Design of unit cells and demonstration of methods for synthesizing Huygens metasurfaces

The systematic design of unit cells for a Huygens metasurface, a particular class of metasurface, is presented here. The design of these unit cells uses transmission-line theory. This is validated through application to ID refraction and Gaussian-to-Gaussian beam focusing. The 1D refraction is further validated experimentally. These applications demonstrate the practical utility of these Huygens metasurfaces. The Huygens metasurfaces presented here are printed on two bonded boards instead of many stacked, interspaced layers. This simplifies fabrication and enables the scaling down of the metasurfaces to shorter wavelengths. These two bonded boards implement a single, collocated layer of electric and magnetic dipoles. The electric and magnetic dipoles are synthesized using sub-wavelength arrays of printed. elements. These printed elements can be manufactured using standard PCB fabrication techniques, and are capable of synthesizing the full range of impedances required. Furthermore, in contrast to frequency-selective surfaces (FSSs) and traditional transmitarrays, which are on the order of a wavelength thick, these designs are only lambda/10 thick while incurring minimum reflections losses. (C) 2014 Elsevier B.V. All rights reserved.