Metamaterials are a periodic array of meta-atom, which is very smaller than wavelengths, and have unique optical properties that does not exist in nature, thus emerging as a candidate that can overcome existing limitations in various fields of research. Metamaterials with high refractive index is an important research topic in designing very thin and efficient absorber or in designing very small form factor antennas. In this research, metamaterials consisting of core-shell structures are proposed and the electrical and magnetic properties of these metamaterials were discussed. Using the dielectric core and conductive shell structure, the control of the capacitive effect between two conductive particles was used to achieve a very high effective electric permittivity while controlling the diamagnetic effects to achieve a very high effective magnetic permeability. This research is expected to be applicable to beam control and small antenna systems in 5G industries in the future.