Microwave devices based on composite right/left-handed (CRLH) transmission line metamaterials

Recent research on metamaterials with simultaneously negative permittivity (ε) and permeability (μ), more commonly referred to as left-handed (LH) materials, has stimulated the development of novel concepts and applications. Since right-handed (RH) effects are unavoidable, practical LH materials (LHM) are in reality composite right/left-handed (CRLH) materials. Interestingly, the co-existence of LH and RH contributions in CRLH materials, far from being detrimental, leads to useful phenomena. By applying a transmission-line (TL) approach towards CRLH metamaterials, the unique properties of these metamaterials have been used to realize novel microwave devices including antennas with characteristics (functionalities or performance) surpassing those of conventional (i.e., RH) materials.