We consider invisibility cloaking of active/radiating objects in acousticView original: http://arxiv.org/abs/1202.2802
scattering via the approach of transformation optics. A general lossy layer is
incorporated into the construction of the near-cloaking devices. We derive very
accurate estimates of the scattering amplitude in terms of the regularization
parameter and the material parameters of the lossy layer in different settings.
Our results on the one hand show how to cloak active contents more efficiently,
and on the other hand indicate the optimal choice of choosing the lossy layer.