JP3813898B2 - Phased array antenna, beam forming circuit thereof and beam forming method - Google Patents

Description

[0001]
BACKGROUND 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 that contributes to reduction in size and weight and improvement in reliability.
[0002]
[Prior art]
Conventional phased array antennas can be roughly classified into the following three types.
(1) All radiation element independent control type
FIG. 11 shows a phased array antenna fed by an all-radiation element independent control type beam forming circuit. That is, after the input signal supplied to the input terminal in is distributed to the signals a-1,..., AN by the number of radiating elements by the distribution circuit a, the phase control circuits b1, b2, b3, b4,. .., BN output terminals out1, out2, out3, out4,..., OutN from the radiation elements f1, f2, f3, f4. ..., fN is fed to form a beam.
(2) Subarray independent control type
FIG. 12 shows a phased array antenna fed by a sub-array independent control type beam forming circuit. Several radiating elements f1, f2, f3, f4,..., FN are grouped, that is, sub-arrayed, thereby reducing the circuit scale of the beam forming circuit. After the input signal supplied to the input terminal “in” is distributed to the subarray signals a−1,..., AM, the phase of the respective signals is controlled by the phase control circuits b1, b2,. The circuits c1, c2,..., CM feed the radiating elements f1 and f2, f3 and f4,. In FIG. 12, a sub-array is constituted by two elements.
(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 matrix circuit MC having different output phase distributions according to the input terminals in1, in2, in3, in4, ..., inN is applied to the beam forming circuit. A typical example is a butler matrix applied to a beam forming circuit. By switching the input terminal of the butler matrix, the irradiation region of the forming beam can be switched.
[0003]
[Problems to be solved by the invention]
The conventional techniques are roughly classified into three categories.
(1) All radiation element independent control type
Since all the radiating elements can be fed with an arbitrary phase, beam forming with a high degree of freedom can be realized, but as many phase control circuits as the number of radiating elements are required as shown in FIG. In particular, when a plurality of beams are formed at the same time, phase control circuits corresponding to (the number of radiating elements × the number of beams) are required, so that the circuit scale becomes large. As the circuit scale increases, the weight, shape, and power consumption of the beam forming circuit increase, and the number of parts increases, so the reliability decreases. Considering the limited environment of satellites, increasing the circuit scale itself becomes a problem.
(2) Subarray independent control type
The subarray independent control type is one of the methods for solving the problem of the all radiating element independent control type of (1). However, when the number of radiating elements constituting the subarray is increased, there is a problem that a grating lobe is generated. A grating lobe is a phenomenon that occurs when the spacing between radiating elements increases. In the case of the subarray independent control type, the grouped radiating elements forming the subarray are fed with the same phase even if the individual radiating element intervals are arranged on the condition that no grating lobe is generated. This is equivalent to disposing one radiating element having a large aperture at a wide element interval. Therefore, grating lobes may occur due to grouping.
(3) Collective control type using matrix circuit
When the Butler matrix is applied to a beam forming circuit, the phase distribution is limited to the number of input terminals, so that there is a problem that a beam with a high degree of freedom cannot be formed and the radiation direction cannot be set arbitrarily.
[0004]
The present invention has been made in view of the above circumstances, and the number of phase control circuits can be reduced, and a beam forming with a higher degree of freedom can be realized without causing a grating lobe, thereby changing the radiation direction. An object of the present invention is to provide a phased array antenna that can be arbitrarily set, a beam forming circuit thereof, and a beam forming method.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention forms one beam in a beam forming circuit of a phased array antenna including first to Nth (N is an integer of 3 or more) radiating elements arranged at equal intervals. In this case, the beam forming signal input from the input terminal is distributed by the distributing means to M (M is an integer of 2 or more, N> M), and the M signals distributed by the distributing means are first to first. After the phase is individually controlled by the M phase control means, L (L is an integer of 2 or more) is distributed in the same phase by the first to Mth in-phase distribution means, and L outputs distributed by each in-phase distribution means Each one of the signals is transmitted by the first to Mth transmission means, and among the output signals distributed by the first to Mth in-phase distribution means, to the first to Mth transmission means Other than the signal, the phase difference is within 180 degrees and the in-phase component is different. Two signals from the first to (N-M) two-signal combining means are input to the respective input terminals for synthesis, and the first to Mth in-phase distribution means, the transmission means, The paths connecting the two-signal combining means have the same electrical length, and the outputs of the first to M-th transmitting means and the outputs of the first to (N−M) -two-signal combining means are the first and second, respectively. Power is supplied to the Nth radiating element.
[0006]
In the beam forming circuit of the phased array antenna configured as described above, if the phase difference between the two signals to be combined is within 180 degrees, the number of phase control means is smaller than the number of radiating elements, and the phase difference between adjacent radiating elements is 90. The radiating element can be fed with a phase distribution having an arbitrary phase difference within a degree. In this case, it is necessary to add a distribution control means and a two-signal combining means. However, 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 also requires a circuit for controlling them. In other words, power is consumed and the reliability is lowered due to the possibility of failure, so that the effect of reducing the number of phase control means is very great.
[0007]
Specifically, when compared with the all-radiation element independent control type described in the problem (1), the number of phase control means is reduced, so that the circuit scale can be reduced, the power consumption can be reduced, and the reliability can be improved. . Compared with the sub-array independent control type described in the problem (2), all the radiating elements can be fed with a phase distribution having a uniform phase difference. Depends on. As a result, it is possible to suppress the occurrence 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), an arbitrary phase difference can be realized, so that it is possible to realize a beam forming with a high degree of freedom, thereby arbitrarily setting the radiation direction. become able to.
[0008]
In the beam forming circuit of the phased array antenna having the above-described configuration, when forming X beams, a beam forming signal corresponding to the number of beams X (X is an integer of 2 or more) from the first to Xth input terminals. Are distributed to the M (M is an integer of 2 or more, N> M) systems by the first to Xth distribution means, respectively, and then the first to Mth phase control means of the first group to the Xth group Respectively, and the outputs of the first to M-th phase control means of the first group to the X-th group are the outputs of the first to M-th phase control means of each group, respectively. The beam is synthesized by inputting to the beam synthesis means, and each beam synthesis output is inputted to the first to Mth in-phase distribution means.
[0009]
With this configuration, it is possible to perform phase control independently for each beam by the first to Mth phase control means of the first group to the Xth group, thereby enabling multi-beam formation.
[0010]
As the first to M-th transmission means, two-signal synthesis means each having characteristics equivalent to those of the first to (N-M) two-signal synthesis means and having one input terminal terminated, A configuration in which a signal from the first to Mth in-phase distribution means is input from the other input terminal of each of the two signal combining means, and the output is fed to the radiating element, the first to (N−M) th respectively. A configuration using a transmission line having the same electrical length as the two-signal combining means, and a configuration using amplitude control means having the same electrical length as the first to (N−M) th two-signal combining means can be considered.
[0011]
By using the two-signal combining means having one input terminated, the difference from the signal level of the first to (N−M) th two-signal combining means can be reduced, so that the maximum gain with respect to the phase difference of the two signals can be reduced. The radiation angle at which the maximum value can be obtained can be shifted from the front direction (0 degree). Since the gain fluctuation in beam scanning is determined by the level difference, the radiation angle for obtaining a constant gain can be widened by shifting the maximum value from the front direction. The same effect can be obtained when a transmission line is used.
[0012]
In addition, when the amplitude control means is used, the signal amplitude to the radiating element can be adjusted, whereby the amplitudes of all the radiating elements can be made uniform at an arbitrary phase difference.
[0013]
Furthermore, if the input amplitude control means is provided in the input stage of the distribution means, it becomes possible to adjust the radiated power of the forming beam by controlling the amplitude of the input signal, and particularly the radiated power associated with the phase control. It becomes possible to suppress the change.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
[0015]
(First embodiment)
FIG. 1 is a block diagram showing a configuration of a first embodiment of a phased array antenna according to the present invention. A signal input from the input terminal in of the beam forming circuit is divided into M with equal amplitude by the distribution circuit a, and signals output from the respective output terminals a1, a2,. Are phase-controlled by the phase control circuits b: b1, b2,..., BM, and then L-distributed in the same phase and with the same amplitude by the in-phase distribution circuits c: c1, c2,.
[0016]
Signals output from the output terminals c1-1,..., C1-L, c2-1,..., C2-L,. Each signal is supplied to one input terminal of a first group of two-signal synthesis circuits e: e1, e2,..., EM. In these two-signal synthesis circuits e1 to eM, the other input terminals are terminated by termination resistors r1, r2,..., RM, and the signals supplied to the input terminals are output as they are.
[0017]
Among the output signals c1-1 to c1-L, c2-1 to c2-L,..., CM-1 to cM-L of the in-phase distribution circuits c1 to cM, two signals having a phase difference within 180 degrees are , F (N−M) are supplied to the input terminals of the second group of two-signal synthesis circuits f: f1, f2,. These two-signal combining circuits f1 to f (N−M) input and output two signals each having a phase difference of 180 degrees or less.
[0018]
Here, 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.
[0019]
The output signals of the first group of two-signal combining circuits e1 to eM are fed to the radiating elements g1, g3,..., GN via the output terminals out1, out3,. The output signals of the second group of two-signal combining circuits f1 to f (N−M) are radiated elements g2, g4,... Via the output terminals out2, out4,. , G (N-1). The radiating elements g: g1 to gN are evenly arranged on the same line at intervals d.
[0020]
The processing operation of the above configuration will be described below. However, in order to simplify the description here, it is assumed that the number of radiating elements in FIG. 1 is 3 (N = 3) and the distribution circuit a performs signal distribution in the same phase.
[0021]
If 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 output of the in-phase distribution circuit c1 The signals c1-1 and c1-2 have the same amplitude, and the phase is θ1 and θ2 relative to the phase of the input signal. Similarly, the output signals c2-1 and c2-2 of the in-phase distribution circuit c2 have the same amplitude and the phases are θ1 and θ2 relative to the phase of the input signal.
[0022]
Here, the output signal c1-1 of the in-phase distribution circuit c1 is input to the first group of two-signal combining circuits e1, and the output signal c1-2 of the in-phase distribution circuit c1 and the in-phase distribution circuit are input to the second group of two-signal combining circuits f1. The output signal c2-1 of c2 is input, and the output signal c2-2 of the in-phase distribution circuit c2 is input to the first group of two-signal synthesis circuits e2. In the second group of two-signal synthesis circuits f1, since the two input signals are vector-synthesized, if the amplitudes of the two signals are equal and the phase difference is within 180 degrees, the phase of the synthesis signal is the phase of the two signals. The intermediate value of Since the paths connecting the in-phase distribution circuits c1, c2 and the two-signal combining circuits e1, e2, f1 have the same electrical length, the phases of the signals combined by the first group of two-signal combining circuits e1, e2 are respectively The phase of the signal synthesized by the second signal synthesizing circuit f1 is relatively (θ1 + θ2) / 2 relative to the phase of the input signal. That is, the phased array antenna is excited with a phase distribution of {(θ1 + θ2) / 2} intervals.
[0023]
When the distribution circuit a is not in-phase distribution or when 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 circuits b1 to bM can perform desired phase control. In addition, the phase difference of the distribution circuit a and the phase control so as to cancel the electrical length difference between the phase control circuits b1 to bM and the in-phase distribution circuits c1 to cM can be regarded as in-phase distribution. When it is desired to give the phase distribution with the phase difference of θ to the adjacent radiating elements g1 to gN, the phase distribution is given to the adjacent phase control circuits b1 to bM so as to have the phase difference of 2θ. This can be realized by inputting two signals having a phase difference of 2θ to the signal synthesis circuits f1 to f (M−1).
[0024]
FIG. 1 shows a configuration when the radiating elements are arranged on the same line, but the configuration when the radiating elements are arranged on the same plane will be described.
[0025]
First, when the radiating elements are arranged in a square array, the elements arranged on the line may be arranged in a plurality of rows at equal intervals. In the case of a triangular array, the configuration becomes complicated. Therefore, FIG. 2 shows an example of connection between the in-phase distribution circuit c and the two-signal synthesis circuits e and f, and will be specifically described.
[0026]
In FIG. 2, a double circle represents a first group of two-signal synthesis circuits e, a single circle represents a second group of two-signal synthesis circuits f, and an asterisk represents an in-phase distribution circuit c. Specifically, the positions of the two-signal synthesis circuits e and f are shown in correspondence with the arrangement positions of the radiation elements (not shown). The radiating element is arranged at each vertex when the triangles are continuous, whereas the synthesis circuit e is made to correspond to one vertex that does not overlap each other in the adjacent triangle, and the synthesis circuit f is made to correspond to the remaining vertex.
[0027]
In the above arrangement, the in-phase distribution circuit c has a distribution number of 7 (L = 7) and corresponds to the first group of two-signal synthesis circuits e, and any of the distribution output terminals c-1 is connected to the synthesis circuit e. And the remaining distribution output terminals c-2 to c-7 are connected to six second-group two-signal synthesis circuits f around the synthesis circuit e. By connecting the in-phase distribution circuit c and the two-signal synthesis circuits e and f in this way and performing appropriate phase control with the phase control circuit b, it is possible to feed the radiating element g with a phase distribution of an arbitrary phase difference. It becomes.
[0028]
FIG. 3 shows the maximum gain with respect to the phase difference Δθ (0 ° ≦ Δθ <180 °) of the two signals input to the second group of two-signal combining circuits f and the maximum gain of the phased array antenna of this embodiment. The characteristic figure which measured and plotted each radiation angle for obtaining is shown. The calculation in this case was performed assuming an isotropic antenna in which 11 radiating elements are arranged on the line at intervals of one wavelength.
[0029]
From this characteristic diagram, it can be confirmed that the value of the maximum gain changes with respect to the phase difference of the two signals. This is because the phase difference Δθ (0 ° ≦ Δθ < This is because there is a composite loss (dB) represented by the following equation (1) with respect to (180 °), and a difference occurs in the excitation amplitude.
20log _Ten {Cos (Δθ / 2)} [dB] (1)
FIG. 4 shows a characteristic diagram plotted by measuring the combined loss with respect to the phase difference between the two signals input to the two-signal combining circuit f. From the characteristics shown in FIGS. 3 and 4, in the case of the phased array antenna of the present embodiment, when the phase difference Δθ between the two signals is 120 °, all the output terminals have the same amplitude, and the maximum with respect to the phase difference between the two signals. It can be seen that the value is obtained.
[0030]
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 a conventional all-radiating element independent control type in a triangular arrangement. That is, the number of radiating elements 19, 37, 61, 91, 127, 169, 217, 271, 271,..., 19, 37, 61, 91, 127, 169, 217 is the same as the number of elements in the all radiating element independent control type. , 271,... Are required, but in the present embodiment, 7, 19, 19, 37, 37, 61, 61, 91,.
[0031]
Therefore, the phased array antenna according to the configuration of the present embodiment can significantly reduce the number of phase control circuits required for the number of radiating elements when compared with the conventional all radiating element independent control type. A reduction in size, weight, power consumption, and improvement in reliability can be realized by reducing the circuit scale.
[0032]
Also, compared to the conventional subarray independent control type, all the radiating elements can be fed with a phase distribution having a uniform phase difference, so that the grating lobe depends only on the conditions of the individual radiating element spacing. Thus, the generation of grating lobes can be suppressed by adjusting the radiation element interval d.
[0033]
Furthermore, compared to the conventional batch control type, the phase difference can be controlled so as to be excited with a phase distribution having a continuous phase difference, so that it is possible to realize a beam forming with a high degree of freedom, and thereby the radiation direction. Can be set arbitrarily.
[0034]
(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 phased array antenna of the first embodiment, the configuration of this embodiment has M first group two-signal synthesis circuits e: e1, e2,..., EM having the same electrical length as that of the two-signal synthesis circuit. Transmission lines h: h1, h2,..., HM. This means that the electrical length of the transmission line h is equal to the electrical length of the second group of two-signal combining circuits f.
[0035]
FIG. 6 shows the maximum gain with respect to the phase difference Δθ of the two signals input to the second group of two-signal combining circuit f and the radiation angle for obtaining this maximum gain for the phased array antenna of the second embodiment. The characteristic diagram 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 intervals of one wavelength, as in the case of FIG.
[0036]
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 with respect to the phase difference between the two signals. This is because the loss of −3 dB of the first group of two-signal synthesis circuits e is eliminated by the replacement with the transmission line h, and the signal level is increased. From this, it can be confirmed that the gain fluctuation is small when beam scanning is performed as compared with the phased array antenna of the first embodiment.
[0037]
(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 phased array antenna of the first embodiment, the configuration of this embodiment has M first group two-signal synthesis circuits e: e1, e2,..., EM having the same electrical length as that of the two-signal synthesis circuit. The amplitude control circuit i is replaced with i1, i2,..., IM. This means that the electrical length of the amplitude control circuit i is equal to the electrical length of the second group of two-signal synthesis circuits f.
[0038]
FIG. 8 shows the measurement of the maximum gain for the phase difference Δθ of the two signals input to the second group of two-signal combining circuits f and the radiation angle for obtaining the maximum gain for the phased array antenna of the third embodiment. In the figure, A, B, C, and D indicate characteristics when gains of +3, 0, −3, and −6 dB are given by the amplitude control circuit i, respectively. The calculation in this case was performed assuming an isotropic antenna in which 11 radiating elements are arranged on the line at intervals of one wavelength, as in the case of FIGS.
[0039]
As apparent from FIG. 8, the maximum value for the phase difference Δθ between the two signals can be adjusted by adjusting the amplitude of the output signal by the amplitude control circuit i. This is because the amplitudes of all the output terminals can be made uniform for an 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 those of the first and second embodiments, respectively.
[0040]
(Fourth embodiment)
FIG. 9 is a block diagram showing the configuration of the fourth embodiment of the phased array antenna according to the present invention. The configuration of this 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 through an amplitude control circuit j having a power control function. In the phased array antenna of the first embodiment, a difference occurs in the amplitude of the output terminal out and the total power sum depending on the set value of the phase control circuit b, and a difference occurs in the radiated power of the entire antenna. According to the configuration of the present embodiment, by controlling the power of the input signal by the amplitude control circuit j, it is possible to equalize the radiated power of the entire antenna regardless of the set value of the phase control circuit b.
[0041]
In this embodiment, as in the second embodiment, the first group of two-signal combining circuits e is replaced with a transmission line h having the same electrical length as the circuit, and the first group of two signals as in the third embodiment. It is also possible to replace the synthesis circuit e with an amplitude control circuit i having the same electrical length as that of the circuit, thereby obtaining the same effects as those of the second and third embodiments.
[0042]
(Fifth embodiment)
FIG. 10 is a block diagram showing the configuration of the fifth embodiment of the phased array antenna according to the present invention. The configuration of this embodiment includes an input terminal in, a distribution circuit a, and M phase control circuits b1 to bM according to the number of beams X in the phased array antenna of the first embodiment.
[0043]
Specifically, input signals supplied to the input terminals in1, in2,..., InX are divided into M by distribution circuits a1, a2,..., AX, respectively, and the respective M distribution outputs a1-1 to a1-M, a2 are distributed. -1 to a2-M, ..., aX-1 to aX-M can be arbitrarily controlled by phase control circuits b1-1 to b1-M, b2-1 to b2-M, ..., bX-1 to bX-M. Are supplied to M beam combining circuits k1, k2,..., KM. That is, each of the beam combining circuits k1 to kM inputs, synthesizes and outputs signals obtained by individually performing phase control on the input signals from the input terminals in1 to inX.
[0044]
The output signals of the beam combining circuits k1 to kM are respectively supplied to the corresponding in-phase distribution circuits c1 to cM and distributed to L with equal amplitude. Thereafter, as in the first embodiment, the first group of two signal combining circuits e1 to eM and the second group of two-signal synthesis circuits f1 to f (N−M) are appropriately combined and supplied to the radiating elements g1 to gN from the output terminals out1 to outN. With this configuration, it is possible to set the phase distribution for each input signal supplied to the input terminals in1 to inX, and it is possible to deal with multi-beams.
[0045]
In the present embodiment, the first group of two-signal combining circuits e is replaced with a transmission line h having the same electrical length as that of the circuit as in the second embodiment. It is also possible to replace the signal synthesis circuit e with the amplitude control circuit i having the same electrical length as that circuit, or to control the power of the input signal with the amplitude control circuit j in the same manner as in the fourth embodiment. Effects similar to those of the embodiment, the third embodiment, and the fourth embodiment are obtained.
[0046]
(Other embodiments)
The antenna configuration is generally known to have reversibility, and the same applies to the present invention. That is, the above embodiment is a configuration when used as a transmitting antenna, but it can be used as a receiving antenna by viewing the combining circuit as a distributing circuit, the distributing circuit as a combining circuit, and the input terminal as an output terminal. Can do. Further, in the first embodiment, the case of the square arrangement and the triangular arrangement has been described as the arrangement method of the radiating elements. However, the present invention is not limited to this, and is similarly implemented if the element arrangements are equally spaced. Is possible. Further, although not specifically mentioned in the above embodiment, it goes without saying that either analog beam forming or digital beam forming can be performed.
[0047]
【The invention's effect】
As described above, the beam forming circuit of the phased array antenna of the present invention can reduce the number of phase control circuits when compared with the conventional all-radiation element independent control type, and the size, weight, and power consumption due to circuit scale reduction. Reduction and improvement in reliability can be expected. 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, excitation is performed with a phase distribution having a continuous phase difference, so that it is possible to emit a beam in an arbitrary direction.
[0048]
Therefore, according to the present invention, the number of phase control circuits can be reduced, and a beam forming with a higher degree of freedom can be realized without causing the generation of grating lobes. An antenna and its beam forming circuit can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a phased array antenna according to a first embodiment of the present invention.
FIG. 2 is a wiring diagram showing connections between a synthesis 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 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 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 embodiment of the present invention.
FIG. 10 is a block diagram showing a configuration of a phased array antenna according to a fifth embodiment of the present invention.
FIG. 11 is a block diagram showing a configuration of a conventional all-radiating element independent control type phased array antenna.
FIG. 12 is a block diagram showing a configuration of a conventional subarray 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 terminals of the beam forming circuit,
out1 to outN: output terminals of the 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 resistance,
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 terminals (signals) of the in-phase distribution circuit,
d: Element spacing,
e, e1 to eM, a first group of two-signal synthesis circuits;
f, f1 to f (N−M)...
g, g1 to gN: radiation element,
h, h1 to hM: transmission line,
i, i1 to iM, j... amplitude control circuit,
k, k1 to kM... beam combining circuit.

Claims (10)

In a beam forming circuit of a phased array antenna comprising first to Nth (N is an integer of 3 or more) radiating elements arranged at equal intervals,
An input terminal for inputting a signal for beam formation by the first to Nth radiating elements;
Distributing means for distributing the signal input from the input terminal to M (M is an integer of 2 or more, N> M) system with equal amplitude ;
First to M-th phase control means for individually controlling the phases of the M signals distributed by the distribution means;
First to M-th in-phase distribution means for distributing M signals phase-controlled by the first to M-th phase control means in the same phase and L in equal amplitude (L is an integer of 2 or more);
First to M-th transmission means for transmitting each one of L output signals distributed by the first to M-th in-phase distribution means;
Of the output signals distributed by the first to M-th in-phase distribution means, two signals from the adjacent in- phase distribution means other than the signals to the first to M-th transmission means are input terminals respectively. Comprising first to (N-M) two-signal combining means for input to and combining,
The transmission means and the two-signal combining means are alternately arranged in the arrangement direction of the radiating elements in correspondence with the arrangement of the radiating elements, and the first to Mth in-phase distribution means, the transmitting means, and the two-signal combining The paths connecting the means are set to have the same electrical length, and the outputs of the first to M-th transmission means and the outputs of the first to (N-M) two-signal combining means correspond to the respective arrangements . Power is supplied to the 1st to Nth radiating elements ,
By providing a phase distribution so that the phase difference of the outputs of the phase control means adjacent to the first to Mth phase control means is 2θ within 180 degrees, the first to (N−M) th (N−M) Two signals having a phase difference of 2θ are input to each of the two signal combining means, and a phase distribution is given so that the phase difference of the inputs of the radiating elements adjacent to the first to Nth radiating elements is θ. A beam forming circuit for a phased array antenna. In a beam forming circuit of a phased array antenna comprising first to Nth (N is an integer of 3 or more) radiating elements arranged at equal intervals,
First to Xth input terminals for inputting signals according to the number of beams X (X is an integer of 2 or more) formed by the first to Nth radiating elements;
First to Xth distribution means for distributing signals input from the first to Xth input terminals to M (M is an integer of 2 or more, N> M) systems with equal amplitudes ;
A first group to an Xth group of first to Mth phase control means for individually controlling the phase of the distribution outputs of the first to Xth distribution means;
Of the outputs of the first to M-th phase control means of the first group to the X-th group, the first to M-th beam synthesis means for performing beam synthesis by inputting the output of one phase control means of each group. When,
First to M-th in-phase distribution means for distributing the combined outputs of the first to M-th beam combining means in the same phase and in equal amplitude L (L is an integer of 2 or more);
First to M-th transmission means for transmitting each one of L output signals distributed by the first to M-th in-phase distribution means;
Of the output signals distributed by the first to M-th in-phase distribution means, two signals from the adjacent in- phase distribution means other than the signals to the first to M-th transmission means are input terminals respectively. Comprising first to (N-M) two-signal combining means for input to and combining,
The transmission means and the two-signal combining means are alternately arranged in the arrangement direction of the radiating elements in correspondence with the arrangement of the radiating elements, and the first to Mth in-phase distribution means, the transmitting means, and the two-signal combining The paths connecting the means are set to have the same electrical length, and the outputs of the first to M-th transmission means and the outputs of the first to (N-M) two-signal combining means correspond to the respective arrangements . Power is supplied to the 1st to Nth radiating elements ,
By giving a phase distribution to the first to Mth phase control means of the first group to the Xth group so that the phase difference of the outputs of the phase control means adjacent to each group is 2θ which is within 180 degrees. , Two signals having a phase difference of 2θ are input to each of the first to (N−M) two-signal combining means, and the input phase difference of the radiating elements adjacent to the first to Nth radiating elements is A beam forming circuit for a phased array antenna, characterized in that a phase distribution is given so as to be θ .   Each of the first to M-th transmission means is a two-signal synthesis means having characteristics equivalent to those of the first to (N-M) two-signal synthesis means and having one input terminal terminated, 3. The signal from the first to Mth in-phase distribution means is input from the other input terminal of the two-signal combining means, and the output is fed to the radiating element. Beam forming circuit for phased array antenna.   3. The phased circuit according to claim 1, wherein each of the first to M-th transmission means is a transmission line having an electric length equal to that of each of the first to (N−M) -th two-signal combining means. Array antenna beam forming circuit.   3. The phased circuit according to claim 1, wherein the first to M-th transmission means are amplitude control means each having an electrical length equal to that of the first to (N−M) -th two-signal combining means. Array antenna beam forming circuit.   3. The beam forming circuit for a phased array antenna according to claim 1, further comprising input amplitude control means for controlling the amplitude of a signal input to the distribution means.   A phased array antenna comprising the beam forming circuit according to claim 1. It is used for a phased array antenna comprising the beam forming circuit according to claim 1,
A phased array antenna characterized in that the first to Mth phase control means perform phase control so as to make the electrical length from the input terminal to the in-phase distribution means equal to each other along with phase control accompanying beam formation. Beam forming method. A phased array antenna comprising the beam forming circuit according to claim 5,
The beam forming of the phased array antenna, wherein the maximum value of the maximum gain with respect to the phase difference of the signals input to the two-signal combining means is adjusted by adjusting the amplitude of the first to Mth amplitude control means Method. A phased array antenna comprising the beam forming circuit according to claim 6,
A method of forming a beam for a phased array antenna, wherein the input amplitude control means controls the amplitude of an input signal of the distribution means to suppress a change in radiated power accompanying phase control by the phase control means.

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