Balanced CRLH cell based on a microstrip line loaded with CSRRs (inset) and dispersion diagram (a), and frequency response (b). The structure has been implemented in the Rogers RO3010 substrate with dielectric constant and thickness . Dimensions are line width , external radius of the outer ring , rings width , and rings separation ; the interdigital capacitor, formed by 28 fingers separated by 0.16 mm, has been used to achieve the required capacitance value. From [15]; copyright © 2007 IEEE, reprinted with permission.