Array antenna, sparse rectangular array and antenna design method

Abstract

The embodiment of the present invention relates to the field of antenna technology, and discloses an array antenna, a sparse rectangular array, and an antenna design method. In the embodiment of the present invention, a sparse array antenna is disclosed, and the sparse array antenna includes at least one array element; the numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit array element spacing, and the second ratio is the ratio of the array aperture to the unit array element spacing; the array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements. In the embodiment of the present invention, a type of sparse array antenna is provided, which can be reflected as the structural state of the minimum redundant linear array, and is more suitable for the practical application of array antennas in the electronic countermeasure reconnaissance and direction finding system of unmanned aerial vehicle platforms. At the same time, the direction finding performance is relatively strong.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to an array antenna, a sparse rectangular array and an antenna design method. Background Art

[0002] With the continuous development of radar countermeasure equipment, the single-beam scanning amplitude comparison direction finding method is commonly used in the mainstream radar countermeasure reconnaissance equipment currently in service. The accuracy and angular resolution of this direction finding method depend on the beam width, which is difficult to achieve a high level.

[0003] In order to change this situation, phase interferometer direction finding has been gradually used to replace amplitude ratio direction finding in equipment development. This can effectively improve the estimation accuracy, but it cannot distinguish multiple signals at the same time.

[0004] In comparison, the array direction finding system, which is widely adopted in many fields such as radar, communication, and sonar, has the ability to find the direction of multiple signals simultaneously, with high direction finding accuracy and strong anti-interference ability.

[0005] However, as far as UAV platforms are concerned, the uniform array antennas commonly used in radars cannot be well adapted to the application scenario of UAV platforms and their performance is poor.

[0006] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0007] The main purpose of the present invention is to provide an array antenna, a sparse rectangular array and an antenna design method, which are more suitable for the practical application of the array antenna in the electronic countermeasure reconnaissance and direction finding system of the unmanned aerial vehicle platform, and at the same time, the direction finding performance is relatively strong.

[0008] To achieve the above object, an embodiment of the present invention provides a sparse array antenna, wherein the sparse array antenna includes at least one array element;

[0009] The numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit array element spacing, and the second ratio is the ratio of the array aperture to the unit array element spacing;

[0010] The array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements.

[0011] Preferably, the sparse array antenna is a sparse linear array with a continuous difference virtual array without holes and minimum array redundancy under the same array aperture;

[0012] The sparse array antenna is also a sparse linear array with minimal array element coupling effect under the same array aperture.

[0013] To achieve the above object, an embodiment of the present invention provides a sparse rectangular array, wherein the sparse rectangular array includes the sparse array antenna as described above;

[0014] At least one sparse array antenna in the sparse rectangular array is placed in parallel according to a preset interval.

[0015] Preferably, the sparse rectangular array is a unidirectional optimal redundant rectangular array;

[0016] One sparse array antenna in the unidirectional optimal redundant rectangular array is placed opposite to another adjacent sparse array antenna.

[0017] To achieve the above object, an embodiment of the present invention provides an integrated array antenna, wherein the integrated array antenna includes the sparse rectangular array as described above;

[0018] Each sparse rectangular array corresponds to a different band.

[0019] Preferably, the sparse rectangular array includes a top layer of patch antennas for C, X, and Ku bands, and a bottom layer of patch antennas for S band;

[0020] The top layer patch antenna is located above the bottom layer patch antenna.

[0021] To achieve the above objective, an embodiment of the present invention provides a radar reconnaissance device, wherein the radar reconnaissance device includes the integrated array antenna described above.

[0022] To achieve the above object, an embodiment of the present invention provides an antenna design method, which includes the following steps:

[0023] Determine the antenna structure of the sparse array antenna according to preset constraints;

[0024] The preset constraint condition includes a first constraint condition, the first constraint condition is that the numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit array element spacing, and the second ratio is the ratio of the array aperture to the unit array element spacing;

[0025] The preset constraint condition includes a second constraint condition, and the second constraint condition is that the array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements.

[0026] Preferably, after determining the antenna structure of the sparse array antenna according to the preset constraint conditions, the antenna design method further includes:

[0027] The array element positions of the sparse array antenna are determined according to a first mapping table, wherein the first mapping table includes a correspondence between the number of array elements in a minimum redundant linear array and the array aperture.

[0028] Preferably, determining the array element positions of the sparse array antenna according to the first mapping table includes:

[0029] Acquire a first mapping table, wherein the first mapping table includes a correspondence between the number of array elements in a minimum redundant linear array and an array aperture;

[0030] Determine a maximum value in the first mapping table where the array aperture is smaller than a preset aperture, and a current number of array elements corresponding to the maximum value;

[0031] Acquire at least one sparse linear array structure whose array aperture is the preset aperture and whose number of array elements is the current number of array elements;

[0032] Acquire current difference virtual arrays respectively corresponding to the at least one sparse linear array structure;

[0033] Determine a fully scalable linear array from the current difference virtual array, and determine array element positions of a generalized minimum redundancy array according to the fully scalable linear array;

[0034] Determining the array coupling degree according to the difference virtual array element weight function of the generalized minimum redundancy array;

[0035] According to the array coupling degree, the array element positions of the optimal redundant linear array in the generalized minimum redundant array are determined.

[0036] Preferably, it also includes:

[0037] Placing the sparse array antennas in parallel at a preset interval to form a sparse rectangular array;

[0038] The sparse rectangular arrays are integrated to form an integrated array antenna.

[0039] In the embodiment of the present invention, a type of sparse array antenna is provided, which can be reflected as a minimum redundant linear array structure, and is more suitable for the practical application of array antennas in electronic countermeasure reconnaissance and direction finding systems of UAV platforms. At the same time, the direction finding performance is relatively strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of array redundancy of a first embodiment of a sparse array antenna according to the present invention;

[0041] Figure 2 A schematic diagram showing the relationship between the minimum redundant linear array and the optimal redundant linear array of the second embodiment of the sparse array antenna of the present invention;

[0042] Figure 3aA schematic diagram of a mutually prime array of a second embodiment of a sparse array antenna of the present invention;

[0043] Figure 3b A schematic diagram of a nested array of a second embodiment of a sparse array antenna according to the present invention;

[0044] Figure 3c A schematic diagram of a super nested array of a second embodiment of a sparse array antenna according to the present invention;

[0045] Figure 3d Schematic diagram of various sparse arrays of the second embodiment of the sparse array antenna of the present invention;

[0046] Figure 4a A schematic diagram of a difference virtual array element of a mutually prime array of a second embodiment of a sparse array antenna of the present invention;

[0047] Figure 4b A schematic diagram of a difference virtual array element of a generalized mutually prime array of a second embodiment of a sparse array antenna of the present invention;

[0048] Figure 4c A schematic diagram of a difference virtual array element of a nested array of a second embodiment of a sparse array antenna of the present invention;

[0049] Figure 4d A schematic diagram of a difference virtual array element of a super nested array of a second embodiment of a sparse array antenna of the present invention;

[0050] Figure 4e A schematic diagram of difference virtual array elements of an optimal redundant linear array of a second embodiment of a sparse array antenna according to the present invention;

[0051] Figure 5a This is a schematic structural diagram of a mutually prime rectangular array when the number of array elements is 36 in the first embodiment of the sparse rectangular array of the present invention;

[0052] Figure 5b It is a schematic diagram of the structure of a nested rectangular array when the number of array elements is 36 in the first embodiment of the sparse rectangular array of the present invention;

[0053] Figure 6a It is a schematic diagram of the structure of a sparse rectangular array in a first embodiment of a sparse rectangular array of the present invention;

[0054] Figure 6b It is a schematic diagram of the structure of a difference virtual array in the first embodiment of a sparse rectangular array of the present invention;

[0055] Figure 7a It is a schematic diagram of the structure of a unidirectional optimal redundant rectangular array in the first embodiment of a sparse rectangular array of the present invention;

[0056] Figure 7bIt is a schematic diagram of the structure of a bidirectional optimal redundant rectangular array in the first embodiment of a sparse rectangular array of the present invention;

[0057] Figure 8 A distribution diagram of array elements of a single-layer multi-band two-dimensional optimal redundant array antenna in another embodiment of the integrated array antenna of the present invention;

[0058] Fig. 9 It is a distribution diagram of array elements of a double-layer multi-band integrated optimal redundant array antenna in another embodiment of the integrated array antenna of the present invention;

[0059] Fig.10 A schematic diagram of a flow chart of a first embodiment of an antenna design method of the present invention;

[0060] Fig.11 A schematic diagram of a flow chart of a second embodiment of an antenna design method according to the present invention;

[0061] Fig.12 for Fig.11 Schematic diagram of the process of step S20.

[0062] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0063] The following will analyze the uniform array antenna used in the related art.

[0064] Sparse arrays can be applied in UAV platforms.

[0065] (1) A sparse array is an array structure obtained by sparsely selecting elements from a uniform array. Compared with an equal-aperture uniform array, a sparse array has fewer elements and a correspondingly lighter antenna weight, which is more in line with the characteristics of limited load on UAV platforms.

[0066] (2) The reduction in the number of array elements also means a reduction in the number of channels, which reduces the power consumption of the system and is more suitable for the limited power supply of UAV platforms.

[0067] (3) The sparse array structure with smaller aperture is more adaptable to the size limitations of UAV platforms.

[0068] In summary, small sparse arrays are more suitable for the practical application of array antennas in the electronic countermeasure reconnaissance and direction finding system of UAV platforms than uniform arrays.

[0069] As follows, embodiments of the present invention disclose an array antenna, a sparse rectangular array, and an antenna design method.

[0070] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0071] The first embodiment of the sparse array antenna of the present invention is as follows.

[0072] In a first embodiment, the sparse array antenna includes at least one array element;

[0073] The numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit array element spacing, and the second ratio is the ratio of the array aperture to the unit array element spacing;

[0074] The array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements.

[0075] It can be understood that the type of sparse array antenna described in the first embodiment can satisfy two constraints (also referred to as restriction conditions).

[0076] The first constraint of the two constraints is that the ratio of the distance difference between any two array elements in the array to the unit array element spacing d covers the range less than ρ max All positive integers. Among them, ρ max It represents the ratio of array aperture to unit element spacing d.

[0077] Among them, ρ max This is the second ratio mentioned above.

[0078] The second constraint of the two constraints is that, under the condition of the same array element number S, the array redundancy of the current array is the minimum.

[0079] In one embodiment, when the number of array elements S is given, the array redundancy R e Can be,

[0080]

[0081] Among them, ρ max It represents the ratio of array aperture to unit element spacing d.

[0082] In one embodiment, the sparse array antenna may be a sparse linear array.

[0083] In one embodiment, the sparse linear arrays satisfying the two constraints described in the first embodiment may be referred to as minimum-redundancy linear-arrays (MRA).

[0084] In this embodiment, a type of sparse array antenna is provided, which can be reflected as a minimum redundant linear array structure, and is more suitable for the practical application of array antennas in electronic countermeasure reconnaissance and direction finding systems of UAV platforms. At the same time, the direction finding performance is relatively strong.

[0085] To facilitate understanding of the first embodiment of the sparse array antenna of the present invention and the first embodiment of the antenna design method of the present invention described below, the attached Figure 1 Described with antenna example.

[0086] For example, to intuitively demonstrate the array redundancy and two constraints of the sparse array, assume that the coordinates of the sparse linear array element are P S ={0,d,3d,5d}, and consider this sparse linear array as a uniform linear array with some array elements output zero, we can get Figure 1 The right side of is a sparse covariance matrix containing many zero-valued elements (e.g., zero-valued covariance).

[0087] See also Figure 1 , array redundancy R e The denominator in the calculation formula is equal to Figure 1 The number of all elements in the dashed box (e.g. ρ max is 5), that is, the main diagonal (i.e. Figure 1 The number of all diagonals below the main diagonal in the right matrix (e.g., 5). e The numerator S(S-1) / 2 in the calculation formula is equal to Figure 1 The number of non-zero elements (e.g., non-zero covariance) on the diagonals of each level in the solid triangle box in is S(S-1) / 2=(1,2,1,1,1).

[0088] Wherein, S represents the number of physical array elements, which can be regarded as a variable for different arrays.

[0089] When there are non-zero elements on each level of the diagonal, it also means that the first constraint of the minimum redundant array is met.

[0090] Based on the analysis of the Toeplitz property of the uniform linear array covariance, we know that Figure 1 The covariances on the diagonal have the same theoretical value, so when there are multiple non-zero values ​​on the same diagonal, the covariance matrix is ​​redundant. The minimum redundant array has the lowest number of repetitions of elements with the same theoretical value.

[0091] In addition, under the condition of the same number of array elements S, the minimum redundant linear array has the largest aperture among all fully scalable sparse linear arrays, and the array direction finding accuracy is the highest under the same DOA (Direction Of Arrival) estimation method.

[0092] In addition, unlike coprime arrays and nested arrays, the element positions of a minimum redundant array generally have no analytical expression. Given the number of elements S, the array structure can be determined by an exhaustive method.

[0093] For example, currently, specific array element positions of all minimum redundant linear arrays with an array aperture of 101 times a half wavelength (ie, S≤17) are known.

[0094] Table 1 below shows the corresponding relationship between the number of array elements of a known minimum redundant array and the array aperture.

[0095] Table 1 Corresponding relationship between the number of array elements and array aperture of the minimum redundant linear array

[0096]

[0097] The following is a second embodiment of the sparse array antenna of the present invention.

[0098] According to Table 1, although the direction finding performance of the minimum redundant linear array is strong, there are only five array structures with array apertures between 10 and 40 times the half wavelength, and there is no corresponding minimum redundant linear array structure under the condition of apertures exceeding 5 / 6. Therefore, in actual array design, it is difficult to give full play to the direction finding performance advantages of the redundant linear array.

[0099] Among them, the aperture condition exceeding 5 / 6 can be understood by giving an example: from 10 to 40, there are 31 aperture lengths in total, at least 26 of which have no corresponding minimum redundant linear array structure, 26 / 31, that is, exceeding 5 / 6.

[0100] To this end, referring to the minimum redundant linear array in the first embodiment of the sparse array antenna of the present invention, the second embodiment of the sparse array antenna of the present invention proposes a generalized minimum redundant linear array (GMRA, Generalized MRA).

[0101] At the same time, based on the sparse linear array evaluation criteria, the optimal redundant linear array structure suitable for small sparse array design can be designed.

[0102] Among them, the evaluation criteria for sparse linear arrays can be understood as, under the condition of a certain aperture, there are few physical array elements and a large virtual aperture.

[0103] In order to obtain a sparse linear array with minimum redundancy under arbitrary aperture conditions, the second embodiment of the sparse array antenna of the present invention proposes a generalized minimum redundancy linear array in combination with the minimum redundancy linear array in the first embodiment of the sparse array antenna of the present invention.

[0104] In the second embodiment, the sparse array antenna is a sparse linear array with a continuous, hole-free difference virtual array and minimum array redundancy under the same array aperture;

[0105] The sparse array antenna is also a sparse linear array with minimal array element coupling effect under the same array aperture.

[0106] It can be understood that the generalized minimum redundancy criterion is that under the same array aperture, the difference virtual array is a sparse linear array with no holes and the minimum array redundancy, that is, GMRA.

[0107] For example, refer to Table 2, as follows,

[0108] Table 2 Number of types of generalized minimum redundant linear arrays with different apertures

[0109]

[0110] Among them, Table 2 shows the number of GMRAs N corresponding to each aperture when the array aperture is less than 20 times the half wavelength. G .

[0111] It can be seen that based on the generalized minimum redundancy criterion, when the array apertures are the same, multiple generalized minimum redundancy arrays usually appear.

[0112] Furthermore, although these generalized minimum redundancy arrays determined based on the generalized minimum redundancy criterion have the same redundancy, the array element arrangements are different and the array coupling effects are also different.

[0113] By comparison, the GMRA with the smallest array coupling effect among multiple GMRAs can be selected.

[0114] It can be understood that, under the same array aperture, the GMRA with the least effect of array element coupling is the Optimal Redundancy Linear Array (ORLA).

[0115] For example, the coupling effect between array elements is mainly related to the array element spacing, and as the array element spacing increases, the coupling effect between array elements decreases rapidly. Therefore, we can cyclically compare the order of first-order to high-order coupling degrees and select the generalized minimum redundant array with the lowest coupling degree of each order, which is ORLA.

[0116] In this embodiment, the sparse array antenna can be set as a type of ORLA, which not only has a high direction finding performance for a minimum redundant linear array, but can also adapt to arbitrary aperture conditions, and at the same time, the influence of array element coupling is minimized.

[0117] Under the same aperture, there may be multiple minimum redundant linear arrays, but among the multiple minimum redundant linear arrays, only the minimum redundant linear array with the smallest element coupling is the optimal redundant linear array. Moreover, under each aperture, there is an optimal redundant linear array, but not necessarily a minimum redundant linear array structure.

[0118] Figure 2 In FIG. 5 , the relationship between the minimum redundant linear array and the optimal redundant linear array is shown.

[0119] Figure 2The small circle on the left represents the part of the sparse linear array structure that belongs to the minimum redundant linear array but not the optimal redundant linear array. The small circle in the middle represents the part that belongs to both the minimum redundant linear array and the optimal redundant linear array. The small circle on the right represents the part that belongs to the optimal redundant linear array but not the minimum redundant linear array. For specific examples, please refer to the following Figure 3d The minimum redundant line array and the optimal redundant line array only have intersection, and no inclusion relationship.

[0120] Figure 3a , Figure 3b , Figure 3c and Figure 3d Various sparse arrays are shown in FIG.

[0121] Figure 3a , Figure 3b , Figure 3c and Figure 3d The horizontal axis represents the array element position coordinates, and the vertical axis represents the array aperture.

[0122] Compared to Figure 3a-3d Among the several sparse linear arrays, the above-mentioned optimal redundant linear array is more suitable for the design of small sparse array antenna structure.

[0123] From above Figure 3a-3d It can be seen that for small sparse linear arrays, there are fewer optional array structures for coprime arrays, nested arrays, and super nested arrays, which is not conducive to practical array design. The optimal redundant linear array has a continuous array aperture, which is suitable for the limited array aperture characteristics of the UAV platform.

[0124] The array performance of the optimal redundant linear array can be analyzed in depth, and the specific analysis process is as follows.

[0125] The array performance of the optimal redundant linear array under the condition of 10 array elements can be simulated and calculated below, and compared and analyzed with four typical sparse linear arrays.

[0126] In order to highlight the performance advantages of the designed optimal redundant linear array, the minimum redundant linear array with the largest aperture under the condition of 10 array elements was not selected. Instead, the optimal redundant linear array that was not a minimum redundant linear array was selected, and the array aperture was 35d.

[0127] Figure 4a-4e , the difference virtual arrays of various types of linear arrays and the corresponding weight functions are shown.

[0128] Figure 4a The difference virtual array element coordinates and weight coefficients of the coprime array are shown.

[0129] Figure 4b The difference virtual array element coordinates and weight coefficients of the generalized coprime array are shown.

[0130] Figure 4cThe difference virtual array element coordinates and weight coefficients of the nested array are shown.

[0131] Figure 4d The difference virtual array element coordinates and weight coefficients of the super nested array are shown.

[0132] Figure 4e The difference virtual array element coordinates and weight coefficients of the optimal redundant linear array are shown.

[0133] contrast Figure 4a-4e It can be seen that: (1) under the condition of the same number of array elements, the differential virtual array aperture of the optimal redundant linear array is the largest and the array coupling effect is the lowest; (2) the differential virtual array of the nested array has the largest array element weight coefficient on both sides of the 0 coordinate, and the corresponding array element coupling effect is the largest.

[0134] Based on the difference virtual array and the actual physical array element distribution, the specific performance indicators of the optimal redundant linear array are shown in Table 3 below:

[0135] Table 3 Optimal redundant linear array performance index table

[0136]

[0137] From the analysis of Table 3, we can find that: (1) the optimal redundant linear array has the largest array freedom; (2) the array expansion of the optimal redundant linear array, nested array and super nested array is 100%, and they are all fully scalable sparse arrays; (3) the array sparsity of the optimal redundant linear array is the largest, indicating that the optimal redundant linear array has a higher economic efficiency; (4) the first-order array coupling of the optimal redundant linear array and the super nested array is the smallest. Further comparison Figure 4d and Figure 4e It can be found that the second-order coupling degree of the optimal redundant linear array is 2, while the second-order coupling degree of the super nested array is 4, so the array coupling degree of the optimal redundant linear array is smaller.

[0138] In summary, based on the sparse linear array evaluation criteria, compared with the four existing sparse linear arrays, the optimal redundant linear array mentioned above has better direction finding performance and is more suitable for small sparse linear array design.

[0139] Under the condition of the same number of array elements, the sparse rectangular array has higher two-dimensional direction finding accuracy than the sparse parallel array. Therefore, a small sparse rectangular array structure can be designed.

[0140] Specifically, based on the unidirectional optimal redundant parallel array, a unidirectional optimal redundant rectangular array structure can be proposed. Referring to the bidirectional optimal redundant parallel array structure, a bidirectional optimal redundant rectangular array can be proposed, which further reduces the array coupling effect of the optimal redundant rectangular array.

[0141] The following is a first embodiment of a sparse rectangular array according to the present invention.

[0142] Figure 5a , Figure 5b , two typical sparse rectangular array structures are shown, including mutually prime rectangular arrays and nested rectangular arrays.

[0143] Among them, the X-axis and Y-axis represent the coordinate axes of the array in the length and width directions.

[0144] Figure 5a Schematic diagram of the structure of a mutually prime rectangular array when the number of array elements is 36 in the first embodiment of the sparse rectangular array of the present invention.

[0145] Figure 5b It is a schematic diagram of the structure of a nested rectangular array when the number of array elements is 36 in the first embodiment of the sparse rectangular array of the present invention.

[0146] Figure 5a , Figure 5b , showing a schematic diagram of array element distribution of two types of sparse matrix arrays.

[0147] Different from the array element position model of sparse linear array, the array element position of sparse rectangular array is a two-dimensional coordinate, as shown above Figure 5a , Figure 5b As shown in the two sparse rectangular array structures, the total number of array elements is S R The element positions of the sparse rectangular array are

[0148]

[0149] Among them, S R is the total number of array elements, p x ,p y are the coordinates on the X-axis and Y-axis respectively, p 2-si It is a two-element array representing two-dimensional coordinates.

[0150] Similar to the sparse parallel array, the coordinates P of the difference virtual array of the sparse rectangular array are RD It can be expressed as

[0151]

[0152] Among them, S represents the total number of physical array elements, p 2-si Represents the two-dimensional coordinates of the i-th sparse array element.

[0153] The following example illustrates the position relationship of array elements in a sparse rectangular array and a corresponding difference virtual array.

[0154] If we assume that the coordinates of the sparse rectangular array P RS for

[0155] P RS={(0,0),(0,d),(d,0),(d,d),(3d,0),(3d,d),(0,3d),(d,3d),(3d,3d)},

[0156] Then the coordinates P of the corresponding difference virtual array are RD , as Figure 6a , Figure 6b shown.

[0157] Figure 6a Schematic diagram of the structure of a sparse rectangular array in the first embodiment of the sparse rectangular array of the present invention.

[0158] Figure 6b It is a schematic diagram of the structure of the difference virtual array in the first embodiment of the sparse rectangular array of the present invention.

[0159] In the first embodiment, the sparse rectangular array includes at least one sparse array antenna as described in the first embodiment or the second embodiment of the sparse array antenna of the present invention;

[0160] At least one sparse array antenna in the sparse rectangular array is placed in parallel according to a preset interval.

[0161] It can be understood that the sparse rectangular array described in the first embodiment of the sparse rectangular array of the present invention is an optimal redundant rectangular array.

[0162] The optimal redundant rectangular array may be a sparse rectangular array formed by placing a plurality of optimal redundant linear arrays having the same structure in parallel at a certain interval.

[0163] Furthermore, the sparse rectangular array is a unidirectional optimal redundant rectangular array.

[0164] Furthermore, one sparse array antenna in the unidirectional optimal redundant rectangular array is placed opposite to another adjacent sparse array antenna.

[0165] Furthermore, the sparse rectangular array is a bidirectional optimal redundant rectangular array.

[0166] It can be understood that the optimal redundant rectangular array can be further divided into a unidirectional optimal redundant rectangular array and a bidirectional optimal redundant rectangular array.

[0167] The array element spacing between multiple optimal redundant linear arrays is still consistent with a certain optimal redundant linear array, that is, the sparse rectangular array is an optimal redundant linear array in both length and width dimensions.

[0168] Furthermore, the one-way optimal redundant rectangular array is a fully expandable rectangular array, and the two-dimensional difference virtual array of the one-way optimal redundant rectangular array is continuous and has no holes.

[0169] The element position of the unidirectional optimal redundant rectangular array can be expressed as,

[0170]

[0171] Among them, P ORLA The coordinates of the array elements representing the optimal redundant linear array are univariate coordinates.

[0172] The structure of a unidirectional optimal redundant rectangular array with a total number of 36 elements is as follows Figure 7a shown.

[0173] Figure 7a It is a schematic diagram of the structure of a unidirectional optimal redundant rectangular array in the first embodiment of the sparse rectangular array of the present invention.

[0174] Figure 7b It is a schematic diagram of the structure of a bidirectional optimal redundant rectangular array in the first embodiment of a sparse rectangular array of the present invention.

[0175] Furthermore, the unidirectional optimal redundant rectangular array is a fully scalable rectangular array, and a unidirectional optimal redundant parallel array structure exists in the unidirectional optimal redundant rectangular array.

[0176] Furthermore, one sparse array antenna in the unidirectional optimal redundant rectangular array is placed opposite to another adjacent sparse array antenna.

[0177] It is understandable that the coupling effect of the optimal redundant rectangular array can be reduced by placing one of two adjacent optimal redundant linear arrays in the unidirectional optimal redundant rectangular array in reverse order.

[0178] Specifically, directly Figure 7a The unidirectional optimal redundant parallel array in the dotted box of the unidirectional optimal redundant rectangular array is replaced by a bidirectional optimal redundant parallel array, and finally a bidirectional optimal redundant rectangular array is formed. The array element position at this time can be expressed as,

[0179]

[0180] Among them, p x represents the coordinate on the X-axis, and d is half the wavelength.

[0181] It can be understood that the bidirectional optimal redundant rectangular array reduces the coupling effect of the array elements by placing the array elements of adjacent optimal redundant linear arrays in reverse, but at the same time also sacrifices the number of difference virtual array elements, thereby reducing the direction finding accuracy of the array. Therefore, the bidirectional optimal redundant rectangular array structure is suitable for high-frequency signals with strong array coupling effects, such as Ku-band array antennas.

[0182] The following is a first embodiment of the integrated array antenna of the present invention.

[0183] Considering that the array antenna is affected by the size of the antenna element and the spacing between the array elements, the frequency band coverage is narrow.

[0184] In order to expand the signal coverage range, based on the optimal redundant rectangular array and combined with the actual size of the antenna, a single-layer small multi-band integrated optimal redundant array antenna structure can be designed to achieve effective coverage of multiple narrowband signals in the 2-18GHz frequency band.

[0185] In this embodiment, the integrated array antenna includes the first embodiment of the sparse rectangular array of the present invention;

[0186] Each sparse rectangular array corresponds to a different band.

[0187] For example, different bands include four frequency bands: Ku, X, C, and S. The sparse rectangular arrays corresponding to different bands can be simply referred to as antenna subarrays.

[0188] The following is another embodiment of the integrated array antenna of the present invention.

[0189] A single-layer small-sized multi-band integrated optimal redundant array antenna structure is described in detail below.

[0190] The integrated array antenna may be a single-layer multi-band small two-dimensional sparse array antenna with a size of 1.5 meters in length and 0.3 meters in width.

[0191] By integrating four groups of optimal redundant array antennas with different frequency band coverage capabilities into the same antenna plane, coverage of multiple narrowband signals in the 2-18 GHz frequency band is achieved.

[0192] This full-band antenna specifically includes antenna subarrays for four frequency bands: Ku (12-18GHz), X (8-12GHz), C (4-8GHz), and S (2-4GHz). The corresponding initial uniform subarray element sizes are 36*30, 36*20, 36*14, and 36*2, respectively. The actual number of physical elements are 10*9, 10*8, 10*6, and 10*2, respectively. The number of sparse physical elements is less than 1 / 9 of that of the corresponding uniform array antenna.

[0193] The signal processing systems of each antenna subarray are independent of each other.

[0194] Array element distribution, such as Figure 8 shown.

[0195] The following is another embodiment of the integrated array antenna of the present invention.

[0196] In order to reduce the size of the antenna and improve the two-dimensional direction finding accuracy, a double-layer small multi-band integrated optimal redundant array was proposed.

[0197] Hereinafter, a double-layer multi-band integrated optimal redundant array is described in detail.

[0198] With the development of modern wireless communication systems, the application of multi-frequency antenna technology has developed rapidly. For example, smartphones usually contain more than two antennas with different frequency bands. In order to further improve the direction finding performance of the S-band subarray and reduce the size of the antenna, a double-layer patch structure can be considered.

[0199] Further, the sparse rectangular array includes a top layer of patch antennas for C, X, and Ku bands, and a bottom layer of patch antennas for S band;

[0200] The top layer patch antenna is located above the bottom layer patch antenna.

[0201] To this end, this embodiment proposes a double-layer multi-band integrated optimal redundant array antenna structure with a size of 1.5 meters long and 0.25 meters wide, as follows Fig. 9 shown.

[0202] The top-layer patch antenna and the bottom-layer patch antenna may share an antenna plane.

[0203] Fig. 9 In the figure, the array elements within the solid box are located on the top patch, and the dotted box part is for S-band signals and is located on the bottom patch. The array elements in the solid box part and the dotted box part share the same antenna plane. The initial uniform sub-array element scales of the four frequency bands Ku, X, C, and S of the double-layer multi-band antenna are 36*30, 36*20, 36*14, and 36*7, respectively. The actual number of physical array elements is 10*9, 10*8, 10*6, and 10*4, respectively. The number of sparse physical array elements is less than 1 / 9 of the corresponding uniform array antenna.

[0204] The signal processing systems of each antenna subarray are also independent of each other and are only integrated at the data processing layer.

[0205] The subarray structures of the C, X, and Ku bands of the above two multi-band integrated optimal redundant arrays are exactly the same, while the corresponding subarray aperture in the S-band double-layer multi-band integrated optimal redundant array antenna is larger and occupies a smaller area. Therefore, without considering the impact of the double-layer arrangement on the antenna direction finding performance, the performance of the double-layer multi-band integrated optimal redundant array antenna is better, but the corresponding antenna is more difficult to manufacture.

[0206] The following is a first embodiment of the radar reconnaissance equipment of the present invention.

[0207] In this embodiment, the radar reconnaissance equipment includes the integrated array antenna described in any embodiment of the integrated array antenna of the present invention.

[0208] Reference Fig.10 , Fig.10FIG. 1 is a flow chart of a first embodiment of an antenna design method according to the present invention.

[0209] In a first embodiment, the antenna design method comprises the following steps:

[0210] Step S10, determining the antenna structure of the sparse array antenna according to preset constraints.

[0211] Among them, the preset constraints include a first constraint, the first constraint is that the numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit element spacing, and the second ratio is the ratio of the array aperture to the unit element spacing.

[0212] The preset constraint condition includes a second constraint condition, and the second constraint condition is that the array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements.

[0213] It can be understood that, through the first embodiment of the antenna design method, the antenna structure of a type of sparse array antenna can be determined. The given type of sparse array antenna is more suitable for the practical application of array antennas in the electronic countermeasure reconnaissance and direction finding system of the UAV platform. At the same time, the direction finding performance is relatively strong.

[0214] The sparse linear array that can be determined in this embodiment can be recorded as a minimum redundant linear array.

[0215] The first embodiment of the antenna design method of the present invention has overlapping or similar technical contents with the embodiment of the sparse array antenna of the present invention, which will not be repeated here.

[0216] Reference Fig.11 , Fig.11 This is a flow chart of the second embodiment of the antenna design method of the present invention. Fig.10 The first embodiment shown provides a second embodiment of the antenna design method of the present invention.

[0217] In the second embodiment, after step S10, the antenna design method further includes:

[0218] Step S20: determining the array element positions of the sparse array antenna according to a first mapping table, wherein the first mapping table includes a correspondence between the number of array elements in a minimum redundant linear array and the array aperture.

[0219] It can be understood that the first mapping table can refer to Table 1 in the first embodiment of the sparse array antenna of the present invention.

[0220] In this embodiment, the array element position may be determined by the first mapping table.

[0221] Furthermore, unlike coprime arrays and nested arrays, the array element positions of a minimum redundant array generally have no analytical expression. When the number of array elements S is given, the array structure can be determined by an exhaustive method.

[0222] For example, the specific array element positions of all minimum redundant linear arrays with an array aperture of 101 times a half wavelength (ie, S≤17) are currently known, as shown in Table 1.

[0223] Furthermore, based on the simulation analysis of the direction finding performance of various sparse linear arrays, it can be seen that when the number of array elements is the same, the minimum redundant linear array has the largest direction finding degree of freedom, the highest direction finding accuracy, the strongest angular resolution and the least coupling effect.

[0224] Further, the step S20 includes steps S201-S207, see Fig.12 .

[0225] In this embodiment, for the second embodiment of the sparse array antenna of the present invention, a method for calculating array element positions with higher efficiency may also be proposed.

[0226] Based on the definition of the optimal redundant linear array, a more efficient method for calculating the position of the array element can be proposed in combination with the corresponding relationship between the minimum redundant array and the aperture in Table 2. This more efficient method for calculating the position of the array element can calculate the position of all optimal redundant linear array elements within 40 times the half wavelength based on an ordinary personal computer.

[0227] In addition, using high-performance computers, it is also possible to realize the array element positions of all optimal redundant linear arrays within an array aperture of 101 times the half wavelength. ORLA It is fixed and only needs to be calculated once. It can be directly selected by looking up a table (the table looked up is a new table obtained according to the optimal redundant linear array calculation method) for subsequent use.

[0228] The method for calculating the element positions of the optimal redundant linear array includes the following specific calculation steps.

[0229] Input: Table of minimum redundant linear array aperture and number of array elements.

[0230] Output: Array element positions of the optimal redundant linear array.

[0231] Step S201: obtaining a first mapping table, wherein the first mapping table includes a correspondence between the number of array elements in a minimum redundant linear array and the array aperture.

[0232] Step S202: determining the maximum value of the array aperture in the first mapping table that is smaller than the preset aperture, and the current number of array elements corresponding to the maximum value.

[0233] The aperture in the second row of lookup table 1 is smaller than the preset aperture M dThe maximum value of , and the S value corresponding to the maximum value (that is, the number of physical array elements S of the optimal redundant linear array).

[0234] Subsequently, the element positions of the generalized minimum redundancy array will be calculated.

[0235] Step S203: acquiring at least one sparse linear array structure whose array aperture is the preset aperture and whose number of array elements is the current number of array elements.

[0236] Based on permutations and combinations, search for the aperture that satisfies the preset aperture M d All sparse linear array structures with S array elements.

[0237] Step S204: obtaining current difference virtual arrays respectively corresponding to the at least one sparse linear array structure.

[0238] Compute a virtual array of differences for each sparse line array.

[0239] Step S205 : determining a fully scalable linear array from the current difference virtual array, and determining array element positions of a generalized minimum redundancy array according to the fully scalable linear array.

[0240] Determine the continuity of the difference virtual array and select all fully scalable linear arrays, so as to obtain the aperture M d At this point, the element positions of the generalized minimum redundant matrix will be obtained.

[0241] Step S206: determining the array coupling degree according to the difference virtual array element weight function of the generalized minimum redundancy array.

[0242] The difference virtual array element weight functions of all generalized minimum redundancy arrays are calculated to obtain the corresponding array coupling degree.

[0243] Step S207: determining the array element positions of the optimal redundant linear array in the generalized minimum redundant array according to the array coupling degree.

[0244] For example, the array coupling degrees can be compared cyclically from the first order to the higher order, and the generalized minimum redundant array with the smallest coupling degree of the order is selected each time for the next cycle;

[0245] Until only the last sparse line array is left, it is the optimal redundant line array.

[0246] Furthermore, according to the four progressive array design principles of more direction finding degrees of freedom, high array expansion, large array sparsity and small array coupling, an optimal redundant linear array structure suitable for the design requirements of small sparse linear arrays can be designed.

[0247] Among them, there is no clear expression for the position of the array elements in the minimum redundant linear array, but the array element position table under small aperture can be obtained through exhaustive search by computer equipment. When designing a small sparse linear array, you can directly look up the table to select the minimum redundant linear array with the largest aperture that does not exceed the upper limit of the array size.

[0248] Furthermore, it also includes:

[0249] Placing the sparse array antennas in parallel at a preset interval to form a sparse rectangular array;

[0250] The sparse rectangular arrays are integrated to form an integrated array antenna.

[0251] The repeated or similar technical contents in this embodiment and the above-mentioned sparse rectangular array embodiment and integrated array antenna embodiment are not repeated here.

[0252] Other embodiments or specific implementation methods of the antenna design method described in the present invention can refer to the above-mentioned sparse array antenna embodiment, sparse rectangular array embodiment and integrated array antenna embodiment, which will not be repeated here.

[0253] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0254] The serial numbers of the embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In a unit claim that lists several means, several of these means may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order and these words may be interpreted as names.

[0255] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory, RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a communication device, etc.) to execute the methods described in each embodiment of the present invention.

[0256] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A sparse array antenna, characterized in that: The sparse array antenna includes at least one array element; The numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit array element spacing, and the second ratio is the ratio of the array aperture to the unit array element spacing; The array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements; The sparse array antenna is a sparse linear array with a continuous, hole-free difference virtual array and minimum array redundancy under the same array aperture; The sparse array antenna is also a sparse linear array with minimal array element coupling effect under the same array aperture; Wherein, the array redundancy for, in, Represents the array aperture and unit element spacing The ratio of S Indicates the number of array elements.

2. A sparse rectangular array, characterized in that: The sparse rectangular array comprises at least one sparse array antenna as claimed in claim 1; At least one sparse array antenna in the sparse rectangular array is placed in parallel according to a preset interval.

3. The sparse rectangular array according to claim 2, characterized in that: The sparse rectangular array is a unidirectional optimal redundant rectangular array; One sparse array antenna in the unidirectional optimal redundant rectangular array is placed opposite to another adjacent sparse array antenna.

4. An integrated array antenna, characterized in that: The integrated array antenna comprises at least one sparse rectangular array as claimed in claim 2 or 3; Each sparse rectangular array corresponds to a different band.

5. The integrated array antenna according to claim 4, characterized in that: The sparse rectangular array includes a top-layer patch antenna for C, X, and Ku bands, and a bottom-layer patch antenna for S band; The top layer patch antenna is located above the bottom layer patch antenna.

6. A design method for any one of the antennas as claimed in claims 1, 4 and 5 and the arrays as claimed in claims 2 and 3, characterized in that: The design method comprises the following steps: Determine the antenna structure of the sparse array antenna according to preset constraints; The preset constraint condition includes a first constraint condition, the first constraint condition is that the numerical range of the first ratio is a set of positive integers less than the second ratio, wherein the first ratio is the ratio of the distance difference between any two array elements in the sparse array antenna to the unit array element spacing, and the second ratio is the ratio of the array aperture to the unit array element spacing; The preset constraint condition includes a second constraint condition, and the second constraint condition is that the array redundancy of the sparse array antenna is the minimum array redundancy corresponding to the current number of array elements.

7. The design method according to claim 6, characterized in that: After determining the antenna structure of the sparse array antenna according to the preset constraint conditions, the design method further includes: The array element positions of the sparse array antenna are determined according to a first mapping table, wherein the first mapping table includes a correspondence between the number of array elements in a minimum redundant linear array and the array aperture.

8. The design method according to claim 7, characterized in that: The determining the array element position of the sparse array antenna according to the first mapping table comprises: Acquire a first mapping table, wherein the first mapping table includes a correspondence between the number of array elements in a minimum redundant linear array and an array aperture; Determine a maximum value in the first mapping table where the array aperture is smaller than a preset aperture, and a current number of array elements corresponding to the maximum value; Acquire at least one sparse linear array structure whose array aperture is the preset aperture and whose number of array elements is the current number of array elements; Acquire current difference virtual arrays respectively corresponding to the at least one sparse linear array structure; Determine a fully scalable linear array from the current difference virtual array, and determine array element positions of a generalized minimum redundancy array according to the fully scalable linear array; Determining the array coupling degree according to the difference virtual array element weight function of the generalized minimum redundancy array; According to the array coupling degree, the array element positions of the optimal redundant linear array in the generalized minimum redundant array are determined.

9. The design method according to claim 7, characterized in that: Also includes: Placing the sparse array antennas in parallel at a preset interval to form a sparse rectangular array; The sparse rectangular arrays are integrated to form an integrated array antenna.

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