Large-scale wide-angle scanning phased-array antenna performance calculation and simulation verification method

Abstract

The invention relates to a large-scale wide-angle scanning phased-array antenna performance calculation and simulation verification method, and belongs to the technical field of microwave antennas. According to the law of conservation of energy and the design theory of an array antenna, in combination with a practical route of theoretical derivation and finite element method simulation verification, through calculation of a series of small arrays with different scales, high trueness of finite element simulation and completeness of theoretical derivation are combined, and by means of the strong numerical calculation capability of Matlab, a high-precision and high-precision array antenna is obtained. The high-accuracy performance calculation of the large-scale phased array is realized, the calculation efficiency of the traditional large-scale phased array is greatly improved (hundreds of times), the problem that the performance of the large-scale array antenna cannot be accurately and efficiently estimated in engineering is solved, and the design cost of the antenna is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave antennas, and in particular to a method for calculating and simulating the high-efficiency performance of wide-angle scanning phased array antennas, which is used in the simulation design field of large-scale high-performance wide-angle scanning phased array antennas. Background Art

[0002] At present, antenna arrays have been widely used in military fields such as communications, remote sensing, radar, and electronic warfare. In particular, they are widely used in national defense, such as land-based radars, airborne and shipborne radars. In these applications, most antennas are phased array antenna arrays, which are often large in scale, up to thousands or even tens of thousands of units, and have functions such as multi-beam scanning and wide-angle coverage. Therefore, the increasingly advanced large-scale phased array antennas have put forward higher requirements for the antenna design methods of the new era.

[0003] Traditional phased array antennas can often be divided into two situations. When the scale is not large, simulation software such as HFSS and CST are usually used to solve the entire antenna array surface to obtain the antenna design plan; when the scale is very large, due to limited computing resources, the entire array cannot be calculated, and the small array analysis method is usually used, that is, a small array of a certain scale is designed and a pre-processed version is used for actual measurement to estimate the entire array. However, most of the existing array antennas are very large in scale. Although the small array analysis method can solve the problem that the entire array cannot be calculated, it still has a considerable scale, usually not less than 5 times the wavelength. Taking the half-wavelength spacing commonly used in engineering as an example, that is, an array scale of ≥10×10, there are at least hundreds of solution ports. An array of this scale still requires several hours of calculation time, which makes the design efficiency low and cannot detect problems in time and update and iterate. Summary of the invention

[0004] The technical problems to be solved by the present invention are:

[0005] The existing large-scale phased array antenna design is usually implemented by unit debugging plus small array analysis method. The small array analysis method has many solution ports, low calculation efficiency, and long design cycle. It is far from meeting the actual needs today when scientific research tasks are becoming increasingly tense. In order to avoid the shortcomings of the prior art, the present invention provides a high-efficiency performance calculation and simulation verification method for wide-angle scanning phased array antennas, which is used to improve the design efficiency of large-scale phased array antennas, reduce design costs, and reduce unnecessary simulation time.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna, characterized in that the large-scale wide-angle scanning phased array antenna has an array size of ≥16×16, comprising:

[0008] Obtain the relationship between the ideal phased array antenna unit pattern and active reflection coefficient;

[0009] Splitting the phased array antenna into a plurality of phased array antenna units, and simulating the phased array antenna units by simulation software to obtain a preliminary simulated active reflection coefficient;

[0010] Determining the preliminary simulated active reflection coefficient, and performing array simulation on the phased array antenna unit based on the determination result to obtain 3D active gain pattern data of the phased array antenna unit;

[0011] The 3D active gain pattern data are numerically calculated, and the active reflection coefficient of the unit in the phased array at different scanning angles and frequencies is solved according to the relationship expression between the ideal phased array antenna unit pattern and the active reflection coefficient; at the same time, the 3D active gain pattern data are synthesized using the pattern product theorem to obtain the whole array gain pattern at different scanning angles.

[0012] A further technical solution of the present invention is as follows: the relationship between the ideal phased array antenna unit pattern and the active reflection coefficient is expressed as follows:

[0013]

[0014] in, is the active reflection coefficient, θ, is the coordinate value of the spherical coordinate system, a is the unit aperture area, and λ is the operating wavelength.

[0015] A further technical solution of the present invention is as follows: the method of simulating the phased array antenna unit by simulation software to obtain a preliminary simulated active reflection coefficient comprises:

[0016] An initial simulation model of the phased array antenna unit is established in HFSS. The periodic boundary analysis method included in HFSS is used to set different scanning angles of different sections of the unit antenna to obtain the preliminary simulated active reflection coefficients of the units in the array at different scanning angles.

[0017] A further technical solution of the present invention: the determination of the preliminary simulated active reflection coefficient comprises:

[0018] The preliminary simulated active reflection coefficient is compared with a threshold value 2, and if it is less than or equal to 2, an array simulation is performed on the phased array antenna unit.

[0019] A further technical solution of the present invention: the array simulation of the phased array antenna unit comprises:

[0020] Arrange the phased array antenna unit in an odd-sized uniform array as the central unit, and connect all the unit ports except the central unit to a 50-ohm load.

[0021] The central unit is fed to obtain active radiation patterns of the units in the array at different frequencies, and the 3D active gain radiation pattern data of the phased array antenna unit is obtained.

[0022] A further technical solution of the present invention: the odd number scale is 9×9.

[0023] A further technical solution of the present invention is to perform numerical calculation on the 3D active gain pattern data, and solve the active reflection coefficient of the unit in the phased array at different scanning angles and different frequencies according to the relationship expression between the ideal phased array antenna unit pattern and the active reflection coefficient, including:

[0024] The 3D active gain pattern data is exported to MATLAB or EXCELL for numerical calculation, and the active reflection coefficient of the unit in the phased array at different scanning angles and frequencies is solved according to the relationship expression between the ideal phased array antenna unit pattern and the active reflection coefficient.

[0025] The beneficial effects of the present invention are:

[0026] The invention provides a method for calculating and simulating the high-efficiency performance of a wide-angle scanning phased array antenna. Based on theoretical analysis, the method is used to completely derive theoretical formulas, and the idea of ​​breaking the whole into parts is combined with HFSS simulation software to cleverly design different types of small-scale simulation models. The idea of ​​combining the port characteristics of the array antenna with the far-field radiation characteristics is used to estimate the characteristics of the entire array by only calculating a small-scale array of 1-2 ports. Finally, the MATLAB numerical calculation method is used to obtain accurate simulation results of the entire array. The invention can greatly simplify the design of the array antenna, improve the design efficiency by dozens or even hundreds of times, greatly reduce the design cost, and speed up the design cycle.

[0027] The present invention realizes the high-efficiency performance calculation of large-scale wide-angle scanning phased array antennas through theoretical deduction and simple simulation calculation, combined with MATLAB's numerical calculation method. It solves the problem of low calculation efficiency of traditional phased array antennas, greatly improves the design efficiency of large-scale phased array antennas, and has great application prospects in the fields of communications, remote sensing, radar, electronic warfare, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0029] Figure 1 A flow chart for simulating the design of the present invention;

[0030] Figure 2 It is a simulation model of periodic boundary unit of the present invention;

[0031] Figure 3 Simulating the standing wave ratio of the periodic boundary unit antenna of the present invention;

[0032] Figure 4 This is the 9*9 array simulation model of the present invention: (a) is a three-dimensional diagram; (b) is a simulation port diagram;

[0033] Figure 5 is the full port simulation time of the present invention;

[0034] Figure 6 It is the simulation time proposed by the present invention;

[0035] Figure 7 This is a comparison simulation diagram of the active standing wave ratio of the present invention;

[0036] Figure 8 The antenna gain pattern of the present invention when scanning at 0°;

[0037] Fig. 9 The antenna gain pattern of the present invention when scanning at 45°; DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] The present invention provides a large-scale wide-angle scanning phased array antenna performance calculation and simulation verification method for a 16×16 array scale. Based on theoretical analysis and combined with HFSS simulation software, different types of small-scale simulation models are cleverly designed. By combining the port characteristics of the array antenna with the far-field radiation characteristics, the entire array characteristics can be estimated by calculating only a small-scale array of 1-2 ports. Finally, the MATLAB numerical calculation method is used to obtain accurate simulation results for the entire array. The invention can greatly simplify the design of array antennas, improve the design efficiency by dozens or even hundreds of times, and can be fully applied to the design field of phased array antennas.

[0040] Step 1: Study the theory and refine the formula. Based on the array antenna design theory, integrate the idea of ​​the law of conservation of energy, refine the inseparable relationship between the antenna port characteristics and the far-field radiation characteristics, summarize the potential laws of the active unit pattern and the active reflection coefficient, obtain the formula expression and physical meaning of the ideal unit pattern, and form a complete theoretical system and clear guiding formula.

[0041] According to array antenna theory, when there is only one antenna in space, the radiation field in space can be expressed as:

[0042]

[0043] When the second antenna exists in isolation in space, the radiation field in space can be expressed as:

[0044]

[0045] When two units are placed together to form an array, the radiation field in space can be expressed as:

[0046]

[0047] At this point, the two-element antenna array can be regarded as a two-port network, and its mutual impedance matrix is:

[0048]

[0049] Since the antenna unit itself is lossless, according to the law of conservation of energy, the active power output by the constant current source should be equal to the power of the electromagnetic wave radiated by the antenna array, so:

[0050]

[0051] The above formula shows that the mutual impedance between antenna units can be expressed as the integral of the antenna spectral pattern, that is, the far-field characteristics and port characteristics of the antenna are closely connected. Therefore, the far-field pattern of the array active unit and the active reflection coefficient can be expressed by the following formula:

[0052]

[0053] That is, the active reflection coefficient of a unit in the array can be represented by the far-field pattern of the unit:

[0054]

[0055] in, is the active reflection coefficient, θ, is the coordinate value of the spherical coordinate system, a is the unit aperture area, and λ is the operating wavelength.

[0056] The physical meaning of the above formula is:

[0057] 1) The active unit radiation pattern and active reflection coefficient of the antenna are closely related and can be expressed mutually. If the active unit radiation pattern of the antenna has been measured experimentally, the active reflection coefficient of the antenna can be calculated;

[0058] 2) If the antenna can achieve good matching during the scanning process, the active unit pattern of the antenna must be in the form of cosθ, and it has nothing to do with the specific unit form. Any attempt to use omnidirectional antenna arrays to obtain full-space wide-angle scanning characteristics will fail, which is determined by the law of conservation of energy.

[0059] 3) The scanning blind area (zero point) of the phased array antenna is actually the zero point of the active unit radiation pattern, and it is also the unit active reflection coefficient. The point where the active reflection coefficient is 1 can be used to predict the blind spot problem of the phased array antenna.

[0060] Step 2: Refer to the formula and simulate. The core indicators of phased array antennas are gain and active reflection coefficient under scanning state. Under lossless conditions, according to the theoretical formula described in step 1, it can be obtained that by solving any data of gain or active reflection coefficient, the other parameter can be obtained, and the two correspond one to one. For large-scale array antennas, most antenna units are in the same environment, and an infinite planar antenna array can be used for analysis. According to Floquet's theorem, it is only necessary to analyze the field distribution within a periodic unit, and other units only need to gain one phase in turn to analyze the performance of the entire array. Therefore, the periodic boundary analysis method included in HFSS can be used to realize the simulation analysis of the unit antenna, so as to estimate the performance of the entire array. Using HFSS modeling, the unit antenna is set to different scanning angles of different sections, and the unit standing wave ratio of the array at different scanning angles under this condition is obtained. When the antenna unit performance is better under periodic boundary conditions, the unit is arrayed in an odd size (such as 9*9) by analogy with the small array analysis method. Different from the small array analysis method, in the HFSS simulation design, all unit ports except the central unit are deleted and modified to 50 ohm impedance boundary conditions. Since the number of ports is reduced to 1 / 81, the calculation time can be greatly reduced. After the final calculation is completed, the active directional diagram of the unit in the array is exported to MATLAB for data processing.

[0061] Step 3: Data analysis and secondary processing. Using the simulation verification method described in step 2, export the original simulation data to MATLAB for numerical calculation. According to formula (1.10), the simulation results of the active reflection coefficient at different scanning angles of the array units are solved. At the same time, the unit directional pattern can be synthesized using the directional pattern product theorem to obtain the whole array gain directional pattern at different scanning angles, draw curves, and view the simulation data.

[0062] Embodiment 1:

[0063] Please refer to Figures 1 to 9 The present invention proposes a method for calculating and simulating the high-efficiency performance of a large-scale wide-angle scanning phased array antenna, and implements the design of the phased array antenna through theoretical derivation, simulation verification, and numerical calculation. The specific steps are as follows:

[0064] Step 1: Based on the array antenna design theory and the idea of ​​the law of conservation of energy, the inseparable relationship between antenna port characteristics and far-field radiation characteristics is extracted:

[0065]

[0066] The above formula shows that the mutual impedance between antenna units can be expressed as the integral of the antenna spectral pattern, that is, the far-field characteristics and port characteristics of the antenna are closely connected. Summarizing the potential laws of the active unit pattern and the active reflection coefficient, the formula expression and physical meaning of the ideal unit pattern are obtained, and the far-field pattern and active reflection coefficient of the array active unit are expressed by the following formula:

[0067]

[0068] That is, the active reflection coefficient of a unit in the array can be represented by the far-field pattern of the unit:

[0069]

[0070] Step 2: According to the antenna design theory, the initial simulation model of the unit antenna is established in HFSS. The periodic boundary analysis method included in HFSS is used to simulate and analyze the unit antenna, and the preliminary simulated active reflection coefficient of the unit antenna is obtained. If the preliminary simulated active reflection coefficient is less than or equal to 2, the unit antenna is arranged in a uniform array of odd scale (such as 9*9), and all unit ports except the central unit are connected to 50 ohm loads. This method can greatly reduce the calculation time and improve the calculation efficiency. After the modeling is completed, the central unit is fed to obtain the active radiation pattern of the unit at different frequencies (Realized Gain needs to be checked). The unit 3D active gain radiation pattern data is exported for the next step.

[0071] Step 3: Import the 3D active gain pattern data exported in step 2 into MATLAB for numerical calculation. According to formula (1.10), the simulation results of the active reflection coefficient at different scanning angles and frequencies of the units in the array are solved. At the same time, the unit pattern can be integrated using the pattern product theorem to obtain the gain pattern of the entire array at different scanning angles, draw curves, and view the simulation data.

[0072] Simulation verification:

[0073] like Figure 1As shown, the main steps of the method proposed in the present invention are shown in the block diagram. Combining the law of conservation of energy and array design theory, the present invention has formed a formula that can be relied on as shown in formula (1.16). For simulation verification, the present invention uses a classic dipole antenna with a cavity for simulation verification experiments. The following are the basic parameters of the array antenna:

[0074] Working frequency: 5.1-5.7GHz;

[0075] Polarization mode: linear polarization;

[0076] Scanning angle: 2D ±45°;

[0077] Array size: 96×96;

[0078] Array spacing: 30mm.

[0079] First, the unit antenna is subjected to periodic boundary conditions ( Figure 2 ) simulation, and preliminary impedance matching is achieved by adjusting the unit size. Figure 3 The simulation results of the standing wave ratio of the antenna unit period boundary at different scanning angles are given. On this basis, the antenna units are arrayed in a 9*9 scale, and all the unit ports except the central unit are connected to a 50 ohm load, such as Figure 4 shown.

[0080] The solution was performed on a computer with 128GHz memory and Intel(R) Core(TM) i9-10900X CPU@3.70GHz CPU. From the simulation solution data, we can see that the 9*9 full-port array took 3 hours and 5 minutes ( Figure 5 ), while the simulation time proposed by the present invention only takes 41 minutes ( Figure 6 ), the calculation time is only 22% of the traditional simulation, which greatly improves the simulation efficiency. It is worth noting that when the array scale is larger, the efficiency of the method proposed in the present invention will be higher, and the calculation needs to be repeated dozens or even hundreds of times during the antenna design process. Shortening the calculation time each time to 22% of the traditional one can improve the overall design efficiency by hundreds or thousands of times.

[0081] According to formula (1.16), MATLAB numerical calculation is used to calculate the simulation raw data and compared with the traditional simulation method. Figure 7 The calculation results are given (for the convenience of comparison, the active reflection coefficient has been converted into the active voltage standing wave ratio). It can be seen from the figure that the calculation result of the active standing wave ratio in the method proposed by the present invention is basically correct, and the degree of consistency is higher than that of the traditional method. Figure 8 Fig. 9The comparison results of the gain patterns (@5.4GHz) calculated by the method proposed in the present invention and the traditional method are given. It can be seen from the figure that the gain patterns calculated by the two methods are highly consistent. The above two figures can prove the effectiveness of the calculation results of this method.

[0082] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A large-scale wide-angle scanning phased array antenna performance calculation and simulation verification method, characterized in that: The large-scale wide-angle scanning phased array antenna has an array size of ≥16×16, including: Obtain the relationship between the ideal phased array antenna unit pattern and active reflection coefficient; Splitting the phased array antenna into a plurality of phased array antenna units, and simulating the phased array antenna units by simulation software to obtain a preliminary simulated active reflection coefficient; Determining the preliminary simulated active reflection coefficient, and performing array simulation on the phased array antenna unit based on the determination result to obtain 3D active gain pattern data of the phased array antenna unit; The 3D active gain pattern data are numerically calculated, and the active reflection coefficient of the unit in the phased array at different scanning angles and frequencies is solved according to the relationship expression between the ideal phased array antenna unit pattern and the active reflection coefficient; at the same time, the 3D active gain pattern data are synthesized using the pattern product theorem to obtain the whole array gain pattern at different scanning angles.

2. The method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna according to claim 1, characterized in that: The relationship between the ideal phased array antenna unit pattern and the active reflection coefficient is expressed as follows: in, is the active reflection coefficient, θ, is the coordinate value of the spherical coordinate system, a is the unit aperture area, and λ is the operating wavelength.

3. The method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna according to claim 1, characterized in that: The step of simulating the phased array antenna unit by using simulation software to obtain a preliminary simulated active reflection coefficient includes: An initial simulation model of the phased array antenna unit is established in HFSS. The periodic boundary analysis method included in HFSS is used to set different scanning angles of different sections of the unit antenna to obtain the preliminary simulated active reflection coefficients of the units in the array at different scanning angles.

4. The method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna according to claim 3, characterized in that: Determining the preliminary simulated active reflection coefficient includes: The preliminary simulated active reflection coefficient is compared with a threshold value 2, and if it is less than or equal to 2, an array simulation is performed on the phased array antenna unit.

5. The method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna according to claim 4, characterized in that: The performing array simulation on the phased array antenna unit includes: Arrange the phased array antenna unit in an odd-sized uniform array as the central unit, and connect all the unit ports except the central unit to a 50-ohm load. The central unit is fed to obtain active radiation patterns of the units in the array at different frequencies, and the 3D active gain radiation pattern data of the phased array antenna unit is obtained.

6. The method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna according to claim 5, characterized in that: The odd number size is 9×9.

7. The method for calculating and simulating the performance of a large-scale wide-angle scanning phased array antenna according to claim 1, characterized in that: The 3D active gain pattern data is numerically calculated, and the relationship between the ideal phased array antenna unit pattern and the active reflection coefficient is solved for different scanning angles of the unit in the phased array. Active reflection coefficients at different frequencies, including: The 3D active gain pattern data is exported to MATLAB or EXCELL for numerical calculation, and the active reflection coefficient of the unit in the phased array at different scanning angles and frequencies is solved according to the relationship expression between the ideal phased array antenna unit pattern and the active reflection coefficient.

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