The
coordinate transformation on the space that contains
electromagnetic sources is studied. In 2006, J. Pendry et al. proposed the pioneering coordinate transformation concept to arbitrarily control electromagnetic (EM) fields. In this paper, The Authors further illustrate that such coordinate transformation can even be applied to a space containing EM sources. The closed-form solution obtained from a full wave analysis that combines the coordinate transformation and green’s function principle shows that
in this case, not only the permittivity and permeability tensors, but also the EM sources can be transformed at will. In particular, a source of arbitrary shape and position in the free space can be replaced by another source, given access to a properly
designed metamaterial coating, without being detected by outer observers. As examples to illustrate the possible applications of this kind of transformation, The Authors designed two conformal antennas — which always attracts interests of microwave engineers — by transforming a simple dipole
antenna and a standard array antenna, separately. The closed form formulations and the calculations show that the metamaterial coatings carrying specific currents have the same radiation patterns as the original antennas’ in the zones of interest. The method proposed in this paper provides a brand-new approach in the development of novel active EM devices, and enlightens a wider exploration in the field of the EM coordinate transformation.
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