JPH02119302A - Multi-beam antenna device - Google Patents

Abstract

PURPOSE:To form each multi-beam independently in an arbitrary direction and with high accuracy by forming a beam signal by generating complex weight data by a first arithmetic means, correcting the data by a second arithmetic means, and processing each antenna element signal by corrected data. CONSTITUTION:Plural pieces of independent initial phase data corresponding to the pointing direction of respective beam for the required number of beams are generated by each beam scan computing element 33 in azimuth plane circuit substrates 301-30N, and they are outputted to a null weight computing element 34. The null weight computing element 34 generates plural pieces of phase data in which respective beam forms null in the neighborhood of the peak direction of another beam based on the initial phase data. Such operation is executed repeatedly on each beam. A beam forming apparatus 35 performs weighting by the complex weight data corresponding to each of reception digital data and the accumulative addition of the data sequentially, then, a reception multi-beam controlled independently can be formed.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention is mainly used in radar equipment, and is a multi-purpose antenna based on required processing of element signals of each antenna element constituting an array antenna. The present invention relates to a multi-beam antenna device that forms beams.

(Prior Art) When a single antenna is used to form a multi-beam with little loss in gain in the azimuth and elevation planes in a radar [f], an antenna HIi& as shown in FIG. 9 is used.

That is, this antenna device has multiple stages of azimuth plane circuit boards 111 to 11N that form orthogonal multi-beams in the azimuth plane.
It is mainly composed of two parts: and a plurality of stages of elevation plane circuit boards 121 to 12M that form orthogonal multi-beams in the elevation plane.

Of these, the azimuth plane circuit boards 111 to 11N each include M array antenna elements a1 to aH arranged at equal intervals in the same direction. The high frequency signals of
Form orthogonal multi-beams.

On the other hand, the elevation plane circuit boards 121 to 12M are configured to receive the multi-beam signals of the same column of the azimuth plane circuit boards 111 to 11N, respectively, and pass the input multi-beam signals to the phase shifters d1 to 12M, respectively. d, to the Patler matrix circuit e, and this Butler matrix circuit ! - Form N orthogonal multi-beams in the elevation plane through the RIX circuit e.

In this way, according to this antenna device, MXN orthogonal multibeams are formed in the azimuth plane and the elevation plane.

(Problem to be solved by the invention) By the way, in such conventional antenna devices, the patroller
Since the beams of each antenna element are made orthogonal to each other using a matrix, it is possible to suppress the gain reduction to a relatively small amount. cannot be pointed with high precision. Furthermore, it is extremely difficult to independently control the side lobes of each beam. These problems are the same even when a Fourier transform circuit (for example, FFT) having the same function as a Pattler matrix circuit is used as the multi-beam forming means.

This invention was made in view of these circumstances, and it is possible to form multi-beams with high gain in any direction with high precision, and also to be able to independently control the pattern of each beam 18. It is an object of the present invention to provide a multi-beam antenna device that can reliably avoid mutual interference of these beams.

(Structure of the Invention) (Means for Solving the Problems) In the present invention, a first antenna that generates complex weight data for beam scanning according to a desired beam pattern in correspondence with each element signal of the antenna element. and based on the generated complex weight data, null (nLIll>
a second calculation means for correcting complex weight data for beam scanning according to each desired beam pattern so as to form a beam pattern; weighting each of the element signals using the corrected complex weight data; and weighting these weights. and a beam signal forming means for forming a beam signal by synthesizing and adding the obtained signals.

(Operation) If the above beam signal formation is performed using the complex weight data generated by the first demonstration means,
At least it is possible to form multiple beams independently, in any direction, and with high precision. Therefore, the complex weight data generated by the first calculation means is corrected as described above through the second calculation means,
If the same beam signal formation as above is performed using this corrected complex weight data, each beam that is formed independently and accurately in any direction will be able to form each beam with respect to the peak direction of the other beams. will now form a null, and these beams will no longer interfere with each other.

(Embodiment) FIGS. 1 to 4 show an embodiment of the multi-beam antenna device according to this explanation.

As shown in FIG. 1, this embodiment antenna device has the following features:
Broadly speaking, antenna elements 1011 to 1018 and 1021 to 102M are arranged in a plane at predetermined intervals.

... Transmission/reception (゛D/R) modules 2011 to 2 that transmit and receive high frequency (RF) signals from 1ON1 to IQNH, and convert the received signals to take them out by frequency conversion.
018.2021~202M,...,2ON1~20
8M, azimuth plane circuit boards 301 to 3ON that form multi-beams in the azimuth plane, elevation plane circuit boards 501 to 50H that form multi-beams in the elevation plane, and a transmitter exciter 60 that generates transmission signals. , an elevation plane transmission signal distributor 70 that distributes transmission signals in the elevation direction, and azimuth plane transmission signal distributors 401 to 4ON that distribute transmission signals in the azimuth direction.

Also, among these, the above T/R modules 2011 to 201
8.2021~202M, ..., 2ON1~20
+1, as shown in FIG.
A phase shifter 21 that shifts the phase as required according to the phase data given from each corresponding one, and a high power amplifier 'a22 that amplifies this phase-controlled transmission signal to a high power signal.
, a circulator 23 that supplies this amplified transmission signal to each corresponding antenna element, an RF amplifier 24 that amplifies the radio frequency (RF) signal received by the antenna element and taken out via this circulator 23, and this amplified signal. A mixer 25 that mixes the RF multiplied signal local vibration signal 08C1 and converts it into an intermediate frequency (IF) signal;
An IF reception processor 26 that removes unnecessary frequency components from the F@ signal, and a hybrid 27 to this IF reception processed signal! The phase detection of the same IF signal is performed by mixing the received local northerly signals 08C2 that have a phase of 90 degrees with each other, that is, the orthogonal component 1 is extracted from the same IF signal.
．． The azimuth plane circuit boards 301 to 3ON are configured to include mixers 28 and 29, respectively, which extract Q (1 and 0 represent the real part and imaginary part, respectively).
/ A plurality of analog-to-digital converters 311 to 31H1 each converting the output (received signal) of the R module into digital data Each analog to digital converter 311 to
A plurality of delay devices 321 to 32 each delay the output data of 31H with delay times set in stages.
A beam scanning calculator 33 that generates initial phase data according to an arbitrary beam orientation direction when H1 transmission < g, and calculates initial weight data according to an arbitrary beam orientation direction when receiving, and this beam scanning calculator 33 when transmitting. The above initial phase data is used to calculate phase data corresponding to a beam pattern that forms a null in the peak direction of other beams, and upon reception, the initial weight is calculated by the beam scanning modulator 33. A null weight calculator 34 uses the data to calculate weight data corresponding to a beam pattern that is null in the peak direction of other beams, and the delay units 321 to 32H are processed through a so-called systolic array circuit. By sequentially cumulatively adding the determined data to the null way 1 using the weight data calculated by the oil compensator 34 to the output data string of The elevation plane circuit boards 501 to 5
0M inputs the calculation result of each beamformer 35 on the azimuth plane circuit boards 301 to 3ON and outputs the result to the delay unit 32.
Similar to 1 to 328, this is a step-by-step set of various fields.
A plurality of delay devices 511 to 5 each delaying the extension time separately.
1N, a beam scanning calculator 52 that calculates initial weight data according to an arbitrary beam pointing direction in the elevation plane, and the above-mentioned initial way! by this beam scanning calculator 52! - A null weight calculator 53 that uses the data to calculate weight data according to a beam pattern that forms a null in the peak direction of other beams, and, like the beam former 35, a so-called system! - By weighting each of the output data strings of the delay units 511 to 51N using the weight data calculated by the null weight sieve 53 through the block array circuit, and sequentially accumulating the weighted data. , and a beam former 54 that forms multiple beams in the elevation plane. The configuration of the beam former 35 or 54 in the azimuth plane circuit boards 301 to 3ON and the elevation plane circuit boards 501 to 50M is related to the beam scanning waveform device 33 or 52 and the null weight calculator 34 or 53. It is illustrated in detail in Figure 3, including the following. However, for convenience, FIG. 3 representatively shows the configuration of the beam former 35 in the azimuth plane circuit boards 301 to 3ON. FIG. 4 shows each arithmetic cell (811 to 5HN) constituting this beamformer 35 (or 54).
The detailed configuration is shown for reference. In FIG. 4, Sa indicates a multiplication sieve (weighting) device, and sb indicates an adder. Further, each subscript 1.0 of this person's output signal indicates the real part and imaginary part of the orthogonal component of the received signal described above for the T/R module (FIG. 2), respectively.

The operation of the antenna device of this embodiment constructed in this manner will be described in detail below.

First, the operation during transmission will be explained.

During transmission, the transmission signal exciter 60 generates, for example, a pulsed transmission signal. The generated transmission signal is input to the elevation plane transmission signal distributor 70, where it is divided into N in the elevation direction and input to each of the azimuth plane transmission signal distributors 401 to 4ON. The azimuth plane transmission signal distributors 401 to 4ON roughly divide the inputted transmission signals into M and divide them into T/
R module 2011~2018.2021~202M
, . . 2ON1 to 2ONH (more precisely, to the phase shifter 21 thereof).

On the other hand, each beam scanning calculator 33 of the azimuth plane circuit boards 301 to 3ON generates a plurality of independent initial phase data according to the direction of each beam for the required number of beams, and null-weights this data. It is output to the arithmetic unit 34. The null weight calculator 34 generates a plurality of phase data such that each beam forms a null near the peak direction of the other beams based on the initial phase data input from the beam scanning calculator 33. . This includes:
For example, the following algorithm is used (co-authored by Meiki and Chiba: "Pattern formation method using only phase Φ", 8 IEICE technical report, p. 85-64 (October 1, 1985).
7th)).

That is, ν times! ! exp of the nth element calculated back
(jDn(θ1.ψ1))] ... (1) It is observed. Note that here, n21 On(1), ψ)=2yr (yn −Si
n θ-sin ψ+ zn-cos θ)/λ where, μ: convergence coefficient, ~: number of elements, M: number of null points yn, zn
: Y, z coordinates θm of the n-th element, φm - toward the m-th null point ○: Set as the amplitude weight of the n-th element.

In this way, the phase data generation operations in the beam scanning calculator 33 and the null weight loss calculator 34 are performed for each beam individually based on the desired directional content of all the beams.
For example, when the desired number of beams is P, the beam scanning calculator 33 and the null weight calculator 34 perform the following steps:
Each phase data corresponding to the platform beam is generated using the procedures shown in FIGS. 5(a) and 5(b), respectively.

Incidentally, in the beam scanning calculator 33, as shown in FIG.
Depending on the input of direction data for each of the q beams,
The initial phase data of the q-th beam is calculated from the beam direction of the q-th (q: arbitrary value, 1≦q≦P), and this calculated q
The operation of outputting the initial phase data of the second beam and the direction data of the other beams to the null weight calculator 34 is repeated P times for each beam, and the other null weight calculator 34 outputs the initial phase data of the second beam and the direction data of the other beams to the null weight calculator 34. As shown in [b], each time the initial phase data of the q-th beam calculated above and the direction data of other beams are given from this beam scanning calculator 33, the , calculate phase data that can form a null in the peak direction of other beams (preferably with a width that covers the main lobe), for example, by repeating the calculation in (1) above, and calculate this calculated phase data. The operation of outputting the signal to each corresponding T/R module is repeated P times for each beam.

Now, each T/R module 2011 to 2018.2021 is supplied with the transmission signal distributed as described above, and the phase data thus generated is sequentially added.
~202H, . After adding a gradient and further amplifying the transmission signal with this phase gradient as required through the high power amplifier 22, it is sent to the M through the circulator 23.
XN array antenna elements 101 arranged in a plane
1~10114.1021~102M,...,1ON
It operates to supply each corresponding element among 1 to 1 ONH. As a result, each of these transmission signals is radiated as a radio wave, and on the curved surface of the antenna device of this embodiment, a beam that lasts for the length of the time-divided transmission signal changes over time, and its directivity direction is changed over time. The beams are formed as multiple beams, each of which is controlled independently. Moreover, all of these beams form a null near the peak direction of the other beams, and there is no interference between them.

Next, the operation of the antenna device of the same embodiment during reception will be explained.

The above MXN array antenna elements "1011 to 101"
8, 1021~102M, -, 10N11~1 ONM
are arranged at equal intervals on a plane, and during reception, the frequency (RF) signals received through each of these antenna elements are sent to T/R modules 2011 to 201M and 2021, respectively.
~202M, . . . , 2081~2ONH are input to corresponding modules. These T/R modules, as shown in FIG.
The F amplifier 24 amplifies the amplified RF low signal local oscillation signal 08C1, and the mixer 25 mixes the amplified RF low signal local oscillation signal 08C1 to convert the same RF signal into an intermediate frequency (IF) signal. After removing unnecessary frequency components from the signal, the received and processed IF multiplied signal mixer 28.2
9 and performs phase detection on the same IF signal mentioned above, and signals representing the orthogonal component 1.0 of these IF multiplied signals are extracted from each of these T/R modules. . In this way, each T/R module 2011~2018.2021~202M,...,2
The 1 and Q component signals taken out from ON1-2ONH are then input to corresponding ones of azimuth plane circuit boards 301-3ON. Each of these azimuth plane circuit boards converts each input signal into an analog-to-digital converter 31.
Digital signal (time series data X1 (n
) ~XH(n) (consisting of (XI, The beamformer 3 is delayed from each other at regular intervals.
5.

As shown in FIG. 3, this beam former 35 is constructed by arranging arithmetic cells 811 to SHN in M rows and N columns. Time series data X1 (n) from 321 to 32M
XH(n> is input sequentially, and from the next stage onwards, the time series data of the previous row is input sequentially. In addition, each calculation cell 811 to SH also receives complex weight data Wll to WMN from the null weight calculator 34. Also enter.

Here, the arithmetic cells Sit to SMN each have a memory function (not shown), and the complex weight data w11 to wHH from the null weight arithmetic unit 35 are temporarily stored and stored. It has become. Also,
Its calculation structure is f! As shown in Figure 54, the time-series 4-column data xin from the previous row is (Xlin, XQin)
, Song Yin from the front row (Ylin, YQin
), and the complex weight data W is (Wl, WQ), then the output data yout = (Yl.

ut, Y Qout) using the following formula.
It is constructed.

YIout=XIin −Wl −XQ+n −
WQ +”yMin... (2) YQout=XIin −WQ +XQin −
Wl +YQin... (3) Note that the above left subscript 1. Q represents the real part and imaginary part, respectively, and the right subscripts in and out represent the input signal and output signal, respectively.

Further, the sampling frequency of the analog-to-digital converters 311-37H and the delay amount of the delay devices 321-32H are set according to the calculation speed of the calculation cells S11-SON, respectively.

On the other hand, each beam scanning operation i3? ! At the time of reception, the i33 generates a plurality of independent initial weight data (complex way 1-data) according to the direction of each beam for the required number of beams, and applies this to a null weight calculator. Output to 34. As a result, the null weight calculator 34 uses the initial weight data input from the beam scanning calculator 33 to calculate a beam pattern that forms a null in the vicinity of the peak direction of each other beam. Generate complex weight data W11 to WHN.

For example, the following algorithm is used (Ohmsha's "Antenna Engineering Handbook" edited by the Institute of Electronics and Communication Engineers, Vol. 2).
(See page 28).

In other words, the complex number of the n-th element measured ν times is
When the weight is set to vJWν, exo(-jkdnsin(0m))... (4) The desired complex weight data is written respectively.
91% required. Here, k=2π/λ where μa: convergence coefficient, N: number of elements, M: number of null points S: Steering vector dn: distance from the origin of the nth element θl: distance of the mth null point direction.

In this way, the operation of generating complex weight data at the time of reception in the beam scanning calculator 33 and the null weight calculator 34 is also repeatedly executed for each beam based on the desired direction contents of all the beams. For example, when the desired number of beams is P, the beam scanning calculator 33 and the null weight calculator 34 perform the operations shown in FIGS. 6(a) i and (b), respectively.
Phase data corresponding to each beam is generated each time using the procedure shown in .

Incidentally, in the beam scanning calculator 33, as shown in FIG. 6(a), P
Depending on the input of direction data for each of the q beams,
Sieve the initial weight data of the q-th beam from the beam direction of the q-th beam (q: arbitrary value, 1≦q≦P), and null the calculated initial weight data of the q-th beam and the direction data of other beams. The operation of outputting the output to the weight calculation unit 34 is repeated P times for each beam, and the other null weight calculation unit 34 outputs the output to the weight calculation unit 34 as shown in FIG. 6 1b). Each time the initial weight data of the q-th beam calculated above and the direction data of other beams are given, the peak direction of the other beam (preferably covering its main lobe) is determined corresponding to the q-th beam. For example, by repeating the operation (4) above, the complex weight data that can form a null for (with a width such as The operation of outputting to the cell is repeated P times for each beam.

Now, as mentioned above, the time-series received digital data XI (n) ~
XH<n) is input, and the complex way l-data W11 to W generated in this way from the null weight disabler 34
The beamformer 35 to which the MN is given weights each of the received digital data with corresponding complex weight data and sequentially accumulates the weighted data based on the above equations (2) and (3). Perform addition. As a result, a plurality of beams whose directivity directions are independently controlled with respect to the azimuth plane, that is, reception multi-beams are formed. Of course, all of these beams also form a null in the vicinity of the Peter direction of the other beams, and there is no interference between them.

On the other hand, the elevation plane circuit boards 501 to 50M contain the output data (beam signals b1(1) to bN(n)) of the same column of the beam former 35 of the azimuth plane circuit boards 301 to 3ON, respectively.
are input to the beamformer 54 after being delayed by delay devices 511 to 51N, respectively. however,
This beam former 54 is connected to the azimuth plane circuit boards 301 to 3O.
Since it has exactly the same configuration as the N beamformer 35 except that the number of rows and columns is reversed, a description of this beamformer 54 will be omitted. Of course, the functions and operations of the beam scanning calculator 52 and the null weight calculator 53 on the circuit boards 501 to 50H are also common to the functions and operations of the beam scanning calculator 33 and the null weight calculator 34 during reception, respectively. .

As a result, multi-beams are formed in any direction in both the azimuth plane and the elevation plane. Moreover, in this case, the direction of directivity of the multi-beams, the mode of removing mutual interference, and the beam patterns such as the side lobes of each beam are initialized and calculated through the beam scanning calculator 33.52 and the null way 1 to calculator 34.53. Controlled arbitrarily by complex way 1-data.

FIGS. 7 and 8 show a comparison between a multibeam formed by a conventional multibeam antenna device and a multibeam formed through the antenna device of the above embodiment, respectively.

For example, if two beams are to be formed for both transmission and reception, the beams (2 multi-beams) formed through the conventional antenna device are shown in Figure 7 fa) and (b).
As shown in , there are sidelobes of transmitting beam 2 and receiving beam 2 in each beam direction of transmitting beam 1 and receiving beam 1, and conversely, sidelobes exist in each beam direction of transmitting beam 2 and receiving beam 2. For transmit beam 1. Side lobes of receive beam 1 are present. Therefore, a two-way beam, that is, a beam obtained by multiplying both the transmitting beam and the receiving beam, has the form shown in FIG. 7fc). If we pay attention to the two-way beam 1 shown in FIG. 7(C), it can be seen that a large side lobe is formed in the direction of the other two-way beam 2. That is, it can be seen that beam 1 interferes with beam 2. The opposite is also true.

On the other hand, the beams (2 multi-beams) formed through the antenna device of the above embodiment are as shown in FIGS. 8(a) and (
As shown in b), both the transmit beam and the receive beam,
A null occurs with respect to the direction of direction of the other beam. Therefore, in this case, the two-way beam also has a null with respect to the pointing direction of the other beam, as shown in FIG. 8(C). This shows that mutual interference between these beams is avoided.

It goes without saying that the above effects of the antenna device of this embodiment can be similarly obtained even when the number of beams is further increased.

As described above, according to the multi-beam antenna device having the above configuration, it is possible to form a transmission multi-beam in any direction by adjusting the phase data using an appropriate algorithm, and also to form a transmission multi-beam in an arbitrary direction by adjusting the complex weight data using an appropriate algorithm. By adjusting, a receiving multi-beam can be formed in any direction in the azimuth plane and the elevation plane, and it is easy to increase the precision by increasing the number of data bits. Moreover, since no interference occurs between beams in both transmission and reception, regardless of the direction of each beam, extremely stable operation is guaranteed.

In addition, in the above embodiment, the configuration is such that both the transmitting beam forming system and the receiving beam forming system have the function of forming a null in the peak direction of each other beam.
Alternatively, even if only the receiving beam forming system is provided with such a function, sufficient effects similar to those described above can be obtained.

Further, in the above embodiment, the antenna device according to the present invention is applied to a planar array, but the antenna device according to the present invention can also be applied to a linear array in which the antenna elements are arranged in a straight line. It can be applied to beam formation in a direction perpendicular to a straight line, and can also be applied to an array on any plane if the antenna elements are arranged in the horizontal and vertical directions. Furthermore, it goes without saying that the beam formation in the elevation plane may be performed before the beam formation in the azimuth plane.

Furthermore, in the above embodiment, each circuit related to beam control is provided separately on the azimuth plane circuit board and the elevation plane circuit board, but if the calculation processing is concentrated in one circuit, the size can be reduced. It can also be submitted to In particular, when performing calculation processing related to generation of the phase data and complex weight data, it is also possible to use a ROM (read only memory) or the like in which each data is made into a table in advance.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to form multi-beams with high gain in any direction and at a high angle of 1i degrees without mutual interference. Moreover, the pattern of each beam can be controlled independently.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the overall configuration of an embodiment of the multi-beam antenna device according to the present invention, and FIG. 2 is a diagram illustrating the T/R module of the embodiment device shown in FIG. Block diagram showing specific configuration, Part 3
4 is a block diagram showing the specific configuration of the beamformer of the device according to the embodiment; FIG. 4 is a block diagram showing the cell configuration of each calculation cell in the beamformer shown in FIG. 3; and FIG. is a flowchart showing an example of the operation at the time of transmission in the beam scanning calculator and the null weight calculator of the embodiment shown in FIG. 1, and FIG.
A flowchart showing an example of the operation at the time of reception in the 7Q calculator and the null weight calculator, FIG. 7 is a miniature diagram showing the multi-beam aspect formed by the conventional multi-beam antenna Half, and FIG. 8 is the same as shown in FIG. 1. Diagram showing the multi-beam aspect formed by the embodiment device shown in FIG.
The figure is a schematic perspective view showing a configuration example of a conventional multi-beam antenna device. 1011~101N, 1021~102N,...
1ON1 to 1ONM...Array antenna element, 201
1~2018.2021~202H,... 2ON1
~2ONM...T/R module, 21...Phase shifter, 22...High power amplifier, 23
...Circulator, 24...RF amplifier, 25.
28°29...Mixer, 26...IF reception processor,
27...90°hybrid, 301~3ON...
Azimuth plane circuit board, 311-31M...Analog-digital converter, 321-328, 511-51N...Delay device, 33.52...Beam scanning calculator, 34.53
... Null weight calculator, 35.54... Beam former, 401-4ON... Azimuth direction transmission signal distributor,
501 to 50M... Elevation plane circuit board, 60... Transmission signal exciter, 70... Elevation direction transmission signal distributor. (X+rn, XoIn) Figure 4 Figure 5 (b) Figure 6 (b)

Claims (2)

[Claims] (1) In a multi-beam antenna device that processes the element signals of each antenna element constituting an array antenna as required to form a multi-beam, complex weight data for beam scanning according to a desired beam pattern is transferred to the element signal. and a first calculation means that generates data corresponding to each of the desired beam patterns, and based on these generated complex weight data, a first calculation means that generates data corresponding to each of the desired beam patterns so as to form a null in the peak direction of each of the other beams. a second calculation means for correcting complex weight data for beam scanning; using the corrected complex weight data, weighting each of the element signals and combining and adding these weighted signals to form a beam signal; A multi-beam antenna device comprising: a beam signal forming means for forming a beam; (2) the multi-beam antenna device includes third calculation means that generates phase data corresponding to an arbitrary pointing direction of each of the multi-beams, corresponding to each of the transmission signals supplied to each of the antenna elements; a fourth calculation means for correcting the phase data corresponding to each arbitrary pointing direction so as to form a null with respect to the peak direction of each other beam, based on the generated phase data; The multi-beam according to claim 1, further comprising: transmission control means for controlling the phase shift of each of the transmission signals using phase data and supplying the phase-shifted transmission signal to each of the corresponding antenna elements. antenna device.