Slow-Wave Effect of Electronically-Controlled Composite Right/Left-Handed (CRLH) Transmission Line

Sungjoon LIM  

Publication
IEICE TRANSACTIONS on Communications   Vol.E91-B   No.5   pp.1665-1668
Publication Date: 2008/05/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.5.1665
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Antennas and Propagation
Keyword: 
left-handed metamaterial,  composite right/left-handed (CRLH) transmission line,  slow wave,  leaky-wave antenna,  phase shifter,  

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Summary: 
A dispersion diagram is useful in interpreting the characteristics of a periodic structure. In particular, the fast-wave region, where the wave is radiating, and the slow-wave region, where the wave is guided, can be determined from the dispersion diagram. An electronically-controlled composite right/left-handed (CRLH) transmission line (TL) was previously proposed and utilized as a leaky-wave (LW) antenna operating in the fast-wave region. However, since a guided-wave application operates in the slow-wave region, it is meaningful to study slow-wave effects of the proposed TL. In this paper, the dispersion diagram is used to investigate the slow-wave factor (SWF), which is necessary to understand the fast/slow-wave operations. Furthermore, the frequency characteristics are measured to find the cut-off frequencies in the LH and RH regions. Based on experimental results, it is observed at a fixed frequency, 2.6-GHz, that the phase of a proposed 6-cell structure can be changed by up to 280 in the LH slow-wave region.