实现散射场强整形的微散射体阵列逆向设计方法

本文提出一种基于全介电微散射体的散射阵列结构逆向设计方法,用以实现散射电场强度整形.该方法基于空域傅里叶变换与角谱变换,从给定目标区域处期望实现的散射场强分布出发,逆向求得所需的感应源,再利用电磁感应源理论,逆向设计微散射体阵列,且只需通过解析计算便能够快速地求取出微散射体阵列的电磁参数值分布.基于提出的逆向设计方法,文中提供了三维情况下的具体算例,实现了给定方形面目标区域的散射场强整形.理论计算结果与全波仿真结果符合良好,表明本文提出的逆向设计方法具有可行性与有效性.

Inverse design method of microscatterer array for realizing scattering field intensity shaping

It is a novel and interesting idea to inversely design the scattering structure with the desired scattering field intensity distribution in a given target area as the known information.The inverse design method proposed in this paper does not need to be optimized,and the spatial distribution and dielectric constant distribution of the micro-scatterer array can be quickly analytically calculated according to the desired scattering field intensity in the target area.First,based on the spatial Fourier transform and angular spectrum transformation,the plane wave sources required in all directions are inversely obtained from the electric field intensity distribution required in the target area.Then,based on the theory of induced source,a method of irradiating the array of all-dielectric micro-scatterers with incident electromagnetic field to generate the required plane wave source is proposed.The scattering fields generated by these micro-scatterers will be superimposed on the target area to achieve the desired scattering field strength intensity.Finally,according to the proposed inverse design theory model,a specific three-dimensional(3D)design is carried out.In the 3D example,we study the scattering field intensity distribution of the point-focused shape of the square surface target area,and show an all-dielectric micro-sphere distribution design.Its spatial distribution and permittivity distribution are both obtained through the rapid analytical calculation of the desired scattered field intensity shape in the target area.Finally,based on the principle of linear superposition,we quickly and easily generate the complex shapes of“I”,“T”,and“X”in the target area.The satisfactory results of full-wave simulation show that the proposed inverse design method is effective and feasible.