Cramér–Rao Bounds for Determination of Permittivity and Permeability in Slabs

We compute the Cramér-Rao lower bounds for determination of isotropic permittivity and permeability in slabs using reflection and transmission data. The results apply to three common measurement situations: free space, rectangular waveguides, and coaxial waveguides. The bounds depend only on the available data and not on the actual inversion method used, making them suitable to evaluate a particular experimental setup. The results are illustrated with several measurements in a rectangular waveguide setting.