## 4 Results  
Measurements were carried out on two samples of material with known values of dielectric permittivity and magnetic permeability to confirm the reliability and estimate the accuracy of the created laboratory model (UWB measuring complex) and the developed method. Plexiglas sheet with a thickness of 14.1 mm was chosen as the first known sample. Measured values of the complex dielectric permittivity and magnetic permeability obtained for it are presented below (Figure 10). In the graphs below and subsequent ones, two ordinate axes are used. On the left are the values of the real part of both dielectric permittivity and magnetic permeability. Figure 8: Vector reflectometer CABAN R140. Figure 9: Measured amplitude and phase at the installation surface. At frequencies 2.5, 3, 6, and 12 GHz. On the right are the values of the imaginary part of the corresponding permeabilities. The reference value of the real part of the dielectric permittivity for plexiglas is \(Re(\varepsilon)\) = 2.6 [26]. To check the repeatability, 100 measurements were taken. Due to the fact that the Mathcad program does not allow placing more than 16 curves on the graphs, eight curves were taken from the real part of both the magnetic permeability and the dielectric permittivity. Eight curves were taken for the imaginary parts of the magnetic permeability and dielectric permittivity. The average value of the real part of the dielectric permittivity was \(Re(\varepsilon)\) = 2.61. This is 0.3% more than the reference value. The second known material sample was textolite with a thickness of 20.6 mm. Measured values of the relative dielectric permittivity and magnetic permeability are presented below (Figure 11). The reference value of the real part of the dielectric permittivity for textolite is \(Re(\varepsilon)\)= 3.8 [26]. The average value of the real part of the dielectric constant according to the graph in Figure 11 was \(Re(\varepsilon)\) = 3.76. The error for the obtained value was 1.1%. The error in the values of the real part of the dielectric constant was no more than 3.2%, which does not exceed the percentage of error for the known methods described in the literature. For the second sample, the measurement data were also averaged. The graph does not show all the results obtained for ease of understanding. Measurement accuracy was based on repeated reading data (100 measurements per sample). To find the error, the discrete sampling formula \(\sigma=\sqrt{\frac{1}{n-1}\sum\limits_{i=1}^{n}(x_{i}-\overline{x})^{2}}\) was used. After finding a discrete sample, the confidence interval \(\Delta x=t\cdot\frac{\sigma}{\sqrt{n}}\) was determined. Confidence intervals are specified for maximum and minimum errors. In addition, two experiments were carried out with a composite material having a high dielectric permittivity. A material composed of polyurethane and graphite was chosen as an example. The percentage of graphite in the used sample was 15%, and polyurethane and hardener were 85% when mixing 1 to 1. The resulting composite was mixed to create a homogeneous mass. In this case, graphite does not dissolve in aqueous solutions and acids, thus forming inclusions of  
Figure 11: Measured values of relative dielectric permittivity (**a**) and magnetic permeability (**b**) for textolite. Figure 10: Measured values of relative dielectric (**a**) and magnetic (**b**) permeability for plexiglas. inhomogeneities [21; 27]. The resulting composite was poured into a plane mold with dimensions 180 \(\times\) 180 \(\times\) 15 mm for subsequent measurement using a setup (Figure 11(a)). A PNA-L vector network analyzer and dielectric probe kit 85070E slim form from Agilent were used to verify the dielectric values. The actual dimensions of the finished composite were 180 \(\times\) 180 \(\times\) 10 mm (Figure 11(b)). The measurements were carried out on both installations. The data obtained using the developed laboratory model were compared with the data obtained by the Agilent installation.