An Analysis of Modified Microstrip Loop Antennas：改进的微带环形天线分析.ppt

ELE 623-Project Electromagnetic Scattering From Chiral Media Atef Z. Elsherbeni atef@olemiss.edu The University of Mississippi Outline Objectives Properties of Chiral material Example of Chiral Objects Problem Geometry Solution Techniques FDTD Solution Boundary Value Solution Iterative Solution Verifications Numerical Results and Applications Conclusion Objectives Techniques for the scattering from arbitrary shaped two-dimensional chiral, dielectric and conducting scatterers. RCS reduction and field focusing using composite scatterers. Properties of Chiral Material Unlike dielectric or conducting cylinders, chiral scatterers produce both co-polarized and cross-polarized scattered fields. A chiral medium is therefore characterized by right-hand circularly polarized waves (RCP) and left-hand circularly polarized waves (LCP). Coating with chiral material can reduce or enhance the radar cross-section of targets. Chiral Media Parameters Constitutive Relation for the Chiral Material Time Domain Solution Technique Multiple Frequency FDTD Formulation for Chiral Media Multiple Frequency FDTD Formulation for Chiral Media Reflection and Transmission from a One Dimensional Chiral Slab of ?r = 2 and ? = 0.3 Scattering from a Chiral Sphere using the FDTD at 1 GHz with ?r = 4 Scattering from a Chiral Sphere using the FDTD at four different frequencies of ?r = 4 and ? = 0.5 Scattering from a Chiral Sphere using the FDTD at four different frequencies of ?r = 4 ? = 0.5 Frequency Domain Solution Techniques Problem Geometry Plane Wave Excitation-Incident E H E-polarized incident wave TMz The corresponding ? component of the H-polarized incident wave Scattered and Internal Co-Polarized Fields Scattered and Internal Cross-Polarized Fields Boundary Value Solution(BVS) Boundary Conditions at the Surface of One Chiral Cylinder (Cylinder “i”, ?i = ai ) To solve for the unknown coefficients, the boundary conditions must be applied on cylinder i Transformatio