This work is devoted to experimental studies of the influence of dielectric inhomogeneities on electromagnetic waves in a transmission line. A series of experiments is described, united by one aim: the development of new methods and approaches in the study, parameters reconstruction and the creation of new functional materials. During the work, the related tasks were successfully solved: refinement of the waveguide method for measuring the electrophysical parameters of materials, verification of an experimental study of the half-waveguide measuring method, designing of an experiment for measuring the parameters of materials in free space, discernibility and resonance of inhomogeneities in transmission lines. All experiments were carried out in the microwave range.