The bulk modulus and density are analogs of permittivity and permeability in electromagnetic metamaterials. The permittivity and the dielectric thickness are the determining parameter for capacitors. The maximum energy is a function of dielectric volume, permittivity, and dielectric strength. The dielectric constant (or relative permittivity) of LiF is 9.0. In effect, the vacuum behaves like a medium having a dielectric permittivity more than unity. The historical term for the relative permittivity is "dielectric constant". Hence we define the "relative" permittivity (or dielectric constant) , and the "relative" permeability . The invention achieves simultaneous negative permittivity and permeability over a common band of frequencies. This results in control over material parameters known as permittivity and magnetic permeability. Any material can be used as long as the permeability, permittivity, and conductivity are specified. Only the vacuum permittivity and permeability are used, and there is no D or H. The susceptibility (or equivalently the permittivity) is frequency dependent. In a conducting medium, permittivity and index of refraction are complex-valued. The phenomenon of a frequency-dependent permittivity is an example of material dispersion. This dimensionless quantity is also often and ambiguously referred to as the "permittivity".