  Coordinate-transformation approaches to invisibility cloaking rely on the
design of an anisotropic, spatially inhomogeneous "transformation medium"
capable of suitably re-routing the energy flux around the region to conceal
without causing any scattering in the exterior region. It is well known that
the inherently magnetic properties of such medium limit the high-frequency
scaling of practical "metamaterial" implementations based on subwavelength
inclusions (e.g., split-ring resonators). Thus, for the optical range,
non-magnetic implementations, based on approximate reductions of the
constitutive parameters, have been proposed.
  In this paper, we present an alternative approach to non-magnetic
coordinate-transformation cloaking, based on the mapping from a
nearly-transparent, anisotropic and spatially inhomogeneous virtual domain. We
show that, unlike its counterparts in the literature, our approach is amenable
to exact analytic treatment, and that its overall performance is comparable to
that of a non-ideal (lossy, dispersive, parameter-truncated) implementation of
standard (magnetic) cloaking.
