Large-spacing limited scanning array antenna and design method

Abstract

The invention discloses a large-spacing limited scanning array antenna and a design method, the large-spacing limited scanning array antenna comprises an antenna array plane, the antenna array plane is formed by arranging regular modular sub-arrays according to a mixed array arrangement rule, a rectangular coordinate system is established by taking a geometric center, and the whole array plane is composed of a left array plane, a middle array plane and a right array plane. The mixed arraying rule comprises two arraying modes of annular arraying and rectangular arraying, a boundary line is arranged, the shape of the boundary line can be a circle, an ellipse or a polygon, the geometric center of the antenna sub-arrays forms rectangular arraying in the sub-arrays surrounded by the boundary line, and the geometric center of the antenna sub-arrays forms rectangular arraying. And the geometric centers of the antenna sub-arrays are annularly arranged on the peripheral sub-arrays on the left and right sides of the boundary. According to the low-cost high-performance large-spacing array antenna, a large-spacing array with any length-width ratio can realize a better grating lobe suppression effect while ensuring a lower side lobe.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and in particular relates to a large-spacing limited scanning array antenna and a design method thereof. Background Art

[0002] Array antennas are widely used in radar, communications, measurement and control and other fields due to their unique fast radio beam scanning and agile characteristics. In order to ensure large-angle scanning characteristics, the unit spacing of array antennas is often set close to half a wavelength. At this time, the array scale is often large in high-power and high-gain application scenarios, and the number of antenna units increases exponentially. In some scenarios with limited angle scanning, the array scale can be reduced by increasing the unit spacing to design a large-spacing limited scanning array, thereby reducing system costs and reducing the difficulty of heat dissipation and structural design. Large-spacing limited scanning arrays will inevitably have grating lobes during the array scanning process, and the side lobes will also deteriorate, and the synthetic gain of the array will decrease.

[0003] How to solve the engineering implementation problem of large-spacing limited scanning arrays and effectively suppress grating lobes and side lobes. Scholars have proposed two solutions: unit-level non-periodic arrays and sub-array-level non-periodic arrays. The array element spacing of unit-level non-periodic arrays is mostly irregularly arranged, and the entire array presents a random distribution. This method has a high suppression effect on grating lobes, but a complex and large switching network is required between irregular antenna units and regular TR components, resulting in additional insertion loss, complex structural implementation, and reduced reliability. The difference between sub-array-level non-periodic arrays and unit-level non-periodic arrays is that it uses a standard regular sub-array as the basic unit. The antennas and back-end components in the sub-array constitute a common regular module, and the sub-arrays are irregularly arranged. This design can effectively solve the engineering implementation problems brought about by unit-level non-periodic arrays. This method is widely used in engineering, such as GBR radar arrays.

[0004] The two commonly used methods of subarray-level non-periodic array are: subarray-level staggered arrangement and subarray-level ring grating arrangement. The basic idea of ​​subarray-level staggered arrangement is to make the connecting line of the phase center of the antenna subarray no longer a straight line, but an irregular curve. In the Chinese invention patents "A subarray-level non-periodic array antenna and design method based on mirror module" (application number 202110113429.1), "A large unit spacing phased array antenna based on subarray level" (authorization number CN106911010B), "Ultra-large spacing array grating lobe-free large-angle scanning array arrangement method" (application number 202110281818.5), and "Research on distributed array grating lobe suppression algorithm based on improved genetic algorithm" published in "Fire Control Radar Technology" and other patent papers all adopt the subarray-level staggered arrangement method. This method uses an array comprehensive optimization algorithm with high gain and low grating lobes as design constraints to comprehensively optimize the staggered distance between subarrays and the unit spacing within the subarray. The design constraint requirements can be obtained through a large number of simulation optimizations.Radiation However, this method also has its inherent shortcomings. First, the comprehensive optimization requires repeated adjustment of the optimization parameters. The calculation is time-consuming. Secondly, the performance requirements and frequency bands of the array need to be re-optimized after changes, which does not meet the requirements of rapid design and versatility. Thirdly, this method leads to a more complex structural design of the array, and the installation of TR components, the layout of liquid cooling pipes, and the layout of cables are very complicated.

[0005] The basic idea of ​​subarray-level ring-grating arrangement is to use the inherent asymmetry of the ring array to suppress grating lobes. In the paper "A New Limited Scanning Air-fed Phased Array Antenna", it is proposed to use a ring grid structure and a subarray plug-in box structure to suppress grating lobes. This method has a significant effect in suppressing grating lobes, but there are many types of antenna subarrays, which makes the connection between the back-end components and the antenna subarrays complicated. In the paper "Grating Lobe Suppression of Large-spacing Subarray-level Arrays Based on Concentric Rings", the ring grid structure is improved. By using modular subarrays arranged in concentric rings on the array surface, combined with algorithm optimization, a better grating lobe suppression effect is obtained, and the engineering feasibility is further improved. However, when the unit spacing becomes larger, the subarrays in the middle of the ring are sparse and the surroundings are dense, resulting in a sharp deterioration of the sidelobe level of the array, especially the first sidelobe level. At the same time, this method also has a high dependence on computing resources.

[0006] The inventor proposed a design method for a large-spacing array antenna based on a hybrid array of rectangular and ring gratings in "A large-spacing array antenna based on a subarray-level hybrid array and design method (ZL202210377033.2)", which can achieve a good grating lobe suppression effect while ensuring low side lobes, and the use of modular subarrays greatly simplifies the design and implementation of the array. However, this method is only applicable to rectangular arrays or circular arrays with equal aspect ratios. It is no longer applicable to platforms with limited array size, especially when the aspect ratio is unequal. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems of the prior art and disclose a large-spacing limited scanning array antenna and a design method, which take into account grating lobe suppression, side lobe suppression, engineering feasibility and design efficiency.

[0008] On the one hand, the purpose of the present invention is achieved by the following technical solutions:

[0009] A large-spacing limited scanning array antenna, the large-spacing limited scanning array antenna comprising an antenna array surface, the antenna array surface is formed by regular modular sub-arrays arranged according to a hybrid array rule, and the entire antenna array surface is composed of three array surfaces of left, middle and right along the X-axis;

[0010] The mixed array rule includes two array modes: rectangular array and circular array, and a dividing line is provided;

[0011] The antenna subarrays whose geometric centers are within the dividing line form a rectangular arrangement, and the antenna subarrays whose geometric centers are on the outer subarrays on the left and right sides of the dividing line form a ring arrangement.

[0012] According to a preferred embodiment, the shape of the dividing line includes a circle, an ellipse or a polygon.

[0013] According to a preferred embodiment, a rectangular xoy coordinate system is established with the geometric center, the array length is L, the array width is W, the array length direction is defined as the X axis, and the array width direction is defined as the Y axis;

[0014] All sub-arrays in the rectangular arrangement are symmetrical about the X-axis and the Y-axis.

[0015] According to a preferred embodiment, the sub-arrays of each ring of the annular arrangement are evenly arranged in the width direction and symmetrically distributed about the X-axis.

[0016] On the other hand, the present invention also discloses:

[0017] A method for designing a large-spacing limited scanning array antenna, wherein the large-spacing limited scanning array antenna is arranged in a rectangular manner and comprises the following steps:

[0018] S11: determining an initial arrangement of the rectangular array, evenly arranging the initial rectangular array in an area with a length of W and a width of W, and the initial rectangular array is divided into M rows and N rows;

[0019] S12: Determine the final arrangement of the rectangular array, and make a judgment based on the positional relationship between the centers of all antenna subarrays in the initial rectangular array and the dividing line. If the geometric center of the i-th antenna subarray is outside the dividing line, the entire antenna subarray is deleted; otherwise, it is retained, and i represents the i-th subarray of the initial rectangular array.

[0020] According to a preferred embodiment, in step S11, M and N are determined by the following formula:

[0021] [M] = W / (L0 + Δd)

[0022] [N] = W / (L0 + Δd)

[0023] Where [·] indicates rounding up, L0 indicates the length of the antenna subarray, and Δd indicates the distance between adjacent subarrays.

[0024] According to a preferred implementation, in step S12, the value range of i is: i∈[1,M×N].

[0025] According to a preferred embodiment, the large-spacing limited scanning array antenna is arranged in a ring, comprising the steps of:

[0026] S21: Determine the arrangement of the left annular array. Evenly arrange several annular arrays outside the boundary line and in an area with an array length of L and a width of W. The radius r corresponding to the center of each annular subarray is n and the number of subarrays N n Determined by the following formulas:

[0027]

[0028] in

[0029] In the formula, [·] means rounding up, {·} means rounding down, n means the nth circle array of the annular array, and r0 represents the maximum value of the dividing line in the length direction;

[0030] S22: Determine the arrangement of the right annular array. The right annular array is symmetrical with the left annular array about the Y axis. The arrangement of the right annular array can be obtained by making the left annular array symmetrical about the Y axis.

[0031] The aforementioned main scheme of the present invention and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection by the present invention. After understanding the scheme of the present invention, those skilled in the art can understand that there are multiple combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present invention, and they are not exhaustively listed here.

[0032] Beneficial effects of the present invention:

[0033] (1) High design efficiency and fast simulation calculation speed. The array layout rules of the present invention are simple and reliable, and no optimization algorithm is required to perform complex comprehensive optimization of array performance. The computing resources are low, and no re-optimization is required after changes in array size, unit spacing, operating frequency, etc., which greatly improves the design efficiency.

[0034] (2) Simple engineering implementation. The hybrid array and modular design of the subarrays according to the same modular subarrays are very conducive to the realization of large-scale high-gain arrays. At the same time, based on the combination of ring and rectangular layout, compared with the staggered layout at the subarray level, the installation of antenna subarrays and TR components, the layout of liquid cooling pipes, and the layout of power supply and frequency cables are simpler and more conducive to maintenance.

[0035] (3) It can significantly reduce the number of array channels and obtain lower grating lobes and side lobes. The present invention can be applied to array designs with large array element spacing greater than one wavelength or even two wavelengths, while significantly reducing the number of array channels and ensuring lower grating lobes and side lobes.

[0036] (4) Able to adapt to array design under spatial constraints of arbitrary aspect ratios. The present invention can still achieve good array performance such as grating lobes and side lobes when the aspect ratios of array sizes are not equal. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a modular sub-array diagram of the array of the present invention;

[0038] Figure 2 is the initial rectangular arrangement diagram of the array of the present invention;

[0039] Figure 3 It is the final rectangular arrangement diagram of the array of the present invention;

[0040] Figure 4 This is the left annular arrangement diagram of the array of the present invention;

[0041] Figure 5 It is the arrangement diagram of the left ring array and the right ring array of the present invention;

[0042] Figure 6 is the overall arrangement diagram of the array of the present invention;

[0043] Figure 7 yes Figure 6 Normal pattern of the array shown;

[0044] Figure 8 yes Figure 6 The array shown scans 10 degrees in the X-axis direction;

[0045] Fig. 9 yes Figure 6 The array shown scans 10 degrees in the Y-axis direction;

[0046] Fig.10 yes Figure 6 The array shown scans a 15-degree pattern in the X-axis direction;

[0047] Fig.11 yes Figure 6 The array shown scans a 15 degree pattern in the Y direction. DETAILED DESCRIPTION

[0048] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0049] On the one hand, the present invention discloses a large-spacing limited scanning array antenna, which includes an antenna array surface, and the antenna array surface is composed of regular modular sub-arrays arranged according to a mixed array rule. The entire antenna array surface is composed of three array surfaces on the left, middle and right along the X-axis.

[0050] Preferably, the mixed array rule includes two array modes: rectangular array and circular array, and a dividing line is provided.

[0051] Furthermore, the shape of the dividing line may be circular, elliptical or polygonal.

[0052] Preferably, the antenna subarrays whose geometric centers are inside the dividing line form a rectangular arrangement, and the antenna subarrays whose geometric centers are outside the dividing line form a ring arrangement.

[0053] Furthermore, a rectangular xoy coordinate system is established with the geometric center, the array length is L, the array width is W, and the array length direction is defined as the X-axis and the array width direction is defined as the Y-axis.

[0054] Preferably, all sub-arrays in the rectangular arrangement are symmetrical about the X-axis and the Y-axis. In the annular arrangement, the sub-arrays of each ring are evenly arranged in the width direction and symmetrically distributed about the X-axis.

[0055] On the other hand, the present invention further discloses: a method for designing a large-spacing limited scanning array antenna, wherein the large-spacing limited scanning array antenna is arranged in a rectangular manner and comprises the following steps:

[0056] Step S11: Determine the initial arrangement of the rectangular array, evenly arrange the initial rectangular array in an area with a length of W and a width of W, and the initial rectangular array is divided into M rows and N rows.

[0057] Preferably, in step S11, M and N are determined by the following formula:

[0058] [M] = W / (L0 + Δd)

[0059] [N] = W / (L0 + Δd)

[0060] Where [·] indicates rounding up, L0 indicates the length of the antenna subarray, and Δd indicates the distance between adjacent subarrays.

[0061] Step S12: Determine the final arrangement of the rectangular array, and make a judgment based on the positional relationship between the centers of all antenna subarrays in the initial rectangular array and the dividing line. If the geometric center of the i-th antenna subarray is outside the dividing line, the entire antenna subarray is deleted; otherwise, it is retained, and i represents the i-th subarray of the initial rectangular array. In step S12, the value range of i is: i∈[1,M×N].

[0062] Preferably, the circular arrangement of the large-spacing limited scanning array antenna comprises the following steps:

[0063] S21: Determine the arrangement of the left annular array. Evenly arrange several annular arrays outside the boundary line and in an area with an array length of L and a width of W. The radius r corresponding to the center of each annular subarray is n and the number of subarrays N n Determined by the following formulas:

[0064]

[0065] in

[0066] In the formula, [·] means rounding up, {·} means rounding down, n means the nth circle array of the annular array, and r0 represents the maximum value of the dividing line in the length direction;

[0067] S22: Determine the arrangement of the right annular array. The right annular array is symmetrical with the left annular array about the Y axis. The arrangement of the right annular array can be obtained by making the left annular array symmetrical about the Y axis.

[0068] Example

[0069] like Figure 1 As shown, the modular sub-array of the array of this embodiment is an N×N rectangular uniform array (here N is 4), the unit spacing is d0=2λ, λ is the wavelength corresponding to the working frequency, and the side length of the sub-array is L0=8λ. The antenna unit can be selected from a horn antenna, a dielectric rod antenna, a microstrip or a dipole array. The detailed unit design diagram is not given here.

[0070] See also Figure 2 , Figure 3 The length of the array is selected as L = 100λ, the width is selected as W = 50λ, a rectangular xoy coordinate system is established with the geometric center, the length direction of the array is defined as the X axis, the width direction of the array is defined as the Y axis, the dividing line is selected as a circle, and the radius of the circle is r0 = 15λ.

[0071] First, determine the positions of all subarrays in the rectangular arrangement, including the following steps:

[0072] (1) Determine the initial arrangement of the rectangular array. Select the distance between adjacent sub-arrays Δd = 0.6λ, and evenly arrange the initial rectangular array in an area with a length of r0 and a width of W. The initial rectangular array can be divided into M and N rows. M and N are determined by the following formula:

[0073] [M] = W / (L0 + Δd)

[0074] [N] = W / (L0 + Δd)

[0075] In the formula, [·] means rounding up, and we can get M = N = 6. From this, we can get the initial arrangement of the rectangular array as follows Figure 2 shown.

[0076] (2) Determine the final arrangement of the rectangular array. According to the distance d between the center of all antenna subarrays in the initial rectangular array and the geometric center, i Make a judgment, if d i If it is greater than r0, the entire antenna subarray is deleted, otherwise it is retained. i represents the i-th subarray of the initial rectangular array. Thus, the final arrangement of the rectangular array after removing the rectangular array beyond the dividing line can be obtained as follows: Figure 3 As shown, the circles in the figure represent the antenna subarrays within the dividing line, and the x-shapes represent the subarrays outside the dividing line.

[0077] Then determine the positions of all sub-arrays in the annular arrangement, wherein the sub-arrays of each ring of the annular arrangement are evenly arranged in the width direction and symmetrically distributed about the X-axis. The steps are as follows:

[0078] (1) Determine the arrangement of the left circular array. Multiple circular arrays are evenly arranged outside the boundary line and in an area with a length of L and a width of W. The radius r corresponding to the center of each circular array is n and the number of subarrays N n Determined by the following formulas:

[0079] r n =r0+n×(L0+Δd)

[0080]

[0081] in,

[0082] In the formula, [·] means rounding up, {·} means rounding down, n means the nth circle array of the circular array, and the maximum value of n is 3, which means that the left circular array is three rings. Then we can get r1=23.6λ, α1=88°, N1=6; r2=32.2λ, α2=30.6°, N2=4; r3=40.8λ, α3=47.4°, N3=4. The sub-arrays of each of the three circular arrays are evenly arranged in the width direction, and we get Figure 4 The left circular array antenna sub-array arrangement is shown.

[0083] (2) Determine the arrangement of the right circular array. The right circular array is symmetrical with the left circular array about the Y axis. After making the left circular array symmetrical about the Y axis, the arrangement of the right circular array can be obtained, as shown below: Figure 5 shown.

[0084] See also Figure 6 .Will Figure 3 The distribution and Figure 5 The sub-arrays arranged in an annular pattern are distributed and arranged together to form the overall array arrangement diagram of the present invention. The entire array has 40 sub-arrays, all of which are modular sub-arrays, including 12 sub-arrays arranged in a rectangular shape in the middle, 14 sub-arrays arranged in an annular pattern on the left and right, and a total of 640 array elements.

[0085] See also Figures 7 to 11 . Figures 7 to 11 They are Figure 6 The array's normal pattern, pattern when scanning 10 degrees in the X-axis direction, pattern when scanning 10 degrees in the Y-axis direction, pattern when scanning 15 degrees in the X-axis direction, and pattern when scanning 15 degrees in the Y-axis direction are shown in the following table. The array performance statistics at different scanning angles are shown in the following table.

[0086] Table 1 Array performance statistics at different scanning angles

[0087]

[0088] As can be seen from Table 1, there is no grating lobe in the normal direction of the array. When the beam scans to 10°, the grating lobe suppression capability reaches -15dB. When the beam scans to 15°, the grating lobe suppression capability is -9dB, which has good grating lobe suppression capability. At the same time, all side lobes of the array in the normal direction and beam scanning direction are suppressed below -13dB. This shows that the large-spacing array designed by this method has good grating lobe and side lobe performance.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A large-spacing limited scanning array antenna, characterized in that: The large-spacing limited scanning array antenna includes an antenna array surface, and the antenna array surface is composed of regular modular sub-arrays arranged according to a hybrid array rule, and the entire antenna array surface is composed of three array surfaces on the left, middle and right along the X-axis; The mixed array rule includes two array modes: rectangular array and circular array, and a dividing line is provided; The antenna subarrays whose geometric centers are within the dividing line form a rectangular arrangement, and the antenna subarrays whose geometric centers are on the outer subarrays on the left and right sides of the dividing line form a ring arrangement.

2. The large-spacing limited scanning array antenna according to claim 1, characterized in that: The shape of the dividing line includes a circle, an ellipse or a polygon.

3. The large-spacing limited scanning array antenna according to claim 1, characterized in that: A rectangular xoy coordinate system is established with the geometric center, the array length is L, the array width is W, the array length direction is defined as the X axis, and the array width direction is defined as the Y axis; All sub-arrays in the rectangular arrangement are symmetrical about the X-axis and the Y-axis.

4. The large-spacing limited scanning array antenna according to claim 3, characterized in that: The sub-arrays of each ring of the annular arrangement are evenly arranged in the width direction and symmetrically distributed about the X-axis.

5. A method for designing a large-spacing limited scanning array antenna, characterized in that: The large-spacing limited scanning array antenna described in claim 4 is arranged in a rectangular manner and comprises the following steps: S11: determining an initial arrangement of the rectangular array, evenly arranging the initial rectangular array in an area with a length of W and a width of W, and the initial rectangular array is divided into M rows and N rows; S12: determining the final arrangement of the rectangular array, judging according to the positional relationship between the centers of all antenna subarrays in the initial rectangular array and the dividing line, if the geometric center of the i-th antenna subarray is outside the dividing line, the entire antenna subarray is deleted; Otherwise, keep it, i represents the i-th sub-matrix of the initial rectangular matrix.

6. The method for designing a large-spacing limited scanning array antenna according to claim 5, characterized in that: In step S11, M and N are determined by the following formula: [M] = W / (L0 + Δd) [N] = W / (L0 + Δd) Where [·] indicates rounding up, L0 indicates the length of the antenna subarray, and Δd indicates the distance between adjacent subarrays.

7. The method for designing a large-spacing limited scanning array antenna according to claim 6, characterized in that: In step S12, the value range of i is: i∈[1,M×N].

8. The method for designing a large-spacing limited scanning array antenna according to claim 6, characterized in that: The circular arrangement of the large-spacing limited scanning array antenna comprises the following steps: S21: Determine the arrangement of the left annular array. Evenly arrange several annular arrays outside the boundary line and in an area with an array length of L and a width of W. The radius r corresponding to the center of each annular subarray is n and the number of subarrays N n Determined by the following formulas: in In the formula, [·] means rounding up, {·} means rounding down, n means the nth circle array of the annular array, and r0 represents the maximum value of the dividing line in the length direction; S22: Determine the arrangement of the right annular array. The right annular array is symmetrical with the left annular array about the Y axis. The arrangement of the right annular array can be obtained by making the left annular array symmetrical about the Y axis.

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