超材料孔径成像雷达的辐射场自由度评价

Degree of freedom evaluation in the radiation field for metamaterial aperture imaging radar

针对目前尚无超材料孔径成像雷达辐射场评价体系的问题,提出使用辐射场测量矩阵列互相关系数的一阶和二阶统计量两个指标实现辐射场自由度评价的方法,并详细分析了超材料孔径成像雷达的重建性能.首先,分析了仅使用测量矩阵互相关系数均值评价指标的问题;然后,引入互相关系数方差指标来完善评价体系;最后,结合压缩感知理论,通过相变图在两个评价指标和成像重建精度之间建立了对应关系.仿真结果表明,所提方法可有效地对辐射场自由度进行评价,对超材料孔径成像雷达的设计具有指导作用.

There has no complete evaluation system to measure the radiation field of metamaterial imaging radar currently. This paper presents a method of using the first and second cross-correlation statistics of the measurement matrix to assess the degree of freedom of the radiation field, and the reconstruction performance of metamaterial imaging radar is analyzed based on the method. The inaccuracy caused by using only the mean value of measurement matrix cross-correlation is analyzed first. Then the cross-correlation coefficient variance indicator is introduced to develop a new evaluation system. Finally, combined with the compressed sensing theory, the corresponding relationship between imaging reconstruction precision and the two indicators is established through the phase diagram. Simulation results show that our method effectively evaluates the degree of freedom of the radiation field and guides the design of metamaterial imaging radar.