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dc.contributor.supervisor Bridges, Gregory (Electrical and Computer Engineering) en_US
dc.contributor.author Kandic, Miodrag
dc.date.accessioned 2011-10-07T16:52:26Z
dc.date.available 2011-10-07T16:52:26Z
dc.date.issued 2011-10-07
dc.identifier.uri http://hdl.handle.net/1993/4958
dc.description.abstract Abnormal electromagnetic wave propagation characterized by negative group velocity and consequently negative group delay (NGD) has been observed in certain materials as well as in artificially built structures. Within finite frequency intervals where an NGD phenomenon is observed, higher frequency components of the applied waveform are propagated with phase advancement, not delay, relative to the lower frequency components. These media have found use in many applications that require positive delay compensation and an engineered phase characteristic, such as eliminating phase variation with frequency in phase shifters, beam-squint minimization in phased array antenna systems, size reduction of feed-forward amplifiers and others. The three principal questions this thesis addresses are: can a generic formulation for artificial NGD structures based on electric circuit resonators be developed; is it possible to derive a quantitative functional relationship (asymptotic limit) between the maximum achievable NGD and the identified trade-off quantity (out-of-band gain); and, can a microwave circuit exhibiting a fully loss-compensated NGD propagation in both directions be designed and implemented? A generic frequency-domain formulation of artificial NGD structures based on electric circuit resonators is developed and characterized by three parameters, namely center frequency, bandwidth and the out-of-band gain. The developed formulation is validated through several topologies reported in the literature. The trade-off relationship between the achievable NGD on one hand, and the out-of-band gain on the other, is identified. The out-of-band gain is shown to be proportional to transient amplitudes when waveforms with defined “turn on/off” times are propagated through an NGD medium. An asymptotic limit for achievable NGD as a function of the out-of-band gain is derived for multi-stage resonator-based NGD circuits as well as for an optimally engineered linear causal NGD medium. Passive NGD media exhibit loss which can be compensated for via active elements. However, active elements are unilateral in nature and therefore do not allow propagation in both directions. A bilateral gain-compensated circuit is designed and implemented, which overcomes this problem by employing a dual-amplifier configuration while preserving the overall circuit stability. en_US
dc.subject negative group delay en_US
dc.subject metamaterial en_US
dc.subject NGD en_US
dc.subject group delay compensation en_US
dc.subject abnormal propagation en_US
dc.subject superluminal propagation en_US
dc.subject group velocity en_US
dc.subject group delay en_US
dc.subject Kramers-Kronig relations en_US
dc.subject causal medium en_US
dc.subject causal media en_US
dc.subject causality en_US
dc.subject constant phase shifter en_US
dc.subject phased array en_US
dc.subject feed-forward amplifier en_US
dc.subject reciprocal circuit en_US
dc.subject bilateral circuit en_US
dc.subject delay circuit en_US
dc.subject distributed parameter circuit en_US
dc.subject active device en_US
dc.subject gain compensation en_US
dc.subject negative refractive index en_US
dc.subject NRI en_US
dc.subject LHM en_US
dc.subject left handed material en_US
dc.subject cloaking en_US
dc.title Asymptotic limits of negative group delay phenomenon in linear causal media en_US
dc.degree.discipline Electrical and Computer Engineering en_US
dc.contributor.examiningcommittee Oliver, Derek (Electrical and Computer Engineering) Page, John (Physics and Astronomy) Frank, Brian (Queen’s University, Electrical and Computer Engineering) en_US
dc.degree.level Doctor of Philosophy (Ph.D.) en_US
dc.description.note February 2012 en_US


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