无相位近场测量和全息诊断中基于泛函极值的相位恢复方法

A Phase Retrieval Technique Based on Functional Extremes for Phaseless Near-Field Measurements and Holographic Diagnoses

相位恢复是无相位近场测量和全息诊断的关键技术.本文考虑探头修正,构造加权目标泛函,给出避免局部极值的无相位测量条件.为提高计算效率和工程实用性,对Fletcher-Reeves共轭梯度法采取再开始技术、FFT算法和构造迭代初值等改进措施.数值模拟表明,应利用有关天线和近场测量的先验信息,选取尽量少的搜索变量.实验结果验证了本文方法的正确性和有效性.

Phase retrieval techniques are key to phaseless near-field measurements and holographic diagnoses. Based on the probe correction, the weighed functional are constructed and the phaseless measurement condition is presented to avoid local extremes. For the purpose of iterative efficiency and practicality, Fletcher-Reeves conjugate gradient method is modified by the application of re-beginning technique, FFT algorithm and construction of initial guess. Numerical simulations show that the search variables should be selected as less as possible in virtue of a priori information on the antenna under test and near-field measurements. Experimental results prove this technique to be accurate and efficient.