Polarimetric Bistatic Scattering From Multiple Parallel Cylinders

Abstract

Electromagnetic scattering from multiple cylinders has been an active research topic in many research fields, and the special case of parallel cylinders has seen important applications ranging from remote sensing to biology. Yet, the rigorous treatments have been mostly focusing on the 2-D cases, whereas for the more realistic 3-D cases, approximated approaches are often adopted. This article proposes a more rigorous treatment of 3-D polarimetric multiple scattering from parallel cylinders by extending our previously proposed virtual partition method (VPM) for single-cylinder case to multiple-cylinder case. The appeal of the method includes the appreciably reduced longitudinal dimension for subcylinders and its corresponding encircling sphere so as to effectively address the otherwise thorny issue of violation of the required mutual exclusion of encircling spheres of large aspect ratio cylinders by the conventional multiple scatterers' equation. The proposed VPM demonstrates the capability of capturing very well the polarimetric bistatic scattering amplitudes and phases, and of meeting physical requirements of energy conservation and reciprocity theorem. A systematic examination of the coupling effect is carried out against a number of factors, including average interneighbor-cylinder (intercylinder for short) distance, cylinder size, dielectric constant, and cylinder number, with the numerical results clearly revealing the complicated pattern of coupling effect. The studied cases suggest that the coupling effect may still be felt for a large average intercylinder distance. For electromagnetic wave propagation in the parallel cylinders, the coupling effect is visible, yet it tends to be mitigated by the average process.