Some Studies on Metamaterial Transmission Lines and Their Applications
Electrical Engineering Some studies on metamaterial transmission lines and their applications XIN HU Doctoral Thesis in Electromagnetic Theory Stockholm, Sweden 2009 ISSN 1653-7610 Division of Electromagnetic Engineering ISBN 978-91-7415-217-3 School of Electrical Engineering, Royal Institute of Technology (KTH) S-100 44 Stockholm, SWEDEN Akademisk avhandling som med tillstånd av Kungl Tekniska Högskolan framlägges till offentlig franskning för avläggande av teknologie doktorsexamen torsdagen den 2 April 2009 klokan 10:00 i sal F3, Lindstedtsvägen 26, Kungl Tekniska Högskolan, Stockholm ©Xin Hu, February, 2009 Tryck: Universitetsservice US AB 2 Abstract This thesis work focuses mostly on investigating different potential applications of meta-transmission line (TL), particularly composite right/left handed (CRLH) TL and analyzing the new phenomena and applications of meta-TL, mostly left-handed (LH) TL, on other realization principle. The fundamental electromagnetic properties of propagation in the presence of left-handed material, such as the existence of backward wave, negative refraction and subwavelength imaging, are firstly illustrated in the thesis. The transmission line approach for left-handed material (LHM) design is provided together with a brief review of transmission line theory. As a generalized model for LHM TL, CRLH TL provides very unique phase response, such as dual-band operation, bandwidth enhancement, nonlinear dependence of the frequency, and the existence of critical frequency with zero phase velocity. Based on these properties, some novel applications of the now-existing CRLH transmission line are then given, including notch filters, diplexer, broadband phase shifters, broadband baluns, and dual band rat-ring couplers. In the design of notch filters and diplexers, CRLH TL shunt stub is utilized to provide high frequency selectivity because of the existence of critical frequency with zero phase velocity.
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