Fano Resonance Based Multiple Angle Retrodirective Metasuface

In this paper, a Fano resonance based multi-angle retrodirective metasurface is introduced. The aim is to investigate the potential of Fano-resonating structures, to suppress the losses and complexity of metasurface designs with high super-cell periodicities. A dolmen structure is given in this case which is well known for its Fano-resonating characteristics. It consists of two sub-radiant modes and one super-radiant mode. The design is given following the generalized phase law of reflection and surface impedance modulation for higher efficiency. The super-cell design has been given with a periodicity of $5.74 \lambda$, and frequency of 24 GHz. This is to achieve numerous retro-reflections at different incident angles based on Floquet harmonic analysis. When the sub-radiant mode is excited, retrodirectivity has been achieved at 17 angles of incidence. On the other hand, by exciting the super-radiant mode, retrodirectivity has been achieved at three incident angles due to the coupling between the individual elements of the Fano-resonating structure. The monostatic RCS has been calculated to determine the performance of the retrodirective metasurface.