On the Minimal Scattering Response of PEC Cylinders in a Dielectric Cloak

Recently, it was shown that an infinite perfectly conducting (PEC) cylinder can be nearly perfectly cloaked from normally incident electromagnetic waves using a single-layer homogeneous dielectric cladding. Here we study the electromagnetic response of such structures with the goal to understand the main mechanisms underpinning this cloaking phenomenon. We introduce a simple model of the cloaked PEC cylinder, replacing it by an omnidirectional electric-line scatterer and a bipolar magnetic one; accordingly, the far field is determined in a compact closed form. The analysis of the results shows that the optimal cloaking regime corresponds to the frequency point where the total electric moment is drastically mitigated and thus the radiation pattern of the device resembles that of a magnetic-dipole line. In the vicinity of the optimal cloaking frequency we observe the response close to that of Huygens' pairs of electric and magnetic line scatterers.