The metamaterials by use of L_C lumped_elements in the transmission line have the preternatural characteristic,which is different from the conventional dielectrics.We report the experimental results in the left_handed range with anti_parallel phase and group velocities in the metamaterials,with the negative refractive index, and we find the bandgap corresponding to zero averaged refractive index.The configuration offers some significant advantages:it is more compact in si ze,the material parameters can be tuned,and the method of fabrication is easy to carried out.