Polarization Control Using Tensor Huygens Surfaces

Controlling the polarization of the electromagnetic field is a crucial aspect of many communication and imaging systems. Building off of previous work on Huygens surfaces, which are surfaces used to manipulate wavefronts using electric and magnetic surface impedances, the concept of a tensor Huygens surface is introduced. A tensor Huygens surface consists of electric and magnetic surface impedances which are tensors as opposed to scalars. In this paper we show how the polarization can be modified from a given initial state to a desired state specifically using a tensor Huygens surface. We examine the fields at the surface to find the required impedance tensors to manipulate the polarization. We also come up with an equivalent circuit model which captures the behavior of the surface as well as its equivalent S-parameter representation. Furthermore, we examine how chiral functionality can be realized using two cascaded Huygens surfaces. We validate these results using a TLM solver as well. Finally, we demonstrate a possible implementation of a tensor Huygens surface made up of skewed dipoles and loops.