סמינר מחלקתי- אלקטרוניקה פיזיקאלית ויטלי קוזלוב

~~You are invited to attend a lecture

ELECTROMAGNETIC SCATTERING GOVERNED BY MOVING SCATTERERS AND MAGNETO-ELECTRIC COUPLING
By:
Vitali Kozlov
M.Sc student under supervision of Dr. Pavel Ginzburg

Abstract
Contemporary commercial numerical tools, such as CST, Lumerical and COMSOL are commonly used to solve various electromagnetic, thermal and mechanical problems, to name a few. The above solutions are mostly designed for static problems – yet our world is not static. Scatterers move all the time, they may break into smaller pieces, collide to form bigger ones or otherwise change their shape or other scattering properties in time. To formulate the equations of EM scattering from such dynamic objects, velocities and accelerations must be included alongside the geometry of the objects when applying the boundary conditions of Maxwell’s equations.
This seminar deals with two topics, the first is the micro-Doppler shifts generated by a rotating wire. The wire is effectively a 1D object which makes it relatively simple to solve analytically, allowing physical insight into the phenomena. Intuitively one might expect that since various parts of the wire move at different speeds, the scattered field would have continuous Doppler shifts. Detailed analysis as well as experiments show that the scattered field has discrete frequencies only, forming a micro Doppler comb where the separation between the peaks is an integer multiple of the rotational frequency. The second part of the seminar is related to metamaterials, which have effective characteristics that are interesting for numerous applications in optics and RF, spanning from cloaking, solar cells, optical diodes and more. A hybrid magneto electric meta-atom is presented, made out of a straight wire and a split ring resonator with a unique property of asymmetric backscattering. This means that the meta-atom scatters radiation backwards differently depending on the direction of the incident field. Meta-atoms are the building blocks of metamaterials and it is expected that such meta-atoms could form new and exciting metamaterials with interesting properties.

On Monday, March 20, 2017, 11:00
Room 512, floor 5, Tohna building