JP2010200166A - Array antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make measures to cope with a side lobe of an array antenna compatible with cost reduction. <P>SOLUTION: Sizes of sub arrays are unified and the sub arrays are arranged regularly but the sub arrays are arranged while meeting the condition that phase centers of the sub arrays are positioned equally to antenna element intervals. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an array antenna having a plurality of subarrays.

  As disclosed in Patent Document 1, subarraying is known as one of cost reduction techniques for a phased array antenna. In the sub-arrayed active phased array antenna, beam phase control is performed in units of sub-arrays, so that the phase amount error of each antenna element has periodicity and causes side lobes. In particular, the influence is large when the interval between the phase centers of the subarrays is wider than between the antenna elements. As a countermeasure against this, it is already known in Patent Document 1 that the sub-arrays are varied in size and are randomly arranged.

  However, if a plurality of subarrays are arranged at random, the accompanying transmission / reception modules and phase shift modules must be arranged at random. Therefore, the number of circuit types increases, such as a distribution circuit that distributes and supplies transmission signals to each module, a synthesis circuit that synthesizes reception signals from each module, and a distribution circuit that distributes power and control signals to each module. There is a problem that the performance deteriorates.

JP-A-6-291535

Although sub-arraying is effective as a cost reduction measure for a phased array antenna, side lobes are likely to occur, and the measure may be costly.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an array antenna that achieves both sidelobe countermeasures and cost reduction.

  In order to achieve the above object, according to one aspect of the present invention, in an array antenna in which subarrays each having a plurality of antenna elements are two-dimensionally arranged, the plurality of subarrays are arranged in a one-dimensional position of the phase center for each subarray. An array antenna is provided that is regularly arranged under the condition that projected intervals are equal to the intervals of the antenna elements.

  By taking such means, the subarrays are regularly arranged, but the condition that the interval between the phase centers is substantially equal to the interval between the antenna elements is satisfied. As a result, the occurrence of third lobes can be suppressed, and the arrangement of the subarrays can be regularly arranged to prevent complication of the apparatus configuration. That is, by providing regularity to the subarray arrangement, it is possible to prevent deterioration of antenna performance while preventing complication of configuration and deterioration of manufacturability.

  According to the present invention, it is possible to provide an array antenna that achieves both sidelobe countermeasures and cost reduction.

The figure which shows embodiment of the phased array antenna concerning this invention. The figure which shows an example of arrangement | positioning of the subarrays 611-6mn in connection with this invention. The figure which shows the known example of arrangement | positioning of the subarrays 611-6mn.

  FIG. 1 is a diagram showing an embodiment of an array antenna according to the present invention. This array antenna includes subarrays 611 to 6mn, and transmission / reception modules 511 to 5mn that perform amplification and phase control of transmission / reception signals for each of the subarrays 611 to 6mn. The subarrays 611 to 6mn include a plurality of antenna elements 7111 to 71nN and distribution synthesizers 811 to 81n. Transmission / reception signals, drive power supplies, and control signals to the respective transmission / reception modules 511 to 5 mn are the high-frequency / power / control power supply circuits 41 to 4 m, the high-frequency signal distribution / synthesis circuit 10, the power / control signal distribution circuit 20, and the transmission / reception device 1. Supplied from the scanning controller 2 and the power supply unit 3.

  In FIG. 1, a transmission signal output from the transmission / reception device 1 is distributed and supplied from a high-frequency signal distributor / synthesizer 10 to high-frequency / power / control feeding circuits 41 to 4m. Further, it is distributed and supplied to each of the transmission / reception modules 511 to 5 mn through the high frequency / power / control feeding circuits 41 to 4 m. The transmission / reception modules 511 to 5mn provide the power / control signal distribution circuit 20 and the high frequency / power / control feeding circuits 41 to 4m to the transmission / reception modules 511 to 5mn with the amplification gain of the transmission signal and the phase control signal from the scanning controller 2, respectively. . The transmission / reception modules 511 to 5mn receive these controls and perform gain and phase control of the transmission signal.

  The power supply unit 3 supplies drive power to the transmission / reception modules 511 to 5 mn through the same path as the phase control signal, that is, the power / control signal distribution circuit and the high frequency / power supply / control feeding circuit. The transmission signals amplified and phase-controlled in the transmission / reception modules 511 to 5 mn are input to the subarrays 611 to 6 mn and radiated from the antenna elements 7111 to 71 nM to the space via the distribution synthesizers 811 to 81 n. The received signal follows the same path as described above.

FIG. 2 is a diagram showing an example of the arrangement of subarrays 611 to 6mn according to the present invention. Since one transmission / reception module is connected to each subarray, phase control of transmission / reception signals is performed in units of subarrays. The phase center position of the subarray is indicated by (■) in the figure.
In this embodiment, the phase control amount at the phase center position of the subarray is calculated, and each subarray is arranged so that the phase center position is equal to the antenna element interval d. The position of the antenna element is indicated by (◯) in the figure, and when this array is projected in one dimension, the interval is d. On the other hand, when the phase center position of the subarray is projected in a one-dimensional manner, the interval in FIG. 2 is d which is the same as the antenna element interval.

  Moreover, the arrangement of the subarrays in FIG. 2 has regularity. In FIG. 2, five subarrays are arranged diagonally to form one block, and the blocks are regularly arranged. As a result, the arrangement of the transmission / reception modules at the phase center position of the sub-array is also regular (same intervals), and only one type of high-frequency / power / control feeding circuits 41 to 4m for supplying signals to the transmission / reception modules is required. Further, in the case of using wiring, it is possible to prevent the wiring from becoming complicated. That is, it becomes possible to route the control line to the phase shifter, the power supply cable, and the like for each block, and the wiring complexity can be remarkably reduced as compared with a completely random arrangement. In FIG. 2, regularity in the vertical direction appears.

  FIG. 3 is a diagram showing a known example of the arrangement of the subarrays 611 to 6mn for comparison. In FIG. 3, the arrangement and size of subarrays (4 or 2 antenna elements) are also irregular. For this reason, the arrangement of the wiring cable and the structure of the support mechanism become complicated, and the cost tends to increase.

  In contrast, in this embodiment, the size of the subarray is standardized and each subarray is regularly arranged. However, the subarray is arranged after satisfying the condition that the position of the phase center is equal to the antenna element interval. Like to do. Therefore, it is possible to obtain a merit that the configuration is simplified, and it is possible to reduce the side lobes by distributing the phase error due to the subarray.

  In other words, the existing technology does not consider the condition that the position of the phase center of each subarray is equal to the antenna element interval. Therefore, there are conflicting circumstances that the side lobe is increased in the regular arrangement and the cost is increased in the random arrangement. According to this embodiment, it is possible to provide an array antenna that solves both of these and achieves both sidelobe countermeasures and cost reduction.

  The present invention is not limited to the above embodiment. For example, in this embodiment, four antenna elements are provided in the subarray and the sizes thereof are unified, but this is not a necessary condition. In short, it suffices if the interval between the phase centers of the subarrays is equal to the interval between the antenna elements. That is, even if sub-arrays having different sizes are mixed, the object can be achieved if the above conditions are satisfied.

  Further, FIG. 2 shows an array shifted by one element, but any number of elements may be shifted as long as the above condition is satisfied. Further, in FIG. 2, the horizontal method does not need to be regular if the vertical subarray phase center interval is not changed. Further, in FIG. 2, subarrays may be formed in the horizontal direction instead of the vertical direction. Further, FIG. 2 shows a subarray in which antenna elements are arranged one-dimensionally, but the same effect can be obtained by using, for example, a subarray in which two antenna elements are arranged two-dimensionally in the vertical and horizontal directions.

  Furthermore, there is a technique called a thinning array (or thinning array) for reducing the cost of the phased array antenna. This is because, in contrast to the sub-array method in which one transmission / reception module is connected to a plurality of antenna elements, the antenna element / transmission / reception module pair is randomly selected from the arrayed antenna elements in a range that does not affect the performance. This is a technique for reducing the number of transmission / reception modules by thinning out the data. The same idea can be applied to such an array antenna. That is, a thinning arrangement can be realized by thinning out the subarrays as appropriate from the configuration of FIG.

  Furthermore, the present invention can also be applied to a DBF (Digital Beam Forming) antenna that converts a received signal obtained for each subarray into a digital signal and combines these digital signals to form a desired plurality of beams. .

  Furthermore, 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.

  DESCRIPTION OF SYMBOLS 10 ... High frequency signal distribution synthesis circuit, 20 ... Power supply / control signal distribution circuit, 1 ... Transmission / reception device, 2 ... Scanning controller, 3 ... Power supply unit, 41-4m ... High frequency / power supply / control feeding circuit, 511-5mn ... Transmission / reception Module, 611 to 6 mn ... subarray, 7111 to 71 nN ... antenna element, 811 to 81n ... distribution synthesizer

Claims (5)

In an array antenna in which subarrays each having a plurality of antenna elements are two-dimensionally arranged,
An array antenna, wherein the plurality of subarrays are regularly arranged under a condition that an interval in which a position of a phase center for each subarray is projected in one dimension is equal to an interval between the antenna elements. The array antenna according to claim 1, wherein each of the subarrays includes a plurality of antenna elements arranged in one dimension. The array antenna according to claim 1, wherein each of the subarrays includes a plurality of antenna elements arranged in two dimensions. The array antenna according to claim 1, wherein the subarrays are thinned. 2. The array antenna according to claim 1, further comprising digital beam forming means for digitizing a received signal obtained for each subarray to form a beam.

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