Berdnik S. Formation of electromagnetic fields by combined vibrator-slot radiating structures in electrodynamic volumes with impedance boundaries

The dissertation is devoted to the development of the theory of combined vibrator-slot radiating structures, creation of physically correct mathematical models, and improvement of numerical-analytical methods for solving corresponding boundary value problems of electrodynamics, which allow a theoretical analysis of physical properties of excitation fields (the radiation, scattering) and functional characteristics of combined vibrator-slot structures containing impedance vibrators and slot radiators, as well as their multi-element systems located in different electrodynamic volumes with impedance boundaries (including coating of metamaterial) and filled with material. New concepts of effective induced impedances of electric and magnetic types are introduced into electrodynamic analysis of electrically thin radiators, which allowed to formulate of current integral equations for radiators of electric and magnetic types in dual-symmetric form. The problem of constructive realization of magnetic type impedance is solved. The problems of excitation and radiation of electromagnetic fields by transverse and longitudinal slots in the wide wall of a rectangular waveguide, inside and outside of which there are vibrators (monopoles) with variable surface impedance have been solved by taking into account the full interaction between all elements of the vibrator-slot structures. The conditions for the realization of the radiation coefficient of the structures close to unity and the conditions for controlling the frequency characteristics are determined. The optimal parameters of a Klevin-type radiator with impedance vibrators when radiating into half-space over an infinite plane for the formation of fields with given characteristics are determined. For the first time by the generalized method of induced magnetomotive forces, the distributions of currents in a multi-element combined slot-vibrator array with impedance radiators are determined. It was found that such a system allows one to obtain a radiation pattern similar to the pattern of the Yagi-Uda array while ensuring good matching with the waveguide path. The problems of excitation of electromagnetic fields in waveguide joints (tees) with vibrator-slot structures in the area of communication, dielectric inserts and impedance surfaces were solved. The conditions for separation of the powers of the waves in a given ratio, the conditions for equal power separation between waveguide modes in the side waveguide (provided its multimode operation) and between all physical channels of power-sharing with good matching were determined. The general resonance condition for waveguide joints with a dielectric insert was formulated. The problems of excitation and radiation of electromagnetic waves by a narrow resonant slot cut in an ideally conducting sphere of the arbitrary radius when a slot is excited by a semifinite rectangular waveguide with impedance end wall; by a rectangular waveguide with single- and double-slot through resonator. It is determined that the placement of the passage resonator in the waveguide path significantly increases the quality factor of the system, while the resonance curve has a large steepness, and its shape is close to rectangular. The presence of the second slot in the diaphragm leads to a narrowing of the bandwidth by half the radiation power to 50%. The problem of forming electromagnetic fields by a structure consisting of a resonant slot in an ideally conducting sphere and two radial impedance vibrators was solved. The conditions for the implementation of a Klevin-type radiator on a sphere were determined. For the first time, a multifrequency radiator has been implemented based on an electrically long slot in a narrow wall of finite thickness of a multimode rectangular waveguide when the waveguide is excited by higher types of waves at different frequencies. A new method of impedance synthesis of the radiation pattern of antenna arrays with impedance vibrator and slot elements is proposed. For the first time, analytical formulas are obtained for the real and imaginary parts of the surface impedances of the array elements, which ensure the formation of the radiation pattern of the array with a maximum in the given direction. The correspondence of the constructed models to real physical processes is confirmed by comparison with the experimental data known from the literature and the original results of experimental studies for vibrator, slot and combined structures. The obtained results are the basis for the development and creation of a new element base of radio-electronic means of meter and microwave ranges, which allows to significantly expand their functionality, will contribute to solving the problems of ensuring electromagnetic compatibility, noise immunity, signal selection, miniaturization.