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 synthesize the desired scattering field strength intensity. Finally, according to the proposed inverse design theory model, a specific three-dimensional (3-D) design case was carried out. In the 3-D example,we studied the scattering field intensity distribution of the point-focused shape of the square surface target area, and showed an all-dielectric micro-sphere distribution design. Its spatial distribution and permittivity distribution are all obtained through the rapid analytical calculation of the desired scattered field intensity shape at the target area. Finally, based on the principle of linear superposition, we quickly and easily generated 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.
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