Design and applications of Huygens metasurfaces

We present a complete methodology for the design of Huygens metasurfaces (HMS), structures combining electric and magnetic polarizable particles to tailor the fields on their aperture based on the equivalence principle. This includes a semianalytical spectral formalism to design metasurface radiators for a variety of excitation configurations, and a systematic method for engineering printable subwavelength elements to implement them, which, together, extend the potential range of HMS applications substantially beyond beam manipulation. As an example, a single-feed cavity-excited HMS is optimized to exhibit a high aperture efficiency of 88%.