| Phased array antenna is a kind of multi-function, high reliability and adaptive capacity of the detection system, in particular, it has the ability to quickly scan beam and beam shape rapidly changing capability and can track multiple targets at the same time the advantages of making Phased Array antennas have been more widely used.Phased array antenna is the biggest advantage of the direction the plan is controllable, you can control the element array of incentives and the rate of phase to obtain the necessary plans in all directions, you can not move of their own circumstances to achieve full-space The rapid scanning, can also track multiple targets, in some direction to achieve interference suppression, etc., which are generally difficult to achieve the antenna, and to achieve the above functions must use pattern synthesis technology.This article is in the array direction of the plan on the basis of an analysis based on the actual situation array direction of the plan is comprehensive, so the main content of this article has two parts: the antenna array pattern analysis and synthesis.Antenna array antenna is the number of units in accordance with the laws of certain antenna from the group, in uniform arrays, each unit is the same, but the most simple one-dimensional array is uniform array (ALU), a Victoria uniform array element is the same element and also the same pitch N modules and antenna with a straight line. According to the principle of multiplication pattern (in real terms is different element of the wave radiation in space coherent superposition of the results), formed in the space of a certain magnitude and phase distribution of the beam. If meet certain conditions in the air will be formed with a main beam, including the majority of energy, there are some Sidelobe Max.In the antenna pattern, the main valve must have a certain gain, but also a certain width, and other indicators of the direction of the main valve, the main valve with the largest relative Vice flap a certain level of the main level than the flap. Determine the direction of the main valve of the main antenna scanning direction, the main valve must have a certain width, from the physical conditions or restrictions from the practical requirements of the main valve will have a certain width, Vice flap determine the level of anti-interference capability of the antenna, the general Under terms of flap, the lower level, the ability of anti-jamming antenna will be strong. To this point, people under the direction of the design principles of the plan is the product of many strong directional arrays, which are advantages and disadvantages of each design, how should this be strong directional array of research has been engaged.Antenna is integrated in the plan is to set the conditions (general direction of the main valve, width, Vice-level valve, 0.1, etc.), through various means access to a single element of the incentive factor (including the magnitude and phase). From the mathematical point of view, the pattern of an integrated approach is the main analytical method, semi-analytical and semi-numerical method, numerical; physics from the angle of view, the pattern of an integrated approach that only the main phase-weighted method, the weighted rate of only law and Complex weighting system. This paper discussed the direction of the two plans an integrated approach: Based on the FFT of the semi-numerical semi-analytical method, based on the array polynomial Schelkunoff unit circle and the only phase-weighted method, in addition to a brief discussion of some of the classic pattern Comprehensive law, such as Fourier series Law and Chebyshev comprehensive law.Array antenna pattern that the variety of ways, including by using Schelkunoff in the unit circle to express array factor. This method will be the main array of flap-flap-level and width of 0.1 on the same information that a flat circle, so it is easy to adjust the direction of the plan is 0.1 to control the pattern width of the main valve, 0.1 location, Also in a specific direction is home. Polynomial array array is another pattern that, on behalf of polynomial 0.1 0.1 direction of the plan, such arrays on the polynomial and units corresponding to a round, flat side through the adjustment of 0.1 yen on the location Array direction to achieve the goal of comprehensive plans, on the other units through the circle and the relationship between the array polynomial, according to the unit circle in the 0.1 to write array polynomial, will array polynomial can get a RUF Yuan incentives. In fact, here are the incentives only encourage the phase information contained in the array will polynomial with a mapping unit circle when the default element of the incentive rate of 1. Also in this way the direction of comprehensive plans, in some cases, units may be incentive to 0, only when the element of the integral to 2 times the power to ensure that all the time element incentive not to 0. In the relevant theoretical analysis and calculations, this article is also available in Matlab the simulation, the simulation results proved very good, the authenticity of this approach.Based on the Fast Fourier Transform (FFT) spectrum analysis of the space pattern synthesis method is a semi-numerical semi-analytical methods. The above-mentioned three methods: analytical method, semi-numerical semi-analytical method, the value of their characteristics, analytical method has the advantage of a simple calculation, but not enough flexibility, and high-precision numerical method, but the complexity, usually iterative The method requires a large amount of calculation, the convergence will not. Based on the FFT of the semi-analytical and semi-numerical law on the one hand with the analytic method is simple to calculate the advantages of a small amount, on the one hand with high-precision numerical law, the use of the advantage of flexibility.Based on the FFT pattern synthesis technology is also an adaptive approach, it needs a target pattern, and the need to carry out some out in order to deal with the iteration, the calculation of specific steps are as follows:(1) in accordance with the direction of the target array interval mapping a reference map pattern, and then refer to the direction of expansion plans not visible to the region;(2) expanding the use of the FFT pattern space spectrum transform, by the element of motivation, and generate comprehensive pattern;(3) under certain conditions, based on the objectives of the comprehensive pattern to determine if the conditions are met the end of iteration, if not satisfied the conditions, using objective and comprehensive pattern pattern generate a new reference pattern, Back to the first step, the next iteration.FFT law as long as the small number of iterative (normally 5-7) on the convergence can be achieved very good results, than the average numerical method to be much faster, and because of the FFT calculation of time is very short, so the overall computing time Many smaller. In precision, since the implementation of the accuracy of control (in the direction of comprehensive plans for judgement), can be achieved purely numerical method accuracy. FFT of the highly robust, normally does not appear divergent circumstances.In short, this first part of a more detailed discussion of the array pattern of performance, said the main focus of flap, flap of some directional characteristics and enhance the way in the latter part of the discussion focused on a detailed map of the comprehensive two directions The method, based on the unit circle Schelkunoff only phase-weighted method and the space-based FFT spectral analysis, and through Matlab simulation proved the reliability of these two methods, and achieved very good results. |
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