Background. Currently, the application of various types of dielectric waveguides in the millimeter wavelength range is very promising, including metal-dielectric structures and functional units based on them. This is due to the simplicity and low cost of manufacturing dielectric waveguides and functional units based on them, the possibility of their integration with active elements, the use of various dielectrics and polymers having both a wide range of dielectric constants and a variety of mechanical properties (in particular, some dielectric materials have significant flexibility).Objectives. To optimize the method of excitation of one of its eigenwaves in a inverted strip dielectric waveguide with a metal plane through a series of physical experiments.Materials and methods. The studied electrodynamic structure belongs to the class of hybrid metal-dielectric structures. Its basis is a inverted strip dielectric waveguide with a metal plane. A feature of the used inverted strip dielectric waveguide is its composition: the main part of the waveguide rod adjacent to the metal plane is made of polystyrene, the second part is made of fluoroplastic. The evaluation of the excitation efficiency was carried out by the magnitude of the introduced attenuation into the tract. Using the method of a moving probe, the degree of concentration of the electromagnetic field near a complex compositional waveguiding rod was estimated. The fields were visualized using the contour method.Results. Based on a series of experimental studies, the method for exciting an inverted strip dielectric waveguide with a metal plane is optimized. The effect of optimal excitation was achieved through the use of the composite design of the dielectric waveguiding rod. With the optimal ratio of the material constants of the layers forming the waveguiding rod and the geometric parameters of these layers, it was possible to significantly expand the working frequency band, within which the level of insertion loss did not exceed the specified values. It was found that the electromagnetic field is concentrated mainly near the dielectric rod, providing a stable wave mode. It has been established that with a certain ratio of structure parameters, the frequency selection mode can be implemented in it. Conclusions. In the course of physical measurements, it was found that a inverted strip dielectric waveguide with a metal plane with the optimal choice of parameters is able to effectively maintain the wave mode with a low level of insertion loss. In general, a structure with a certain choice of parameters can operate in two regimes: waveguiding mode and frequency selection mode.
Optimization of the method for exciting an inverted strip dielectric waveguide with metal plane