Manipulating polarization and impedance signature: a reciprocal field transformation approach.

We introduce a field transformation method for wave manipulation based on completely reciprocal and passive materials. While coordinate transformations in transformation optics (TO) change the size and shape of an object, field transformations give us direct control on the impedance and polarization signature of an object. Using our approach, a new type of perfect conductor can be realized to completely convert between transverse electric and transverse magnetic polarizations at any incidence angles and a perfect magnetic conductor of arbitrary shape can be mimicked by using anisotropic materials. The approach can be further combined with TO to enhance existing TO devices. For example, a dielectric cylinder can become completely transparent for both polarizations using bianisotropic materials.