JP4877155B2 - Antenna device and horizontal plane pattern switching method - Google Patents

Description

  The present invention relates to an antenna device having a reflecting mirror that mechanically rotates the outer periphery of a primary radiator and a method of switching a horizontal plane pattern thereof.

  As a related art of the present invention, the inventor of the present invention has already proposed a reflector-type antenna device in which a primary radiator is fixed, a movable contact is eliminated, and a rotating reflecting mirror is disposed around it (Japanese Patent Application). 2006-073281). The outline of this antenna apparatus will be described below.

  FIG. 8 is a diagram showing an external appearance of the reflector type antenna device of the related art, and FIG. 9 is a diagram showing a configuration of a primary radiator and a feeding system. The antenna device includes a reflecting mirror 11, a primary radiator 12, and a rotation driving device 13. The rotation driving device 13 has a rotating plate 13b that rotates on a horizontal plane on a fixed platen 13a, and is mounted on the rotating plate 13b. Is rotated around the primary radiator 12 fixed to the fixed platen 13a. Further, the primary radiator 12 is configured by arranging a plurality of radiating elements 123 arranged at equal intervals on the circumference around the support column 122 in a plurality of stages in the vertical direction, and is accommodated in the cover 121.

  In this antenna device, three reflecting mirrors 11 having an offset parabolic curved surface are arranged at intervals of 120 ° on the outer periphery with the primary radiator 12 as the center. Further, the primary radiator 12 includes three switches (SW) 124 corresponding to the three reflecting mirrors 11 at a 120 ° angular interval in each of the plurality of radiating elements 123 arranged in a cylindrical shape. The connection with a plurality of radiation elements can be switched in synchronization with the rotation of the mirror, and the radiation elements near the focal point of the three reflecting mirrors 11 are always selected. The feeding of RF signals to the plurality of radiating elements 123 is performed from a transmission / reception module or the like (not shown), and the plurality of radiating elements 123 in the vertical direction constitute a phased array that can scan the beam in the elevation direction by phase control by the phase shifter 125, The beam for the transmission / reception signal of the primary radiator 12 can be rotated on a horizontal plane, and the beam can be scanned in the elevation direction.

  Although the related art shown in FIGS. 8 and 9 includes three reflecting mirrors and switches, the operation of forming a rotating beam or the like can be explained by a combination of a single reflecting mirror and a switch.

  FIG. 10 is a diagram showing the relationship between the rotation of the single reflecting mirror 11 and the switching timing of the primary radiator 12 in the related art. The switching of the radiating elements 123 forming the beam 14 of the related art forms a phased array in the vertical (vertical) direction when the focal position of the rotating reflector reaches an intermediate position between the adjacent radiating elements No1 and No2. A method is adopted in which all the radiating elements No1 in a row are simultaneously switched to the next adjacent radiating element No2 by a switch.

  As described above, the antenna device in which the primary radiator is fixed and the reflecting mirror is rotated around the primary radiator is a system in which the excitation element array of the primary radiator is switched by a switch in synchronization with the rotation of the reflecting mirror. This eliminates the need for an electrically movable contact to connect to the radiating element, eliminates slip rings or rotary joints, etc., and has the significant advantages of being reliable and inexpensive, and is suitable for radar antenna devices, etc. ing.

  However, in this antenna device, the reflecting mirror continuously rotates, whereas the plurality of radiating elements constituting the vertical phased array are switched to a plurality of adjacent radiating elements by switches at intermediate positions between the radiating elements. Since switching is performed at the same time, a periodic shift (referred to as “focus shift”) occurs between the continuous displacement of the focal point of the reflecting mirror and the center of the phase of the horizontal plane pattern formed by the plurality of vertical radiating elements. As a result, there is a problem that an azimuth error occurs and the azimuth accuracy deteriorates.

(the purpose)
An object of the present invention is to solve the above-described problems, and to provide an antenna device and a horizontal plane pattern switching method with improved azimuth error.

  An antenna device according to a first aspect of the present invention is an antenna device having a primary radiator in which a plurality of radiating elements arranged in a circle are stacked in multiple stages, and a reflecting mirror that mechanically rotates the outer periphery of the primary radiator. A beam synchronized with the rotation of the reflecting mirror is formed by making a difference in time for sequentially switching the horizontal plane pattern of the primary radiator of each stage.

  According to a second aspect of the present invention, there is provided a horizontal plane pattern switching method in which the primary radiator of the antenna device that mechanically rotates the reflecting mirror around the outer periphery of the primary radiator in which a plurality of radiating elements arranged in a circle are stacked in multiple stages. The horizontal plane pattern switching method is characterized in that a beam synchronized with the rotation of the reflecting mirror is formed by providing a difference in time for sequentially switching the horizontal plane pattern of the primary radiator of each stage by a switch.

  According to the present invention, the time for sequentially switching the horizontal plane pattern of the primary radiator of each stage is configured to make a difference at each stage, a beam synchronized with the rotation of the reflecting mirror can be formed, and the focus shift can be reduced. Therefore, it is possible to improve the azimuth error.

Next, an antenna device for a radar device as an embodiment of the antenna device and horizontal plane pattern switching method of the present invention will be described in detail with reference to the drawings.
(First embodiment)
(Description of configuration)
FIG. 1 is a diagram showing the appearance of the first embodiment of the present invention. The external configuration of the antenna device for a radar device is as follows: a rotary driving device 13 including a lower fixed platen 13a and a rotary platen 13b having an opening in the upper center; The primary radiator 12 is fixed and disposed so as to penetrate the opening of the upper turntable 13b, and the reflecting mirror 11 is fixed on the turntable 13b.

  The primary radiator 12 has a configuration in which a plurality of radiating elements arranged in a cylindrical shape at equiangular intervals are arranged in a plurality of stages in the vertical direction, and the radiating elements in each stage arranged in the vertical direction form a horizontal plane pattern. The reflecting mirror 11 has a parabolic curve in the shape of a horizontal cross section of the reflecting surface. In the example of radio wave emission, the radio wave emitted from the primary radiator 12 is converged to form a sharp beam on a horizontal plane.

  With this configuration, the reflecting mirror 11 is rotated by the rotation of the turntable 13b of the rotation driving device 13, and the stages arranged in the vertical direction facing the reflecting mirror 11 of the primary radiator 12 in synchronization with the rotation of the reflecting mirror 11. The radiating element is put into operation, thereby realizing a high gain antenna that can scan the antenna beam in a horizontal plane.

Next, the configuration of the primary radiator and the signal system will be described in detail.
FIG. 2 is a diagram illustrating a configuration example of a system diagram of the primary radiator 12. The primary radiator 12 is composed of an element array in which a plurality of (N) stages of a plurality of radiating elements 123 arranged in a circle are stacked. Specifically, the primary radiator 12 is configured by a plurality of radiating elements 123 arranged circumferentially at equal angular intervals by columns 122 and at equal intervals in the vertical direction, and is covered with a cover 121.

  Further, the radiating elements 123 of the respective stages # 1 to #N arranged in the vertical direction of the primary radiator 12 are configured to be connectable by the transmission / reception modules 1 to N and the switches 124 provided corresponding to the radiating elements 123, respectively. Further, the transmission / reception modules 1 to N receive the RF signal from the signal generator via the distributor, and output the reception signal from the primary radiator to the reception side Rx via the combiner. The radiating elements 123 arranged in a circle are switched from the radiating elements arranged in the vertical direction of each stage to the radiating elements arranged in the vertical direction of each adjacent stage by the switch 124 according to the rotation of the reflecting mirror, and reflected. A radiating element located near the focal point of the mirror radiates radio waves to the reflecting mirror or receives radio waves from the reflecting mirror.

  Furthermore, one row of radiating elements 123 in each stage arranged in the vertical direction constitutes a phased array in which the directivity in the vertical direction is controlled by a phase shifter built in the transmission / reception module 125 or the like, and an RF signal by the phase shifter With this phase control, electron scanning of the beam in the elevation angle direction is possible. Note that the transmission / reception module 125 is a component used in the phased array and is well known to those skilled in the art and is not directly related to the present invention, and thus detailed description thereof is omitted.

  FIG. 3 is a diagram showing the relationship between the rotation (focal point) position of the reflecting mirror 11 and the switching timing of the primary radiator 12 according to this embodiment. FIG. 4 shows the switch switching and beam azimuth change at each stage according to this embodiment. FIG. 3 and 4 show beam switching examples when the primary radiator is configured as a four-stage array of radiating elements # 1 to # 4.

  In the case of the related art, as can be seen from FIG. 10, when the focal position of the rotating reflecting mirror reaches an intermediate position between the adjacent radiating elements No 1 and No 2, etc. The radiating elements are switched simultaneously.

  On the other hand, in the switching of the radiating elements of this embodiment, as shown in FIG. 3, the time difference between the radiating elements No1 and No2 by the switch in each stage (one unit) during the period between the adjacent radiating elements No1 and No2. To switch sequentially. Specifically, in the case of four radiating elements, the focal position of the reflecting mirror has reached a position of m × 1/8 (m: 1, 3, 5, 7) between adjacent radiating elements No1 and No2. At the time, a switching method is adopted in which the radiation elements are sequentially switched from No1 to No2.

(Description of operation)
Next, the operation of the present embodiment will be described in detail by comparison with the operation of the related art.

  First, an operation example when the horizontal plane pattern switching operation of the primary radiator of the related art shown in FIG. 10 is applied to the four-stage array configuration shown in FIG. 3 will be described. In this case, in the switching operation of the related art, all the radiating elements are switched from No1 to No2 at the point c in FIG. That is, the reflecting mirror rotates at a constant speed in the order of A → B → C → D → E, and the focal position of the reflecting mirror is displaced in the order of a → b → c → d → e on the circumference where the radiating elements are arranged. However, the row of radiating elements constituting the vertical phased array changes stepwise from beam 14a to 14e by switching the switch at point c.

  Now, assuming that the reflecting mirror is at the position A, the row of No. 1 radiating elements constituting the vertical phased array is in an operating state and the beam 14a is formed, and the phase center at this time is reflected at the position a. It matches the position of the focal point of the mirror. However, since the reflecting mirror continuously rotates to the positions B and C even in the operating state of the row of the radiating elements of No. 1, the focal point is displaced from the position a to the positions b and c. The focus shifts ab and ac gradually increase from the original focus position a with respect to 14a.

  Next, when the reflecting mirror is rotated to the position C, the No. 1 radiating element row is switched to the No. 2 radiating element row, so that the beam is also switched from the beam 14a to the beam 14e. At this time, the direction of the focus shift is reversed, and further, the focus shift gradually decreases with respect to the original position e as the reflecting mirror rotates from the position C to the positions D and E. When the reflecting mirror rotates to the position E, the beam 14e and the position e of the focal point again coincide. Subsequent operations are similarly repeated.

  As described above, in the related art horizontal plane pattern switching method, the position of the focal point of the reflecting mirror is switched at the midpoint between one row of radiating elements arranged in the vertical direction. The position of the focal point of the reflector of the center and the parabolic antenna periodically deviates greatly between ac and ce, and this focus shift appears as a beam shift of the secondary pattern, so it is ignored when used as an antenna for a radar device. It becomes a direction error that cannot be done.

  In this embodiment, by changing the time for switching the horizontal plane pattern of the primary radiator of each stage with a difference in each stage, the position of the center of the phase of the horizontal plane pattern is rotated in small increments, and the rotation of the reflecting mirror is changed. Improve synchronization. That is, it is configured such that the switching time of the switches connecting the radiating elements arranged in the vertical direction of the primary radiator and the phase shifter or the like is made different at each stage, thereby improving the synchronization with the horizontal plane pattern.

  Next, the switching operation of the horizontal plane pattern of the primary radiator will be described with reference to FIGS. 3 and 4 in the example of the vertical four-stage array configuration of the present embodiment.

  In this embodiment, as shown in FIG. 3, the switching point of the radiating element is divided into four parts between the radiating elements No1 and No2, and one radiating element is switched at each intermediate point. Also, A, B, C, D, and E shown in FIG. 4 represent the selection states by the switches corresponding to the positions of the reflecting mirrors shown in FIG. 3, and the radiation elements selected by the switches in each state The relationship with the beams 14a, 14b, 14c, 14d, and 14e is shown.

  When the reflecting mirror is at position A, the radiating element No1 is selected and operated at all stages from # 1 to # 4, and the beam 14a is formed. At position B, the # 1 stage switches from radiating element No1 to radiating element No2. At position C, the # 2 stage switches from radiating element No1 to radiating element No2. At position D, # 3 is switched from radiating element No1 to radiating element No2. At position E, # 4 stage is switched from radiating element No1 to radiating element No2, and radiating element No2 operates at all stages from # 1 to # 4. In this way, the active elements of each stage are switched at sequential time intervals without simultaneously switching, so that the formed beam is rotated in small increments as shown in 14a to 14e, and synchronized with the rotation of the main reflector. Is improved.

  FIG. 5 is a diagram showing an example of the pattern of the primary radiator according to the present embodiment. The result of calculating the directivity pattern of the primary radiator in the configuration example in which the radiating elements arranged in a circle are arranged in four stages with a pitch of 10 degrees is shown, and it can be confirmed that the peak positions are sequentially rotated in small increments.

6A and 6B are diagrams showing changes in focus shift (azimuth error). FIG. 6A shows the case of beam switching according to the related art, and FIG. 6B shows the case of beam switching according to the present embodiment.
In the case of the related art, the radiating elements to be operated are switched at the focal positions at the positions of the reflectors C, which are the midpoints of the respective focal points at the positions of the reflectors A and E. Since the operation element is switched from No1 to No2 at all stages at the same time, the focus shift (azimuth error) largely changes until the switching time as shown in FIG.

  In the present embodiment, switching is performed with a time difference for each stage in units of one radiating element at the midpoint of each focal point at positions A, B, C, D, and E of the reflector. As shown, the change in focus shift (azimuth error) is reduced to ¼ compared to FIG. 6A of the related art.

  As described above, in the present embodiment, in the system in which the elements of the primary radiator are circumferentially arranged in a plurality of stages at equal angular intervals and in the vertical direction, and the excitation element is switched in synchronization with the rotation of the reflecting mirror. A time difference is added at each stage for switching the excitation element array of the radiator, and the center of the peak and phase of the beam are rotated in small increments, and finely synchronized with the focal point displacement of the reflecting mirror in synchronization with the rotation of the reflecting mirror. As a result, the primary radiator pattern can be rotated in small increments to reduce the focus shift, and the azimuth error can be greatly improved. Further, as shown in FIG. 5, the amplitude pattern of the primary radiator is rotated in small increments and irradiated to the reflecting mirror, so that the efficiency of the antenna is improved, the gain deviation of the secondary radiation characteristic is reduced, and the side lobe is improved. Can also be achieved.

(Second Embodiment)
In the first embodiment, an example is shown in which the operation elements that are switched with a time difference at each stage are switched in units of one radiating element. However, it is possible to configure each switching radiating element in units of a plurality of units. It is.

  FIG. 7 is a diagram showing a second embodiment of the present invention. It consists of a primary radiator in which a plurality of radiating elements arranged in a circle are arranged in eight stages in the vertical direction. Switching from a plurality of radiating elements No1 to No2 in the vertical direction is performed four times between radiating elements No1 and No2. Divided into two, and at each intermediate point, two radiating elements (# 1 and # 5, # 3 and # 7, # 2 and # 6, # 4 and # 8) are sequentially dispersed and switched. is doing.

  In this embodiment, according to the number of stages of a plurality of radiating elements in the vertical direction, the number of divisions between radiating elements No1 and No2 (the number of switching), the number of units of radiating elements at the time of individual switching, and the like are appropriately selected. Is possible. By switching a plurality of radiation elements as a unit, it is possible to improve the accuracy of the phase center in the vertical direction (elevation direction).

(Other embodiments)
In the above embodiment, an antenna device using a single reflecting mirror has been shown. However, as another embodiment of the present invention, a plurality of reflecting mirrors that rotate the outer periphery around the primary radiator at a predetermined angle interval. Thus, the present invention can also be applied to an antenna device that forms a multi-beam.

  As shown in FIGS. 8 and 9, this embodiment can be configured as an antenna device using, for example, three reflecting mirrors. Reflector mirrors such as offset parabolic curved surfaces are mounted on the rotating disk of the rotation drive device at intervals of 120 °, and the primary radiator fixed on the fixed disk is rotated. As shown in FIG. 9, the primary radiator has a structure in which a plurality of radiating elements arranged at equal intervals on the circumference around the support are arranged in a plurality of stages in the vertical direction, and the primary radiator corresponds to three reflecting mirrors. Each of the plurality of radiating elements arranged in a cylindrical shape includes three switches that rotate at an angular interval of 120 °, and a plurality of radiating elements and a phase shifter (or a transmission / reception module) in synchronization with the rotation of the reflecting mirror. ), And the radiating elements in the vicinity of the focal points of the three reflecting mirrors are always selected. Furthermore, in the present embodiment, the reflectors (focal points) to be sequentially switched in units of stages or in units of multiple stages are selected by dividing between adjacent radiating elements selected in accordance with the number of stages in the vertical direction. The switching timing of the radiating element is determined.

  In the embodiment shown in FIG. 2, the configuration is such that one radiating element (array) is switched by a switch by one transmission / reception module 125 at each stage and the reflector is irradiated with radio waves. However, as another embodiment, radiation is performed. It is possible to load the transmitting / receiving module for each element and switch the operating module. That is, a plurality of radiating elements and a plurality of transmission / reception modules can be connected in advance, and the transmission / reception modules can be selectively operated by switching the transmission / reception modules using switches.

  Furthermore, in the embodiment shown in FIG. 2, the active phased array method using the transmission / reception module 125 has been described. However, as another embodiment, a passive phased array method using only a phase shifter for reception is used. Is possible.

  According to the present invention, it is possible to reduce the deviation between the focal point of the rotating reflector and the horizontal plane pattern of the primary radiator in a reflector-type antenna device suitable for radar that does not have an electrically movable contact. It can be applied to long-range radar.

It is a figure which shows the external appearance of 1st Embodiment of the antenna device which concerns on this invention. It is a figure which shows the structural example of the systematic diagram of the primary radiator 12 of this embodiment. It is a figure which shows the relationship between the rotation (focal point) position of the reflective mirror 11 of this embodiment, and the switching timing of the primary radiator 12. FIG. It is a figure which shows switch switching and beam azimuth | direction change of each stage of this embodiment. It is a figure which shows the example of the pattern of the primary radiator of this embodiment. It is a figure which shows the change of a focus shift | offset | difference (azimuth | direction error), (B) is the case of the beam switching of related technology, (B) is the case of the beam switching of this embodiment. It is a figure which shows the 2nd Embodiment of this invention. It is a figure which shows the external appearance of the already proposed antenna apparatus of the related technique of this invention. It is a figure which shows the circuit system of the primary radiator of an antenna apparatus. It is a figure which shows the switching operation | movement of the radiation element of the related technology of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Reflector 12 Primary radiator 121 Cover 122 Support | pillar 123 Radiation element 124 Switch 125 Module 13 Rotation drive device 13a, 13b Rotation drive device 14 Element pattern 14a-14e Element pattern

Claims (18)

  In an antenna apparatus having a primary radiator in which a plurality of radiating elements arranged in a circle are stacked in multiple stages, and a reflector that mechanically rotates the outer periphery of the primary radiator, the horizontal plane of the primary radiator in each stage An antenna device characterized in that a beam synchronized with the rotation of a reflecting mirror is formed by providing a difference in time for sequentially switching patterns at each stage.   The horizontal plane pattern is switched by providing a switch for operating each stage of the radiating elements arranged in the vertical direction of the primary radiator, and changing the switch switching time at each stage. 1. The antenna device according to 1.   The switching of the switch is switching from a radiating element arranged in the vertical direction of each stage to a radiating element arranged in the vertical direction of each adjacent stage in one or more different radiating element units of the primary radiator. The antenna device according to claim 2.   4. The antenna apparatus according to claim 1, wherein the plurality of radiating elements arranged in the vertical direction of each stage can be electronically scanned with a beam in an elevation angle direction by a phase shifter.   5. The multi-beam according to claim 1, comprising a plurality of switches for selecting different radiating elements at each stage arranged in the vertical direction of the primary radiator, and a plurality of reflecting mirrors to form a multi-beam. The antenna device according to 1.   6. The antenna apparatus according to claim 5, wherein the reflecting surface of the reflecting mirror is an offset parabolic curved surface.   7. The antenna device according to claim 1, wherein the antenna device is applied to a long-range radar device. The switch is an antenna device according to claim 2 or 5, characterized in that a switch for selecting the transceiver module and loaded onto a radiating element of each stage. The switch is an antenna device according to claim 2 or 5, characterized in that a switch for connecting the radiating element phase shifter or transceiver modules in each stage.   In the method of switching the horizontal plane pattern of the primary radiator of the antenna device that mechanically rotates the reflecting mirror on the outer periphery of the primary radiator in which a plurality of radiating elements arranged in a circle are stacked in multiple stages, the primary radiation of each stage A horizontal plane pattern switching method characterized in that a beam synchronized with the rotation of the reflecting mirror is formed by making a difference in time for sequentially switching the horizontal plane pattern of the vessel by a switch.   The horizontal plane pattern is switched by providing a switch for operating each stage of the radiating elements arranged in the vertical direction of the primary radiator, and changing the switch switching time at each stage. The horizontal plane pattern switching method according to 10.   The switching of the switch is switching from a radiating element arranged in the vertical direction of each stage to a radiating element arranged in the vertical direction of each adjacent stage in one or more different radiating element units of the primary radiator. The horizontal plane pattern switching method according to claim 11.   The horizontal plane pattern switching according to any one of claims 10, 11 and 12, wherein a plurality of radiating elements arranged in the vertical direction of each stage can be electronically scanned with a beam in an elevation direction by a phase shifter. Method.   The multi-beam is formed by comprising a plurality of switches for operating different radiating elements at each stage arranged in the vertical direction of the primary radiator and a plurality of reflecting mirrors. The method for switching the horizontal plane pattern described in 1.   15. The method for switching a horizontal pattern of an antenna device according to claim 14, wherein the reflecting surface of the reflecting mirror is an offset parabolic curved surface.   The horizontal plane pattern switching method according to any one of claims 10 to 15, which is applied to a long-range radar device.   17. The horizontal plane pattern switching method according to claim 11, wherein the switch is a switch for selecting a transmission / reception module loaded on each radiating element.   17. The horizontal plane pattern switching method according to claim 11, wherein the switch is a switch that connects a radiation element of each stage and a phase shifter or a transmission / reception module.

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