Fig. 10. (a) Modeled and measured capacitances Cmodel and Cexp between the ring electrodes as a function of the permittivity 
of the environmental material. The permittivity of the access tube and sensor holder are acc = hold = 3.35. (b) Modeled normalized sensor readings Nmodel and normalized readings Nexp measured in the laboratory (with the FEP shrink tube on the access tube) together with the interpolation function (Nexp).