Composite right/left-handed metamaterial transmission lines with unconventional dispersion and applications

In this article, novel metamaterial transmission lines exhibiting right-handed wave propagation at low frequencies and left-handed wave transmission at high frequencies are presented. The unconventional dispersion characteristics of these composite right/lefthanded transmission lines is obtained by parallel connecting left-handed and right-handed unit cells, both implemented by using complementary split-ring resonators. Thanks to the diplexer action of the structure, either the right-handed (tuned at the lower frequency band) or the left-handed (tuned at the upper frequency band) unit cell transmits the injected power, thus achieving the unconventional dispersion of the structure. It is also shown in this article that these artificial lines are of interest for the design of certain microwave components exhibiting dual-band characteristics. Examples are provided including design and characterization. The measurements are indicative of good device performance at the two operating bands and wide bandwidths. © 2010 Wiley Periodicals, Inc.