram.
15 and 118 are tied together at 0 degrees. Since the power at the input terminal of the hybrid circuit 18 is reduced due to the coupler 48, the curves 114,1
15 and 118 are smaller.

The curves 116 and 117 shown in FIG.
These curves are not shown in Figure 4 because they are attenuated lower than B.

FIG. 5 is a graph of the difference pattern radiated from circular antenna array 6G by beamforming network 10 shown in FIGS. 1 and 2. FIG. Line 16 to directional coupler 5
2.54 to the lines 53, 57, but not through the directional coupler 48, as microwave energy having an amplitude and phase as shown in Table 1. Output terminals 23, 37.
45, 35° 36, 46, 38, phase shifter 63
After being appropriately phase shifted by .about.69, it gives a pattern as shown in FIG.

Difference beam intensity and phase terminal when cutting table line 49
Mode Amplitude (dB) Phase (degrees) 23 0
-19.072 0.037 -1 -
3.282 180.045 -2 -12.
067 180.035 -3 -13.37
6 180.036 +3 -15.628
0.046 +2 -9.806
0.038 +1 -5.535 0.0 5th
In the figure, the vertical axis represents power (dB), and the horizontal axis represents polar angle (degrees). Curve 120 shows the difference pattern, curve section 121 shows the desired depth of the attenuation notch in the difference pattern, and curve sections 122 and 123 show the difference pattern.
shows the undesirable depth attenuation 180 degrees removed from .

Figure 6 shows that the microwave energy is on the line 16.49°53
．． 57 is a graph of the pattern from the elliptical antenna array 60 generated by the beamforming network 10 shown in FIGS. 1 and 2 when coupled via 57; FIG. 6th
In the figure, the vertical axis represents power (dB), and the horizontal axis represents polar angle (degrees). Curve 125 represents an omnidirectional pattern;
Curved portion 126 represents the difference pattern. The curves shown in FIG.
, 53. The fourth generated from microwave energy on 57
This is a composite of the curves shown in Figure 5 and Figure 5.

As can be seen from Figure 6, in the range of -120 degrees to -180 degrees and +120 degrees to +iso degrees, the amplitude ranges from 11 dB to Table 2 -1 64 26.418 31.4
18-2 65-30.941-2
0.941-3 66 -109.165
-94.165+3 67 -106.16
5 -124.165+2 68 - 30
．． 941 - 40.941+1 69
26.418 21.418 By adjusting the phase shifters 63 to 69, it is possible to turn the number of turns. For example, in order to rotate the patterns shown in FIGS. 3 to 6 by 5 degrees, the following adjustments are made to the phase shifters 63 to 69. The phase shifters 63 to 69 have phase shift amounts of 0, 5, 10, 15, . -15. -10. It has a phase shift amount of -5 degrees. Table 3 shows the amount of phase shift for φ equal to 5 degrees.

To obtain the difference pattern, the signals on lines 71-83 fed to Butler matrix 62 and the amplitude are It is shown in Table 7.

Table 7 Intensity and phase of filled-in difference pattern applied to Butler matrix 77 0 -19.7
02 0.00078 -1 -3.28
2 -153.58279 -2 -12.0
67 149.05980 -3 13.
736 70.83581 +3 -15
．． 628 −109.16582 +2 −
9.806 - 30.94183+1-5.53
5 26.418 or more, approximately 1 in a given radial plane
The process of generating a difference beam having maximum attenuation in a first direction and a second direction that are 80 degrees apart, and generating a sum beam having a predetermined amplitude in the second direction. A method for generating a difference beam with omnidirectional side lobes in a first direction, and a device for implementing this method, comprising the step of reducing said maximum attenuation in two directions, has been described.

[Brief explanation of drawings]

1 is a schematic diagram of one embodiment of the invention, FIG. 2 is a block diagram of the antenna and feedback network shown in FIG. 1, and FIG. 3 is a block diagram of the antenna and feedback network generated by the embodiment of FIG. A graph of a sum pattern minus a difference pattern, FIG. 4 is a graph of a sum pattern minus a difference pattern rotated by 180 degrees generated by the embodiment of FIG. 12, and FIG. 5 is a graph of a sum pattern minus a difference pattern generated by the embodiment of FIG. 6 is a graph of the difference pattern and sum pattern generated and combined according to the embodiment of FIG. 2, and FIG. 7 is a graph of one of the hybrid circuits shown in FIG. 1. FIG. 3 is a plan view of the embodiment. 10 Fighting Beam Forming Network, 18, 24.32゜4
2Φ...Φ hybrid circuit, 22.28.48. 52.54...Directional coupler, 60...Circular antenna array, 62@...Φpatler matrix, 63-6...Phase shifter, 101-1081...
antenna element. 0 -1 -2 -3 +3 ◆
2+IFIG, / E Δ F/σ, 2

Claims (6)

[Claims] (1) The first two planes are approximately 180 degrees apart in a given radial plane.
generating a difference beam having maximum attenuation in the direction of the direction and a second direction; A method for generating a difference beam with omnidirectional side lobes in a first direction, comprising the step of reducing the maximum attenuation in the second direction by generating in a second direction. (2) means (52, 54, 24, 42, 32) for generating a difference beam with maximum attenuation in a direction approximately 180 degrees apart in a given plane of radiation and a second direction; In an apparatus for generating a difference beam in a first direction having a rope, means (48, 18, 22, 28, 24, 42, 32) for generating a sum beam in the second direction having a predetermined amplitude.
Apparatus for generating a differential beam in a first direction with omnidirectional side ropes, characterized in that the maximum attenuation in the second direction is reduced. (3) The device according to claim 2, wherein the means (52, 54, 24, 42, 3
2) is a circular antenna array (60) and an input signal (23, 37, 45, 35, 36, 4) to a linear antenna array.
a Butler matrix (62) coupled to said circular antenna array (60) for converting the input signal (6, 38) into an input signal to a circular antenna array; (
23, 37, 45, 35, 3 to phase shift the input signals (23, 37, 45, 35, 38)
a plurality of phase shifters (63-6) coupled to
9) and the input signal (23, 37, 45, 35, 36
, 46, 38).
3-69) through the Butler matrix (62)
a beamforming network (10) coupled to a beamforming network (10). (4) Apparatus according to claim 3, wherein the beamforming network (10) has an input terminal (16) and a predetermined beamforming network (10) that is connected to the input terminal (16). a plurality of couplers (52, 54) providing said microwave energy at a power level to its input terminal (16);
) and a plurality of hybrid circuits (32, 42, 42, 24). (5) An apparatus according to claim 4, wherein the sum beam generating means is coupled to the input terminal (16) for coupling a predetermined power level to the input terminal (16). a first coupler (48), the output (49) of said first coupler being connected to a first hybrid circuit (18) for generating signals of predetermined power levels in-phase and out-of-phase with respect to the input (49) ), and the input terminal (
Each said in-phase signal and each said out-of-phase signal are connected to at least one combiner (22) to generate a plurality of second signals of predetermined power levels that are in-phase and out-of-phase with respect to
, 28), and the sum beam generating means comprises at least one
three of the second signals to the plurality of hybrid circuits (3
2, 42, 24). (6) comprising an input terminal (16), the input terminal (16);
A predetermined power is applied to the first to third wires (49, 53, 5
7), the input terminal (16) is connected to the first to
The first to third lines (49, 53, 57) are coupled in series via a third coupler (48, 52, 54), and the first to third lines (49, 53, 57)
is coupled to a first port of a hybrid circuit (18, 32, 42), and the input terminal (16) is connected to the first to third coupler (48).
, 52, 54) and then to the first port of the fourth hybrid circuit (24), and the first to fourth
Each hybrid circuit (18, 32, 42, 24) has first to fourth ports, and the first port (49, 5
3, 57, 16) whose phase differs by 180 degrees from the input signal at the second port (20, 34, 44, 26).
) to the third port (14, 29, 40, 20
) without giving a signal to the fourth port (19, 33,
43, 25), and the third port (1
4, 29, 40, 20) does not provide a signal to the first port (49, 53, 57, 16), and the in-phase signal is sent to the second port (24, 34, 44, 26). )
and the fourth port, and the fourth port (19) of the first hybrid circuit (18) is connected to the first output terminal (23) via the fourth coupler (22). ), an output from the fourth coupler (22) is coupled to the third port (40) of the third hybrid circuit (42), and an output from the fourth coupler (22) is coupled to the third port (40) of the third hybrid circuit (42); The second port (20) is connected to the third port (29) of the fourth hybrid circuit (24) via a fifth coupler (28).
coupled to the fourth, third, and second hybrid circuits (24
, 42, 32) of the fourth port (25, 43, 33)
) is the first output terminal (37) and the third output terminal (45
) and a fourth output terminal (35), respectively, and the second, third and fourth hybrid circuits (32,
42, 24) said second port (34, 44, 26)
are the fifth output terminal (36) and the sixth output terminal (46)
and a seventh output terminal (38), respectively, for generating a difference pattern with omnidirectional side ropes.