Fresnel coefficients for a permittivity‐permeability phase space encompassing vacuum, anti‐vacuum, and nihility

The concept of the electromagnetic trinity comprising vacuum, anti‐vacuum, and nihility is extended to a zone in the 4‐D εr‐μr phase space that was largely inaccessible until the recent emergence of negative‐phase‐velocity materials. Expressions for Fresnel coefficients are derived for the reflection of plane waves at the planar interface of vacuum and a homogeneous, isotropic, dielectric‐magnetic medium with constitutive properties lying in that zone.