JP2013179440A - Array antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an array antenna device of a simpler feeding configuration when compared with prior art, which can reduce or eliminate the grating lobe in the radiation pattern.SOLUTION: A first sub-array is configured by grouping a plurality of element antennas, each including a first excitation circuit (10) and a second excitation circuit (20), for each first set consisting of more than one element antennas. A second sub-array is configured by grouping a plurality of element antennas for each second set consisting of more than one element antennas, so that at least one element antenna is included out of the element antennas configuring the first sub-array, in combination different from the first set. One or a plurality of first and second sub-arrays are arranged.

Description

  The present invention relates to a configuration of an array antenna apparatus that transmits and receives signals using a plurality of antennas in satellite communication and ground communication.

  In satellite communication or the like, when an antenna is mounted on a moving body for communication with a moving body such as a vehicle or an aircraft, the loading space and the loading weight are limited. Therefore, the antenna is required to be small and lightweight. An array antenna that transmits and receives signals using a plurality of antennas is one of the means that satisfies this requirement. As a conventional satellite-mounted array antenna, a configuration using a horn antenna as an element antenna is known. (For example, refer to Patent Document 1).

  In addition, the antenna may be required to share orthogonal polarization. In order to realize this, there is a method in which two rectangular horn antennas are crossed and arranged vertically (see, for example, Patent Document 2).

  Furthermore, as a simpler configuration, a method has been proposed in which a feeding probe for exciting one polarized wave is arranged on a substrate, and such a substrate is arranged in two layers so that the feeding probes are orthogonal to each other. (For example, see Patent Document 3).

Japanese Patent Laid-Open No. 2002-76761 US Patent Application Publication No. 2007/0085744 JP 2011-199499 A

However, the prior art has the following problems.
When an array antenna is configured by arranging a plurality of antennas as shown in Patent Document 3 as element antennas, if a tournament connection is made for all the element antennas, the feeding structure becomes complicated. As a result, the manufacturing cost and the manufacturing process increase.

  FIG. 14 is a schematic diagram showing an example of a feeding circuit of an array antenna composed of a total of 64 elements of 8 elements in the x direction and 8 elements in the y direction in the prior art. FIG. 14 shows a structure corresponding to the polarization in the x direction. In addition, in order to feed the polarized wave in the y direction, a structure obtained by rotating FIG. 14 by 90 ° is additionally required.

  Further, in order to reduce the loss in the power feeding circuit, when the power feeding circuit is entirely composed of a waveguide, the weight and volume of the power feeding circuit increase in addition to a complicated structure. As a countermeasure, it is conceivable that a part of the feeder circuit is configured using a strip line on the same plane as the feeder probe, and the wiring is pulled down to the lower part of the antenna and then connected by a waveguide (hereinafter referred to as the antenna lower part). The part pulled down vertically is called the vertical feeding part). The vertical power feeding unit can be constituted by, for example, a coaxial line or a waveguide composed of a center conductor and an outer conductor.

  FIG. 15 is an exploded perspective view showing a configuration example in which a conventional strip line is used for these four elements with four element antennas as sub-array units. The array antenna includes a first cavity portion 1, a first excitation circuit 10, a second excitation circuit 20, and a second cavity portion 30.

  The bottom of the first cavity part 1 is closed. The first excitation circuit 10 excites the first polarization. The second excitation circuit 20 excites the second polarization. The second cavity part 30 has a through hole.

  The first excitation circuit 10 includes a first power supply probe 11 and a first transmission line 12. The first power supply probe 11 is composed of a pair of elements. The pair of elements are fed in the dielectric substrate 14 in opposite phases to each other for each element antenna. The first transmission line 12 distributes the signal to the first feeding probe 11 of the element antenna that constitutes the subarray.

  Ground layers 15 and 16 having through holes having the same shape as the openings of the first cavity portion 1 are arranged above and below the dielectric substrate 14 so that the first transmission line 12 becomes a strip line.

  Similarly, the second excitation circuit 20 includes a second power feeding probe 21 and a second transmission line 22. The second power supply probe 21 is composed of a pair of elements. The pair of elements is fed into the dielectric substrate 24 in opposite phases to each other for each element antenna. The second transmission line 22 distributes the signal to the second feeding probe 21 of the element antenna that constitutes the subarray.

  Ground layers 25 and 15 having through holes having the same shape as the openings of the first cavity portion 1 are arranged above and below the dielectric substrate 24 so that the second transmission line 22 becomes a strip line.

  Accordingly, the ground layer 15 serves as a ground for both the first excitation circuit 10 and the second excitation circuit 20. Further, the second excitation circuit 20 has a 90 ° arrangement with the first excitation circuit 10 so that the polarization excited by the first power supply probe 11 and the polarization excited by the second power supply probe 21 are orthogonal to each other. It has a rotated structure.

  The first vertical feeding unit 13 feeds power to the first transmission line 12, passes through the ground layer 16 and the first cavity unit 1, and reaches the lower part of the antenna. The second vertical feeder 23 feeds power to the first transmission line 22, passes through the ground layer 15, the first excitation circuit 10, the ground layer 16, and the first cavity portion 1 and reaches the lower part of the antenna.

  When a plurality of subarrays having the four-element configuration shown in FIG. 15 are arranged, the connections after the vertical feeding section are guided by the same method as in FIG. The number of branches of the tube is reduced and the configuration is simplified.

  FIG. 16 is a schematic diagram showing the xy plane of the second excitation circuit 20 in FIG. Note that a, b, and c shown in FIG. 16 will be described later. The second power supply probe 21 is located above the opening of the first cavity portion 1.

  Further, the second transmission line 22 is disposed at a position other than the opening of the first cavity portion 1. That is, the second transmission line 22 is disposed at a position where the metal of the ground layers 25 and 15 is present above and below to form a strip line.

  FIG. 16 shows an example in which, in the second transmission line 22, the line length is determined so that the opposing second feeding probe 21 is in reverse phase, and the wiring is designed so that the element antennas are in phase. Yes.

  As shown in FIG. 15, the first feeding probe 11 and the first transmission line 12 are formed on the xy plane inside the first excitation circuit 10. The second power supply probe 21 and the second transmission line 22 are formed on the xy plane inside the second excitation circuit 20. Therefore, no physical interference occurs in these two excitation circuits.

  On the other hand, since the first vertical power feeding unit 13 and the second vertical power feeding unit 23 extend in the −z direction, they coexist on the same xy plane, and FIG. 16 shows such a state. Is shown. That is, it can be seen that the first vertical power feeding unit 13 and the second vertical power feeding unit 23 are close to each other on the xy plane. Therefore, in order to arrange the element antennas so that the first vertical power supply unit 13 and the second vertical power supply unit 23 do not physically or electrically interfere with each other, it is necessary to increase the distance between the element antennas as compared with the related art.

  As a result, the radiation pattern of the array antenna is deteriorated. In particular, when the element antenna interval exceeds one wavelength, a grating lobe occurs in the radiation pattern, and radio waves are radiated in an unnecessary direction.

  The present invention has been made in order to solve the above-described problems, and reduces or eliminates a grating lobe with a simple power supply configuration and a radiation pattern as compared with a conventional array antenna apparatus. An object of the present invention is to obtain an array antenna apparatus capable of

An array antenna apparatus according to the present invention includes a first excitation circuit that radiates radio waves of a first polarization,
Grouping a plurality of element antennas each having a second excitation circuit that radiates radio waves of a second polarization orthogonal to the first polarization into a first set of two or more element antennas. Thus, the first sub-array for the first polarization is configured, and at least one element antenna is included among the element antennas configuring the first sub-array, and the combination is different from the first set. In addition, by grouping a plurality of element antennas into a second set of two or more element antennas, a second subarray for the second polarization is formed, and the first subarray and the second subarray are formed. Are arranged to form an array antenna.

  According to the array antenna device of the present invention, the first antenna array configured in the first excitation circuit and the second array array configured in the second excitation circuit are formed by the same antenna element group. By grouping so as not to be configured, it is possible to obtain an array antenna apparatus that can reduce or eliminate grating lobes with a simple power supply configuration and a radiation pattern as compared with a conventional array antenna apparatus. .

It is the disassembled perspective view which showed the external appearance of the whole array antenna apparatus in Embodiment 1 of this invention. It is the schematic diagram which showed Example 1 of the electric power feeding range of the 1st excitation circuit and 2nd excitation circuit of an array antenna which has 9 elements in x direction and 8 elements in y direction in Embodiment 1 of this invention. It is the schematic diagram which showed the xy plane of the 1st excitation circuit in FIG. 1 of Embodiment 1 of this invention, and a 2nd excitation circuit. It is an example of the characteristic of the radiation pattern at the time of comprising the array antenna in Embodiment 1 of this invention. It is the schematic diagram which showed Example 2 of the feeding range of the 1st excitation circuit and 2nd excitation circuit of an array antenna which has 9 elements in x direction and 8 elements in y direction in Embodiment 1 of this invention. FIG. 6 is a schematic diagram illustrating an example of a first excitation circuit for a right end element and a second excitation circuit for a left end element in FIG. 5 according to the first embodiment of the present invention. It is the schematic diagram which showed Example 3 of the electric power feeding range of the 1st excitation circuit and 2nd excitation circuit of an array antenna which has 8 elements in x direction and 8 elements in y direction in Embodiment 1 of this invention. It is the schematic diagram which showed Example 4 of the feed range of the 1st excitation circuit and the 2nd excitation circuit of an array antenna which has 8 elements in x direction and 8 elements in y direction in Embodiment 1 of this invention. It is the schematic diagram which showed Example 5 of the feed range of the 1st excitation circuit and 2nd excitation circuit of an array antenna which has 8 elements in x direction and 8 elements in y direction in Embodiment 1 of this invention. It is the schematic diagram which showed the xy plane of the 1st excitation circuit and 2nd excitation circuit in Embodiment 2 of this invention. It is an example of the characteristic of the radiation pattern at the time of comprising the array antenna in Embodiment 2 of this invention. It is the schematic diagram which showed the xy plane of the 1st excitation circuit and the 2nd excitation circuit in Embodiment 3 of this invention. It is an example of the characteristic of the radiation pattern at the time of comprising the array antenna in Embodiment 3 of this invention. It is the schematic diagram which showed the example of the electric power feeding circuit of the array antenna conventionally comprised by a total of 64 elements of the x direction 8 elements and the y direction 8 elements. FIG. 5 is an exploded perspective view showing an example in which a conventional strip line is used for these four elements with four element antennas as sub-array units. It is the schematic diagram which showed the xy plane of the 2nd excitation circuit in FIG.

  Hereinafter, preferred embodiments of an array antenna apparatus of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is an exploded perspective view showing the appearance of the entire array antenna apparatus according to Embodiment 1 of the present invention. The array antenna according to the first embodiment includes a first cavity portion 1, a first excitation circuit 10, a second excitation circuit 20, and a second cavity portion 30.

  The bottom of the first cavity part 1 is closed. The first excitation circuit 10 excites the first polarization. The second excitation circuit 20 excites the second polarization. The second cavity part 30 has a through hole. In FIG. 1, the cross-sectional shape of the antenna opening is a quadrangle, but is not limited to this example, and may be various cross-sectional shapes such as a polygon, a regular polygon, or a circle. The element antenna to which the present invention can be applied is not limited to this example, and any antenna having the first excitation circuit 10 and the second excitation circuit 20 may be used.

  Further, FIG. 1 particularly illustrates a case where four element antennas are used as units of subarrays, and strip lines are used for these four elements. In FIG. 1, two sets of subarrays relating to the first excitation circuit 10 and the second excitation circuit 20 are illustrated. However, more subarrays may be arranged in the x direction or more in the y direction. May be arranged.

  The first excitation circuit 10 includes a first power supply probe 11 and a first transmission line 12. The first power supply probe 11 is composed of a pair of elements. The pair of elements are fed in the dielectric substrate 14 in opposite phases to each other for each element antenna. The first transmission line 12 distributes the signal to the first feeding probe 11 of the element antenna that constitutes the first subarray.

  Ground layers 15 and 16 having through holes having the same shape as the openings of the first cavity portion 1 are arranged above and below the dielectric substrate 14 so that the first transmission line 12 becomes a strip line.

  Similarly, the second excitation circuit 20 includes a second power feeding probe 21 and a second transmission line 22. The second power supply probe 21 is composed of a pair of elements. The pair of elements is fed into the dielectric substrate 24 in opposite phases to each other for each element antenna. The second transmission line 22 distributes the signal to the second feeding probe 21 of the element antenna that constitutes the second subarray.

  Ground layers 25 and 15 having through holes having the same shape as the openings of the first cavity portion 1 are arranged above and below the dielectric substrate 24 so that the second transmission line 22 becomes a strip line.

  Accordingly, the ground layer 15 serves as a ground for both the first excitation circuit 10 and the second excitation circuit 20. Further, the second excitation circuit 20 has a 90 ° arrangement with the first excitation circuit 10 so that the polarization excited by the first power supply probe 11 and the polarization excited by the second power supply probe 21 are orthogonal to each other. It has a rotated structure.

  The first vertical feeding unit 13 feeds power to the first transmission line 12, passes through the ground layer 16 and the first cavity unit 1, and reaches the lower part of the antenna. The second vertical feeding portion 23 feeds power to the second transmission line 22, passes through the ground layer 15, the first excitation circuit 10, the ground layer 16, and the first cavity portion 1 and reaches the lower part of the antenna.

  For the subsequent connections, the number of branches of the waveguide is reduced and the configuration is simplified, for example, by connecting with a waveguide as in the conventional case.

  Here, the technical feature of the present invention is that the first sub-array configured in the first excitation circuit 10 and the second sub-array configured in the second excitation circuit 20 are the same as in the prior art. The plurality of element antennas constituting the first sub-array and the plurality of element antennas constituting the second sub-array are partially or entirely overlapping with each other, but are not composed of the element antennas It is in the point comprised with an element antenna.

  Therefore, this technical feature of the present invention will be specifically described with reference to FIG. The numbers in parentheses described in the second cavity portion 30 in FIG. 1 indicate the element antenna numbers as a two-dimensional array in the xy plane.

  In the first excitation circuit 10, a plurality of element antennas are grouped into a first set of two or more element antennas to form a first subarray. That is, the first excitation circuit 10 has a configuration including four element antennas (1, 1), (2, 1), (1, 2), and (2, 2) as the first first subarray. Yes. Subsequently, the first excitation circuit 10 has a configuration including four element antennas (3, 1), (4, 1), (3, 2), (4, 2). 1 sub-array.

  Then, power is supplied to each of the first subarrays determined in this way via the first vertical power supply unit 13 extending in the z direction. Specifically, as shown in FIG. 1, the first vertical feeder 13 for the first first sub-array includes element antennas (1, 1), (2, 1), (1, 2), ( 2 and 2), and is disposed at a position not contacting the element antennas. Similarly, the first vertical feeder 13 for the second first subarray is surrounded by four element antennas (3, 1), (4, 1), (3, 2), and (4, 2). In addition, these element antennas are disposed at positions that do not come into contact with each other.

  In FIG. 1, through holes corresponding to the first vertical power feeding portions 13 are indicated by circles on the ground layer 16 and the first cavity portion 1.

  On the other hand, in the second excitation circuit 20, a plurality of element antennas are included so as to include at least one element antenna among the element antennas constituting the first subarray, and to be different from the first group. A second sub-array is formed by grouping each second set of That is, the second excitation circuit 20 has a configuration including four element antennas (2, 1), (3, 1), (2, 2), and (3, 2) as the first second subarray. Yes. In addition, the second excitation circuit 20 has a configuration including four element antennas (4, 1), (5, 1), (4, 2), and (5, 2). 2 sub-arrays.

  Then, power is supplied to each of the second sub-arrays determined in this way via the second vertical power supply unit 23 extending in the z direction. Specifically, as shown in FIG. 1, the second vertical feeder 23 for the first second sub-array includes element antennas (2, 1), (3, 1), (2, 2), ( 3 and 2), and is arranged at a position not contacting the element antennas. Similarly, the second vertical feeder 23 for the second second sub-array is surrounded by four element antennas (4, 1), (5, 1), (4, 2), and (5, 2). In addition, these element antennas are disposed at positions that do not come into contact with each other. As a result, the first vertical power feeding unit 13 and the second vertical power feeding unit 23 are respectively arranged at positions separated by an element antenna interval where a plurality of element antennas are arranged.

  In FIG. 1, through holes corresponding to the second vertical power feeding portions 23 are indicated by circles on the ground layers 15 and 16 and the first cavity portion 1.

  Further, in the case of an array antenna having 2M + 1 elements (M is an integer of 1 or more) in the x-axis direction and 2N elements (N is an integer of 1 or more) in the y-axis direction, the first excitation circuit 10 is configured. The first subarray and the second subarray constituting the second excitation circuit 20 are expressed by general formulas as follows.

  The first excitation circuit 10 includes (2m−1, 2n−1) th, (2m, 2n−1) th, integer m (1 ≦ m ≦ M) and integer n (1 ≦ n ≦ N), The (2m-1, 2n) -th and (2m, 2n) -th four elements are defined as the first sub-array, and power is fed through the first vertical power feeding unit 13 arranged at a position surrounded by these four elements. Is done.

  Similarly, the second excitation circuit 20 includes (2m, 2n−1) th, (2m + 1, 2n−1) th with respect to integer m (1 ≦ m ≦ M) and integer n (1 ≦ n ≦ N). , (2m, 2n) -th and (2m + 1, 2n) -th four elements are defined as the second sub-array, and power is fed through the second vertical power feeding unit 23 disposed at a position surrounded by these four elements. The

In the above description, the case where the first subarray and the second subarray are configured by four elements is illustrated using FIG. 1, but the configuration of the subarray in the present invention is limited to four elements. It is not a thing. In other words, the technical features of the present invention are as follows.
(Characteristic 1) A plurality of element antennas corresponding to the first excitation circuit 10 that radiates radio waves of the first polarization are grouped for each first set of two or more element antennas, and the first polarization is obtained. A first sub-array for waves is constructed.
(Characteristic 2) On the other hand, the second polarized radio wave is radiated so as to include at least one element antenna among the element antennas constituting the first sub-array and to have a different combination from the first group. The second sub-array for the second polarization is configured by grouping each second group of the plurality of element antennas corresponding to the second excitation circuit 20.
(Characteristic 3) By arranging one or a plurality of first subarrays and second subarrays each having such a configuration, the first vertical power feeding unit 13 and the second vertical power feeding unit 23 have the same element. They are not arranged at positions surrounded by the set, and are arranged at positions separated by one element antenna interval or more.

  The specific configurations of the first subarray and the second subarray having these features 1 to 3 will be described later with reference to FIGS. 2, 5, 7, 8, and 9. In these drawings, the solid line represents the power supply range of the first excitation circuit 10. Then, a first sub-array is configured by grouping each first set of element antennas surrounded by the solid line. The dotted line represents the power supply range of the second excitation circuit 20. Then, a second sub-array is formed by grouping each second group of element antennas surrounded by the dotted line.

  In the configuration shown in FIG. 1, each of the four elements constituting the first subarray and the second subarray has two elements in common, and the other two elements are configured differently. .

  FIG. 2 shows Example 1 of the feeding range of the first excitation circuit 10 and the second excitation circuit 20 of the array antenna having 9 elements in the x direction and 8 elements in the y direction in the first embodiment of the present invention. It is a schematic diagram. In FIG. 2, the leftmost element is not used as the second excitation circuit 20. Similarly, the rightmost element is not used as the first excitation circuit 10. That is, the number of elements used for the first excitation circuit 10 and the second excitation circuit 20 is the same. Therefore, the radiation pattern between polarized waves is ideally the same. In this example, it operates as an array antenna of 8 × 8 elements for any polarization.

  FIG. 3 is a schematic diagram showing an xy plane of the first excitation circuit 10 and the second excitation circuit 20 in FIG. 1 according to the first embodiment of the present invention. Note that a, b, and c shown in FIG. 3 will be described later in comparison with FIG. The first power supply probe 11 and the second power supply probe 21 are located above the opening of the first cavity portion 1.

  Further, the first transmission line 12 and the second transmission line 22 are arranged at a position other than the opening of the first cavity portion 1. In other words, the first transmission line 12 is arranged at a position where the metal of the ground layers 15 and 16 exists above and below, and the second transmission line 22 is arranged at a position where the metal of the ground layers 25 and 15 exists above and below. Each forms a strip line.

  In FIG. 3, in the first transmission line 12 and the second transmission line 22, the line length is determined so that the first feeding probe 11 and the second feeding probe 21 facing each other are in opposite phases, and the element antennas Shows an example in which the wiring is designed to be in phase.

  As described above, the first feeding probe 11 and the first transmission line 12 are formed on the xy plane inside the first excitation circuit 10 as shown in FIG. Moreover, the 2nd electric power feeding probe 21 and the 2nd transmission line 22 are formed on the xy plane inside the 2nd excitation circuit 20, as shown in FIG.3 (b). Therefore, no physical interference occurs in these two excitation circuits.

  On the other hand, as shown in FIG. 1, the first vertical power feeding unit 13 and the second vertical power feeding unit 23 extend in the −z direction, and therefore coexist on the same xy plane. However, as is apparent from FIG. 3, the first and second subarrays are different in configuration, and therefore, the first vertical feed unit 13 and the second vertical feed unit 23 are the element antennas surrounded by them. Because the arrangement is different, the distance between the element antennas is separated by about one opening in FIG. 3 and does not come into physical contact. Therefore, in order to prevent the first vertical power feeding unit 13 and the second vertical power feeding unit 23 from physically interfering with each other when surrounded by the same four elements (see FIG. 16) as in the prior art. There is no limitation on the arrangement interval of the element antennas.

  In FIG. 1, the second vertical power feeder 23 passes through the first excitation circuit 10. However, as is apparent from FIG. 3, the second vertical feeding portion 23 does not come into contact with the first transmission line 12, and no electrical influence occurs. Therefore, deterioration of the radiation pattern of the array antenna can be avoided.

  Next, calculation examples of the element antenna interval and the radiation pattern are shown below. More specifically, a, b, and c in FIGS. 3 and 16 will be described based on numerical values. In FIG. 3, the cavity diameter a indicates the diameter of the opening in the first cavity portion 1 (hereinafter, the width of the opening in the first cavity portion 1 is referred to as the diameter of the opening). Further, the inter-cavity gap b is a gap between the adjacent cavity portions 1, the second transmission line 22 and the second vertical power feeding portion 23 are disposed, and the physical gap with the first vertical power feeding portion 13 is disposed. The gap value required when interference is avoided is shown. The element antenna interval c is defined as the sum of the cavity diameter a and the inter-cavity gap b. Here, the same element antenna spacing is used in both the x and y directions.

  When the cavity diameter a was 0.67λ (λ: wavelength), the inter-cavity gap b was 0.37λ. As a result, the element antenna interval c (= a + b) is 1.04λ.

  As a comparison with FIG. 3, FIG. 16 is a schematic diagram showing the xy plane of the second excitation circuit 20 in the configuration of the excitation circuit using the conventional strip line shown in FIG. In FIG. 16, the definitions of the cavity diameter a, the inter-cavity gap b, and the element antenna interval c are the same as those in FIG.

  When the cavity diameter a was 0.67λ, the inter-cavity gap b was 0.44λ. As a result, the element antenna interval c (= a + b) is 1.11λ. Here, the same element antenna spacing is used in both the x and y directions.

  FIG. 4 is a characteristic example of a radiation pattern when the array antenna according to Embodiment 1 of the present invention is configured. This array antenna is composed of a total of 64 elements of 8 elements in the x direction and 8 elements in the y direction, using the element antenna interval in the first embodiment and the conventional element antenna interval. Note that the radiation pattern on the xz plane and the radiation pattern on the yz plane are the same. In FIG. 4, the characteristics of the array antenna according to the first embodiment corresponding to FIG. 3 are indicated by solid lines, and the characteristics of the conventional array antenna corresponding to FIG. 16 are indicated by dotted lines.

  Since both the first embodiment and the conventional element antenna interval c exceed 1λ, it can be seen that a grating lobe is generated. In FIG. 4, the lobes near ± 65 ° in the first embodiment and the lobes near ± 60 ° in the prior art correspond to grating lobes. Comparing the characteristics of the two, in the first embodiment, it is possible to reduce the element antenna interval as compared with the conventional case, so that the grating lobe shifts to the wide angle side. This indicates that the radiation pattern is improved.

  FIG. 5 shows Example 2 of the feeding range of the first excitation circuit 10 and the second excitation circuit 20 of the array antenna having 9 elements in the x direction and 8 elements in the y direction in the first embodiment of the present invention. It is a schematic diagram. In FIG. 2, the case where the leftmost element is not used as the second excitation circuit 20 and the rightmost element is not used as the first excitation circuit 10 has been described. On the other hand, FIG. 5 shows a case where the left and right end elements are used as the first excitation circuit 10 and the second excitation circuit 20, respectively.

  That is, in the first excitation circuit 10, as a result of grouping for each first group, the rightmost element antennas that are not grouped and are not used form a new group, together with the first group, By being grouped, it is defined and used as the first sub-array. Further, in the second excitation circuit 20, as a result of grouping for each second group, the leftmost element antennas that are not grouped and not used form a new group, together with the second group, By being grouped, it is defined and used as a second subarray. Then, a vertical power feeding unit may be installed at the left and right ends, and a two-distributed excitation circuit may be applied to the two element antennas at the end to use the elements at the end.

  FIG. 6 is a schematic diagram illustrating an example of the first excitation circuit 10 for the element at the right end and the second excitation circuit 20 for the element at the left end in FIG. 5 according to the first embodiment of the present invention. As for the elements at the right end and the left end, the number of distributions is changed from 4 to 2, as compared with the 4 elements constituting the subarray in FIG. Since the operation other than that is the same as in the case of four elements, a description thereof will be omitted.

  In the case of an array antenna having 2M elements (M is an integer of 2 or more) in the x-axis direction and 2N elements (N is an integer of 1 or more) in the y-axis direction, the first excitation circuit 10 is an integer m. (1 ≦ m ≦ M) and integer n (1 ≦ n ≦ N), (2m−1, 2n−1) th, (2m, 2n−1) th, (2m−1, 2n) th, ( 2m, 2n) power is supplied to the 4th element, and the second excitation circuit 20 has an integer m ′ (1 ≦ m ′ ≦ M−1) and an integer n (1 ≦ n ≦ N). You may comprise so that it may supply with electric power to four elements of (2n-1) th, (2m '+ 1, 2n-1) th, (2m', 2n) th, and (2m '+ 1, 2n) th.

  FIG. 7 shows an example 3 of the feeding range of the first excitation circuit 10 and the second excitation circuit 20 of the array antenna having eight elements in the x direction and eight elements in the y direction in the first embodiment of the present invention. It is a schematic diagram. In FIG. 7, elements at both ends are used as the first excitation circuit 10, but elements at both ends are not used as the second excitation circuit 20. Therefore, in the polarization by the first excitation circuit 10, it operates as an 8 × 8 element array antenna. On the other hand, since the elements at both ends are not used in the polarization by the second excitation circuit 20, it operates as a 6 × 8 element array antenna.

  If a set of element antennas at both ends not included in the second sub-array is newly defined as a second sub-array, and power is supplied using a structure with the same distribution number as 2 in FIG. Even in the polarization by the second excitation circuit 20, it is possible to operate as an array antenna having 8 × 8 elements.

  Up to this point, the case where the strip line is used for the four elements and the first excitation circuit 10 and the second excitation circuit 20 are arranged shifted by one element only in the x direction has been shown. However, the present invention is not limited to this.

  FIG. 8 shows an example 4 of the feeding range of the first excitation circuit 10 and the second excitation circuit 20 of the array antenna having eight elements in the x direction and eight elements in the y direction in the first embodiment of the present invention. It is a schematic diagram. For example, as shown in FIG. 8, the first excitation circuit 10 and the second excitation circuit 20 may be arranged so as to be shifted by one element in each of the x direction and the y direction.

  FIG. 9 shows an example 5 of the feeding range of the first excitation circuit 10 and the second excitation circuit 20 of the array antenna having eight elements in the x direction and eight elements in the y direction in the first embodiment of the present invention. It is the shown schematic diagram. For example, as shown in FIG. 9, the number of elements distributed between the first excitation circuit 10 and the second excitation circuit 20 may be different. FIG. 9 illustrates a case where the number of elements distributed by the first excitation circuit 10 is four elements and the number of elements distributed by the second excitation circuit 20 is eight elements.

  As described above, according to the first embodiment, the plurality of element antennas corresponding to the first excitation circuit that radiates the first polarized radio wave arranged in the array antenna is formed of two or more element antennas. The first subarray for the first polarization is configured by grouping each group. In addition, the second antenna that radiates radio waves of the second polarization so as to include at least one element antenna among the element antennas constituting the first subarray and to be different from the first set. By grouping a plurality of element antennas corresponding to the excitation circuit into second groups each including two or more element antennas, a second sub-array for the second polarization is configured.

  Thus, by preventing the first vertical power feeding unit and the second vertical power feeding unit from being arranged at a position surrounded by the same set of elements, the element antenna interval becomes shorter than in the past, and simple power feeding is possible. It is possible to obtain an array antenna apparatus having a configuration and capable of reducing grating lobes in the radiation pattern of the array antenna.

Embodiment 2. FIG.
In the second embodiment, the arrangement of the first vertical power feeding unit 13 and the second vertical power feeding unit 23 described in the first embodiment is the same particularly in the x-axis direction between a plurality of element antennas. A case will be described in which the gap between the cavities in the x direction is made narrower than the gap between the cavities in the y direction by arranging them in a straight line. In addition, you may arrange | position on the same straight line with respect to the y-axis direction instead of the x-axis direction.

  FIG. 10 is a schematic diagram showing an xy plane of the first excitation circuit 10 and the second excitation circuit 20 according to the second embodiment of the present invention. The difference from FIG. 3 described in the first embodiment is that the first vertical power feeding unit 13 and the second vertical power feeding unit 23 are arranged on the same straight line when viewed from the + z direction.

  That is, in FIG. 10, the y coordinate where the first vertical power feeding unit 13 is located and the y coordinate where the second vertical power feeding unit 23 is located are the same, and the first vertical power feeding unit 13 and the second vertical power feeding unit are the same. The parts 23 are arranged on the same straight line parallel to the x axis between the element antennas. As a result, the x-axis direction can be arranged so as to narrow the distance between the element antennas without receiving any interference from any of the vertical power feeding units 13 and 23. The arrangement interval in the y-axis direction is the same as that in the first embodiment.

  Next, calculation examples of the element antenna interval and the radiation pattern are shown below. More specifically, a, b, c that define the dimension in the x-axis direction and a ′, b ′, c ′ that define the dimension in the y-axis direction in FIG. 10 will be described based on numerical values. In FIG. 10, the definitions of the cavity diameters a and a ′, the gaps b and b ′ between the cavities, and the element antenna intervals c and c ′ are the same as those in FIG. This is the same as in the case of FIG.

  Assuming that the cavity diameters a and a ′ are the same 0.67λ as in FIGS. 3 and 16, the inter-cavity gap b ′ is 0.37λ in the y direction, as in the first embodiment. . As a result, the element antenna interval c ′ (= a ′ + b ′) is 1.04λ.

  On the other hand, in the x direction, the gap b between the cavities was 0.3λ. As a result, the element antenna interval c (= a + b) is 0.97λ. Therefore, in the second embodiment, the element antenna interval is different between the x direction and the y direction, and the element antenna interval in the x direction can be less than 1λ.

  FIG. 11 is a characteristic example of a radiation pattern when the array antenna according to Embodiment 2 of the present invention is configured. This array antenna is composed of a total of 64 elements of 8 elements in the x direction and 8 elements in the y direction, using the element antenna interval in the second embodiment and the conventional element antenna interval. In FIG. 11, the characteristics of the array antenna corresponding to the xz plane of the second embodiment corresponding to FIG. 10 are indicated by solid lines, and the characteristics of the array antenna corresponding to the yz plane of the second embodiment are shown. Is indicated by a one-dot chain line, and the characteristics of the conventional array antenna corresponding to FIG. 16 are indicated by a dotted line.

  Since both the y-direction in the second embodiment and the conventional element antenna spacing exceed 1λ, both the yz plane (one-dot chain line) and the conventional (dotted line) corresponding to the y-direction are gratings. It can be seen that a lobe has occurred. However, comparing the characteristics of both the present embodiment 2 and the conventional one, in the yz plane pattern, the present embodiment 2 can reduce the element antenna spacing in the y direction as compared with the conventional case. The robe moves to a wide angle. This indicates that the radiation pattern of the array antenna in the second embodiment is improved as compared with the conventional case. This is the same as in the first embodiment.

  On the other hand, since the element antenna interval in the x direction in the second embodiment is less than 1λ, no grating lobe occurs in the xz plane pattern. As a result, the radiation pattern in the xz plane of the array antenna is further improved than the radiation pattern in the yz plane.

  As described above, according to the second embodiment, the subarray is configured in the same manner as in the first embodiment, and the arrangement of the first vertical power feeding unit and the second vertical power feeding unit with respect to the x-axis direction They are arranged on the same straight line. As a result, the element antenna spacing in the x-axis direction is shorter than in the prior art, and it is possible to obtain an array antenna apparatus that can reduce or eliminate grating lobes in the radiation pattern of the array antenna with a simple power supply configuration. In particular, by setting the element antenna interval to less than 1λ, it is possible to obtain a radiation pattern characteristic in which no grating lobe is generated.

Embodiment 3 FIG.
In the third embodiment, in the arrangement of the first vertical feeding unit 13 and the second vertical feeding unit 23 described in the first and second embodiments, in particular, it is arranged at the center between the element antennas, By providing a notch in the antenna opening (each point on each surface of the first cavity portion 1 and the ground layers 15, 16, 25), the first vertical feeding portion 13 and the second vertical feeding portion 23 are provided. A case will be described in which a space for arrangement is ensured and the gaps between the cavities in the x and y directions are both narrowed. Here, the center between the element antennas refers to a position equidistant from each position of the element antenna surrounding the vertical feeding portion.

  FIG. 12 is a schematic diagram showing an xy plane of the first excitation circuit 10 and the second excitation circuit 20 according to Embodiment 3 of the present invention. The difference from FIG. 3 shown in the first embodiment is that the first vertical feeding unit 13 and the second vertical feeding unit 23 are arranged at the center between the element antennas when viewed from the + z direction, and This is that a cutout is provided at each point on each surface of the first cavity portion 1 and the ground layers 15, 16, 25.

  As a result, a space for arranging the vertical feeding portion can be secured at a position surrounded by the four elements. Note that this notch may be provided only in the ground layers 15, 16, and 25. As a result, both the x-axis direction and the y-axis direction can be arranged with the element antenna interval narrowed without receiving interference from the vertical feeding portion.

  Next, calculation examples of the element antenna interval and the radiation pattern are shown below. More specifically, a, b, and c in FIG. 12 will be described based on numerical values. In FIG. 12, the definitions of the cavity diameter a, the inter-cavity gap b, and the element antenna interval c are the same as those in FIGS. 3, 10, and 16. Here, the element antenna spacing is the same in both the x and y directions.

  When the cavity diameter a is 0.67λ, which is the same as in FIGS. 3, 10, and 16, the inter-cavity gap b is 0.3λ. As a result, the element antenna interval c (= a + b) is 0.97λ. That is, both the element antenna intervals in the x direction and the y direction can be less than 1λ.

  FIG. 13 is a characteristic example of a radiation pattern when the array antenna according to Embodiment 3 of the present invention is configured. This array antenna is composed of a total of 64 elements of 8 elements in the x direction and 8 elements in the y direction, using the element antenna interval in the third embodiment and the conventional element antenna interval. Note that the radiation pattern on the xz plane and the radiation pattern on the yz plane are the same. In FIG. 13, the characteristics of the array antenna according to the third embodiment corresponding to FIG. 12 are indicated by solid lines, and the characteristics of the conventional array antenna corresponding to FIG. 16 are indicated by dotted lines.

  Since the element antenna intervals in the x and y directions in the third embodiment are both less than 1λ, it can be seen that no grating lobe is generated.

  As described above, according to the third embodiment, the subarray is configured in the same manner as in the first embodiment, and the center between the element antennas is arranged with respect to the arrangement of the first vertical feeding portion and the second vertical feeding portion. Furthermore, a notch is provided at each point on each surface of the first cavity portion and the ground layer. As a result, the element antenna interval is shorter in both the x-axis direction and the y-axis direction than in the prior art, and an array antenna apparatus is obtained that can reduce or eliminate the grating lobe with a simple feeding configuration and the radiation pattern of the array antenna. be able to. In particular, by setting the element antenna interval to less than 1λ, it is possible to obtain a radiation pattern characteristic in which no grating lobe is generated.

  In the first to third embodiments of the present invention described above, the combination of the set of element antennas constituting the first subarray and the set of element antennas constituting the second subarray, and the first vertical feeder and the first Although the specific example has been demonstrated regarding the position which arrange | positions the 2 vertical electric power feeding part, this invention is not specified by these illustrations. If necessary, the combination of the element antennas constituting the first and second subarrays and the position where the first and second vertical feeding portions are arranged can be changed, and the same effect can be obtained. .

  DESCRIPTION OF SYMBOLS 1 Cavity part, 10 Excitation circuit, 11 Feed probe, 12 Transmission line, 13 Vertical feed part, 14 Dielectric substrate, 15 Ground layer, 16 Ground layer, 20 Excitation circuit, 21 Feed probe, 22 Transmission line, 23 Vertical feed part 24 dielectric substrate, 25 ground layer, 30 cavity portion.

Claims (14)

a first excitation circuit that radiates radio waves of a first polarization configured in an xy plane;
An array antenna device configured by a plurality of element antennas including a second excitation circuit that radiates radio waves of a second polarization orthogonal to the first polarization,
By grouping the plurality of element antennas into a first set of two or more element antennas, a first sub-array for the first polarization is configured,
Among the element antennas constituting the first sub-array, the plurality of element antennas include two or more element antennas so as to include at least one element antenna and have a different combination from the first group. Forming a second sub-array for the second polarization by grouping each second set of
An array antenna apparatus, wherein an array antenna is configured by arranging one or a plurality of each of the first subarray and the second subarray. The array antenna apparatus according to claim 1,
The second excitation circuit is configured in an upper part or a lower part of the xy plane constituting the first excitation circuit,
The first excitation circuit includes a first vertical power feeding unit extending in a z direction orthogonal to the xy plane in order to feed power for each of the first subarrays.
The second excitation circuit has a second vertical power feeding portion extending in the z direction in order to feed power for each second sub-array,
The first vertical feeder is surrounded by the first set of element antennas constituting the first subarray, and is disposed at a position not in contact with the first set of element antennas,
The second vertical feeder is surrounded by the second set of element antennas constituting the second subarray, and is disposed at a position not in contact with the second set of element antennas,
On the xy plane, the first vertical power feeding unit and the second vertical power feeding unit are respectively arranged so as to be in a positional relationship separated by an element antenna interval where the plurality of element antennas are arranged. An array antenna device characterized by comprising: The array antenna apparatus according to claim 2,
The array antenna apparatus, wherein the first vertical power feeding unit and the second vertical power feeding unit are arranged on the same straight line in the x direction or the y direction between the plurality of arranged element antennas. . The array antenna apparatus according to claim 2 or 3,
The first vertical feeder is disposed at the center between the element antennas constituting the first subarray,
The second vertical feeding unit is arranged at the center between element antennas constituting the second sub-array. The array antenna apparatus according to any one of claims 2 to 4,
An array antenna device, wherein a notch is provided in an antenna opening to secure a space in which the first vertical feeding unit and the second vertical feeding unit are arranged between element antennas. The array antenna device according to any one of claims 1 to 5,
As a result of being grouped for each first set, the element antennas at the end portions that are not grouped form a new set and are grouped together with the first set to form the first sub-array. Prescribed,
As a result of being grouped for each second set, the element antennas at the end portions that are not grouped form a new set and are grouped together with the second set to form the second sub-array. An array antenna apparatus characterized by being defined. The array antenna device according to any one of claims 1 to 6,
An element antenna of 2M + 1 elements (M is an integer of 1 or more) in the x-axis direction and 2N elements (N is an integer of 1 or more) in the y-axis direction is disposed on the xy plane,
In the first excitation circuit, for the integer m (1 ≦ m ≦ M) and the integer n (1 ≦ n ≦ N), the (2m−1, 2n−1) th and (2m, 2n−1) th , (2m-1, 2n) th, (2m, 2n) th four elements are defined as the first sub-array,
In the second excitation circuit, for the integer m (1 ≦ m ≦ M) and the integer n (1 ≦ n ≦ N), the (2m, 2n−1) th, (2m + 1, 2n−1) th, ( (2m, 2n) -th and (2m + 1, 2n) -th four elements are defined as the second sub-array. The array antenna device according to any one of claims 1 to 6,
On the xy plane, an element antenna having 2M elements (M is an integer of 2 or more) in the x-axis direction and 2N elements (N is an integer of 1 or more) in the y-axis direction,
In the first excitation circuit, for the integer m (1 ≦ m ≦ M) and the integer n (1 ≦ n ≦ N), the (2m−1, 2n−1) th and (2m, 2n−1) th , (2m-1, 2n) th, (2m, 2n) th four elements are defined as the first sub-array,
In the second excitation circuit, for the integer m ′ (1 ≦ m ′ ≦ M−1) and the integer n (1 ≦ n ≦ N), the (2m ′, 2n−1) th, (2m ′ + 1, 2n-1), (2m ′, 2n) th, (2m ′ + 1, 2n) th four elements are defined as the second sub-array. The array antenna apparatus according to claim 7, wherein
In the first excitation circuit, for the integer n (1 ≦ n ≦ N), the (2M + 1, 2n−1) th and (2M + 1, 2n) th two elements are further defined as the first subarray. ,
In the second excitation circuit, for the integer n (1 ≦ n ≦ N), the (1,2n−1) th and (1,2n) th two elements are further defined as the second subarray. An array antenna device. The array antenna apparatus according to claim 8, wherein
In the second excitation circuit, for the integer n (1 ≦ n ≦ N), the (2M, 2n−1) th, (2M, 2n) th two elements and the (1,2n−1) th, 1, 2n) The two second elements are each further defined as the second sub-array. The array antenna device according to any one of claims 2 to 10,
The first excitation circuit constituting the first subarray is:
A first feeding probe that radiates radio waves of a first polarization plane;
A first transmission line that feeds power to the first feeding probe;
The first feeding probe is configured by a pair of elements so that power is fed in reverse phase to each other for each element antenna constituting the first subarray.
The starting point of the first transmission line is connected to the first vertical feeding unit, and is connected to each of the first feeding probes in the first subarray by a line branched from the starting point. And distributing power to each of the first feeding probes,
The second excitation circuit constituting the second subarray includes:
A second feeding probe that radiates radio waves of a second polarization plane orthogonal to the first polarization plane;
A second transmission line that feeds power to the second feeding probe;
The second feeding probe is configured by a pair of elements so that power is fed in reverse phase to each other for each element antenna constituting the second sub-array,
The starting point of the second transmission line is connected to the second vertical power feeding unit, and is connected to each of the second power feeding probes in the second subarray by a line branched from the starting point. Thus, the power is distributed to each of the second power feeding probes. The array antenna apparatus according to claim 11, wherein
A first cavity comprising a metal conductor having a bottom closed and an opening on the top surface;
A second cavity made of a metal conductor having a through-hole having the same shape as or similar to the opening of the first cavity,
The first excitation circuit is disposed on an upper surface of the first cavity;
The second excitation circuit is disposed on an upper surface of the first excitation circuit;
The second cavity is disposed on an upper surface of the second excitation circuit;
The first vertical feeding portion extends in the z direction from the starting point of the first transmission line, and pulls out the transmission line to the antenna portion through the first cavity.
The second vertical power feeding unit extends in the z direction from the starting point of the second transmission line, and passes through the first excitation circuit and the first cavity to transmit the transmission line to the antenna unit. An array antenna device characterized by being pulled out. The array antenna apparatus according to claim 11 or 12,
In the first excitation circuit, the first transmission line is disposed inside a first dielectric,
In the second excitation circuit, the second transmission line is disposed inside a second dielectric,
A first conductor ground and a second conductor ground are arranged on the upper and lower surfaces of the first dielectric so that the first transmission line becomes a strip line,
The second conductor ground and the third conductor ground are arranged on the upper and lower surfaces of the second dielectric so that the second transmission line becomes a strip line. Antenna device. The array antenna device according to any one of claims 1 to 13,
The array antenna device, wherein a cross-sectional shape of an antenna opening of each element antenna constituting the array antenna is a polygon, a regular polygon, or a circle.

Images