Microwave seminar | 27 December 2021

Using metasurfaces for beamforming in near- and far-field zones brings many possibilities in antennas and optics applications. Here we describe methods and techniques which allow reaching extreme fields transformations with special unit cells formed so-called omega-bianisotropic metasurfaces (OBMSs). The described algorithm assumes the excitation of evanescence waves traveling along the surface without altering the far-field distribution for incident nor required transmitted field. One of the considered examples is the Gaussian beam expander or reducer for beamforming without any reflections that can find many applications in practical engineering.
The considered approach may be used to implement different types of field transformations: refraction, beam-splitting, wavefront correction, and so on.

Main paper/arXiv, related to the seminar, and other references

Epstein, Ariel, and George V. Eleftheriades. "Arbitrary power-conserving field transformations with passive lossless omega-type bianisotropic metasurfaces." IEEE Transactions on Antennas and Propagation 64.9 (2016): 3880-3895.
Ataloglou, Vasileios G., and George V. Eleftheriades. "Arbitrary Wave Transformations with Huygens' Metasurfaces through Surface-Wave Optimization." arXiv preprint arXiv:2106.07109 (2021).
Epstein, Ariel, and George V. Eleftheriades. "Synthesis of passive lossless metasurfaces using auxiliary fields for reflectionless beam splitting and perfect reflection." Physical review letters 117.25 (2016): 256103.