Array Antenna

Abstract

To provide an array antenna that achieves both low cost and optimization of horizontal beamforming performance.SOLUTION: An array antenna 1 having a plurality of elements 100A and transmitting / receiving radio waves via the elements 100A includes a radio wave control unit. The radio wave control unit inclines a transmission / reception direction of radio waves at least in a first direction x by emitting radio waves having different amplitudes or phases at the plurality of elements 100A. The array antenna 1 has a plurality of element rows 110A in which two or more N elements 100A are arranged side by side at predetermined intervals d1 in a second direction y substantially orthogonal to the first direction. The element rows 110A are configured as sub-arrays, arranged side by side at predetermined intervals d2 in the first direction to form element lines 120, and arranged to be displaced from adjacent elements or element rows 110A in the second direction by approximately d2 / 2 in the first direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an array antenna having a plurality of elements for transmitting and receiving radio waves via the elements. [Background technology]

[0002] Conventionally, base stations for mobile terminals and the like have formed wide-angle coverage areas with sector beams with beam widths of around 90 degrees or 120 degrees. On the other hand, in 5G, in order to improve coverage quality, there are cases where it is required to simultaneously achieve high gain and wide-angle coverage by steering a narrow, high-gain beam with a beam width of 20 degrees or less to a wide angle. FIG. 21 shows an example of the configuration of a base station 5 and a relay device 6. Beams #6 and #2 are directed from the base station 5 to mobile terminals 701 and 702. On the other hand, a beam is directed via a relay device 6 to a mobile terminal 703 located behind a building or the like. To achieve this, in mobile communications, development is underway on high-performance antennas that support digital beamforming using multiple devices and analog beamforming using beamforming ICs. A triangular arrangement as shown in Fig. 23 is known as an arrangement of an array antenna that maximizes beamforming performance (see paragraph 0002 and Fig. 27 of Patent Document 1, etc.). This arrangement can obtain the best beamforming performance by using appropriate element spacing and freely setting the power supply conditions for each element. When the amplitude and phase of all the arranged antenna elements are variable, that is, can be freely adjusted, it is desirable to arrange the antennas in a "triangular arrangement" in terms of the angular range of gain and beam steering, taking into consideration side lobe characteristics, etc. For example, Patent Document 2 describes that in the case of a planar array arranged in a regular triangle, the spacing d between the element antennas of a two-element partial array is the same regardless of the direction in which the two element antennas are combined (paragraph 0064). Hereinafter, the phased array antenna and the beamforming antenna may be simply referred to as the array antenna or the antenna. Also, the antenna element may be simply referred to as the element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-027465 [Patent Document 2] JP 2020-198576 A Summary of the Invention [Problem to be solved by the invention]

[0004] First, the difference between a triangular array and a square array will be explained. FIG. 22 shows an example of the configuration of a square array antenna, and FIG. 23 shows an example of the configuration of a triangular array antenna. In the triangular array shown in Figure 23, adjacent element rows are offset horizontally by d / 2, so the horizontal element spacing can be considered equivalent to an element spacing of d / 2. This improves the horizontal beamforming performance compared to a square array. In particular, when steering at a wide angle, the rise of the side lobe, i.e., the grating lobe, can be suppressed. In this way, in a triangular array, particularly an equilateral triangular array, when the amplitude and phase of each element are variable, it is possible to freely set amplitude and phase conditions for each element, and theoretically, the best beamforming performance can be obtained. However, in order to realize all-element variability, it is necessary to freely set the power supply conditions for each element. For example, as shown in FIG. 24 , it is necessary to provide an amplitude / phase adjustment unit 10 for each element 100, and to prepare a number of amplitude / phase adjustment units 10 in radios, beamforming ICs, and the like corresponding to all elements 100. For example, analog beamforming used in mmWAVE such as the 28 GHz band requires the largest number of BFICs (beam forming ICs), while digital beamforming used in Sub6 and other bands requires the largest number of transceivers, resulting in problems such as increased costs, increased power consumption, and the associated heat generation.

[0005] Therefore, in order to reduce costs, we are considering creating sub-arrays and reducing the number of ICs and transceivers. Fig. 25 shows a possible configuration example. In element array 110, the two elements 100 enclosed by solid lines are designed with a fixed amplitude difference and phase difference. Note that the solid lines indicate combinations and groupings of elements such as subarrays. Also, including in the following explanation, solid lines are not specified for all elements. In other words, elements not specified by solid lines are also grouped in the same way, such as two elements 100. As shown in FIG. 25, when sub-arrays are formed with adjacent elements 100 in the same column, the same performance can be obtained for horizontal beam steering as when the amplitude and phase of each element are variable. However, in the vertical direction, that is, the spacing between elements 100 in the subarray becomes large at 2×d, and degradation such as an increase in side lobes occurs when vertical tilt, that is, beamforming in the vertical direction, is applied. 26 shows another possible configuration example. In element array 110, the two elements 100 enclosed by the solid line are controlled with the same amplitude and phase. In this configuration, the element spacing returns to d in the vertical direction, improving the vertical tilt. However, since the element spacing in the horizontal direction is d, the degree of freedom in phase and amplitude at d / 2 cannot be obtained for horizontal steering.

[0006] When elements are sub-arrayed to reduce the number of ICs and transceivers in order to cut costs, the beamforming performance deteriorates as mentioned above. There is a need to solve these problems and optimize the cost performance of beamforming antennas for mobile communication base stations. In addition, from the perspective of improving communication quality in transmission and reception, such as by increasing the transmission EIRP and reducing noise in the receiving system, a high antenna gain is desirable. However, if performance during beamforming must be guaranteed, the spacing between antenna elements must be narrowed, which reduces the antenna aperture and reduces gain. Assuming that a sub-array will be used to reduce costs, we would like to consider a highly efficient arrangement that increases the array gain while keeping the horizontal beam steering angle range wide. In particular, there is a demand for an array antenna with an array configuration based on sub-arrays, which can reduce the number of radio units and BFICs, widen the horizontal beam steering angle range, and increase array gain, all of which are required for beamforming antennas for mobile communications, regardless of whether they are digital or analog.

[0007] Therefore, an object of the present invention is to provide an array antenna that achieves both low cost and optimal horizontal beamforming performance. Another object of the present invention is to provide an array antenna that simultaneously satisfies three conditions: low cost, optimum horizontal beamforming performance, and high antenna gain. Furthermore, it is an object of the present invention to provide an array antenna that satisfies the above-mentioned objectives and is applicable to both SUB6 and mmWAVE, for example, when considering application to current mobile communications, regardless of frequency. [Means for solving the problem]

[0008] In mobile communications, priority is given to horizontal beamforming, so an arrangement method that can maintain horizontal beamforming performance is desired. In beamforming in mobile communications base station antennas, a wider horizontal beam steering angle range is often required compared to vertical beam tilt. Therefore, when reducing the number of radio units and beamforming ICs, the antenna elements on the vertical side are made into subarrays of two or more elements, and the horizontal beam steering angle range is maintained the same as when all elements are variable, thereby achieving cost reduction while giving priority to improving horizontal beamforming performance. The array antenna according to claim 1 of the present invention comprises: An array antenna having a plurality of elements for transmitting and receiving radio waves through the elements, a radio wave control unit that tilts a transmission / reception direction of the radio wave at least in a first direction by emitting radio waves having amplitudes or phases different from each other in a plurality of elements; a plurality of element rows each including two or more N elements arranged at a predetermined interval d1 in a second direction substantially perpendicular to the first direction, the element rows being configured as sub-arrays; The elements are arranged at a predetermined interval d2 in a first direction to form element rows; The array antenna is characterized in that the element rows are arranged to be shifted in the first direction by approximately d2 / 2 from adjacent elements or element rows in the second direction. The array antenna according to claim 2 of the present invention comprises: 2. The array antenna according to claim 1, wherein an element column in the outermost element row has more elements than element columns in element rows other than the outermost element row. The array antenna according to claim 3 of the present invention comprises: The array antenna of claim 1 or 2, characterized in that an element column in an outer element row with respect to a predetermined central position has a number of elements equal to or greater than the number of elements in an element column in an element row on the central position side. The array antenna according to claim 4 of the present invention comprises: 4. The array antenna according to claim 1, further comprising an array group on the outermost side in the first direction, the array group having a plurality of rows of elements in the first direction. The array antenna according to claim 5 of the present invention comprises: a plurality of array groups on the outside in a first direction, the array groups having a plurality of rows of elements in the first direction; 4. The array antenna according to claim 1, wherein, in the first direction, the outer array group has element rows the number of which is equal to or greater than the number of rows in the inner array group. The array antenna according to claim 6 of the present invention comprises: 6. The array antenna according to claim 4 or 5, wherein the smallest element row has one element. The array antenna according to claim 7 of the present invention comprises: 7. The array antenna according to claim 1, wherein d2 is approximately λ / 2 and d1 is 0.5λ or more, where λ is the wavelength of electromagnetic waves to be transmitted and received. The array antenna according to claim 8 of the present invention comprises: 8. The array antenna according to claim 1, which is a base station antenna or a relay antenna for a mobile terminal, and the first direction is a substantially horizontal direction. [Brief description of the drawings]

[0009] [Figure 1] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Diagram 2] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Diagram 3] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 4] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Diagram 5] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 6] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 7] 1 shows a comparison between an embodiment of the present invention and a square array. [Figure 8] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 9] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 10] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 11] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 12] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 13] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 14] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 15] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 16] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 17] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 18] A comparative example of the embodiment of the present invention is shown. [Figure 19] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 20] 2 shows an example of the configuration of an array antenna in one embodiment of the present invention. [Figure 21] 2 shows an example of the configuration of a base station and a relay device according to an embodiment of the present invention. [Figure 22] 2 shows an example of the configuration of an array antenna. [Figure 23] 2 shows an example of the configuration of an array antenna. [Figure 24] 2 shows an example of the configuration of an array antenna. [Diagram 25] 2 shows an example of the configuration of an array antenna. [Figure 26] 2 shows an example of the configuration of an array antenna. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1 and 4 show an example of the configuration of an array antenna 1 in an embodiment of the present invention. The array antenna 1 has a plurality of elements 100, transmits and receives radio waves via the elements 100, and has a sub-array 110 in the vertical direction in the figure.

[0011] As shown in FIG. 1, there are a plurality of element rows 110 in which two or more N elements 100 are arranged at a predetermined interval d1 in a second direction y that is substantially perpendicular to a first direction x. In this embodiment, for example, two elements 100A form one element array 110A.

[0012] The elements 100 are arranged in a first direction x at a predetermined interval d2 to form element rows 120. Furthermore, the element arrays are arranged so as to be offset in the first direction by approximately d2 / 2 from adjacent elements 100 or element arrays 110 in the second direction y. This offset is indicated as δ in the drawing.

[0013] In this embodiment, one element array 110 has two elements 100, but one element array 110 may have three elements 100, such as one element array 110A having three element arrays 100A as shown in Fig. 2. Also, one element array 110 may have four elements 100, such as one element array 110A having four element arrays 100A as shown in Fig. 3. Note that the solid lines in the figure indicate groupings of element rows, and are designed with fixed amplitude and phase differences. Also, including the following, it is important to note that groupings are not shown for all elements as in Figure 3, and that not all elements are necessarily shown.

[0014] 4, each element 100 in each element row 110 is connected to the same amplitude / phase adjustment unit 10, and the amplitude / phase adjustment unit 10 is connected to a radio wave control unit 2. For example, two elements 100A in an element row 110A are connected to one amplitude / phase adjustment unit 10. The radio wave control unit 2 controls the amplitude and phase for each element row, and causes the elements 100 to emit radio waves with mutually different amplitudes or phases, thereby tilting the transmission and reception direction of the radio waves in at least the first direction.

[0015] In this embodiment, each element array 110 is connected to the same amplitude / phase adjustment unit 10, but as shown in FIG. 5, the amplitude / phase adjustment unit 10 may be divided into an amplifier 11 that adjusts the amplitude and a phase shifter 12 that adjusts the phase, and each element array 110 may be connected to the same amplifier 11 and phase shifter 12. Alternatively, as shown in FIG. 6, a subarray control unit 20 may be provided for each element array 110, and the subarray control unit 20 may have an amplifier 21 and a phase shifter 22. The element array 110 is a subarray, that is, the elements 100 in the same element array 110 are controlled by the same amplitude / phase adjustment section 10.

[0016] In one embodiment, d2 may be approximately λ / 2 and d1 may be 0.5λ or more, where λ is the wavelength of the electromagnetic wave to be transmitted or received. This configuration allows for efficient horizontal tilt while adjusting the value of d1 to achieve optimal gain. In other words, by widening the value of d1 as much as possible, the array gain can be increased while maintaining a wide angle range of horizontal beam steering by pseudo-reducing the element spacing using the offset δ.

[0017] In one embodiment, the antenna is a base station antenna or a relay antenna of a mobile terminal, and the first direction is substantially horizontal. 21, a base station 5 has the array antenna 1 as a base station antenna, and a relay device 6 has the array antenna 1 as a relay antenna.

[0018] In these embodiments, the array antenna is divided into sub-arrays with element spacing d1 in the vertical direction, and arranged with element spacing d2 in the horizontal direction, and the vertical sub-array group in the next row is offset in the horizontal direction by an offset amount δ = d2 / 2. In this configuration, the array antenna is arranged with a horizontal spacing of d2 / 2, which allows the phase difference between horizontal elements to be set at intervals of d2 / 2, thereby suppressing the occurrence of grating lobes. As for the vertical direction, although the subarray configuration limits the beam tilt performance, it can be adjusted flexibly to some extent by adjusting the spacing d1 between two-element subarrays.

[0019] In this embodiment, the offset is in the horizontal direction, but if wide-angle steering is required on the vertical tilt side, it may be rotated by 90 degrees. In other words, the first direction x may be the horizontal direction, and the second direction y may be the vertical direction. Alternatively, the first direction x may be the direction requiring the widest tilt angle, or the second direction y may be the direction requiring the next widest tilt angle among the directions perpendicular to the first direction x, with the first direction x being the direction requiring the widest tilt angle.

[0020] Figure 7 compares this embodiment with a square array, showing the relationship between the horizontal steering angle θ and the antenna gain G. The values ​​for this embodiment are shown as a solid line for Example 1, and the values ​​for the fabrication array are shown as a dashed line. They are arranged with a horizontal offset of d2 / 2 relative to the subarray group. The horizontal phase difference can be set at d2 / 2 intervals, which suppresses the occurrence of Graden lobes and prevents gain reduction.

[0021] In wide-angle steering in the horizontal direction, such as when the steering angle is 60°, the gain of this embodiment is improved by about 1 dB compared to the case of a square arrangement. In addition, the difference between the maximum gain at a steering angle of 0 degrees and the antenna gain at a steering angle of 60 degrees is within 3 dB, so the reduction in antenna gain due to steering is also kept small. In this way, even when a sub-array is configured, it is effective for wide-angle steering in the horizontal direction, while the maximum gain of the antenna can be maintained almost the same as in the case of a square arrangement.

[0022] In the above configuration, by adopting a triangular arrangement on a subarray basis, it is possible to achieve both optimal horizontal beamforming performance and low costs. In particular, it achieves both wide-angle steering and high gain performance in beamforming antennas that are based on sub-array configuration. Reducing the number of ICs and transceivers also leads to lower costs. It can also be applied to any frequency, regardless of whether it is SUB6 or mmWAVE. In particular, it greatly improves the characteristics when the beamforming antenna is made into a sub-array.

[0023] Incidentally, the antenna gain obtained by an array antenna is proportional to the antenna aperture, that is, the area of ​​the array antenna. Considering the performance during beam steering, especially the increase in side lobes, a narrower element spacing is better. However, if the element spacing is narrow, the antenna aperture becomes smaller for the same number of elements, and the gain decreases. In other words, to improve the antenna gain, it is necessary to make the antenna aperture wider. By increasing the number of elements in the outermost subarrays, among the vertical subarrays, compared to the central subarrays, it is possible to improve the antenna gain by the increased aperture while maintaining the same performance during horizontal steering as in the above-mentioned embodiment. Such a configuration will be described below.

[0024] FIG. 8 shows an example of the configuration of an array antenna 1 in an embodiment of the present invention. In this embodiment, element columns 110 in the outermost element row 120 have more elements 100 than element columns 110 in element rows 120 other than the outermost element row. For example, element column 110A in the outermost element row 120 has three elements 100A. In this configuration, the element columns 110 in the outermost element rows 120 have three elements 100, and the element columns 110 in the element rows 120 other than the outermost element rows have two elements 100.

[0025] The element columns 110 in the outermost element rows 120 may have four elements 100 as shown in Figure 9, or may have five elements 100 as shown in Figure 10. The optimum antenna gain can be achieved by setting the number of elements in element columns 110 in the outermost element rows 120 in accordance with the desired antenna gain.

[0026] FIG. 11 shows an example of the configuration of an array antenna 1 in an embodiment of the present invention. In this embodiment, element columns 110 in element rows 120 on the outer side of a predetermined central position have elements 100 in a number equal to or greater than the number of elements 100 in element columns 110 in element row 120 on the central position side. In this embodiment, the central position is the center of the array of elements 100, for example, the midpoint between the outermost elements 100 in both the horizontal direction x and the vertical direction y, and the central position is strictly the center position of the array, but it does not necessarily have to be the center depending on the performance of the antenna, etc. In this embodiment, element array 110 in element row 120 outermost with respect to a predetermined central position has three elements 100, element array 110 in element row 120 next outer with respect to the predetermined central position has two elements 100, and element array 110 in element row 120 further inside has one element 100. Note that in this embodiment, only one element is connected to amplitude / phase adjustment section 10 in element row 120 on the inner side, but in such a configuration, one element is considered to be formed as one element array.

[0027] As in the example shown in Figure 12, the element column 110 in the element row 120 that is outermost with respect to a predetermined central position may have four elements 100, the element column 110 in the element row 120 that is next outer with respect to the predetermined central position may have two elements 100, and the element column 110 in the element row 120 further inside may have one element 100. Alternatively, as shown in FIG. 13, the element column 110 in the element row 120 that is outermost with respect to a predetermined central position may have four elements 100, the element column 110 in the element row 120 next outer with respect to the predetermined central position may have three elements 100, and the element column 110 in the element row 120 further inward may have two elements 100. As in these examples, when the number of elements in element row 120 increases smoothly from the center toward the outside, in other words, when the number of elements increases in several stages, it is easy to adjust the amplitude ratio to suppress side lobes. In other words, when viewed as a whole array antenna, a configuration can be achieved in which the amplitude changes smoothly, and side lobes can be suppressed, compared to a case in which the number of elements increases suddenly in the outermost element rows.

[0028] As in the example shown in Figure 14, the element column 110 in the element row 120 that is outermost with respect to a predetermined central position may have three elements 100, the element column 110 in the element row 120 next outer with respect to the predetermined central position may have three elements 100, and the element column 110 in the element row 120 further inside may have two elements 100. Alternatively, as shown in FIG. 15 , the element column 110 in the element row 120 that is outermost with respect to a predetermined central position may have three elements 100, the element column 110 in the element row 120 that is next outer with respect to the predetermined central position may have three elements 100, and the element column 110 in the element row 120 further inward may have one element 100.

[0029] Alternatively, as shown in FIG. 16, the element columns 110 in the three element rows 120 that are outermost from a predetermined central position may have two elements 100, and the element columns 110 in the element rows 120 further inward may have one element 100. In these configurations as well, the side lobes can be suppressed more efficiently.

[0030] 18 compares an example in which an element column 110 in the outermost element row 120 has three elements 100 and an element column 110 in an element row 120 other than the outermost element row has two elements 100 as shown in FIG. 8 as Example 2, and the above-mentioned example in which an element column 110 has two elements 100 as Example 1, and shows the relationship between the horizontal steering angle θ and the antenna gain G. The values ​​for Example 1 are shown by a solid line, and the values ​​for Example 2 are shown by a dashed-dotted line. In Example 2, the aperture is wider, and therefore, a gain improvement of about 1 dB over Example 1 can be obtained within the steering angle range. In this way, gain can be improved while maintaining horizontal steering performance.

[0031] FIG. 17 shows an example of the configuration of an array antenna 1 in an embodiment of the present invention. The array group 150 is located on the outermost side in the first direction x, and the array group 150 has a plurality of rows of element columns 110 in the first direction x. 17, array group 150A has two element columns 110, each of which has three elements 100A. The same is true for other array groups 150B, 150G, and 150H that are outermost in the first direction x and the second direction y. Also, among the array groups that are outermost in the first direction x and the second direction y, array group 150A has two element columns 110, and each element column has two elements 100.

[0032] The array groups are configured as subarrays and are controlled with the same amplitude and phase. In this embodiment, one array group is connected to the same amplitude and phase adjustment unit 10, but other configurations are also possible as long as they are controlled with the same amplitude and phase. In this embodiment, the number of elements is also increased in the outermost subarray in the horizontal direction where steering performance is desired. In this embodiment, the number of elements is increased by one element, that is, by one element column. In this way, the gain is increased by the amount of the aperture being widened.

[0033] This configuration is effective when you want to obtain more antenna gain without increasing the number of BFICs or transceivers. As shown in FIG. 18, an array group 150 may also have three element columns 110.

[0034] FIG. 19 shows an example of the configuration of an array antenna 1 in an embodiment of the present invention. The array antenna 1 has a plurality of array groups 150 and 151 on the outside in the first direction x. In this embodiment, a total of 16 array groups are provided: array groups 150A, 150B, 150C, 150D, 150E, 150F, 150G, 150H, 151A, 151B, 151C, 151D, 151E, 151F, 151G, and 151H.

[0035] The array group 150 has a plurality of element columns 110 in the first direction x. For example, the array group 10A has three element columns 110A. Each of the element columns 110A has four elements 100A. In the first direction, outer array groups 150A-150H have element arrays in a number equal to or greater than the number of arrays in inner array groups 151A-151H. In this embodiment, outer array groups 150A-150H each have three element arrays 110, and inner array groups 151A-151H each have two element arrays 110. When the number of element rows in the array group increases in several stages in the horizontal direction as in this configuration, side lobes can be more effectively suppressed in the horizontal direction in particular.

[0036] In the above embodiment, an array antenna can be realized that simultaneously satisfies three objectives: optimizing horizontal beamforming performance, reducing costs, and achieving high gain. As explained in each of the above examples, the gain during horizontal beam steering can be increased by devising a subarray arrangement. The antenna gain can be increased by changing the number of elements in the subarray on the outer side and in the center. The subarray configuration reduces the number of ICs and transceivers, making it possible to reduce costs. All of the above embodiments can be applied to any beamforming antenna, regardless of whether it is SUB6 or mmWAVE. In an antenna array based on the assumption of sub-arraying, it is possible to achieve high efficiency, that is, improved array gain, while maintaining a wide angle range of horizontal beam steering.

[0037] It goes without saying that the present invention is not limited to the above-described embodiments, but includes various embodiments within the scope of the present invention. For example, instead of a planar antenna, an antenna provided on a curved surface may also be effective. It can also be applied to standards other than 5G. [Explanation of symbols]

[0038] 1 Array antenna 2 Radio Control Section 5 base station 6. Repeater 701, 702, 703 Mobile terminals 10 Amplitude / phase adjustment section 11, 21 Amplifier 12, 22 Phase shifter 20 Subarray control section 100, 100A element 110, 110A element array 120 Elements Row 150, 150A, 150B, 150C, 150D, 150E, 150F, 150G, 150H, 151, 151A, 151B, 151C, 151D, 151E, 151F, 151G, 151H Array Group

Claims

1. An array antenna having a plurality of elements for transmitting and receiving radio waves through the elements, a radio wave control unit that tilts a transmission / reception direction of radio waves in at least a first direction by emitting radio waves having amplitudes or phases different from each other in the plurality of elements; a plurality of element rows in which two or more N elements are arranged at a predetermined interval d1 in a second direction substantially perpendicular to the first direction, the element rows being configured as sub-arrays; The elements are arranged at predetermined intervals d2 in the first direction to form element rows, the element array is disposed with a shift of approximately d2 / 2 in the first direction from the element or element array adjacent in the second direction, An array antenna, wherein the element column in the outermost element row has more elements than the element columns in the element rows other than the outermost element row.

2. 2. The array antenna according to claim 1, wherein the element columns in the element rows on the outer side of a predetermined central position have a number of elements equal to or greater than the number of elements in the element columns in the element rows on the central position side.

3. an outermost array group in the first direction; One of the array groups is controlled with the same amplitude and phase, 3. The array antenna according to claim 1, wherein the array group has a plurality of rows of elements in the first direction.

4. a plurality of array groups disposed outwardly in the first direction; One of the array groups is controlled with the same amplitude and phase, the array group has a plurality of rows of the elements in the first direction; 3. The array antenna according to claim 1, wherein, in the first direction, the outer array group has element rows in a number equal to or greater than the number of rows in the inner array group.

5. 5. The array antenna according to claim 3, wherein the smallest element row has one element.

6. 6. The array antenna according to claim 1, wherein d2 is approximately .lambda. / 2 and d1 is 0.5.lambda. or more, where .lambda. is the wavelength of electromagnetic waves to be transmitted and received.

7. 7. The array antenna according to claim 1, which is a base station antenna or a relay antenna for a portable terminal, and the first direction is a substantially horizontal direction.

Images