JP2008278034A - Array antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make both radiation pattern shapes different, and suppress side lobes of a transmission and receiving product pattern low as a result even in a case that side lobe levels of respective radiation patterns of a transmission side and a receiving side are aggravated. <P>SOLUTION: The array antenna of the invention comprises a transmission array antenna 10 and a receiving array antenna 20, the transmission array antenna 10 comprises two or more sub-arrays 1a, 1b which are formed by making a plurality of element antennas 1 as a unit, and the receiving array antenna 20 comprises two or more sub-arrays 2c to 2f which are formed by making a plurality of element antennas 2 as a unit. While a distance D<SB>1</SB>between the sub-antennas 1a, 1b, and distances D<SB>2a</SB>, D<SB>2b</SB>, D<SB>2c</SB>between respective sub-array antennas 2c, 2d, 2e, 2f are different from arrangement periods d<SB>1</SB>, d<SB>2</SB>of the element antennas 1, 2, numbers of sub-array antennas are established to be different for the transmission array antenna 10 and the receiving array antenna 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an array antenna device, and more particularly to an array antenna device that is used for radar and the like, includes transmission and reception antennas, and the transmission and reception antennas are composed of a plurality of element antennas. .

  Generally, in an array antenna apparatus, the element antennas are arranged at equal intervals (see, for example, Patent Document 1).

  However, it may be difficult to arrange all the element antennas at equal intervals due to restrictions on the power supply circuit that supplies power to the element antennas and the convenience of providing a member for fixing the antennas. At this time, it is necessary to divide a part of the element antenna array to form a subarray, and arrange the array antennas so that a part of them is unequally spaced. As a result, the side lobe level of the antenna radiation pattern is increased as compared with the array antennas that are all arranged at equal intervals.

  As an example, FIG. 8 is a schematic diagram showing openings of an array antenna apparatus in which a subarray is formed and a part of the element antenna array is unequally spaced. In FIG. 8, it is assumed that a white circle represents a transmission side and a black circle represents a reception side. Reference numeral 1 denotes a transmitting-side element antenna, 10 denotes a transmitting-side array antenna, and the transmitting-side array antenna 10 is formed of two subarrays of transmitting-side subarrays 1a and 1b. The receiving side has the same configuration, 2 is a receiving side element antenna, 20 is a receiving side array antenna, and the receiving side array antenna 20 is formed of two subarrays of receiving side subarrays 2a and 2b.

An example of the radiation pattern of the transmitting array antenna 10 in the arrangement of FIG. 8 is shown in FIG. This is a calculation example in a case where the excitation of each element antenna has the same amplitude and the same phase in a 12 element array, the element interval d ₁ is 0.6 wavelength, and the distance D ₁ between two subarrays is 1.2 wavelength. The evaluation cut surface is the xz plane of FIG. Since the receiving array antenna 20 has the same configuration, the radiation pattern is the same as that in FIG. From FIG. 9, the first side lobe level is −10 dB, which is the first side lobe level −13 dB when the element spacing is equal (when D ₁ is 0.6 wavelength in FIG. 8). It is worse than.

  Note that the change in the radiation pattern shape, that is, the deterioration of the side lobe level depends on how the subarray is divided, and is not divided into two as in the arrangement of FIG. If it is divided into four, the shape of the radiation pattern will be different from that in FIG. However, in either case, the side lobe level is worse than that of the equidistant arrangement.

  On the other hand, in the radar apparatus, the product of both pattern shapes is more important than the individual radiation pattern shapes on the transmitting side and the receiving side. As is apparent from the radar equation, the radar detection capability is determined by the product of the gains of the transmitting antenna and the receiving antenna, and the pattern shape when the product of both is taken is also important in the pattern shape. Hereinafter, the product of both radiation patterns is referred to as a transmission / reception product pattern. For example, the transmission / reception pattern of the array of FIG. 8 is as shown in FIG. 10 from the result of FIG. As described above, since the side lobe level has deteriorated to −10 dB at the time of FIG. 9, the side lobe level in FIG. 10 showing the transmission / reception product pattern is about −20 dB.

Japanese Patent Laying-Open No. 2002-164736 (FIG. 5)

  In an array antenna device in which a conventional subarray is formed and a part of the element antenna array is unequally spaced, the sidelobe level of the array antenna deteriorates as described above. There was a problem that the level deteriorated. As a result, in the radar apparatus, radio waves other than the main beam direction are also transmitted and received, so that performance degradation such as erroneous angle measurement direction may occur.

  Further, even in an array antenna device in which a part of the array is unequally spaced, by setting a plurality of excitation amplitude levels in the element antenna, for example, by providing an amplitude distribution such as a tailor distribution, the side lobe can be reduced. You can also. However, depending on the number of elements and the element spacing, there is a limit to the target side lobe level value at the time of design, and there is a problem that it is difficult to lower the side lobe level beyond a certain value.

  The present invention has been made to solve such a problem, and is a case where a part of the array arrangement of the array antenna becomes unequal and the side lobe levels of the radiation patterns on the transmitting side and the receiving side are deteriorated. However, by making the number of subarrays that make up the transmitting array antenna and the receiving array antenna different from each other, the radiation pattern shape of both is made different. It is an object to obtain an array antenna device showing

  The present invention is an array antenna in which a plurality of element antennas are arranged at a fixed array period, and the array antenna is composed of a transmitting array antenna and a receiving array antenna, and the transmitting array antenna and the receiving antenna Each of the array antennas is composed of two or more subarrays formed by uniting the plurality of element antennas, and the distance between the subarrays is different from the array period of the element antennas, and the number of subarrays. The array antenna apparatus is characterized in that the transmitting array antenna is different from the receiving array antenna.

  The present invention is an array antenna in which a plurality of element antennas are arranged at a fixed array period, and the array antenna is composed of a transmitting array antenna and a receiving array antenna, and the transmitting array antenna and the receiving antenna Each of the array antennas is composed of two or more subarrays formed by uniting the plurality of element antennas, and the distance between the subarrays is different from the array period of the element antennas, and the number of subarrays. Is an array antenna device characterized in that the transmission array antenna is different from the reception array antenna, and therefore, a part of the array arrangement of the array antennas becomes unequal, and the radiation pattern of each of the transmission side and the reception side Even if the side lobe level deteriorates, The number of sub-arrays constituting a use array antenna and both of the radiation pattern shape different by different respectively, as a result, can exhibit a low sidelobe levels as assessed by transmitting and receiving product pattern.

  An embodiment of the present invention will be described below.

Embodiment 1 FIG.
1 is a schematic diagram showing an opening of an array antenna apparatus according to Embodiment 1 of the present invention. In FIG. 1, a white circle represents a transmission side, and a black circle represents a reception side. Reference numeral 1 denotes a transmitting-side element antenna, 10 denotes a transmitting-side array antenna, and the transmitting-side array antenna 10 is formed of two sub-arrays of transmitting-side sub-arrays 1a and 1b, which is the same as in FIG. However, in the present embodiment, the inter-subarray distance D ₁ is set to be different from the element interval (arrangement period) d ₁ of the element antenna 1.

On the other hand, regarding the receiving side, 2 represents a receiving side element antenna, 20 represents a receiving side array antenna, and the receiving side array antenna 20 is formed of four subarrays of receiving side subarrays 2c, 2d, 2e, and 2f. That is, in the present embodiment, the number of subarrays is set to be different between the transmitting array antenna and the receiving array antenna. On the receiving side, if the element spacing (arrangement period) of the element antenna 2 is d ₂ and the distances between the subarrays are D _2a , D _2b , D _2c , the inter-subarray distances D _2a , D _2b , D _2c are: It is set to be different from the element interval (array period) d _{2 of the} element antenna 2.

Since the xz plane radiation pattern of the transmitting-side array antenna 10 has the same configuration as that of FIG. 8, similarly to the case of FIG. 8, the excitation of each element antenna has the same amplitude and the same phase as in the case of FIG. ₁ 0.6 wavelength, if between the two sub-arrays distance _{D 1} was 1.2 wavelength, the characteristic shown in FIG. On the other hand, the arrangement of the receiving array antenna 20 is such that the number of divisions is changed with respect to the transmitting side. At this time, the xz plane radiation pattern of the receiving-side array antenna 20 is a 12-element array, the excitation of each element antenna has the same amplitude and phase, the element interval d ₂ is 0.6 wavelength, and the sub-array distances D _2a and D _2b. , When all D _2c are 1.2 wavelengths, the characteristics shown in FIG. 2 are obtained. As can be seen by comparing the radiation pattern of the transmitting-side array antenna 10 in FIG. 9 with the radiation pattern of the receiving-side array antenna 20 in FIG. 2, each sidelobe level is −10 dB, which is the same amount of deterioration. The direction of occurrence of side lobes that deteriorate is different. Accordingly, the transmission / reception product pattern of the array of FIG. 1 is as shown in FIG. 3 from the results of FIGS. 9 and 2. It can be seen that by taking the product of the different side lobe characteristics, the side lobe level of the transmission / reception product pattern is greatly reduced as compared to FIG. 10 where the products of the same characteristic are taken.

The element arrangement on the side (y direction in FIG. 1) orthogonal to the array direction (x direction in FIG. 1) is not particularly limited. For example, a two-dimensional array antenna as shown in FIG. 4 is formed. Also good. FIG. 4 shows an example in which a single-row 12-element array is configured with three rows on the transmission side and two rows on the reception side. In FIG. 4, reference numeral 11 denotes a transmission-side two-dimensional array antenna. The transmission-side two-dimensional array antenna 11 is formed of two subarrays of transmission-side two-dimensional subarrays 11a and 11b, and each element interval is d _1. , sub-array distance is _{D 1.} Reference numeral 21 denotes a receiving-side two-dimensional array antenna. The receiving-side two-dimensional array antenna 21 is formed of four sub-arrays of receiving-side two-dimensional subarrays 21c, 21d, 21e, and 21f. (Period) is d ₂ , and the distances between the subarrays are D _2a , D _2b , and D _2c . At this time, the inter-subarray distances D _2a , D _2b , D _2c are set to be different from the element interval (arrangement period) d ₂ of the element antenna 2. Even in this case, with the 12-element array, the excitation of each element antenna has the same amplitude and the same phase, and on the transmitting side, the element interval d ₁ is 0.6 wavelength, the distance D ₁ between the two sub-arrays is 1.2 wavelength, and reception is performed. Side, when the element spacing d ₂ is 0.6 wavelength and the inter-subarray distances D _2a , D _2b , and D _2c are all 1.2 wavelengths, the radiation pattern on the xz plane is as shown in FIG. Therefore, the transmission / reception product pattern has the characteristics shown in FIG.

  As described above, in the present embodiment, when configuring an array antenna in which a plurality of element antennas are arranged at a constant arrangement period, the array antenna is configured by a transmitting array antenna and a receiving array antenna, The array antenna and the receiving array antenna are each configured as a subarray by unitizing multiple element antennas, and the distance between the subarrays is set to be different from the array period of the element antennas, and the number of subarrays is set for transmission. When the array antenna and the receiving array antenna are set to be different, a part of the array antenna element arrangement is unevenly spaced, and the sidelobe levels of the radiation patterns on the transmitting side and the receiving side are deteriorated. Even so, the subarrays that make up the transmitting array antenna and the receiving array antenna Was a both radiation pattern shape different by different respectively, as a result, an effect that the side lobe level can be reduced as assessed by transmitting and receiving product pattern.

Embodiment 2. FIG.
In the first embodiment, the relationship between the number of elements in the subarray is not particularly limited in each of the transmitting array antenna and the receiving array antenna. However, in the example of FIG. Each of the transmission side subarrays 1a and 1b is composed of the same number of six element (six) element antennas 1, and the four reception side subarrays 2c, 2d, 2e, and 2f that constitute the reception array antenna 20 are: Each is composed of the same number of three element (three) element antennas 2.

  However, the number of elements in the subarray is not necessarily the same. Therefore, in the second embodiment, for example, as shown in FIG. 5, with respect to the receiving array antenna 20, the total number of receiving subarrays is 4, which is the same as in FIG. When the number of element antennas constituting the receiver subarray 2g is 2 elements, the reception subarray 2h is 4 elements, the reception subarray 2i is 4 elements, and the reception subarray 2j is 2 elements in order from the top of FIG. Represents. Here, for the sake of simplicity, the configuration of the transmitting-side array antenna 10 remains the same as that in FIG. 1, but is not limited thereto. Since other configurations are the same as those in the first embodiment, description thereof will be omitted here, and only portions different from those in the first embodiment will be described.

At this time, the xz plane radiation pattern of the receiving-side array antenna 20 is such that the excitation of each element antenna has the same amplitude and phase, the element interval d ₂ is 0.6 wavelength, and the inter-subarray distances D _2a , D _2b , and D _2c are When all the wavelengths are 1.2, the characteristics shown in FIG. 6 are obtained. FIG. 6 shows characteristics different from the radiation pattern shape of the receiving array antenna shown in FIG. 2, and as a result, the transmission / reception pattern of the arrangement of FIG. The characteristics shown in FIG. 7 are obtained. From this, it can be seen that characteristics different from the transmission / reception product pattern of FIG. 3 are obtained. Therefore, the number of elements constituting the subarray is one parameter in antenna design. As described above, according to the second embodiment, the degree of freedom in designing the array antenna apparatus can be increased.

  As described above, in the second embodiment, the same effect as in the first embodiment described above can be obtained. Further, in the transmitting array antenna or the receiving array antenna, the number of element antennas in the sub-array is Since the sub-arrays are not the same, but are set differently, the degree of freedom in designing the array antenna apparatus can be increased, and the convenience can be improved because it can be appropriately changed according to the use conditions and purpose of use. There is an effect.

Embodiment 3 FIG.
In the first and second embodiments, the relationship between the transmission-side subarray distance and the reception-side subarray distance is not particularly limited. However, in the arrangements of FIGS. 1, 4, and 5, the transmission-side subarray distance D is used. The calculation example of the radiation pattern when ₁ and the distances D _2a , D _2b , D _2c between the receiving side subarrays are all 1.2 wavelengths is shown.

However, the distance between these sub-arrays is not necessarily the same, and the dimensions of D ₁ and D _2a , D _2b , D _2c may be different. Accordingly, in this embodiment, for example, in the case where the transmitting-side sub-array distance _{D 1} is 0.6 wavelength, the receiving-side sub-array distance _{D 2a,} D _2b, also choose _{D 2c} to 0.7 wavelength, etc. Good. Further, the distances D _2a , D _2b , D _2c between the receiving side sub-arrays do not have to be all the same, and some of them may have different dimensions or may all be different. Other configurations are the same as those in the first embodiment, and thus description thereof is omitted here.

  Different radiation pattern shapes are obtained for the transmission-side array antenna and the reception-side array antenna in accordance with these dimensions, and as a result, an array antenna apparatus with a low sidelobe level of the transmission / reception product pattern can be realized. Further, considering the combination of the second embodiment and the present embodiment, the degree of freedom in designing the array antenna device can be further increased.

  As described above, in the third embodiment, the same effect as in the first embodiment described above can be obtained, and the distance between the subarrays in the transmission array antenna and the reception array antenna is set as the transmission array antenna. And the receiving array antenna are not the same, but are set differently, so that the degree of freedom of design of the array antenna device can be increased and can be appropriately changed according to the use conditions and purpose of use. There is an effect of improving the sex.

Embodiment 4 FIG.
In the first to third embodiments, the relationship between the transmission-side element interval and the reception-side element interval is not particularly limited. However, in the arrangements of FIGS. 1, 4, and 5, the transmission-side element interval d ₁ and the reception side It shows a calculation example of a radiation pattern when the element spacing d ₂ were respectively 0.6 wavelength.

However, the transmission-side element interval d ₁ and the reception-side element interval d ₂ are not necessarily the same, and may be different from each other. Therefore, in the present embodiment, for example, when the transmission element interval d _{1 is set} to 0.6 wavelength, the reception element interval d ₂ may be selected to be 0.7 wavelength or the like. Further, in each of the transmitting side array antenna and the receiving side array antenna, the element spacing may be changed between the subarrays. Other configurations are the same as those in the first embodiment, and thus description thereof is omitted here.

  Different radiation pattern shapes are obtained for the transmission-side array antenna and the reception-side array antenna in accordance with these dimensions, and as a result, an array antenna apparatus with a low sidelobe level of the transmission / reception product pattern can be realized. Further, considering the combination of the above-described Embodiments 2-3 and this embodiment, the degree of freedom in designing the array antenna device can be further increased.

  As described above, in the fourth embodiment, the same effect as in the first embodiment described above can be obtained, and further, the element spacing (arrangement period) of the element antennas in the transmitting array antenna and the receiving array antenna is set. Since the transmitting array antenna and the receiving array antenna are not the same and are set differently, the degree of freedom in design of the array antenna device can be increased, and it can be appropriately set according to the use conditions and purpose of use. Since it can be changed, the convenience is improved.

Embodiment 5. FIG.
In the first to fourth embodiments, the total number of elements constituting the transmitting array antenna and the receiving array antenna is not particularly limited. However, in the arrangements of FIGS. 1, 4, and 5, the transmitting array antenna 10 The calculation example of the radiation pattern in the case where the total number of element antennas 1 constituting the antenna element 12 and the total number of element antennas 2 constituting the receiving-side array antenna 20 are each 12 elements is shown.

  However, the total number of elements on the transmitting and receiving array antennas is not necessarily the same, and may be different from each other. For example, with respect to the transmitting-side array antenna 10, the transmitting-side subarrays 1a and 1b may each be configured by 7 elements, and may be configured as a total of 14 elements. Other configurations are the same as those in the first embodiment, and thus the description thereof is omitted here.

  Different radiation pattern shapes are obtained for the transmission-side array antenna and the reception-side array antenna in accordance with the number of elements, and as a result, an array antenna apparatus having a low sidelobe level of the transmission / reception product pattern can be realized. Further, considering the combination of the above embodiments 2 to 4 and the present embodiment, the degree of freedom in designing the array antenna apparatus can be further increased.

  As described above, in the fifth embodiment, the same effect as in the first embodiment described above can be obtained, and the total number of element antennas constituting the transmitting array antenna and the receiving array antenna is equal to that for transmitting. Since the array antenna and the receiving array antenna are not the same and are set differently, the degree of freedom in designing the array antenna device can be increased and can be changed as appropriate according to the use conditions and purpose of use. This has the effect of improving convenience.

Embodiment 6 FIG.
In Embodiments 1 to 5 described above, the element antennas have the same excitation amplitude level. However, as described in the sixth embodiment, an amplitude taper array may be configured by setting a plurality of excitation amplitude levels in the element antennas constituting the transmitting array antenna and the receiving array antenna. For example, in a tailor distribution in which the side lobe level is −20 dB, the amplitude taper may be set so that the array antenna aperture center element is 0 dB and the aperture end element is approximately −4.5 dB. At this time, as described in the section of the problem to be solved by the invention, depending on the number of elements constituting the array antenna and the element spacing, there is a limit to the target side lobe level value at the time of design, and the side It may be difficult to lower the lobe level beyond a certain value. However, by combining the present embodiment with the above-described first to fifth embodiments, it is possible to make the radiation pattern shapes of the transmitting-side array antenna and the receiving-side array antenna different, and as a result, the side of the transmission / reception product pattern An array antenna apparatus having a low lobe level can be realized.

  In addition, the excitation amplitude distribution given to the transmitting side array antenna and the receiving side array antenna may be the same or may be different from each other. That is, how to provide the excitation amplitude distribution becomes one parameter in antenna design, and the degree of freedom in designing the array antenna apparatus can be further increased. Further, since other configurations are the same as those of the first embodiment, description thereof is omitted here.

  As described above, in the sixth embodiment, the same effect as in the first embodiment described above can be obtained, and moreover, a plurality of excitation amplitude levels are applied to the element antennas constituting the transmitting array antenna and the receiving array antenna. By setting the excitation amplitude distribution for each of the transmitting array antenna and the receiving array antenna, the degree of freedom in designing the array antenna apparatus can be increased, and it can be appropriately set according to the use conditions and purpose of use. Since it can be changed, the convenience is improved.

It is the block diagram which showed the structure of the array antenna apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which showed an example of the radiation pattern of the receiving side array antenna in the array antenna apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which showed an example of the transmission / reception product pattern in the array antenna apparatus which concerns on Embodiment 1 of this invention. It is the block diagram which showed the modification of the structure of the array antenna apparatus which concerns on Embodiment 1 of this invention. It is the block diagram which showed the structure of the array antenna apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which showed an example of the radiation pattern of the receiving side array antenna in the array antenna apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which showed an example of the transmission / reception product pattern in the array antenna apparatus which concerns on Embodiment 2 of this invention. It is the block diagram which showed the structure of the conventional array antenna apparatus. It is explanatory drawing which showed an example of the radiation pattern of the transmission side array antenna in the conventional and the array antenna apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which showed an example of the transmission / reception product pattern in the conventional array antenna apparatus.

Explanation of symbols

  1 transmitting side element antenna, 1a, 1b transmitting side subarray, 2 receiving side element antenna, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j receiving side subarray, 10 transmitting side array antenna, 11 transmission Side two-dimensional array antenna, 11a, 11b Transmission side two-dimensional subarray, 20 Reception side array antenna, 21 Reception side two-dimensional array antenna, 21c, 21d, 21e, 21f Reception side two-dimensional subarray.

Claims (6)

An array antenna in which a plurality of element antennas are arranged at a constant arrangement period,
The array antenna is composed of a transmitting array antenna and a receiving array antenna,
The transmitting array antenna and the receiving array antenna are each composed of two or more subarrays formed by unitizing the plurality of element antennas,
An array antenna apparatus, wherein a distance between the subarrays is different from an array period of the element antennas, and a number of the subarrays is different between the transmitting array antenna and the receiving array antenna.   2. The array antenna apparatus according to claim 1, wherein in each of the transmitting array antenna and the receiving array antenna, the number of the element antennas in the subarray differs between the subarrays.   The array antenna apparatus according to claim 1 or 2, wherein a distance between the sub-arrays in the transmitting array antenna and the receiving array antenna is different between the transmitting array antenna and the receiving array antenna.   The array period of the element antennas in the transmitting array antenna and the receiving array antenna is different between the transmitting array antenna and the receiving array antenna, according to any one of claims 1 to 3. The array antenna apparatus described.   5. The total number of the element antennas constituting the transmitting array antenna and the receiving array antenna is different between the transmitting array antenna and the receiving array antenna. An array antenna device according to claim 1.   The transmission array antenna and the reception array antenna each have an excitation amplitude distribution by setting a plurality of excitation amplitude levels in the element antennas constituting the transmission array antenna and the reception array antenna. An array antenna apparatus according to any one of claims 1 to 5.

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