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)


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.



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.