Due to an unfortunate MatLab syntax error, the numerically optimized results report in [1] were incorrect. The authors thank Dr. Wan Chen, Harbin Institute of Technology, for his interest in our work and for questioning the original results. Revisiting the numerical optimization code, the following results were obtained and confirmed independently for the five-layer cylinder having an outer radius r 5 = λ 0 /10 and being excited by a magnetic line source (MLS) located along the φ = 180 •

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... on at the distance 1.05 r 5 from the center axis of the structure. The inner radii of the layers are specified to be r 1 = 0.01 λ 0 , r 2 = 0.03 λ 0 , r 3 = 0.06 λ 0 , and r 4 = 0.08 λ 0 . The relative permittivities in this five-layer structure are: ε 1r = 5.00, ε 2r = 0.15285, ε 3r = −2.02885, ε 4r = 7.4653, and ε 5r = −8.40. The exterior region is free-space with a relative permittivity equal to 1.0. The corresponding m = 0, 1, . . . , 5 scattering coefficients were obtained and used to calculate the directivity.