PLANE WAVE SCATTERING BY PATCHES PERIODICALLY PLACED ON A DIELECTRIC ROD SURFACE

Plane wave diffraction by a finite number of metal cylindrical rectangular strips (patches) periodically placed on a dielectric rod (DR) surface in azimuth direction is considered. The problem is solved by the Method of Moments (MoM) in the spectral domain using Piece Wise Sinusoidal (PWS) basis functions. Topologies with a highly resonant behavior of the patch currents in both azimuth and longitudinal directions are considered. This includes topologies with 1, 2, or 3 patches that are nearly touching, in which case one can also view the topology as a slotted metal cylinder. For these slotted cylinders with one and two slots it is shown that 2D approximate analytical solutions based on the rigorous Riemann-Hilbert approach yield a good agreement with 3D MoM solutions for the natural frequency of the half wavelength resonance until the slot width reaches 40◦. It is found that in the 3D case the natural frequency of the half-wavelength resonance for gap coupled patches tends to zero when the slot is vanishing. The radar cross-section versus frequency, resonant current distributions on the patches and far fields are presented.