An efficient broadband left-handed metamaterials with low-loss

In the past decade, left-handed metamaterials (LHMs), which were first named and theoretically discussed by Veselago [1], have been extensively studied throughout the world. They are composed of arrays of split-ring resonators (SRRs) and wires [2], [3] which exhibit negative permittivity and permeability, respectively. The first LHM was constructed and experimentally demonstrated by Smith et al. in 2000 [4]. Then many groups [5], [6] constructed LHMs by printing the SRRs of different shapes and the wires on both sides of the substrates. However, those given LHMs have the drawbacks of high loss and narrow passband. In order to solve those problems above, we propose a new double-sided LHM in this paper, which consists of triangular electromagnetic resonators (TERs) and wires at the opposite sides of the substrate. The LHM can exhibit a low loss and broad negative refraction passband.