Unit:
Τομέας Ηλεκτρονικής Φυσικής και ΣυστημάτωνLibrary of the School of Science
Dissertation committee:
Δ. Φραντζεσκάκης Καθηγητής (Επιβλέπων), Ι. Τίγκελης Καθηγητής, Ν.Στεφάνου Καθηγητής
Original Title:
Εντοπισμένα κύματα σε μη γραμμικά μεταϋλικά
Translated title:
Localized waves in nonlinear metamaterials
Summary:
The present thesis studies the existence, stability and the propagation
characteristics of localized waves in nonlinear metamaterials. This analysis is
based on the theory of transmission lines, through which discrete models that
simulate nonlinear metamaterials are derived. Initially, it studies
experimentally and analytically a left- handed nonlinear electrical lattice and
then analyses the most realistic case of the composite right- and left-handed
nonlinear transmission line. Then, it studies realistic structures of
metamaterials that have been implemented in experiments such as a nonlinear
coplanar waveguide with an array of split ring resonators being etched at the
bottom of substrate and an one- dimensional array of nonlinear SRR. The
analytical approach is based on a multiscale pertubation method which takes
into regard the discreteness of the systems by considering the carrier
(envelope) of the wave as a discrete (continuous) object. With this approach it
turns out that the voltage envelope function meets a nonlinear Schrodinger
equation which predicts the formation of quasi-discrete solitons, namely the
localization of electromagnetic power in the nonlinear metamaterials. Numerical
simulations about the propagation characteristics and the stability of these
waves are also employed and are found to be in a very good agreement with the
analytical predictions.
Keywords:
Solitons, Metamaterials, Transmission lines, Bacward waves
Number of references:
147
Number of pages:
VIII, 108
