In order to better understand how to improve the performance of a superlens, structural and geometrical arrangements of meta-atoms are investigated. Each meta-atom (i.e. the unit element composing a metamaterial) in our study is an asymmetric 3D "S"-shaped resonator. This structure radiates an enhanced scattered field at several possible resonant frequencies, some of which are out of phase with the incident wave. We retrieve the effective parameters of different metamaterials and discuss the role of meta-atom symmetries and dimensions in affecting the effective refractive index of a metamaterial slab. Relative locations and orientations of individual meta-atoms are investigated to provide desired properties with low loss despite the inevitable finite size of each meta-atom. The results presented provide insights for designing superlenses, resonant antennas, and other potential applications.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.