JP4829137B2 - Phased array antenna apparatus and beam forming method thereof - Google Patents

Description

  The present invention relates to a phased array antenna apparatus used in a radar apparatus that captures and tracks a flying object such as an aircraft and a beam forming method thereof.

  Among various radar devices, the search radar device considers the case where the target is a long distance and a small target, and scans the target at a short distance because the target scans the beam at a detectable speed. There is a problem that the speed becomes slow and the detection performance deteriorates. As an improvement method, it is possible to increase the receiving sensitivity even at the same scanning speed by forming a beam wider than the shaped beam used at a long distance. Such a wide beam is generally called a fan beam.

  As a method of forming a fan beam, the aperture area of the antenna may be physically reduced for the purpose of obtaining a directional pattern having a wide beam width. When using a phased array antenna apparatus, it is common to reduce the number of antenna elements operated for transmission and reception to a required number (see, for example, Patent Document 1). Specifically, with respect to the element array arranged in the direction in which the fan beam is to be molded, only the necessary number of antenna elements are fed from the antenna elements that were fed during the long distance search to other antenna elements. The power supply is turned off electrically.

However, in the phased array antenna apparatus, in order to switch between the normal beam and the fan beam, each phase shifter that sets the phase of each antenna element is shifted separately from the bit signal that specifies the phase shift amount. It is also necessary to transmit a bit signal for controlling the ON / OFF operation of the phase shifter. Therefore, for example, when there is a request to perform the search operation of full aperture and half aperture in a time division with one repetition time as the operation mode of the radar device, it is not possible to turn off only the phase shifters that are not used during the half aperture. difficult. For this reason, there is a need for a fan beam shaping method having a beam width equivalent to that of a half-aperture in which the operation of the antenna element is physically turned off while the phase shifter is always turned on.

As described above, in the conventional phased array antenna apparatus, in response to a request for switching between the pencil beam and the fan beam in a short time, the antenna element is physically turned on with the phase shifter always turned on. There is a need for a method of forming a fan beam having a beam width equivalent to a half-opening whose operation is turned off.

The present invention has been made in order to realize the above-described demand. When switching between a pencil beam with a full aperture and a fan beam with a half aperture, the antenna is physically turned on with the phase shifter always turned on. It is an object of the present invention to provide a phased array antenna apparatus capable of forming a fan beam having a beam width equivalent to that of a half-aperture whose element operation is turned off, and a beam forming method thereof.

In order to achieve the above object, a phased array antenna device according to the present invention feeds high-frequency signals to a plurality of antenna elements arranged in a line or a plane at predetermined intervals, and to each of the antenna elements of the plurality of ports. A plurality of phase shifters for providing a phase shift amount specified in the high-frequency signal, and a phase shift amount for each of the plurality of phase shifters are formed in the power feeding means, the power feed lines of the antenna elements of the plurality of ports, respectively. comprising a scanning controller for controlling in response to the scanning of the beam, the scanning controller, first controlling the amount of phase shift of each of the plurality of phase shifters in phase distribution corresponding to the pointing direction of the molded beam and control means, wherein when an instruction to change the beam width in the molding beam, the first control to the antenna elements of the specific port of the plurality of ports in response to the beam width The phase shift by the phase distribution corresponding to the pointing direction of the stage, characterized in that it comprises a second control means for providing a phase shift uncorrelated.

Further, the beam shaping method for the phased array antenna apparatus according to the present invention includes a plurality of port antenna elements arranged in a line or a plane at predetermined intervals, and a power feeding means for feeding a high frequency signal to each of the plurality of port antenna elements. A plurality of phase shifters that are interposed in the feed lines of each of the antenna elements of the plurality of ports and give a phase shift amount specified in the high-frequency signal; and a phase shift amount of each of the plurality of phase shifters used in phased array antenna apparatus comprising a scanning controller for controlling according to the scanning at the scan controller, the molded beam of the plurality of phase shifters each phase in the phase distribution corresponding to the pointing direction of the It controls the amount, if there is an instruction to change the beam width in the molding beams, specific port of the plurality of ports in response to the beam width The phase shift amount of by the phase distribution according the the pointing direction to the antenna elements, characterized in that impart phase shifts uncorrelated.

In other words, half the opening in the present invention, without electrically OFF operation of the phase shifter, as the opening surface of the opening in a state of ON operation of the entire phase shifter, only a portion equivalent to the opening face Can be changed. As an advantage of the present invention, the scanning controller that controls the beam scanning when the search mode by half aperture and the search mode by full aperture are simultaneously performed without switching the power ON for each phase shifter. The aperture area can be switched and the shaped beams having different beam widths can be switched by simply using a control signal that instructs the phase shift amount to the phase shifter .

As described above, according to the present invention, when switching between the pencil beam with the full aperture and the fan beam with the half aperture, the operation of the antenna element is physically turned off while the phase shifter is always on. It is possible to provide a phased array antenna apparatus capable of forming a fan beam having a beam width equivalent to the half aperture and a beam forming method thereof.

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

  FIG. 1 is a block diagram showing a configuration of an embodiment of a phased array antenna apparatus according to the present invention. In FIG. 1, 11 is an antenna element, and 12 is a phase shifter that sets the feeding phase of the antenna element 11. Here, 100 ports # 1 to # 100 are connected to the high-frequency feeding circuit 13. The phase shifter 12 of each port is provided with a control signal for instructing the amount of phase shift from the scanning controller 14 individually. The scanning controller 14 is given mode information for instructing the beam directing direction and full aperture / half aperture from the radar apparatus main body.

A flow of processing set in the scanning controller 14 is shown in FIG. First, when a scanning angle [deg] is given, a phase distribution based on the scanning angle is obtained, and a phase shift amount θ _m (m = 1 to 100) for each phase shifter 12 is set (step S1). Next, it is determined whether the aperture is a full aperture or a half aperture (step S2). If the aperture is a full aperture, the phase shift amount corresponding to the scanning angle obtained in step S1 is determined as the phase shift amount [deg] designated as 100 ports. If it is a half opening, θ _m + φ _n (m, n = 1 to 100) is given to each port as a phase shift amount (step S3). φ _n can be controlled independently of θ _m, and gives a random amount of phase shift to a port that is unnecessary as a half opening.

  In the phased array antenna apparatus having the above configuration, the beam shaping method of the present invention will be described below in comparison with the conventional beam shaping method.

  First, the conventional method will be described with reference to FIGS.

FIG. 3 shows a conventional method of forming a pencil beam with a full aperture in the configuration shown in FIG. In FIG. 3, 100-port antenna elements 11 are linearly arranged, and an arbitrary port element 11 is supplied with a high frequency having an amplitude A _l and a phase shift amount θ _m via a phase shifter 12. In this example, the amplitude is uniformly distributed. At this time, the phase shift amount θ _m is determined from the scanning angle of the beam and is designated to each phase shifter 12 by the bit signal from the scanning controller 14. The amplitude / phase distribution at this time is as shown in FIGS. 4 (a) and 4 (b), respectively.

  Next, a half opening for forming the fan beam will be described. FIG. 5 shows a conventional fan beam shaping method using the half opening in the configuration shown in FIG. The amplitude / phase distribution at this time is as shown in FIGS. 6 (a) and 6 (b), respectively. That is, in the case of a half opening, as shown in FIGS. 6A and 6B, the opening area is halved by turning off the 25 elements at both ends of the array and turning on the central 50 elements. As a result, the beam width of the fan beam (half aperture) is almost doubled as shown in FIG. 7B with respect to the pencil beam (full aperture) shown in FIG.

  However, in this case, it is necessary to transmit a bit signal for controlling the ON / OFF operation of each phase shifter from the scan controller 14 for controlling each phase shifter, in addition to the bit signal for designating the phase shift amount. is there. Therefore, for example, when there is a request to perform the search operation of full aperture and half aperture in a time division with one repetition time as the operation mode of the radar device, it is not possible to turn off only the phase shifters that are not used at the time of half aperture. difficult. For this reason, there is a need for a fan beam shaping method having a beam width equivalent to that of a half-opening in which the operation of the antenna element is physically turned off while the transfer device is always turned on. The present invention fulfills this need.

FIG. 8 shows a method of forming a pencil beam with a full aperture according to the present invention in the configuration shown in FIG. The amplitude / phase distribution at this time is as shown in FIGS. 9 (a) and 9 (b), respectively. The difference from the conventional method is that the phase shift amount set for each phase shifter 12 by the scanning controller 14 is different from the phase shift amount θ _m specified by each phase shifter determined by the beam scanning angle. has a quantity phi _n, sum of theta _m and phi _n are transmitted as phase shift amount to the phase shifter 12. φ _n is a fixed value assigned to each phase shifter , and as shown in FIGS. 8 and 9B, all values are 0 ° in the case of full aperture.

FIG. 10 shows a method of forming a fan beam with a half opening according to the present invention in the configuration shown in FIG. The amplitude / phase distribution at this time is as shown in FIGS. 11 (a) and 11 (b), respectively. In this molding method, as shown in the amplitude distribution of FIGS. 10 and 11 (a), a total of 50 elements at both the left and right ends, which had been turned off by the conventional method, are turned on in the same manner as in the case of full opening. As shown in the phase distribution of FIG. 11B, φ _n (n = 1 to 25, 76 to 100) corresponding to 50 elements on both the left and right sides is independent of θ _m determined by the scanning angle. Random phase shift amounts are assigned in the range of 0 to 360 °. Note that φ _n (n = 26 to 75) is set to 0 ° as in the case of the full opening.

  From the above, in the beam shaping method shown in FIG. 10 and FIG. 11, the phase shift amount given to each of the ports # 1 to # 25 and # 76 to 100 of the antenna element 11 is random. The emitted high frequency acts to cancel each other when they are superimposed in space. Therefore, the beam is substantially shaped in the central 50 elements (antenna element array number: # 26 to # 75), that is, in the case where only the central 50 elements are turned on as described in the conventional method, each 50 This is equivalent to the beam formed by the wavefront formed by the high frequency radiated from the antenna element.

  Next, FIG. 12 and FIG. 13 compare beam patterns of the fan beam according to the present invention and the fan beam according to the conventional method in which only the central 50 elements described above are operated. FIG. 12 shows beam patterns in the full aperture (FIGS. 3 and 4) and the half aperture (FIGS. 5 and 6) according to the conventional method. The fan beam obtained by the present invention needs to be the same as the half-aperture beam shown in FIG. FIG. 13 shows a pattern comparison result between a fan beam having a half aperture obtained by a conventional method and a fan beam obtained by the present invention. As shown in FIG. 13, since the side lobe is incompletely random, the left and right levels are unbalanced with the main lobe in the center, but the main beam can be molded with the same beam width. I understand.

As described above, when the fan beam is molded, the operation of the phase shifter provided in the antenna element unnecessary for wavefront formation is electrically turned off in the conventional method in order to reduce the opening area. In the method of the present invention, while the operation of the phase shifter unnecessary for wavefront formation is turned on, a random phase shift amount is designated for the unnecessary phase shifter. By doing so, the high-frequency waves transmitted and received via an unnecessary phase shifter cancel the power in space, and as a result, is equivalent to the beam pattern obtained by only the central 50 elements, which is the conventional method. Are the same. That is, according to the present invention, the aperture area and the beam width can be manipulated only by controlling the operation to the phase shifter .

In the above embodiment, the case of the linear array phased array antenna apparatus has been described as an example. However, the present invention can be similarly applied to a planar array phased array antenna apparatus. In this case as well, the present invention may be carried out in the same manner as in the linear arrangement for the antenna elements and phase shifters arranged in the beam width direction in which the fan beam is desired to be molded.

  Further, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The block diagram which shows the structure of one Embodiment of the phased array antenna apparatus which concerns on this invention. The flowchart which shows the flow of a process of the scanning controller shown in FIG. The figure which shows the shaping | molding method of the pencil beam by the conventional full opening in the structure shown in FIG. FIG. 4 is a waveform diagram showing amplitude / phase distribution in the molding method shown in FIG. 3. The figure which shows the shaping | molding method of the fan beam by the conventional half opening in the structure shown in FIG. FIG. 6 is a waveform diagram showing amplitude / phase distribution in the molding method shown in FIG. 5. The figure which shows the beam width of the pencil beam by the shaping | molding method shown in FIG. 3, and the beam width of the fan beam by the shaping | molding method shown in FIG. The figure which shows the shaping | molding method of the fan beam by the full opening of this invention in the structure shown in FIG. FIG. 9 is a waveform diagram showing amplitude / phase distribution in the molding method shown in FIG. 8. The figure which shows the shaping | molding method of the fan beam by the half opening of this invention in the structure shown in FIG. FIG. 11 is a waveform diagram showing amplitude / phase distribution in the molding method shown in FIG. 10. The figure which compares and shows the beam pattern in a full opening (FIG. 3, FIG. 4) and a half opening (FIG. 5, FIG. 6) by the conventional method. The figure which shows the pattern comparison result of the fan beam by the half opening obtained by the conventional method, and the fan beam obtained by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Antenna element, 12 ... Phase shifter, 13 ... High frequency electric power feeding circuit, 14 ... Scanning controller.

Claims (12)

A plurality of port antenna elements arranged at predetermined intervals in a line or plane; and
A feeding means for feeding a high-frequency signal to each of the antenna elements of the plurality of ports;
A plurality of phase shifters that are interposed in the feed lines of each of the antenna elements of the plurality of ports and give a phase shift amount specified in the high-frequency signal;
A scanning controller that controls the amount of phase shift of each of the plurality of phase shifters according to the scanning of the shaped beam;
The scanning controller includes a first control unit that controls a phase shift amount of each of the plurality of phase shifters with a phase distribution corresponding to a directing direction of the shaped beam, and an instruction to change a beam width of the shaped beam. If there is a random phase shift that has no correlation with the phase shift amount due to the phase distribution according to the directivity direction of the first control means on the antenna element of the specific port among the plurality of ports according to the beam width. A phased array antenna apparatus comprising: a second control unit that provides a phase amount. Second control means before Symbol scan controller, the specific phased array antenna apparatus according to claim 1, wherein the amount of phase shift to be applied to the antenna elements other than the port, characterized in that a 0 °. 2. The phased array according to claim 1, wherein the scanning controller adds a phase shift amount controlled by the second control unit to a phase shift amount according to the directivity direction of the first control unit. Antenna device. The second control means of the scanning controller, the specific port of the finalization phased array antenna apparatus according to claim 1, wherein the fixing the amount of phase shift to be applied to that port. The second control means of the scanning controller is for the phase shifter connected to the antenna element of the target port in order to reduce the antenna effective aperture area for the purpose of widening the width of the shaped beam. The phased array antenna apparatus according to claim 1 , wherein a phase shift amount based on a phase distribution prepared separately from the scanning is given.   6. The phased array antenna apparatus according to claim 5, wherein the phase distribution prepared separately is a value obtained at random within a range of a phase shift amount of 0 ° to 360 °. A plurality of port antenna elements arranged at predetermined intervals in a line or plane, a power feeding means for feeding a high-frequency signal to each of the plurality of port antenna elements, and a feed line of each of the plurality of port antenna elements, A phased array antenna comprising a plurality of phase shifters for providing a phase shift amount specified for the high-frequency signal, and a scanning controller for controlling the phase shift amounts of the plurality of phase shifters in accordance with scanning of a shaped beam. Used in the device,
When the scanning controller controls the amount of phase shift of each of the plurality of phase shifters with a phase distribution corresponding to the direction of the shaped beam, and when there is an instruction to change the beam width of the shaped beam , phased, characterized in that it gives a random phase shift amount without correlation with phase shift by the phase distribution corresponding to the pointing direction in the antenna device of the specific port of the plurality of ports in response to the beam width Beam forming method for array antenna apparatus. 8. The beam shaping method for a phased array antenna apparatus according to claim 7, wherein an amount of phase shift given to an antenna element other than the specific port is set to 0 ° . 8. The beam forming method for a phased array antenna apparatus according to claim 7, wherein an uncorrelated phase shift amount given to the antenna element of the specific port is added to a phase shift amount corresponding to the directivity direction. 8. The beam shaping method for a phased array antenna apparatus according to claim 7, wherein after the specific port is determined, a phase shift amount given to the port is fixed. For the purpose of widening the width of the shaped beam, the phase shifter connected to the antenna element of the target port in order to reduce the effective antenna aperture area is based on the phase distribution prepared separately from the scanning. 8. The beam shaping method for a phased array antenna apparatus according to claim 7 , wherein a phase shift amount is provided .   12. The beam shaping method for a phased array antenna apparatus according to claim 11, wherein the separately prepared phase distribution is a value obtained by randomly shifting the phase shift amount within a range of 0 ° to 360 °.

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