A design method for high-efficiency and low-cost large-aperture reflector antenna

Abstract

The present invention discloses a method for designing a large-aperture reflector antenna with high efficiency and low cost, and belongs to the field of antenna technology. The present invention comprises: constructing an initialization model of the antenna; establishing an antenna efficiency calculation model in combination with the actual coverage area and surface accuracy of the mesh panel and the solid panel; estimating the antenna processing and construction cost based on engineering experience; constructing an optimization objective function based on the antenna efficiency and the antenna processing and construction cost, and finding the optimal design of the antenna by global optimization. The present invention is used to design a large-aperture reflector antenna that combines a mesh panel and a full solid panel, and by controlling the respective coverage areas of the mesh panel and the full solid panel, the high efficiency and low cost of the large-aperture reflector antenna can be achieved.

Description

Technical Field

[0001] The invention relates to the field of antenna technology, and in particular to an optimization design method for a high-efficiency, low-cost, large-caliber reflector antenna suitable for a reflector antenna array. Background Art

[0002] Ultra-large aperture reflector antennas are expensive, and the formation of multiple reflector antenna arrays is one of the hot technologies in the future development of reflector antenna technology. The Five-hundred-meter Aperture Sphericalradio Telescope (FAST) is currently the world's largest and most sensitive single-aperture spherical radio telescope. In order to maintain the long-term dominant position of the FAST telescope, the FAST team proposed to build a 40-meter aperture fully movable antenna around the FAST site to form a comprehensive aperture telescope array with FAST, improve the spatial resolution of FAST, and expand the scientific observation field of FAST. The plan to build an array of large-aperture reflector antennas and FAST is to solve the limitations of a single-aperture telescope at the optimal economic and time cost, continue to maintain the core competitiveness of FAST under fierce international competition, and enable Chinese astronomers to continue to produce world-class astronomical results.

[0003] The 40-meter-diameter fully movable antenna requires the lowest possible cost and the highest possible efficiency. Lower cost means that more antennas can be built to participate in the array, and higher efficiency means better array performance, which is especially important for array antennas. A slight improvement in each antenna will bring about a significant improvement in the entire reflective surface antenna array.

[0004] A microwave parabolic TVRO antenna is disclosed in the Chinese patent "A New Structure of Satellite Ground Station Antenna" with publication number CN87208675U. This patent absorbs the respective advantages of existing plate-shaped and mesh-shaped parabolic antennas to make a new structure parabolic antenna combined with a plate and mesh. The center of the parabola of the antenna adopts a plate-shaped structure. The outer edge of the parabola adopts a mosaic mesh structure. The antenna has low cost, small load, high efficiency, and good received image quality. It is a practical device for popularizing satellite TV education.

[0005] A Chinese patent "A mesh parabolic satellite TV receiving antenna" with publication number CN2627767Y discloses a mesh parabolic satellite TV receiving antenna. The patent fills the mesh space of the metal mesh parabola with a filler that isolates the metal mesh from the air, thereby forming a molded and cured mesh parabolic satellite TV receiving antenna. The antenna has the characteristics of good corrosion resistance and durability, low production cost, material saving, high focusing rate, and good viewing effect.

[0006] The above patents all involve mesh parabolic antennas or mesh-solid combined parabolic antennas, which are innovative designs in terms of structural form, but have not formed an effective design method.

[0007] Guo Wangce proposed a large-diameter mesh antenna in his paper "Optimal Design of the Structural Morphology of Ring Truss Mesh Antennas". The paper conducted in-depth research on key issues such as the initial topology, structural morphology, and thermal deformation of the ring truss mesh antenna. However, the main research focus was on structural design, and the design was not combined with antenna efficiency.

[0008] Judging from the existing large-aperture antennas at home and abroad, the large-aperture antennas that use a combination of mesh panels and solid panels mainly include Germany's Effelsberg 100m radio telescope antenna, my country's Miyun 50m radio telescope antenna and Kunming radio telescope antenna. They all use a design of inner circle solid panels and outer circle mesh panels. Due to the limitation of panel accuracy, the inner circle is used in the high frequency band of the antenna and the outer circle is used in the low frequency band of the antenna, which has not achieved the most optimized design.

[0009] At present, the design of high-efficiency, low-cost, large-aperture reflector antennas has the following problems:

[0010] (1) Using mesh panels is one of the effective means to reduce the cost of reflector antennas. However, mesh panels have poor surface accuracy and low efficiency. Current designs focus on improving their strength in terms of structure, making their surface accuracy high, and thus improving antenna efficiency, but do not combine the overall efficiency performance of the antenna to achieve an optimized design.

[0011] (2) The design method of a large-diameter antenna that combines a mesh panel and a solid panel is based only on the characteristics of surface accuracy. The inner circle solid panel has good accuracy and is used in the high-frequency band of the antenna, while the outer circle mesh panel has poor accuracy and is used in the low-frequency band of the antenna. The antenna energy distribution law of the inner and outer circles is not taken into account to optimize the antenna performance.

[0012] (3) Existing designs do not take into account antenna costs and establish a relationship between cost and efficiency to achieve the best cost-effective design.

[0013] It can be seen that from the perspective of design methods, the design methods of high-efficiency, low-cost, large-aperture reflector antennas still need to be improved. Summary of the invention

[0014] In view of the shortcomings of the prior art, the present invention proposes a design method for a high-efficiency, low-cost, large-aperture reflector antenna, which is aimed at a reflector antenna that combines a mesh panel and a solid panel, can reduce the cost of the reflector antenna, improve the antenna efficiency, and achieve the optimal design of a high-efficiency, low-cost, large-aperture reflector antenna suitable for a reflector antenna array.

[0015] In order to achieve the above object, the technical solution adopted by the present invention is:

[0016] A high-efficiency and low-cost large-aperture reflector antenna design method is used to design a large-aperture reflector antenna that combines a mesh panel and a solid panel, and achieves high efficiency and low cost of the large-aperture reflector antenna by controlling the respective coverage areas of the mesh panel and the solid panel; the method comprises the following steps:

[0017] Step 1, constructing an initialization model of the antenna;

[0018] Step 2: Combine the actual coverage area and surface accuracy of the mesh panel and the solid panel to establish an antenna efficiency calculation model;

[0019] Step 3: Estimate the antenna processing and construction cost based on engineering experience;

[0020] Step 4: construct an optimization objective function based on the antenna efficiency and antenna processing and construction cost, and find the optimal design of the antenna through global optimization.

[0021] Further, in step 1, the antenna is in the form of a feedforward parabolic antenna or a dual reflector antenna;

[0022] For a feedforward parabolic antenna, according to the antenna's radiation angle Required to calculate focal ratio , where the illumination angle and focal ratio satisfy the following relationship:

[0023]

[0024] Where, tg represents the tangent function;

[0025] Then, the initialization model of the antenna is constructed according to the focal diameter ratio;

[0026] For dual-reflection antennas, based on the main surface aperture D, the secondary surface aperture Ds, and the main surface focal diameter ratio , Irradiation Angle These four geometric parameters construct the initialization model of the antenna.

[0027] Furthermore, the antenna efficiency calculation model in step 2 is:

[0028]

[0029] Where:

[0030] is the antenna efficiency;

[0031] is the antenna aperture efficiency, which is obtained by actual calculation or estimation. When estimating, the forward feed antenna takes 65% and the rear feed antenna takes 75%;

[0032] is the energy proportion of the area covered by the solid panel, calculated as:

[0033]

[0034] in, is the actual aperture field distribution function of the antenna, is the normalized radius, The maximum diameter covered by the antenna solid panel, is the maximum aperture covered by the antenna mesh panel, and R is the normalized radius of the antenna aperture;

[0035] , They represent the efficiency loss caused by the surface tolerance of the solid panel and the surface tolerance of the mesh panel respectively, and are calculated as follows:

[0036]

[0037] Where n=1 or 2, is the surface tolerance corresponding to different panel areas, and λ represents the wavelength.

[0038] Furthermore, the method for estimating the antenna processing and construction cost in step 3 is:

[0039]

[0040] Where:

[0041] is the antenna cost, in ten thousand yuan;

[0042] The maximum aperture covered by the antenna solid panel;

[0043] Provides antenna mesh panel coverage for maximum aperture.

[0044] Furthermore, the specific method of step 4 is:

[0045] Step 401, construct the optimization objective function:

[0046]

[0047] The constraints are:

[0048]

[0049] In the formula, is the expected maximum cost of the antenna, in ten thousand yuan;

[0050] Step 402, converting the optimization problem constructed in step 401 into an unconstrained optimization problem, the objective function F is:

[0051]

[0052] Where K is the penalty function coefficient;

[0053] Step 403: According to the objective function determined in step 402, the maximum aperture of the antenna real panel is covered. and antenna mesh panels covering the largest aperture These two parameters are globally optimized to complete the design of a large-aperture reflector antenna that takes into account both efficiency and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic diagram of the 40-meter aperture reflector antenna system.

[0055] Figure 2 It is a schematic diagram of the coverage area of ​​the antenna mesh panel and solid panel.

[0056] Figure 3 It is a schematic diagram of the antenna aperture efficiency simulation model.

[0057] Figure 4 It is the distribution curve of antenna aperture efficiency at different antenna elevation angles. DETAILED DESCRIPTION

[0058] The present invention is further described below in conjunction with the accompanying drawings. It should be noted that the protection scope of the present invention is not limited to the following embodiments.

[0059] A high-efficiency, low-cost, large-aperture reflector antenna design method comprises the following steps:

[0060] (1) Construct a reflection surface optimization initialization model according to actual needs; the specific method is as follows:

[0061] (101) Select the antenna type according to the project requirements. Low-cost reflector antennas generally use feedforward parabolic antennas. In addition, dual reflector antennas can also be selected. Then, based on factors such as antenna function, structural form, and user expectations, choose whether to use offset and multi-beam forms;

[0062] (102) Determine the geometric parameters to complete the initialization model construction. The main geometric parameters involved in the feedforward parabolic antenna are focal diameter ratio The recommended focal ratio of the feedforward antenna is 0.25~0.45, and the corresponding illumination angle is 90°~53.1°;

[0063]

[0064] Based on the geometric parameters, the initialization model can be constructed.

[0065] For dual-reflection antennas, based on the main surface aperture D, the secondary surface aperture Ds, and the main surface focal diameter ratio , Irradiation Angle These four geometric parameters construct the initialization model of the antenna. In the field of large-aperture antennas, the secondary aperture Ds is generally 0.1D, and the main focal diameter ratio Generally, it is 0.3~0.35, and the irradiation angle is generally 10°~20°.

[0066] (2) Combined with the actual coverage area of ​​the mesh panel and the solid panel and the achievable surface accuracy, an antenna efficiency calculation model is established. Although the antenna constructed by this method also adopts a construction method that combines mesh panels and solid panels, the entire antenna aperture is used for both high-frequency and low-frequency feed sources. Different from the prior art, this method uses the inner circle solid panel with good accuracy in the high-frequency band of the antenna, and the outer circle mesh panel with poor accuracy in the low-frequency band of the antenna. Therefore, the key to this method is to achieve the optimal high-frequency band efficiency. Specifically, the method of step 2 is:

[0067] Combined with the actual energy distribution on the antenna aperture, the antenna efficiency of different antenna mesh panels and solid panels in the high-frequency band is calculated. According to the project index requirements, the antenna efficiency is Optimize and finally determine the coverage area of ​​the solid panel;

[0068] The antenna efficiency can be calculated using the following formula:

[0069]

[0070] Where:

[0071] is the antenna efficiency;

[0072] The antenna aperture efficiency can be calculated based on actual conditions. It is also estimated for preliminary design. Generally, the forward feed antenna takes 65% and the rear feed antenna takes 75%.

[0073] is the energy proportion of the area covered by the solid panel, which can be obtained by the following formula: is the actual aperture field distribution function of the antenna, is the normalized radius;

[0074]

[0075] , are the efficiency losses caused by the surface tolerance of the solid panel and the surface tolerance of the mesh panel, respectively. The surface tolerance corresponding to different panel areas can be obtained using the following formula:

[0076] .

[0077] (3) Based on engineering experience, estimate the antenna processing and construction costs to provide a reference for cost-effective design; the specific methods are:

[0078] Based on engineering experience and the derived formula, the relationship between antenna cost and the coverage area of ​​antenna mesh panels and solid panels is calculated. Based on the engineering budget, the coverage area of ​​solid panels is calculated.

[0079] Among them, the antenna cost can be estimated using the following empirical formula:

[0080]

[0081] Where:

[0082] is the antenna cost, in ten thousand yuan;

[0083] The maximum aperture covered by the antenna solid panel;

[0084] Provides antenna mesh panel coverage for maximum aperture.

[0085] This empirical formula has many influencing factors that have not been taken into account, especially construction personnel, construction environment, working frequency, panel accuracy, etc. It can only be used for estimation in cost reduction design.

[0086] (4) Construct an optimization objective function, search for global optimality, and complete the optimal design; the specific method is:

[0087] (401) An initialization model is constructed using the antenna form and antenna geometric parameters determined in step (1). Based on the antenna efficiency calculated in step (2) and the antenna cost calculated in step (3), an optimization objective function is constructed as follows:

[0088]

[0089] At the same time, the constraints are:

[0090]

[0091] Where:

[0092] The expected maximum cost of the antenna, in ten thousand yuan.

[0093] (402) The original problem is transformed into an unconstrained optimization problem, and the objective function of the optimization problem is obtained as follows:

[0094]

[0095] (403) According to the optimization objective function determined in (402), the maximum aperture of the antenna solid panel is covered and antenna mesh panels covering the largest aperture Perform global optimization to complete the design of high-efficiency, low-cost, large-aperture reflector antennas.

[0096] In one embodiment, the reflector antenna is a parabolic antenna. Assuming that the normalized radius R of the antenna aperture is known, the antenna solid panel covers the maximum aperture. and antenna mesh panels covering the largest aperture are unknown parameters. This method constructs an optimization objective function based on the antenna efficiency and the antenna installation and construction cost. Through optimization design, the antenna can maintain high efficiency while reducing the antenna construction cost.

[0097] The following is a design example of a high-efficiency, low-cost 40-meter aperture reflector antenna:

[0098] Figure 1 This is a schematic diagram of a 40-meter aperture reflector antenna system. The feed phase center is placed at the focus of the reflector. For this large-aperture antenna system, a high-efficiency and low-cost design solution is developed. Figure 2 Schematic diagram of the coverage area of ​​the antenna mesh panel and solid panel.

[0099] The specific design steps are:

[0100] Step 1: First determine the antenna form, use the feedforward parabolic antenna form; select the antenna focal diameter ratio, the focal diameter ratio is selected as 0.375, and complete the antenna initialization model establishment.

[0101] Step 2: According to the working frequency of 1~10GHz given in the project, the antenna aperture efficiency is required to be greater than 45%. The antenna efficiency is calculated according to the formula, and the maximum aperture covered by the antenna panel is determined based on the highest frequency of 10GHz. .

[0102] The aperture distribution of the standard forward-fed parabolic antenna is Gaussian:

[0103]

[0104] In the formula, is the Gaussian distribution coefficient, is the maximum radius of the antenna aperture.

[0105] The surface tolerance of the solid panel area of ​​this caliber antenna is 0.3mm, and the surface tolerance of the mesh panel area is 1.8mm. The formula is calculated, It is 18.6m.

[0106] Step 3: Further, based on the project cost budget of about 20 million, the maximum diameter of the antenna panel coverage is determined according to the formula , about 16.5m.

[0107] Step 4: Determine through global optimization , Take 18.5m and complete the entire design.

[0108] The aperture efficiency of the designed antenna is calculated using simulation software, such as Figure 3 As shown in Figure 1, the antenna efficiency distribution curve at different elevation angles is calculated according to the structural finite element simulation results. Figure 4 As shown, according to the antenna efficiency calculation results, the antenna efficiency is better than 45% in the entire elevation angle range. In addition, according to the empirical formula, the cost of the antenna designed in this embodiment is estimated to be about 22 million yuan, and the cost of the full solid panel antenna is about 33.5 million yuan, which is a cost reduction of about 35%, achieving a high-efficiency, low-cost design effect.

[0109] In summary, the present invention studies the relationship between antenna cost and antenna efficiency, summarizes the relationship between antenna aperture efficiency and reflector antenna design parameters, gives a curve of the relationship between antenna aperture efficiency and antenna cost, derives a calculation formula for the coverage area of ​​a real panel, and gives a 40-meter aperture reflector antenna design example and performance analysis, verifying the effectiveness of the design method. This method is suitable for the design of large-aperture reflector antennas in the fields of radio astronomy, satellite communications, and deep space exploration.

Claims

1. A method for designing a large-aperture reflector antenna, characterized in that: The method is used to design a large-aperture reflector antenna that combines a mesh panel and a solid panel, and to achieve high efficiency and low cost of the large-aperture reflector antenna by controlling the respective coverage areas of the mesh panel and the solid panel; the method comprises the following steps: Step 1, constructing an initialization model of the antenna, the antenna is in the form of a feedforward parabolic antenna or a double reflector antenna; Step 2: Combine the actual coverage area and surface accuracy of the mesh panel and solid panel to establish an antenna efficiency calculation model: Where: is the antenna efficiency; is the antenna aperture efficiency, which is obtained by actual calculation or estimation. When estimating, the forward feed antenna takes 65% and the rear feed antenna takes 75%; is the energy proportion of the area covered by the solid panel, calculated as: in, is the actual aperture field distribution function of the antenna, is the normalized radius, The maximum diameter covered by the antenna solid panel, is the maximum aperture covered by the antenna mesh panel, and R is the normalized radius of the antenna aperture; , They represent the efficiency loss caused by the surface tolerance of the solid panel and the surface tolerance of the mesh panel respectively, and are calculated as follows: Where n=1 or 2, is the surface tolerance corresponding to different panel areas, and λ represents the wavelength; Step 3: Estimate the antenna processing and construction cost based on engineering experience; Step 4: According to the antenna efficiency and antenna processing and construction cost, construct an optimization objective function to cover the maximum aperture of the antenna solid panel. and antenna mesh panels covering the largest aperture These two parameters are globally optimized to find the optimal design of the antenna.

2. A method for designing a large-aperture reflector antenna according to claim 1, characterized in that: In step 1, for the feedforward parabolic antenna, according to the antenna's irradiation angle Required to calculate focal ratio , where the illumination angle and focal ratio satisfy the following relationship: Where, tg represents the tangent function; Then, the initialization model of the antenna is constructed according to the focal diameter ratio; For dual-reflection antennas, based on the main surface aperture D, the secondary surface aperture Ds, and the main surface focal diameter ratio , Irradiation Angle These four geometric parameters construct the initialization model of the antenna.

3. A method for designing a large-aperture reflector antenna according to claim 2, characterized in that: The method for estimating the antenna processing and construction cost in step 3 is: Where: is the antenna cost, in ten thousand yuan; The maximum aperture covered by the antenna solid panel; Provides antenna mesh panel coverage for maximum aperture.

4. A method for designing a large-aperture reflector antenna according to claim 3, characterized in that: The specific method of step 4 is: Step 401, construct the optimization objective function: The constraints are: In the formula, is the expected maximum cost of the antenna, in ten thousand yuan; Step 402, converting the optimization problem constructed in step 401 into an unconstrained optimization problem, the objective function F is: Where K is the penalty function coefficient; Step 403: According to the objective function determined in step 402, the antenna real panel covers the maximum aperture. and antenna mesh panels covering the largest aperture These two parameters are globally optimized to complete the design of a large-aperture reflector antenna that takes into account both efficiency and cost.

Images