A rotated transmission-line metamaterial unit cell for transformation-optics applications

We introduce a transmission-line metamaterial unit cell to implement an equivalent full, symmetric material tensor, a key criterion in transformation-optics devices. This is achieved by taking an anisotropic metamaterial unit cell and rotating it. The rotation is responsible for the off-diagonal components. We then show how this unit cell can be used to implement transformation-optics devices such as a beam expander. To implement the transmission-line grid for the beam expander, we approximate the spatial variation in the rotation angle by rotating different sections of the grid by the same angle. Full-wave simulation confirms these results.