Theoretical And Experimental Research Numerical Array Amplitude Weighting Based On The Radiation Intensity Distribution

The concept of phased array was first emerged in the research of directional antenna in the late1950s. Phased array technology has been actually used in the fields of satellite communication, aerial reconnaissance and ballistic missile system, radar systems for meteorology, industry nondestructive testing, as well medical diagnosis and noninvasive treatment in recent in the last two decades. Since demand for energy resources and emphasis on ecological environment are on continuous increase in recent years, acoustic phased array has been applied to prospecting for underground resources, geological evaluation, and well logging. The beam forming and scanning in the applications mentioned above depend on the control over the element radiation phases, so as to construct a spatial radiation pattern. These need the support of a delicate phase shifter network and control system with precise and complex structure. The radiation amplitude, which is another controllable quantity of a wave, is not fully utilized. Our study found that a specific radiation pattern can be formed by only weighting the radiation amplitudes of planar array elements. From engineering accomplishment angle, weighting amplitudes is easier than shifting phases.This dissertation first pointed out that is possible to form a specific radiation intensity distribution by controlling the amplitude of radiation emitted by elements. Secondly, half-wave constraint and beam quality evaluation criteria in far field have been put forwarded, and the formula for calculating amplitudes in the case of far-field and near-field have been derived. Finally, a number of instances have been analyzed numerically, and the effectiveness of the method described above has been demonstrated. The potential applications of the method using amplitude-weighted include wartime communication, medical treatment, a special form of non-destructive and non-contact detection etc. This method can be extended to the array in which the element was periodically arranged.