Electromagnetic Metasurfaces. Christophe Caloz

in taking the complex conjugate of the Fourier transform of , i.e. in transforming into , where the plus sign is for a time-even quantity while the minus sign is for a time-odd quantity [28].

      6 6 These relations not only provide the usual reciprocity conditions, but also the nonreciprocity conditions [28], e.g. in the case of a magnetic nonreciprocal medium.