Based On The Magnitude Of The Weighted Two-dimensional Planar Array Near-field Beam Focused Research

Since world warⅡ, research and application of beamforming technologies are never stopped in many fields. The current applications are mostly based on the principle of phased beamforming, and the area of beamforming are defined in far-field in order to simplify the calculation. But with the expansion of the beamforming technology application fields, the far-field assumption cannot satisfy the requirement of development, and using the phased control to realize beamforming in the near-field will increase the cost and complexity. Based on the premise of near-field hypothesis, this paper establish an uniform and symmetrical plane array model of two-dimensional from the symmetric distribution of uniform linear array and explores to realize the focus only weighting the amplitude. This paper also derives the amplitude weights formula of the array elements. Assuming the plane array are focused on a point in the near-field, namely the focus function is an impulse function. Through simulation experiment, we verify that the focus method based on amplitude weighting can focus on a point in the near-field, then we analyze the amplitude error of the simulation results, and point out the reason of the error and the solution.In addition, the traditional phased beam focusing method is reproduced in this paper, and it is applied to two-dimensional plane array that distribute homogeneously in the near-field. We simulate the phased algorithm formula and compare it with the amplitude weighting beam focusing method. Then the method of the amplitude and phase combination control beam focusing is introduced in the paper, and we simulate it by uniting the algorithm of amplitude weighting and phased control. Through the results of the experiments, we get that the focus effect of the plane array is improved through adding the phase constraint in the near-field. At last, the focus effect of amplitude weighting, phased control and amplitude and phase combination control are intercomparsion in this paper, and the advantages and disadvantages of each of them are analyzed. The focus effects of the three methods in the far-fields are simulated and the simple analyses are given too.