Data and Time |
November 22, 2011, 4:00-5:00 PM |
Location |
Sanford Flemming Building, Room B560 |
Host |
Leon Yuan |
Spectral-Impulse-Response Approach for the Analysis of the Aperiodic
Excitation of a Periodic Diffraction Grating
Mohammad Memarian
The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Electromagnetics)
Abstract:
In many electromagnetic and optical applications, a periodic structure is
driven by one or more finite sources placed in its vicinity. Some different
examples are excitation of leaky-wave antennas, sources above artificial
periodic surfaces, super-resolution imaging using diffraction gratings, and
sources near metamaterial structures. Such scenarios share a common
description: "Aperiodic excitation of an otherwise periodic structure". The
difficulty in solving for the field in these scenarios is the violation of
the periodicity due to the aperiodic excitation, rendering the standard
periodic Floquet/Bloch eigenmode analysis insufficient. Ideally, we would
like to find the aperiodic Green's function of the problem, or in other
words the field due to a single point source (impulse) driving the periodic
domain.
In my talk I will propose a spectral method to solve for the transmitted
field through a periodic diffraction grating made of metal strips, when
excited by arbitrary aperiodic sources. Closed form expressions are derived
for the scattered field due to a point source excitation, thus determining
the aperiodic Green's function of the grating for both field polarizations.
The analysis is verified against full wave EM simulations for some cases of
interest, and is shown to accurately predict the transmitted field in
different field zones.
Biography:
Mohammad Memarian received his BASc (Honours Coop) and MASc from the
University of Waterloo. His MASc research was on developing novel dielectric
resonator filters and multiplexers. He is currently a PhD student in the
Electromagnetics Group under the supervision of Professor G. V.
Eleftheriades. His research interests include advanced electromagnetics,
antennas, and RF/microwave devices.
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