Multiband microwave passive devices using generalized negative-refractive-index transmission lines (Invited paper)
This article presents an overview of the generalized negative-refractive-index transmission-line (G-NRI-TL) and summarizes the design equations that determine the frequencies of each of its four passbands. Specific multiband devices to which G-NRI-TLs have been applied are discussed: both a dual-band coupled-line coupler operating at 2.7 and 4.7 GHz and a printed single-ended all-pass cell with two pairs of right- and left-handed bands are explained. The details of how each may be fabricated in a fully-printed layout are provided and simulated and measured results are given.  2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 22:459468, 2012.
generalized negative-refractive-index transmission-line coupler all-pass network artificial transmission line impedance inverter metamaterial