The Physics of Invisibility Cloak

Cloaking in general refers to hiding objects from the eye, and in particular the radar. This paper reviews the various schemes used for cloaking. Depictions of cloaking in fiction and ancient history have been discussed along with actual work that has been carried out. Various letters related to metamaterials, transmission line network and active cancellation have been reviewed. In the end a general comparison of the different methods is done, and drawbacks are discussed.