Irregular aperture sparse array antenna and design method thereof

Abstract

The invention discloses an irregular aperture sparse array antenna and a design method thereof. The irregular aperture sparse array antenna comprises an antenna body, composite assembly holes and antenna array elements. The composite assembly hole is arranged at the edge position of the antenna body, and the antenna array elements are uniformly distributed on the antenna body; applying a genetic algorithm to carry out sparse array distribution on the antenna, taking the maximum sidelobe level as an initial condition, solving an array element position, and adding two constraint conditions of difference beam and phase control scanning; a new antenna form is provided for common-caliber compounding of millimeter waves, infrared rays and lasers, compared with an original scheme, the antenna form reduces a reflecting surface with a large size, design, installation and debugging difficulty is greatly reduced, the antenna adopts a sparse array form, good performance of the antenna is guaranteed, meanwhile, the number of antenna units is reduced, and cost is reduced. The design difficulty and cost of rear-end feed switching are reduced, two-dimensional sum-difference beams can be formed, + / -20-degree two-dimensional phase control scanning is realized, and the detection performance of the millimeter wave antenna is improved.

Description

Technical Field

[0001] The invention relates to the field of array antennas, and in particular to an irregular aperture sparse array antenna and a design method thereof. Background Art

[0002] Millimeter waves have the advantages of all-weather operation and strong anti-interference ability, but their concealment is poor, and their detection and classification and identification capabilities for stationary targets are poor. As the environment becomes more and more complex, higher requirements are placed on the target detection capabilities of radars. The limitations of a single detection method have seriously affected the performance improvement of radars. Since infrared has the advantages of high precision, anti-electronic interference and target detection, and laser has the advantages of anti-electromagnetic interference and high precision, in order to make up for the shortcomings of millimeter waves, millimeter waves are usually combined with infrared and laser to achieve stronger detection performance.

[0003] Among the current schemes for realizing the combination of millimeter waves with infrared and lasers, the common antenna form is the reflector antenna. For example, Qian Kun, Liu Jiaguo and others used a parabolic antenna-Cassegrain optical system composite structure in "Design of Millimeter Wave / Laser / Infrared Co-aperture Composite Optical System". This antenna form requires a larger reflector surface, and the installation position and angle need to be adjusted to ensure the normal performance of the entire system. The main reflector is in the form of a parabola. Although the optical accuracy is guaranteed, its transmission efficiency is not the highest for radar. In addition, this reflector needs to pass the radar signal, which causes certain errors in the amplitude and phase of the radar signal, reducing the performance of the radar antenna.

[0004] Another common antenna form is the array antenna with a center hole. For an array antenna, the antenna pattern characteristics are mainly determined by the amplitude and phase distribution of the array surface. The center hole results in no energy distribution in the center of the array antenna, which leads to the deterioration of the antenna sidelobe level. In this solution, if you want to improve the antenna sidelobe level, you need to reduce the aperture of the center hole, which also limits the aperture of the infrared detector or laser detector, resulting in reduced performance of the detector.

[0005] In summary, the form of the antenna plays a critical role in the performance of the radar system when millimeter waves are combined with infrared and lasers. Therefore, in order to improve the detection performance of the radar, it is particularly important to find a new antenna form. Summary of the invention

[0006] The purpose of the present invention is to provide an irregular aperture sparse array antenna and a design method thereof to address the above-mentioned deficiencies, thereby solving the shortcomings compared with traditional array antennas. Compared with traditional array antennas, the number of channels can be reduced, costs can be saved, and the position of each array element is more free, and the optimal radiation characteristics can be obtained by finding the optimal position through optimization.

[0007] The present invention is achieved through the following scheme:

[0008] An irregular aperture sparse array antenna includes at least but not limited to an antenna body, a composite assembly hole and antenna array elements; the composite assembly hole is arranged at the edge of the antenna body, and the antenna array elements are evenly distributed on the antenna body.

[0009] Based on the structure of the above-mentioned non-regular aperture sparse array antenna, the composite assembly hole can be a circular structure or a rectangular structure, which is selected according to the required laser composite area.

[0010] Based on the structure of the above-mentioned irregular aperture sparse array antenna and the setting of antenna array elements, a genetic algorithm is used to sparsely arrange the antenna, the maximum sidelobe level is used as the initial condition, the position of the array element is solved, and two constraints, difference beam and phased scanning, are added.

[0011] This solution also provides a design method for an irregular aperture sparse array antenna; the method comprises at least the following steps:

[0012] Step 1: Determine the antenna aperture according to the antenna beam width and gain requirements;

[0013] Step 2: According to the size of the area required for infrared and laser, a certain area is divided at the edge of the millimeter wave antenna aperture as a composite assembly hole;

[0014] Step 3: Based on the genetic algorithm, the antenna sidelobe level is set as the optimization condition, and the sum of the maximum sidelobe level of the array azimuth plane pattern and the maximum sidelobe level of the elevation plane pattern is minimized by optimizing the position of each array element, thereby determining the initial distribution position of each array element;

[0015] Step 4. Under this distribution, calculate the gain drop during the zero depth of the antenna difference beam and the two-dimensional phased scanning, and determine whether the above indicators meet the design requirements. If so, terminate the algorithm. If not, perform genetic operations such as selection, crossover and mutation on the individuals in the intermediate population. Repeat this cycle until the termination condition is met, end the cycle, and output the optimal result.

[0016] In step 4, the selection operation adopts the "roulette wheel method", which uses the proportion of each individual's fitness to determine the possibility of its offspring being retained. The greater the individual's fitness, the greater the chance of being selected. In order to select crossover individuals, multiple rounds of selection are performed;

[0017] Specifically, a uniform random number within [0, 1] is generated in each round, and the random number is used as a selection pointer to determine the selected individual; the selected odd-numbered individuals and even-numbered individuals are matched, and for each pair of individuals, some of their genes are exchanged with the crossover probability to form a new pair of individuals; for each individual in the group after the crossover, the gene values ​​on some loci are changed to other allele values ​​with the mutation probability. After individual selection, individual crossover and gene mutation operations, a new population is obtained, the fitness calculation is completed, the optimal individual is retained, and the next genetic operation is carried out; when the given number of cycles is met or the predetermined conditions are met, the algorithm terminates and the optimal solution is output.

[0018] The composite assembly hole is circular, and the position of each antenna unit is determined by a genetic algorithm.

[0019] The composite assembly hole is rectangular, and the position of each antenna unit is determined by a genetic algorithm.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. Compared with the reflector antenna, the antenna provided by this solution reduces the large reflector surface, does not require cumbersome installation and debugging processes, and greatly reduces the diameter and profile of the millimeter wave antenna.

[0022] 2. In order to reserve a composite position for the infrared or laser detector, the present invention designs the hole position at the edge of the antenna. Compared with the traditional center hole method, this method can effectively reduce the degree of deterioration of the antenna sidelobe level caused by the hole, and provides a new option and solution for the position of the infrared and laser detectors during composite.

[0023] 3. In the existing composite schemes, the two-dimensional sum and difference beams and two-dimensional phased scanning of the millimeter-wave antenna are less involved. Therefore, when designing the present invention, the above two performances are used as constraints, and finally the two-dimensional sum and difference beams and ±20° two-dimensional phased scanning of the antenna are realized, thereby improving the detection performance of the millimeter-wave antenna.

[0024] 4. The irregular aperture sparse array antenna proposed in the present invention provides a new antenna form for the co-aperture combination of millimeter waves, infrared and lasers. Compared with the original solution, this antenna form reduces the larger reflection surface, greatly reduces the difficulty of design, installation and debugging, and the antenna adopts a sparse array form, which not only ensures the good performance of the antenna, but also reduces the number of antenna units, reduces the design difficulty and cost of the back-end feed switching, and can also form a two-dimensional sum and difference beam, realize ±20° two-dimensional phased scanning, and improve the detection performance of the millimeter wave antenna.

[0025] 5. The antenna is small in size and reduces the difficulty of design, installation and debugging when millimeter waves are combined with infrared and lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the design process of the irregular aperture sparse array antenna of the present invention;

[0027] Figure 2 This is the array distribution diagram of the irregular aperture sparse array antenna of Example 3 of the present invention;

[0028] Figure 3 The pitch plane and beam scanning ±20° directional pattern of the irregular aperture sparse array antenna of embodiment 3 of the present invention;

[0029] Figure 4 The ±20° directional pattern of the pitch difference beam scanning of the irregular aperture sparse array antenna of Embodiment 3 of the present invention;

[0030] Figure 5 The azimuth plane and beam scanning ±20° directional pattern of the irregular aperture sparse array antenna of embodiment 3 of the present invention;

[0031] Figure 6 The azimuth beam scanning ±20° directional pattern of the irregular aperture sparse array antenna of embodiment 3 of the present invention;

[0032] Figure 7 This is the array surface distribution diagram of the irregular aperture sparse array antenna of Example 4 of the present invention;

[0033] Figure 8 The pitch plane and beam scanning ±20° directional pattern of the irregular aperture sparse array antenna of embodiment 4 of the present invention;

[0034] Fig. 9 The ±20° directional pattern of the pitch difference beam scanning of the irregular aperture sparse array antenna of Embodiment 4 of the present invention;

[0035] Fig.10 The azimuth plane and beam scanning ±20° directional pattern of the irregular aperture sparse array antenna of embodiment 4 of the present invention;

[0036] Fig.11 The azimuth beam scanning ±20° pattern of the irregular aperture sparse array antenna of embodiment 4 of the present invention;

[0037] Figure numerals: 1. antenna body; 2. composite assembly hole; 3. antenna array element. DETAILED DESCRIPTION

[0038] All features disclosed in this specification; or all steps in the disclosed methods or processes; except mutually exclusive features and / or steps; can be combined in any way.

[0039] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0040] In the description of the present invention, it should be understood that the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a predetermined direction, be constructed and operated in a predetermined direction. Therefore, they should not be understood as limitations on the present invention.

[0041] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0042] Example 1

[0043] like Figure 2 As shown, the present invention provides a technical solution:

[0044] An irregular aperture sparse array antenna; it at least includes but is not limited to an antenna body 1, a composite assembly hole 2 and antenna array elements 3; the composite assembly hole 2 is arranged at the edge of the antenna body 1, and the antenna array elements 3 are evenly distributed on the antenna body.

[0045] Based on the above structure, this antenna places the hole position required for compounding with infrared or laser at the edge of the antenna aperture, reducing its impact on the antenna sidelobe level. Compared with the traditional center hole method, this method can effectively reduce the degree of deterioration of the antenna sidelobe level caused by the hole, and provides new options and solutions for the position of infrared and laser detectors during compounding; at the same time, compared with traditional array antennas, it can reduce the number of channels, save costs, and the position of each array element is more free, and the optimal radiation characteristics can be obtained by finding the optimal position through optimization.

[0046] As an example, the composite assembly hole may be a circular structure or a rectangular structure, which is selected according to the required laser composite area.

[0047] As an example, for the setting of antenna array elements, a genetic algorithm is applied to sparsely distribute the antennas, the maximum sidelobe level is used as the initial condition, the array element position is solved, and two constraints, difference beam and phased scanning, are added.

[0048] Example 2

[0049] The present invention provides a technical solution:

[0050] A design method for an irregular aperture sparse array antenna; the method at least comprises the following steps:

[0051] Step 1: Determine the antenna aperture according to the antenna beam width and gain requirements;

[0052] Step 2: According to the size of the area required for infrared and laser, a certain area is divided at the edge of the millimeter wave antenna aperture as a composite assembly hole;

[0053] Step 3: Based on the genetic algorithm, the antenna sidelobe level is set as the optimization condition, and the sum of the maximum sidelobe level of the array azimuth plane pattern and the maximum sidelobe level of the elevation plane pattern is minimized by optimizing the position of each array element, thereby determining the initial distribution position of each array element;

[0054] Step 4. Under this distribution, calculate the gain drop during the zero depth of the antenna difference beam and the two-dimensional phased scanning, and determine whether the above indicators meet the design requirements. If so, terminate the algorithm. If not, perform genetic operations such as selection, crossover and mutation on the individuals in the intermediate population. Repeat this cycle until the termination condition is met, end the cycle, and output the optimal result.

[0055] In step 4, the selection operation adopts the "roulette method", using the proportion of each individual's fitness to determine the possibility of its offspring being retained. The greater the individual's fitness, the greater the chance of being selected. In order to select the crossover individual, multiple rounds of selection are required; each round generates a uniform random number within [0, 1], and the random number is used as a selection pointer to determine the selected individual; the selected odd-numbered individuals and even-numbered individuals are matched, and for each pair of individuals, part of their genes are exchanged with the crossover probability to form a new pair of individuals. For each individual in the crossover population, the gene values ​​on some loci are changed to other allele values ​​with the mutation probability. After the individual selection, individual crossover and gene mutation operations, a new population is obtained, the fitness calculation is completed, and the optimal individual is retained for the next genetic operation; when the given number of cycles is met or the predetermined conditions are met, the algorithm terminates and the optimal solution is output.

[0056] The shape of the composite assembly hole is circular or rectangular, etc., and under the constraint conditions, no array elements are distributed in the area.

[0057] Example 3

[0058] like Figure 3 to Figure 6 As shown, based on the above-mentioned Example 1, this example conducted a verification experiment.

[0059] According to the design process, the infrared and laser composite area is limited to a circle, and the position of each antenna unit is determined by genetic algorithm. The final antenna array distribution is as follows: Figure 2 shown.

[0060] The antenna array is simulated by electromagnetic simulation. Figure 3 The array pitch plane and beam scan ±20° directional pattern, the antenna normal gain at this frequency point is 30.19dBi, the normal first sidelobe is 18.20dB, and when the directional pattern is scanned to ±20°, the gain scan drops to 0.92dB; Figure 4 For the elevation plane differential beam scanning ±20° directional pattern, the normal differential beam zero depth of the antenna at this frequency point is greater than 30dB. When the directional pattern is scanned to ±20°, the differential beam zero depth is greater than 25dB. Figure 5 The array azimuth plane and beam scan ±20° directional pattern, the antenna normal gain at this frequency point is 30.19dBi, the normal first sidelobe is 9.80dB, and when the directional pattern is scanned to ±20°, the gain scan drops to 1.30dB; Figure 6 The azimuth plane difference beam scans the ±20° radiation pattern. The normal difference beam zero depth of the antenna at this frequency point is greater than 52dB. When the radiation pattern is scanned to ±20°, the difference beam zero depth is greater than 38dB.

[0061] The above data show that the sparse array antenna pattern gain, sidelobe level, difference beam zero depth and gain scanning decline all perform well, and can effectively synthesize sum and difference beams and achieve ±20° two-dimensional phased scanning.

[0062] Example 4

[0063] like Figure 7 to Figure 11 As shown, based on the above-mentioned Example 1, this example conducted another verification experiment.

[0064] According to the design process, the infrared and laser composite area is limited to a rectangle, and the position of each antenna unit is determined by genetic algorithm. The final antenna array distribution is as follows: Figure 6 shown.

[0065] The antenna array is simulated by electromagnetic simulation. Figure 8 The array elevation plane and beam scan ±20° directional pattern, the antenna normal gain at this frequency point is 30.10dBi, the normal first sidelobe is 13.78dB, and when the directional pattern is scanned to ±20°, the gain scan drops to 0.83dB; Fig. 9 For the elevation plane differential beam scanning ±20° directional pattern, the antenna's normal differential beam zero depth at this frequency is greater than 29dB. When the directional pattern is scanned to ±20°, the differential beam zero depth is greater than 27dB. Fig.10The array azimuth plane and beam scan ±20° directional pattern, the antenna normal gain at this frequency point is 30.10dBi, the normal first sidelobe is 10.94dB, and when the directional pattern is scanned to ±20°, the gain scan drops to 1.29dB; Fig.11 The azimuth plane difference beam scans the ±20° radiation pattern. The normal difference beam zero depth of the antenna at this frequency point is greater than 50dB. When the radiation pattern is scanned to ±20°, the difference beam zero depth is greater than 37dB.

[0066] The above data show that the sparse array antenna pattern gain, sidelobe level, difference beam zero depth and gain scanning decline all perform well, and can effectively synthesize sum and difference beams and achieve ±20° two-dimensional phased scanning.

[0067] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An irregular aperture sparse array antenna, characterized in that: It at least includes but is not limited to an antenna body, a composite assembly hole and an antenna array element; the composite assembly hole is arranged at the edge of the antenna body, and the antenna array elements are evenly distributed on the antenna body.

2. The irregular aperture sparse array antenna according to claim 1, characterized in that: The composite assembly hole can be a circular structure or a rectangular structure, which is selected according to the required laser composite area.

3. The irregular aperture sparse array antenna according to claim 2, characterized in that: For the setting of antenna array elements, the genetic algorithm is used to sparsely distribute the antennas, the maximum sidelobe level is used as the initial condition, the position of the array elements is solved, and two constraints, difference beam and phased scanning, are added.

4. A design method for an irregular aperture sparse array antenna; characterized in that: At least the following steps are included: Step 1: Determine the antenna aperture according to the antenna beam width and gain requirements; Step 2: According to the size of the area required for infrared and laser, a certain area is divided at the edge of the millimeter wave antenna aperture as a composite assembly hole; Step 3: Based on the genetic algorithm, the antenna sidelobe level is set as the optimization condition, and the sum of the maximum sidelobe level of the array azimuth plane pattern and the maximum sidelobe level of the elevation plane pattern is minimized by optimizing the position of each array element, thereby determining the initial distribution position of each array element; Step 4. Under this distribution, calculate the gain drop during the zero depth of the antenna difference beam and the two-dimensional phased scanning, and determine whether the above indicators meet the design requirements. If so, terminate the algorithm. If not, perform genetic operations such as selection, crossover and mutation on the individuals in the intermediate population. Repeat this cycle until the termination condition is met, end the cycle, and output the optimal result.

5. The design method of a non-regular aperture sparse array antenna according to claim 4, characterized in that: In step 4, the selection operation adopts the "roulette wheel method", which uses the proportion of each individual's fitness to determine the possibility of retaining its offspring. The greater the individual's fitness, the greater the chance of being selected. In order to select crossover individuals, multiple rounds of selection are performed.

6. The design method of the irregular aperture sparse array antenna according to claim 5, characterized in that: Specifically, a uniform random number within [0, 1] is generated in each round, and the random number is used as a selection pointer to determine the selected individual; the selected odd-numbered individuals and even-numbered individuals are matched, and for each pair of individuals, some of their genes are exchanged with the crossover probability to form a new pair of individuals; for each individual in the group after the crossover, the gene values ​​on some loci are changed to other allele values ​​with the mutation probability. After individual selection, individual crossover and gene mutation operations, a new population is obtained, the fitness calculation is completed, the optimal individual is retained, and the next genetic operation is carried out; when the given number of cycles is met or the predetermined conditions are met, the algorithm terminates and the optimal solution is output.

7. The design method of the irregular aperture sparse array antenna according to claim 6, characterized in that: The composite assembly hole is circular, and the position of each antenna unit is determined by a genetic algorithm.

8. The design method of a non-regular aperture sparse array antenna according to claim 6, characterized in that: The composite assembly hole is rectangular, and the position of each antenna unit is determined by a genetic algorithm.

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