Transistor-based Magnetless Faraday Metasurface and Spatial Isolator

We report here a magnetless Faraday metasurface and its application as a spatial isolator. The nonreciprocity of this metasurface stems from time symmetry breaking by transistor-loaded conducting circular ring metaparticles. In contrast to previously reported transistor-ring structures, this metasurface operates in transmission mode rather than in reflection mode, which is more challenging in design and which enables the spatial isolator application. It is shown that this surface is electric-magnetic hybrid insofar as it involves both electric and magnetic rotating dipole moments.