Left-Handed Transmission Characteristics of Ferrite Microstrip Lines without Series Capacitive Loading

Tetsuya UEDA  Makoto TSUTSUMI  

IEICE TRANSACTIONS on Electronics   Vol.E89-C   No.9   pp.1318-1323
Publication Date: 2006/09/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.9.1318
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Metamaterials for Microwave and Millimeter-Wave Applications)
ferrite,  left-handed media,  microstrip lines,  nonreciprocity,  periodic structure,  

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A nonreciprocal left-handed transmission line is proposed and investigated, which is composed of a normally magnetized ferrite microstrip line periodically loaded with inductive stubs but without capacitive loading. The circuit configuration becomes simpler than that of a nonreciprocal left-handed transmission line with both shunt inductive and series capacitive loadings. In the proposed structure, ferrite medium is employed as the substrate not only for the nonreciprocal characteristics but also for negative effective permeability that is essential to establish the left-handedness. After calculations of dispersion curves using equivalent circuit model, scattering parameters along with field patterns are estimated numerically with the help of electromagnetic simulation, and the experiments are also carried out. It is found that the band width of the proposed left-handed transmission line is relatively narrow but the structure still has the high isolation ratio of more than 30 dB.