The generalized negative-refractive-index transmission-line and its applications

The generalized negative-refractive-index transmission-line (NRI-TL) is presented. The generalized NRI-TL is a further development of the traditional NRI-TL and features two left-handed and two right-handed passbands. Thus, the generalized NRI-TL is well suited for making multi-band microwave passive components and antennas. Relevant background information on the traditional NRI-TL is given. The development of the generalized NRI-TL from the traditional NRI-TL is explained. An explanation of the mechanism of operation of the generalized NRI-TL is given and conditions are shown on how to close the corresponding stopbands that normally appear between bands at two frequencies. Several applications that harness the unique properties of the generalized NRI-TL are demonstrated; such applications include a quad-band quarter-wavelength matching circuit and a dual-band bandpass filter. Complete design procedures are presented as well.