Retrieval of electric and magnetic coupling coefficients

We propose a novel method for a direct retrieval of electric and magnetic coupling coefficients in metamaterials with an arbitrary type of inter-element coupling. The proposed technique employs a transformation of the frequency dependence of complex current amplitudes in interacting meta-atoms, enabling separate deduction of the magnetic and electric coupling coefficients. The method is verified on a number of examples using both experimental and simulation data in a wide frequency range from MHz to THz. Our approach is valid for elements of arbitrary shape and should be useful for design of metamaterial structures that employ slow waves of inter-element coupling for manipulation of the near field.