We present numerically and experimentally a dynamic chiral metamaterial (MTM) that creates strong optical activity and circular dichroism. The proposed tunable structure has a very simple and more efficient configuration which introduces flexibility to adjust its EM properties. In addition, it gives a giant negative refractive index due to the high chirality. Our experimental results confirm the strong optical activity for a wide frequency range and agree with the simulation results. Moreover, the proposed chiral MTM provides a wideband and constant/flat chirality over a certain frequency band and thus it can be concluded that the developed chiral MTM based model offers a strong optical activity in terahertz, infrared and even in visible frequencies. (C) 2015 Elsevier GmbH. All rights reserved.