Tensor huygens surfaces

Huygens surfaces are a superposition of scalar electric and magnetic surface impedances which are used to control wavefronts. Here we expand the capabilities of a Huygens surface to also control the polarization of the electromagnetic field. To achieve this, the Huygens surface must now compose of tensor impedances. This allows for the polarization to be altered to any desired state. To verify this idea, we develop an equivalent S-parameter model and use it to determine the required tensor impedances. We then use a custom TLM method to demonstrate a Huygens surface which takes a normally incident, linearly polarized, Gaussian beam and converts it to a circularly polarized Gaussian beam refracted by 30°.