THz plane wave scattering by azimuthally periodic array of conformal graphene patches on circular dielectric rod

Plane wave scattering by a cylindrically conformal periodic array (CCPA) of graphene patches on a dielectric rod (DR) is studied in the THz frequency range. The patches are placed periodically in the azimuth direction. Such a structure is of interest in sensing applications where graphene patch arrays can be used as mid-IR biosensors. The analysis is performed with the Method of Moments (MoM) using sub-domain piece wise sinusoidal (PWS) basis functions. The scattering characteristics are studied for both H- and E-polarised incident plane waves and the resonant frequencies of the bistatic radar cross section (RCS) are determined and validated with CST. In the paper the focus is on the Helmholtz type resonances for the H-polarisation and the half wavelength resonances for the E-polarization. It is shown in the paper that a different number of patches results in a different radiation pattern, leading to the fact that the scattering characteristics depend on the observation angle. Also, in the case of H-polarisation the resonant frequencies of the CCPA with one slotted cylinder behave differently for the graphene and the perfect electrically conducting (PEC) cylinder when the cylinder length in z-direction decreases. Namely, the resonant frequencies decrease for the graphene case and increase for the PEC case. It is observed that for the H-polarisation the total absorption level prevails over the total scattering level, while for the E-polarisation the situation is the opposite. A good agreement with CST Microwave Studio is demonstrated.