Equivalent circuit modeling of symmetric composite right/left-handed coplanar waveguides

Abstract

The composite right/left-handed (CRLH) coplanar waveguide (CPW) consisting of the series interdigital capacitor (IDC) and the shunt meandering short-circuited stub inductor (SSI) in symmetric configuration is investigated theoretically and experimentally. To characterize this structure, the equivalent circuit model composed of inductances, capacitances, and resistances to represent the left-handed (LH), right-handed (RH), and lossy characteristics is established. These equivalent circuit elements are extracted simultaneously from S-parameters based on effective medium theory. The extraction method is to examine both the CRLH microstrip line and the CRLH CPW to illustrate the versatility of the formulation. The application of the CRLH CPW in the compact short circuited stub is presented to highlight the unique feature of the CRLH CPW. Compared to the conventional CPW short-circuited stub, the 51.4% length reduction of the case using the CRLH CPW is achieved at 5 GHz.