## 1 Introduction  
Currently, the development of various materials (of high-strength, lightweight, etc.) is proceeding at a high rate in various industries and it is important to know their exact electrophysical parameters. Thus, the study of the electrophysical parameters of the obtained materials is an urgent task. To study the electrophysical parameters of materials, waveguide [1], coaxial [2; 3; 4; 5; 6; 7; 8; 9; 10], as well as methods based on the use of horn antennas [11] are usually used. Waveguide methods are based on the use of rectangular waveguides. The work conducted in [12] presents an installation in the form of a measuring two-ridge waveguide. The use of this setup allowed the authors to expand the frequency range (7.5-18 GHz) due to the localization of energy between two protrusions. The results obtained for three measured samples with different values of the real part of the permittivity have an error of 2%, 3.3%, and 4.7%. With an increase in the value of the real part of permittivity \(Re(\varepsilon)\), the measurement error increases. It subsequently can adversely affect the measurement of strongly absorbing media. Waveguide methods (or open waveguide methods) also have two approaches: Using one or two ports. The one-port wave method [13; 14; 15; 16; 17; 18; 19; 20; 21] usually consists of several measurements with a change in the thickness of the air gap between the waveguide and test sample. These methods are also measuring the reflected signal when there is air behind the test sample and measure the transmitted signal if the metal is located behind the test sample [4]. The two-port waveguide measurement method uses two sources of electromagnetic waves. This approach allows measurements in a wide frequency band but has a number of limitations that do not allow obtaining data with high accuracy, since there is an air gap between the sample under study and the wide wall of the waveguide. When measuring, the presence of this gap leads to a sharp jump in the electric field strength at the \"air-material\" transition [22]. Coaxial methods are based on the use of a measuring transmission line. Among the coaxial methods, we can mention the setup proposed in [12]. Here, measurements are taken by filling the entire inner space of the cell. This method is the most accurate, but it is necessary that the measuring line passes through the entire test sample. In this experiment, there may be air gaps around the perimeter of the sample, and the imperfect surface of the walls of the transmission line may introduce errors in measurements, which must also be taken into account when obtaining data. The method of studying the dielectric and magnetic permeability using two horn antennas has its advantages, since it can be used in free space. Thus, in [23], an installation is presented using two horn antennas aimed at the material under study. To exclude unwanted reflection from the environment, the setup was located in an anechoic chamber. The measurements were carried out in the frequency range 8-12 GHz. In [24], additional focusing lenses are used to eliminate lateral radiation. The focus of the two antennas is located directly inside the material under study, which makes it possible to determine the electrophysical parameters with high accuracy, as well as carry out measurements outside the anechoic chamber. The authors declare that they managed to achieve an accuracy of 2% when measuring the real part of the dielectric permittivity. Many of the methods discussed are implemented in installations of companies such as SPEAG and Keysight technologies. These installations, in particular the line of SPEAG Dielectric Assessment Kit (DAK) systems, namely the DAK-TL2, make measurements only by the contact method, that is, the emitter must be directly adjacent to the sample under study. Measurements are carried out in a wide frequency range from 5 to 67 GHz (for the DAK-1.2E-TL2 installation). Wherein the area and thickness of the sample should not exceed certain dimensions.