JPS63166305A - Antenna system - Google Patents

Abstract

PURPOSE:To eliminate any undesired wave in an excellent way by using an element forming a main antenna as an auxiliary antenna in common and using a beam signal formed by using plural optional received signals as an auxiliary beam signal for canceling the undesired wave. CONSTITUTION:A part or all elements of the array antenna 10 forming a main antenna are used in common to set the gain as the auxiliary antenna optionally and the undesired wave is eliminated sufficiently in any case. In converting a signal received by each element of the array antenna into a proper digital signal, the signal for forming the main beam and a signal for forming the auxiliary beam are distributed without incurring the level decrease in the received signal. It is not required to convert the received signal into the digital signal by adopting a Batler matrix circuit as a beam forming means 210 applying analogically Fourier transformation to the signal received by each element of the array antenna 10 and outputting one beam signal forming the main beam and plural beam signals forming the auxiliary beam.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is used in various wireless communication devices and radar devices, and when receiving radio waves, the radio waves are received in the side lobe region of a beam in a desired direction. The present invention relates to an antenna device equipped with a sidelobe canceller that cancels unnecessary waves.

(Prior Art) Generally, a sidelobe canceller (SLC) is an antenna device that cancels unnecessary waves received in a sidelobe region of a main antenna using a response of an auxiliary antenna to the unnecessary waves. An example of such an antenna device is shown in FIG.

In other words, this antenna device, as shown in FIG.
An array antenna 10 comprising antenna elements 11 to 1n forming the main antenna, and a signal received by each element of the array antenna 10 (actually phase-shifted as required via an appropriate phase shifter). Adder 2 that adds and synthesizes signals)
For example, in this case, an auxiliary antenna 31°3 consisting of three elements
2.33, and the signals received by these auxiliary antennas 31, 32 and 33 (actually, signals that have been phase-shifted as required via a phase shifter) are sent to the main beam forming circuit. a correlation processor 40 that calculates the correlation with the main beam signal formed by the main beam signal (achieved by integrating the multiplication value of each auxiliary antenna reception signal (auxiliary beam signal) and the main beam signal); A weighting device 51.52.53 performs weighting on each of the received signals of 31, 32, and 33 in accordance with the corresponding resultant values (correlation values), and adds and synthesizes each of these weighted signals. The circuit further includes an auxiliary beam forming circuit having an adder 60 for forming an auxiliary beam signal for the above-mentioned unnecessary waves. We have realized the cancellation of

(Problem to be solved by the invention) Generally, the auxiliary antenna 31°32.33 as described above
should have a gain equivalent to the side lobe level of the array antenna 1o forming the main antenna, and if the array antenna 10 is a planar array antenna as shown in FIG. Auxiliary antenna 31, 3
2.33, a small antenna is used which is arranged around the antenna as shown in FIG.

In this case, if the array antenna (planar array antenna) 10 forming the main antenna is relatively small or has a low side lobe level, the auxiliary antenna 31°32.33 is Even if the array antenna 10 is small, the gain can cover the sidelobe level of the array antenna 10, so it is possible to remove the unnecessary waves mentioned above. If the antenna has a high sidelobe level, the auxiliary antennas 31, 32, 33 will have insufficient gain, and it will be difficult for these auxiliary antennas to sufficiently remove unnecessary waves.

In order to eliminate these inconveniences, the auxiliary antenna may be made large, but it is not preferable to make these auxiliary antennas large due to restrictions such as the overall size and quality of the antenna.

In view of these circumstances, an object of the present invention is to provide an antenna device that can effectively remove any unnecessary waves with a small-scale configuration without affecting the dimensions and mass of the antenna as a whole. shall be.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, some or all of the elements of the array antenna forming the main antenna are also used as the auxiliary antenna, and each element of the array antenna receives a beam forming means for forming a plurality of beam signals corresponding to each of these signals using any plurality of the signals, and a beam forming means for forming a plurality of beam signals corresponding to each of these signals, and a part or all of the formed beam signal is used to assist in canceling the unnecessary waves. Use it as a beam signal.

(Function) As described above, by using some or all of the elements of the array antenna that forms the main antenna as an auxiliary antenna, the gain of the auxiliary antenna can be set arbitrarily, and in any case Also, the side lobe level of the main antenna can be well covered, and unnecessary waves can be removed sufficiently. Moreover, in this case,
If the signals received by each element of the array antenna are converted into appropriate digital signals, the received signals can be converted into main beam forming signals and auxiliary beam forming signals without causing a drop in the level of the received signals. so that the signal can be well distributed. However, the beam forming means performs analog Fourier transform on the signals received by each element of the array antenna to form one beam signal as the main beam and a plurality of beam signals as the auxiliary beams. If a Butler matrix circuit for output is employed, there is no need to convert the received signal into a digital signal.

(Embodiment) FIG. 1 shows an embodiment of the antenna device according to the present invention.

As shown in the figure, in this embodiment antenna device, an array antenna 10 (11 to 1n) forming the main antenna is used.
) (in this example, elements 12 to 1 (n-1)) are also used as an auxiliary antenna.

Now, in this embodiment device, the reception R110 (111 to
11n) represents each element 11 to 1 of the array antenna 10.
This circuit is a well-known circuit that converts each high frequency signal received by an analog/digital converter (hereinafter referred to as an A/D converter) into an intermediate frequency signal.
) is a well-known circuit that further converts the received signal converted into an intermediate frequency signal into a digital signal of appropriate bits, and a phase shifter (digital phase shifter) 130 (131
13n) are circuits that perform appropriate arithmetic processing on the received signals converted into digital signals to shift the phase as required in order to scan the received beams formed below, and each element of the array antenna 10 The signals received at 11 to 1n are converted into intermediate frequency signals by the receiver 110, further converted into digital signals by the A/D converter 120, and then subjected to the above-mentioned phase shift processing by the phase shifter 130. Among them, the main and auxiliary antenna element 1
Signals corresponding to 2 to 1n are respectively distributed to the main beam forming circuit and the auxiliary beam forming circuit as signals for main and auxiliary beam forming. Incidentally, the distribution is a digital value distribution, and such distribution does not cause any power loss to the received signal.

Now, in the main beam forming circuit, the phase-shifted signals corresponding to the dedicated elements 11 and 1n as the main antennas and these distributed signals are respectively received by amplitude setters 140 (141 to 14n) consisting of digital attenuators or amplifiers. After presetting the initial level of the side rope of the main beam to be formed through the setting device 140, the outputs of these setting devices are added and combined in the digital adder 150 to obtain an antenna output corresponding to the main beam signal. .

On the other hand, the auxiliary beam forming circuit forms a plurality of auxiliary beams having a gain that can cover the side lobe level of the main beam, based on the distributed signals. Furthermore, in forming the auxiliary beam, this auxiliary beam forming circuit forms the beam signal so that it has a null in the peak direction of the main beam, which is the desired wave direction.

That is, the beam forming circuit 210 in the auxiliary beam forming circuit is composed of, for example, a fast Fourier transform (FFT) circuit, and converts orthogonal multi-beams (levels of each beam at the same angle) as shown in FIG. This is a circuit that forms and outputs a beam (SMo) that becomes zero when multiplied by the angle and integrated by the angle. At this time, as the orthogonal multi-beams, a beam that coincides with the direction of the main beam MB shown by the broken line in FIG. 2, that is, a beam SBM shown by the dashed-dotted line in FIG. 2, is also formed at the same time. However, in the beam forming circuit 210, since it is necessary to form an auxiliary beam having a null in the peak direction of the main beam (MB) as described above, the beam signal corresponding to this beam SBH is excluded. If unnecessary waves are removed as described above using the auxiliary beam formed and output as the orthogonal multi-beam SM o, the response of the antenna device in the desired wave direction can be kept constant, and the antenna output can be kept constant. The signal-to-noise ratio (S/N') can also be improved.

Incidentally, in FIG. 2, since the horizontal axis is the sine (sinθ) of the angle, the beam S M
The beam widths of o are all equal, but if the angle θ itself is taken as the horizontal axis, the beam width becomes wider as it moves away from the center.

In this way, the level determination circuit 220
The selection circuit 230 is a circuit that compares the levels of a large number of beam signals corresponding to the orthogonal multi-beam SMo outputted from the beam forming circuit 210 to determine the level. This level determination circuit 22 selects only some (m in this example) beam signals that have a particularly high level with respect to unnecessary waves among the signals.
This is a circuit that selects and outputs based on determination information based on 0.

That is, only the beam signals thus selected are each correlated with the main beam signal and weighted by a correlation processor 240, similar to the apparatus shown in FIG. 4 above, but here digitally. 250 (251~
25m), the required I is determined based on each corresponding correlation value, and then the signals are combined through an adder 260.

In this way, by providing the level determination circuit 220 and the selection circuit 230, the number of auxiliary beams to be actually controlled can be arbitrarily reduced, and the number of auxiliary beams that can be controlled from Even if there are restrictions, it is possible to effectively deal with them by effectively utilizing these functions of the device of this embodiment. Subtractor 1
Similar to the apparatus shown in FIG. 1, cancellation of unnecessary waves is achieved by subtracting the composite signal of these auxiliary beam signals controlled as necessary from the main beam signal through 60.

As described above, according to the antenna device of the embodiment shown in FIG. 1, 1) a minimum antenna configuration can be achieved in which a part of the main antenna is also used as an auxiliary antenna;

2) This also allows the gain of the auxiliary antenna to be maintained sufficiently.

3) Moreover, with such an antenna configuration, even when the main beam forming signal and the auxiliary beam forming signal are distributed, the gain of the signals received by each of these antennas does not decrease.

4) The number of auxiliary beams to be actually controlled can be set arbitrarily, and it is also possible to significantly reduce the number.

You can enjoy many excellent effects such as.

In the above embodiment, a part of the array antenna 10 forming the main antenna (the part of elements 12 to 1 (n-1)) is also used as the auxiliary antenna, but all of this is used as the auxiliary antenna and the front antenna. Of course, you can do it as well. Incidentally, in the above-described apparatus, it is preferable to select adjacent antennas at equal intervals as antennas that serve both purposes.

In addition, if the antenna device is capable of controlling many auxiliary beams due to the device configuration, the level determination circuit 220
Also, the selection circuit 230 may be deleted and the same control 611 (weighting controlled) may be applied to all the auxiliary beam signals formed and output by the beam forming circuit 210.

Incidentally, in the above embodiment, the main beam forming circuit and the auxiliary beam forming circuit are configured separately, and the side lobe level of the main beam before unnecessary wave suppression can be arbitrarily set using an amplitude setting device. However, if the sidelobe level of the main beam can be made the same as the sidelobe level of the auxiliary beam, for example, as shown in FIG. One of the orthogonal multi-beams formed in the circuit 210 that matches the desired direction beam.
Two beams 5BN (beams indicated by dashed-dotted lines in Figure 2)
You can also use this as a weapon beam without eliminating it.

Furthermore, when the configuration shown in FIG. 3 is used, a Butler matrix circuit consisting of an analog circuit is used as the beam forming circuit 210 in place of the FFT\iiQ circuit, and the Fourier transform is performed by the Butler matrix circuit. If so, at least the A/D converter 120
(121 to 12n) are only analog circuits that do not require this, that is, phase shifters 130 (131 to
13n) and subsequent circuits can all be configured with analog specifications to configure the antenna device. Of course, this also makes it possible to use the same element as the main and auxiliary antennas to form the main beam and the auxiliary beam, respectively.
Moreover, since these main and auxiliary beams are collectively formed through the Butler matrix 210), the same main and auxiliary beams
The gain of the signal received by the antenna is not reduced when forming the auxiliary beam.

[Effect of the Invention J As described above, according to the present invention, unnecessary waves can be removed with high efficiency using a small-scale configuration without affecting the dimensions or mass of the antenna as a whole.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the antenna device according to the present invention, FIG. 2 is a diagram showing an example of the beam form formed by the beam forming circuit of the embodiment device, and FIG. A block diagram showing another embodiment of the overall antenna arrangement according to the invention, FIG. 4 is a block diagram showing an example of an antenna device having a conventional sidelobe xenseler function, and FIG. 1 is a schematic diagram showing an example of the overall structure of an antenna of an antenna device. 1 0 (1 1 ~'l n) ... Array antenna, 110 (111 ~ 11n) ... By reception, 120 (
121~12n)...A/D converter, 130(
131-13n)...phase shifter, 140 (141-14
n)...Amplitude setter, 150.260...Additional device,
160... Attenuator, 210... Beam forming circuit, 2
20...Level judgment circuit, 230...Selection circuit, 2
40...Correlation processor, 250 (25'l~25m)
...The one with the width is a container. Procedural auxiliary device March 6, 1988

Claims (5)

[Claims] (1) Unwanted waves received in the sidelobe region of the main beam formed based on the signals received by each element of the array antenna are separately formed by performing the required weighting based on the correlation with the main beam. An antenna device having a sidelobe canceller function that uses a response of an auxiliary beam signal to cancel the unwanted waves, the antenna device having a sidelobe canceller function that uses a response of an auxiliary beam signal to cancel the unnecessary waves, the antenna device having a sidelobe canceller function that cancels the unnecessary waves by using a response of an auxiliary beam signal, a beam forming means for forming a plurality of beam signals according to the signal; and from among the formed beam signals, several beam signals having a particularly strong relation to the unnecessary waves are selected according to the radio wave environment at any time. An antenna device comprising a selection means for selecting the selected beam signal as an auxiliary beam signal for canceling the unnecessary waves. (2) The signals used to form the main beam and the auxiliary beam are digital signals obtained by analog/digital conversion of the signals received by each element of the array antenna, and the beam forming means fast Fourier transform means for forming orthogonal multi-beam signals based on signals, and the selection means receives beam signals other than beam signals that coincide with the direction of the main beam from among the orthogonal multi-beam signals formed. The antenna device according to claim 1, wherein some of the received beam signals having a particularly high level are selectively outputted as auxiliary beam signals for canceling the unnecessary waves. (3) The antenna device according to claim (2), in which one orthogonal multi-beam signal formed by the beam forming circuit and not input to the selection means is used as the main beam signal. (4) The beam forming circuit performs Fourier transform on the signals received by each element of the array antenna, and forms and outputs one beam signal serving as the main beam and a plurality of beam signals serving as the auxiliary beams, respectively. The antenna device according to claim 1, which is a Butler matrix circuit. (5) Unwanted waves received in the sidelobe region of the main beam formed based on the signals received by each element of the array antenna are separately formed by performing necessary weighting based on the correlation with the main beam. An antenna device having a sidelobe canceller function that uses a response of an auxiliary beam signal to cancel the unwanted waves, the antenna device comprising: a receiver that converts signals received by each element of the array antenna into intermediate frequency signals; , an analog/digital converter that converts each of these received signals converted into an intermediate frequency signal into a digital signal, a phase shifter that shifts the phase of each of these received signals converted into a digital signal as required, and a beam forming means for forming a plurality of beam signals according to each of these signals using any plurality of received signals, and using the formed beam signal as an auxiliary beam signal for canceling the unnecessary waves. Antenna device used.