Method for the Generation of arbitrary uniform fields based on angular spectral domain and time reversal technique

Abstract

Existing uniform fields are usually based on the special arrangement of the array antenna. The uniform fields generated by flat-top beam shaping in angular far-field area or by point focusing in near-field area are directly subject to the array configuration and cannot be flexibly controlled. This paper presents a uniform field generation method based on the combination of angular spectral domain and improved time reversal techniques. This method is not limited by the array arrangement. It can generate uniform fields of specified size, shape and deflection angle at arbitrary location, including the near field area, in the same array arrangement. In this paper, the reason why this method is not limited by array arrangement is theoretically explained. Secondly, the ability of the fixed array configuration to generate multiple uniform fields is validated numerically. Finally, the time reversal technique of reversal signal amplitude reciprocal weighting is introduced. The problem of deterioration of uniform field flatness caused by amplitude decay and phase delay during the generation of uniform field is solved through this technology. The results show that the quality of the synthesized field is related to the main lobe and sidelobe information of its corresponding angular spectrum domain envelope, and generating arbitrary uniform field must contain at least half of the angular spectrum domain main lobe information and half of the sidelobe information. This method can flexibly control the position, size, shape and deflection angle of one-dimensional and two-dimensional uniform fields, which provides a new approach for flexibly generating uniform fields.