Table 3.

Comparison of materials and their influence on the resulting capacity of the CPT system [108].

Material	Relative Permittivity ${\mathit{\epsilon }}_{\mathit{R}}$	Capacitance (pF)
Air	1.0005	1.77
Rubber	3.0000	3.81
pvc	4.0000	5.31
Glass	7.6000	13.45
Water	80.1030	141.78