JP2003318630A - Phased array antenna and its circuit, and method for forming beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of phase control circuits provided in a phased array antenna, and to arbitrarily set the radiating direction of the antenna. <P>SOLUTION: In the phased array antenna, a distributing circuit (a) distributes input signals from an input terminal 'in' to M systems, and after the distributed signals are individually controlled for phase by means of phase control circuits b1-bM, in-phase distributing circuits c1-cM in-phase distribute the signals as L groups of signals. Of the L groups of signals distributed by means of the in-phase distributing circuits c1-cM, each one signal being inputted to two-signal compositing circuits e1-eM terminated on one sides, and each two signals from different in-phase distributing circuits c1-cM having phase differences of ≤180° other than the signals inputted to the circuits e1-eM are inputted to (N-M) pieces of two-signal compositing circuit f1-f (N-M) and composited. The routes respectively connecting the in-phase distributing circuits c1-cM to two-signal compositing circuits e1-eM and f1-f (N-M) are made to have the same electrical length and the outputs of the two-signal compositing circuits e1-eM and f1-f (N-M) are fed to radiating elements g1-gN arranged at regular intervals. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phased array antenna mounted on, for example, a communication satellite, and more particularly to a technique contributing to reduction in size and weight and improvement in reliability.

[0002]

2. Description of the Related Art The conventional phased array antennas can be roughly classified into the following three types. (1) All radiating element independent control type FIG. 11 shows a phased array antenna fed by a beam forming circuit of all radiating element independent control type. That is, the input signal supplied to the input terminal in is supplied to the distribution circuit a.
, A-N corresponding to the number of radiating elements, and then the phases of the respective signals are controlled by the phase control circuits b1, b2, b3, b4 ,. b
2, b3, b4, ..., bN output terminals out1, out
2, out3, out4, ... OutN from the radiating element f
1, f2, f3, f4, ..., FN are fed to form a beam. (2) Sub-array independent control type FIG. 12 shows a phased array antenna fed by a sub-array independent control type beam forming circuit. By arranging some of the radiating elements f1, f2, f3, f4, ..., FN, that is, forming a sub-array, the circuit size of the beam forming circuit is reduced. After distributing the input signal supplied to the input terminal in to the sub-array signals a-1, ..., AM, the phase of each signal is controlled by the phase control circuits b1, b2 ,. Circuits c1, c2
..., radiating elements f1 and f that form a sub-array with cM
, FN are fed in the same phase to form a beam. In FIG. 12, two elements form a sub-array. (3) Collective control type using matrix circuit FIG. 13 shows a phased array antenna fed by a collective control type beam forming circuit using a matrix circuit. That is, the input terminals in1, in2, in3, in
The matrix circuit MC having different output phase distributions depending on 4, ..., InN is applied to the beam forming circuit. A typical example is the application of a Butler matrix to a beam forming circuit. By switching the input terminals of the Butler matrix, the irradiation area of the formed beam can be switched.

[0003]

The conventional technique is largely divided into three.
Although classified, the issues for each are shown below. (1) All radiating elements independent control type Since all radiating elements can be fed with arbitrary phases, beam formation with a high degree of freedom can be realized, but as shown in FIG. 11, phase control circuits for the number of radiating elements are required. Become. In particular, when a plurality of beams are formed at the same time, the number of phase control circuits corresponding to (the number of radiating elements × the number of beams) is required, which increases the circuit scale. As the circuit scale increases, the weight, shape, and power consumption of the beam forming circuit increase, and the number of parts increases, so that the reliability decreases. Considering the limited environment of satellites, increasing the circuit scale itself becomes a problem. (2) Sub-array independent control type The sub-array independent control type is one of the methods for solving the problem of the total radiating element independent control type of (1). However, if the number of radiating elements forming the sub-array is increased, the grating lobe There is a problem that it will occur. Grating lobes are a phenomenon that occurs when the spacing between radiating elements increases. In the case of the sub-array independent control type, even if the individual radiating elements are arranged under the condition that no grating lobe is generated, the grouped radiating elements that form the sub-array are fed in the same phase, so each sub-array is opened. This is equivalent to arranging one radiating element having a large aperture with a wide element spacing. Therefore, grating lobes may occur due to the grouping. (3) When the batch control type Butler matrix using the matrix circuit is applied to the beam forming circuit,
Since the phase distribution is limited to the number of input terminals, there is a problem that beam formation with a high degree of freedom cannot be performed and the radiation direction cannot be set arbitrarily.

The present invention has been made in view of the above circumstances, and the number of phase control circuits can be reduced, and beam formation with a higher degree of freedom can be realized without causing a grating lobe. An object of the present invention is to provide a phased array antenna in which the radiation direction can be arbitrarily set, a beam forming circuit therefor, and a beam forming method.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides beam forming for a phased array antenna having first to Nth (N is an integer of 3 or more) radiating elements arranged at equal intervals. In the case of forming one beam in the circuit, the beam forming signal input from the input terminal is distributed to M (M is an integer of 2 or more, N> M) system by the distributing means, and the M distributed by this distributing means. The individual signals are individually phase-controlled by the first to M-th phase control means, and then are distributed in-phase (L is an integer of 2 or more) in-phase by the first to M-th in-phase distribution means, and each in-phase distribution is performed. L distributed by means
One of the output signals is transmitted by the first to Mth transmission means, and the first to Mth transmissions of the output signals distributed by the first to Mth in-phase distribution means are transmitted. Other than the signal to the means, the phase difference is within 180 degrees, and two signals from different in-phase distribution means are input to the respective input terminals of the first to the (N−M) th two-signal combining means and combined. In this way, the paths connecting the first to Mth in-phase distributing means and the transmitting means and the two-signal combining means have the same electric length, and the outputs of the first to Mth transmitting means and the first The output of each of the (N-M) th two-signal combining means
~ Power is supplied to the Nth radiating element.

In the beam forming circuit of the phased array antenna having the above-mentioned configuration, if the phase difference between the two signals to be combined is within 180 degrees, the number of phase control means smaller than the number of radiating elements is enough to reduce the number of adjacent radiating elements. The radiating element can be fed with a phase distribution having an arbitrary phase difference within 90 degrees. In this case, it is necessary to add the distribution control means and the two-signal synthesizing means, but since these are passive circuits, there is almost no power consumption and the deterioration of reliability is slight. On the other hand, the phase control means has variable elements such as FETs and switches, and requires a circuit for controlling them. That is, it consumes electric power and becomes a factor of reducing reliability due to the possibility of failure, so that the effect of reducing the number of phase control means is very large.

Specifically, as compared with the all radiating element independent control type described in the problem (1), since the number of phase control means is reduced, the circuit scale is reduced, the power consumption is reduced, and the reliability is improved. Can be improved. Compared with the sub-array independent control type described in problem (2), it becomes possible to feed all the radiating elements with a phase distribution having a uniform phase difference, so that the grating lobe only requires the condition of the individual radiating element spacing. Will depend on. As a result, it is possible to suppress the generation of grating lobes by appropriately adjusting the spacing between the radiating elements. Compared with the collective control type using the matrix circuit described in the problem (3), since an arbitrary phase difference can be realized, beam formation with a high degree of freedom can be realized, whereby the radiation direction can be arbitrarily set. become able to.

In the beam forming circuit of the phased array antenna having the above structure, when forming X beams, the number of beams X from the first to Xth input terminals (X is 2).
Beam forming signals according to the above integers), and the first to Xth distributing means distributes the beams to M (M is an integer of 2 or more, N> M) systems, respectively, and then the first group to the Xth group. First of the group
-The Mth phase control means controls the phases individually, and among the outputs of the first to Mth phase control means of the first to Xth groups, the output of one phase control means of each group. Are input to the first to Mth beam combining means for beam combining, and the respective beam combining outputs are input to the first to Mth in-phase distributing means.

With this configuration, the first group to the Xth group
The first to Mth phase control means of the group can independently perform phase control for each beam, and multi-beam formation becomes possible.

The first to Mth transmission means have the same characteristics as those of the first to (N-M) th two-signal combination means, and one input terminal is terminated to the two-signal combination means. Using the input signal from the first to Mth in-phase distributing means from the other input terminal of each two-signal combining means and feeding the output to the radiating element.
A configuration using a transmission line having an electrical length equal to the (N-M) th two-signal combining unit, and a configuration using an amplitude control unit having an electrical length equal to each of the first to (N-M) th two-signal combining unit. Can be considered.

By using the two-signal synthesizing means whose one input is terminated, the difference from the signal levels of the first to (N−M) th two-signal synthesizing means can be reduced, so that the phase difference between the two signals can be reduced. The radiation angle at which the maximum value of the maximum gain is obtained can be deviated from the front direction (0 degree). Since the gain variation in beam scanning is determined by the level difference, by shifting the maximum value from the front direction, the radiation angle for obtaining a constant gain can be widened. The same effect can be obtained when a transmission line is used.

Further, when the amplitude control means is used, it is possible to adjust the signal amplitude to the radiating elements, so that the amplitudes of all the radiating elements can be made uniform at an arbitrary phase difference.

Further, if the input stage of the distributing means is provided with the input amplitude control means, it becomes possible to adjust the radiated power of the formed beam by controlling the amplitude of the input signal. It is possible to suppress changes in radiated power.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS.

(First Embodiment) FIG. 1 is a block diagram showing the configuration of a first embodiment of a phased array antenna according to the present invention. The signal input from the input terminal in of the beam forming circuit is M-divided into equal amplitudes by the distribution circuit a, and the signals output from the respective output terminals a1, a2, ... explain)
Are phase-controlled by the phase control circuits b: b1, b2, ..., BM, and then the in-phase distribution circuits c: c1, c2 ,.
At cM, L is distributed in phase and with equal amplitude.

Output terminal c1 of each in-phase distribution circuit c1-cM
-1, ..., c1-L, c2-1, ..., c2-L, ..., c
Among the signals output from M-1, ..., CML (hereinafter, described with the same reference numerals as the output terminals), each one signal is a two-signal combining circuit e: e1, e2 ,. , EM is supplied to one of the input terminals. In these two-signal combining circuits e1 to eM, the other input terminals are terminating resistors r1, r2.
, RM, and outputs the signal supplied to the input terminal as it is.

Further, output signals c1-1 to c1-L, c2-1 to c2-L, ..., CM- of the in-phase distribution circuits c1 to cM.
Of the signals 1 to cM-L, the two signals having a phase difference of 180 degrees or less are the second group of two-signal combining circuits f: f1, f2, ..., F.
(NM) is supplied to each input terminal. Each of these two-signal combining circuits f1 to f (NM) inputs two signals having a phase difference of 180 degrees or less, and outputs the combined signals.

Here, the paths connecting the in-phase distribution circuits c1 to cM and the synthesis circuits e1 to eM and f1 to f (N−M) are set to have the same electrical length.

The output signals of the two-signal combining circuits e1 to eM of the first group are output terminals out1 and out of the beam forming circuit.
3, ..., OutN through the radiating elements g1, g3 ,.
The output signals of the (N−M) second group of two-signal combining circuits f1 to f (N−M) are fed to N, and the output signals out2, out4, ..., Out (N−1) of the beam forming circuit. , G (N-1) are fed to the radiating elements g2, g4, ... The radiating elements g: g1 to gN are evenly arranged on the same line at intervals d.

The processing operation of the above configuration will be described below. However, in order to simplify the description, FIG.
It is assumed that the number of radiating elements is 3 (N = 3) and the distribution circuit a distributes signals in phase.

Now, assuming that the phase of the signal input to the distribution circuit a is θ0 and the output signals a1 and a2 of the distribution circuit a are subjected to phase control of θ1 and θ2 by the phase control circuits b1 and b2, the in-phase distribution circuit is assumed. c1 output signals c1-1, c
1-2 have equal amplitudes, and the phases are θ1 and θ2 relatively to the phase of the input signal. Similarly, the in-phase distribution circuit c
The two output signals c2-1 and c2-2 have the same amplitude and the phases are θ1 and θ2 relatively to the phase of the input signal.

Here, the output signal c1-1 of the in-phase distribution circuit c1 is input to the two-signal combining circuit e1 of the first group, and the output signal c1-1 of the second group is input.
The output signal c1- of the in-phase distribution circuit c1 is added to the signal synthesis circuit f1.
2 and the output signal c2-1 of the in-phase distribution circuit c2 are input, and the output signal c2-2 of the in-phase distribution circuit c2 is input to the first-group two-signal combining circuit e2. In the second-group two-signal combining circuit f1, since two input signals are vector-combined, if the amplitudes of the two signals are equal and the phase difference is within 180 degrees,
The phase of the combined signal is an intermediate value of the phases of the two signals. In-phase distribution circuits c1 and c2 and two-signal synthesis circuits e1, e2 and f1
Since the paths connecting and are of the same electrical length, the phases of the signals combined by the two-signal combining circuits e1 and e2 of the first group are θ1 and θ2, respectively, relative to the input signal, and the second group The phase of the signal combined by the two-signal combining circuit f1 of (1) is relatively (θ1
+ Θ2) / 2. That is, the phased array antenna is excited with a phase distribution of {(θ1 + θ2) / 2} intervals.

If the distribution circuit a is not in-phase distribution,
If there is a difference in the path connecting the phase control circuits b1 to bM and the in-phase distribution circuits c1 to cM, the phase control circuit b1
.About.bM, in addition to desired phase control, phase difference of distribution circuit a and phase control circuits b1 to bM and in-phase distribution circuit c1
By controlling the phase so as to cancel the difference in electrical length between .about.cM, it can be regarded as in-phase distribution. Further, when it is desired to give a phase distribution to the adjacent radiating elements g1 to gN with a phase difference of θ, the phase distribution is given to the adjacent phase control circuits b1 to bM so as to have a phase difference of 2θ. This can be realized by inputting two signals with a phase difference of 2θ to the signal combining circuits f1 to f (M-1).

Although FIG. 1 shows the structure in which the radiating elements are arranged on the same line, the structure when the radiating elements are arranged on the same plane will be described.

First, when the radiating elements are arranged in a square array,
What is arranged on a line may be arranged by arranging it in a plurality of columns at equal intervals. In the case of the triangular array, the configuration becomes complicated. Therefore, in-phase distribution circuit c and two-signal synthesis circuits e and f are shown in FIG.
This will be specifically described by showing an example of connection.

In FIG. 2, a double circle represents a first group of two-signal combining circuit e, a single circle represents a second group of two-signal combining circuit f, and an asterisk represents an in-phase distribution circuit c, Here, for the sake of convenience, the positions of the two-signal synthesizing circuits e and f are shown in correspondence with the positions of the radiating elements (not shown). The radiating element is placed at each vertex when the triangles are continuous, while
The synthesizing circuit e is associated with one apex of adjacent triangles that do not overlap each other, and the synthesizing circuit f is associated with the remaining vertices.

In the arrangement described above, the common mode distribution circuit c
Sets the number of distributions to 7 (L = 7), connects one of the distribution output terminals c-1 to the combination circuit e in correspondence with the two-signal combining circuit e of the first group, and the remaining distribution output terminals c. -2-c-
7 is connected to the six second group of two-signal combining circuits f around the combining circuit e. In this way, by connecting the in-phase distribution circuit c and the two-signal combining circuits e and f, and performing the appropriate phase control with the phase control circuit b, it is possible to feed the radiating element g with a phase distribution with an arbitrary phase difference. Becomes

FIG. 3 shows the maximum gain for the phase difference Δθ (0 ° ≦ Δθ <180 °) of the two signals input to the two-group two-signal combining circuit f in the phased array antenna of this embodiment. The characteristic diagram in which the radiation angle for obtaining the maximum gain is measured and plotted is shown. The calculation in this case was performed assuming an isotropic antenna in which 11 radiating elements are arranged on the line at one wavelength intervals.

From this characteristic diagram, it can be confirmed that the value of the maximum gain changes with respect to the phase difference between the two signals.
In the two-signal synthesizing circuit f, the phase difference Δθ between the two input signals
This is because there is a combined loss (dB) represented by the following equation (1) for (0 ° ≦ Δθ <180 °) and a difference occurs in the excitation amplitude. 20log ₁₀ {cos (Δθ / 2)} [dB]
(1) FIG. 4 shows a characteristic diagram in which the combined loss with respect to the phase difference of the two signals input to the two-signal combining circuit f is measured and plotted. From the characteristics shown in FIG. 3 and FIG. 4, in the case of the phased array antenna of the present embodiment, when the phase difference Δθ of two signals is 120 °, all output terminals have the same amplitude, and the maximum with respect to the phase difference of two signals. It turns out that the value is obtained.

Here, in the phased array antenna of the present embodiment, the number of phase control circuits with respect to the number of radiating elements is as follows when compared with the conventional all radiating element independent control type in the triangular array. That is, the number of radiating elements is 19, 37, 61, 91, 127, 169, 217, 2
71, ..., In the total radiating element independent control type, the same number as the number of elements is 19, 37, 61, 91, 127, 169, 21.
, 271, ... are required, but in the present embodiment, 7, 19, 19, 37, 37, 61, 61, 9 are required.
1, ...

Therefore, in the phased array antenna according to the configuration of this embodiment, the number of phase control circuits required for the number of radiating elements can be significantly reduced as compared with the conventional all radiating element independent control type. As a result, it is possible to reduce the size, weight, power consumption, and reliability by reducing the circuit scale.

Further, as compared with the conventional sub-array independent control type, since all the radiating elements can be fed with a phase distribution having a uniform phase difference, the grating lobe depends only on the condition of individual radiating element intervals. By adjusting the radiating element spacing d, the generation of grating lobes can be suppressed.

Further, in comparison with the conventional collective control type,
Since the phase difference can be controlled so as to be excited by a phase distribution having a continuous phase difference, beam formation with a high degree of freedom can be realized, and thus the radiation direction can be arbitrarily set.

(Second Embodiment) FIG. 5 is a block diagram showing the configuration of the second embodiment of the phased array antenna according to the present invention. In the configuration of the present embodiment, in the phased array antenna of the first embodiment, the M first group two-signal combining circuits e: e1, e2, ..., eM have the same electrical length as the two-signal combining circuit. Transmission line h: h1, h
2, ..., hM. This means that the electrical length of the transmission line h is equal to the electrical length of the two-signal combining circuit f of the second group.

FIG. 6 shows the maximum gain with respect to the phase difference Δθ of the two signals input to the two-group two-signal combining circuit f and the radiation angle for obtaining this maximum gain in the phased array antenna of the second embodiment. Is shown and the characteristic diagram is plotted. Similar to the case of FIG. 3, the calculation in this case was performed assuming an isotropic antenna in which eleven radiating elements were arranged on the line at one wavelength intervals.

As is apparent from FIG. 6, in this embodiment, when the phase difference between the two signals is 90 °, all the output terminals have the same amplitude, and the maximum value is obtained for the phase difference between the two signals. This is because the loss of -3 dB of the two-signal combining circuit e of the first group is eliminated by the replacement with the transmission line h, and the signal level rises. From this, as compared with the phased array antenna of the first embodiment, when beam scanning is performed,
It can be confirmed that the gain fluctuation is small.

(Third Embodiment) FIG. 7 is a block diagram showing the configuration of the third embodiment of the phased array antenna according to the present invention. In the configuration of the present embodiment, in the phased array antenna of the first embodiment, the M first group two-signal combining circuits e: e1, e2, ..., eM have the same electrical length as the two-signal combining circuit. Amplitude control circuit i: i1,
i2, ..., iM. This is
This means that the electric length of the amplitude control circuit i is equal to the electric length of the two-signal combining circuit f of the second group.

FIG. 8 shows the maximum gain with respect to the phase difference Δθ of two signals input to the two-signal two-signal combining circuit f and the radiation angle for obtaining this maximum gain in the phased array antenna of the third embodiment. Is a characteristic diagram obtained by measuring and plotting, respectively. In the figure, A, B, C, and D show the characteristics when the amplitude control circuit i gives a gain of +3, 0, -3, and -6 dB, respectively. There is. The calculation in this case is similar to the case of FIG. 3 and FIG.
This is done assuming an isotropic antenna arrayed at wavelength intervals.

As is apparent from FIG. 8, the amplitude control circuit i
By adjusting the amplitude of the output signal with, it is possible to adjust the maximum value for the phase difference Δθ between the two signals. This is because the amplitudes of all the output terminals can be made uniform with respect to the arbitrary phase difference of 0 ° ≦ Δθ <180 °.
The characteristics C and B of −3 dB and 0 dB in FIG. 8 are the same as the characteristics of the first and second embodiments, respectively.

(Fourth Embodiment) FIG. 9 is a block diagram showing the configuration of a fourth embodiment of a phased array antenna according to the present invention. The configuration of the present embodiment is characterized in that, in the phased array antenna of the first embodiment, an input signal is input to the in-phase distribution circuit c via the amplitude control circuit j having a power control function. In the phased array antenna of the first embodiment, the amplitude of the output terminal out and the sum of the total powers differ depending on the set value of the phase control circuit b, which causes a difference in the radiated power of the entire antenna. According to the configuration of this embodiment, by controlling the power of the input signal by the amplitude control circuit j, it is possible to make the radiated power of the entire antenna uniform regardless of the set value of the phase control circuit b.

In the present embodiment, as in the second embodiment, the two-signal combining circuit e of the first group is replaced with the transmission line h having the same electrical length as that of the circuit, as in the third embodiment. It is also possible to replace the two-signal synthesizing circuit e in (1) with an amplitude control circuit i having the same electric length as that of the circuit, and thereby the same effect as in the second and third embodiments can be obtained.

(Fifth Embodiment) FIG. 10 is a block diagram showing the configuration of a fifth embodiment of a phased array antenna according to the present invention. The configuration of this embodiment is the same as the phased array antenna of the first embodiment, except that the input terminal in, the distribution circuit a, and the M phase control circuits b1 to bM are connected to the beam number X.
Prepare accordingly.

Specifically, the input terminals in1, in2,
,, the input signals supplied to inX are respectively distributed to the distribution circuit a.
, A2, ..., aX, M distribution, and respective M distribution outputs a1-1 to a1-M, a2-1 to a2-M, ..., aX-
1 to aX-M are phase control circuits b1-1 to b1-M, b2
, BX-1 to bX-M perform arbitrary phase control, and then M beam combining circuits k1, k2,
..., supply to kM. That is, each beam combining circuit k1
The input signals from the input terminals in1 to inX are subjected to phase control individually, and the signals are combined and output.

The output signals of the respective beam synthesizing circuits k1 to kM are supplied to the corresponding in-phase distributing circuits c1 to cM and L-distributed with equal amplitude. Thereafter, as in the first embodiment, the second group 2 The signal combining circuits e1 to eM and the second group of two signal combining circuits f1 to f (N−M) appropriately combine, and power is supplied from the output terminals out1 to outN to the radiating elements g1 to gN. With this configuration, the input terminals in1 to in1
It is possible to set the phase distribution for each input signal supplied to inX, and it is possible to support multiple beams.

Also in this embodiment, as in the second embodiment, the first group of two-signal combining circuit e is replaced with the transmission line h having the same electrical length as that of the first embodiment, similarly to the third embodiment. It is also possible to replace the two-signal synthesizing circuit e of the group with an amplitude control circuit i having the same electrical length as the circuit, and to control the power of the input signal by the amplitude control circuit j as in the fourth embodiment. The same effects as those of the second, third, and fourth embodiments can be obtained.

(Other Embodiments) The antenna configuration is generally known to have reversibility, and the same applies to the present invention. That is, although the above embodiment is a configuration in which it is used as a transmitting antenna, it can be used as a receiving antenna by viewing the combination circuit as a distribution circuit, the distribution circuit as a combination circuit, and the input terminal as an output terminal. You can Further, in the first embodiment, the case where the radiating elements are arranged in a square arrangement or a triangular arrangement has been described.
The present invention is not limited to this, and can be similarly implemented if the element array is equidistant. Although not particularly mentioned in the above embodiment, it goes without saying that either analog beam forming or digital beam forming can be performed.

[0047]

As described above, the beam forming circuit of the phased array antenna of the present invention can reduce the number of phase control circuits as compared with the conventional all radiating element independent control type, and the size of the circuit scale can be reduced. It can be expected to reduce weight, power consumption and improve reliability. Compared to the sub-array independent control type, since all the radiating elements can be fed with a phase distribution having a uniform phase difference, the grating lobes can be suppressed by adjusting the radiating element spacing. Further, as compared with the collective control type, since excitation is performed with a phase distribution having a continuous phase difference, it is possible to emit a beam in an arbitrary direction.

Therefore, according to the present invention, the number of phase control circuits can be reduced, and beam formation with a higher degree of freedom can be realized without causing a factor to generate a grating lobe, whereby the radiation direction can be arbitrarily set. It is possible to provide a phased array antenna and its beam forming circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a phased array antenna according to a first exemplary embodiment of the present invention.

FIG. 2 is a wiring diagram showing a connection between a combining circuit and an in-phase distribution circuit when radiating elements are arranged in a triangle in the first embodiment.

FIG. 3 is a characteristic diagram showing a maximum gain and a radiation angle with respect to a phase difference of an input signal in the first embodiment.

FIG. 4 is a characteristic diagram showing a combined loss with respect to a phase difference between two signals input to a combining circuit in the first embodiment.

FIG. 5 is a block diagram showing a configuration of a phased array antenna according to a second exemplary embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a maximum gain and a radiation angle with respect to a phase difference of an input signal in the second embodiment.

FIG. 7 is a block diagram showing a configuration of a phased array antenna according to a third exemplary embodiment of the present invention.

FIG. 8 is a characteristic diagram showing a maximum gain and a radiation angle with respect to a phase difference of an input signal in the third embodiment.

FIG. 9 is a block diagram showing a configuration of a phased array antenna according to a fourth exemplary embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a phased array antenna according to a fifth exemplary embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a conventional phased array antenna of independent control of all radiating elements.

FIG. 12 is a block diagram showing a configuration of a conventional sub-array independent control type phased array antenna.

FIG. 13 is a block diagram showing a configuration of a collective control type phased array antenna using a conventional matrix circuit.

[Explanation of symbols]

in, in1 to inX ... input terminal of beam forming circuit, out1 to outN ... output terminal of beam forming circuit, a, a1 to aX ... distribution circuit, a1 to aM, a1-1 to a1-M, aX-1 to aX -M
Distribution output terminals (signals) of the distribution circuit, r1 to rM ... Termination resistors, b, b1 to bM, b1-1 to b1-M, bX-1 to bX
-M ... Phase control circuit, c, c1 to cM ... In-phase distribution circuit, c1-1 to c1-L, cM-1 to cM-L ... Distribution output terminal (signal) of in-phase distribution circuit, d ... Element interval, e , E1 to eM ... First group two-signal combining circuit, f, f1 to f (NM) ... Second group two-signal combining circuit, g, g1 to gN ... Radiating element, h, h1 to hM ... Transmission Lines, i, i1 to iM, j ... Amplitude control circuit, k, k1 to kM ... Beam combining circuit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoichi Kawakami             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F-term (reference) 5J021 AA05 AA06 CA06 DB03 EA02                       FA06 FA32 GA04 GA05 HA01                       HA07 JA07                 5J070 AD11 AF08 AG07 AK08

Claims (10)

[Claims] 1. The first to Nth (N is 3) arranged at equal intervals.
In the beam forming circuit of the phased array antenna having radiating elements of the above integer), an input terminal for inputting a signal for beam forming by the first to Nth radiating elements, and a signal input from this input terminal for M ( M is an integer greater than or equal to 2, and N> M) distribution means, and first to Mth phase control means for individually controlling the phase of each of the M signals distributed by the distribution means, 1st to Mth in-phase distribution means for distributing L (L is an integer of 2 or more) in-phase to the M signals phase-controlled by the 1st to Mth phase control means, and the 1st to Mth Of the L to M output signals distributed by the in-phase distribution means, each of the first to Mth transmission means is transmitted, and among the output signals distributed by the first to Mth in-phase distribution means, The phase difference is 1 except for the signals to the first to Mth transmission means. It is within 0 degrees, 2 from different phase distributor means
The first to input two signals to each input terminal and synthesize
To (N-M) th two-signal combining means, each of the paths connecting the first to Mth in-phase distributing means, the transmitting means and the two-signal combining means has the same electrical length, The outputs of the first to Mth transmission means and the first to the (N−
The outputs of the two-signal synthesizing means M) are respectively set to the first to Nth outputs.
A beam forming circuit for a phased array antenna, characterized in that power is supplied to the radiating element of. 2. The first to N-th (N is 3) arranged at equal intervals.
In the beam forming circuit of the phased array antenna including radiating elements of the above integer), the number of beams X to be beam-formed by the first to Nth radiating elements.
(X is an integer greater than or equal to 2) The 1st-the Xth input terminal which inputs the signal according to, and the signal input from the said 1st-the Xth input terminal are respectively M (M is an integer greater than or equal to 2, N> M) First distribution to system
-Xth distribution means, the 1st group which controls the distribution output of the 1st-Xth distribution means individually, respectively-the 1st-Mth phase control means of the Xth group, and the 1st group A first to Mth beam combining means for inputting an output of one phase control means of each group among the outputs of the first to Mth phase control means of the Xth group, and beam combining, 1st to Mth in-phase distributing means for distributing the combined outputs of the 1st to Mth beam combining means to L (L is an integer of 2 or more), and L distributed by the 1st to Mth in-phase distributing means. First to Mth transmission means for transmitting one of the respective output signals, and the first to Mth transmissions of the output signals distributed by the first to Mth in-phase distribution means Other than the signal to the means, the phase difference is within 180 degrees, and the two from different in-phase distribution means
The first to input two signals to each input terminal and synthesize
To (N-M) th two-signal combining means, each path connecting the first to Mth in-phase distributing means and the transmitting means and the two-signal combining means has the same electrical length. Outputs of 1st to Mth transmission means and 1st to (N-M) th
The beam forming circuit for a phased array antenna, wherein the output of the two-signal combining means is fed to the first to Nth radiating elements. 3. The first to Mth transmission means have the same characteristics as those of the first to (N−M) th two-signal combination means, and one input terminal terminates the two-signal combination. Means from the other input terminal of each two-signal combining means to the first
A beam forming circuit for a phased array antenna according to claim 1 or 2, wherein a signal from the Mth in-phase distributing means is input and its output is fed to the radiating element. 4. The first to Mth transmission means are transmission lines having electrical lengths equal to those of the first to (N−M) th two-signal combining means, respectively. Alternatively, the beam forming circuit of the phased array antenna according to 2 above. 5. The first to Mth transmission means are amplitude control means having electric lengths equal to those of the first to (N−M) th two-signal combination means, respectively. Alternatively, the beam forming circuit of the phased array antenna according to 2 above. 6. The beam forming circuit for a phased array antenna according to claim 1, further comprising an input amplitude control means for controlling an amplitude of a signal input to the distribution means. 7. A phased array antenna comprising the beam forming circuit according to claim 1. Description: 8. A phased array antenna comprising the beam forming circuit according to claim 1, wherein the first to Mth phase control means perform phase control associated with beam formation and the input terminal. 2. A beam forming method for a phased array antenna, characterized in that phase control is performed so that electric lengths from to the in-phase distributing means become equal to each other. 9. A phased array antenna comprising the beam forming circuit according to claim 5, wherein the amplitude of each of the first to Mth amplitude control means is adjusted so that the signal input to the two signal combining means is adjusted. A beam forming method for a phased array antenna, which is characterized by adjusting a maximum value of a maximum gain with respect to a phase difference. 10. A phased array antenna comprising the beam forming circuit according to claim 6, wherein the input amplitude control means controls the amplitude of an input signal of the distribution means, thereby performing phase control by the phase control means. A beam forming method for a phased array antenna, which is characterized by suppressing changes in radiated power.