New composite right/left handed transmission lines based on electrically small open resonators

In this work, composite right/left handed (CRLH) transmission lines implemented by combining open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) are presented for the first time. Both the OSRR and the OCSRR are open particles which can be considered dual counterparts. The OSRR behaves as an open series resonator, whereas the OCSRR can be modeled as an open parallel resonant tank. By connecting the OSRR and the OCSRR in series and shunt configuration, respectively, in a host transmission line, backward and forward wave transmission at low and high frequencies, respectively, is achieved. As compared to split ring resonators (SRRs) and complementary split ring resonators (CSRRs), the open resonators used in this paper are electrically smaller. Thus, compact CRLH transmission lines can be obtained. To illustrate the new approach for the synthesis of metamaterial transmission lines, a CPW-based CRLH transmission line has been fabricated, modeled and characterized. Advantages and drawbacks of the reported approach, as well as potential applications, are also pointed out.