“…These multiple mechanisms may involve interfacial polarization, dipolar orientation, ionic diffusion (e.g., see p. 40, 49, 57 of [31]) and may often require a selection of several types of distributional representations from examples such as the fractional power laws of the Cole-Cole [25,26,31,35,46], the log normal, the uniform, as well as the Debye and Lorentz (although the fractional power law of Cole-Cole is more the rule rather than the exception -p. 39, [31]). These multiple mechanisms are likely present in some weighted combination (e.g., see [36] and p. 369, [40]) and often are manifested in a frequency-dependent manner. It is therefore advantageous to consider interrogation or inverse problems with multiple frequencies (e.g., ranging from RF (10 6 ) to GHz (10 10 )) or broadband excitation signals.…”