Scattering Parameters of the samples, (S_11; S_21; S_22; S_12)

The electromagnetic characterization was performed using a Vector Network Analyzer (VNA) model N5235A (Fig. 2), with the Agilent software package. The VNA emits an electromagnetic pulse (V^+) in the range of 8.2 GHz to 12.4 GHz, where through a waveguide that pulse reaches the test material, and then its diode detectors (receivers) pick up the signal that returns (V^-) and performs the measurements of magnitude and phase of the signal, giving the scattering parameters (S – Parameters (S_11; S_21; S_22; S_12)) of the analysis [22], thus enabling the calculations of the reflection and transmission of the emitted signal.