Berdnik S. Radiation of electromagnetic waves by slots in single-mode and multimode rectangular waveguides

The object is the processes of excitation, emission and scattering of electromagnetic fields by slots. Тhe purpose is the development of theory, mathematical models of the slot radiators of arbitrary length and multiunit waveguide-slot systems, the determination of the physical properties of electromagnetic fields in all zones of radiation; the production of practical recommendations relative to the improvement of the technical characteristics of those acting and creation of new antenna systems and the antenna-feeder devices. The method of integrodifferential equations; the method of moments (Galerkin's method); the method of induced magnetomotive forces; the method of natural waves; the method of Green's function, the method of Hertz's vector were applied. The new results are following. The procedure of the determination of the distribution of electric field in the slot of arbitrary length, based on the use of the limited quantity of trigonometric basic functions in the Galerkin's method is proposed and substantiated. Presence is established and the conditions of realization of the electric field amplitude distribution falling down from the middle to the slot edges in the electrically long slots have been defined. It is shown that on the basis of electrically long slot it is possible to create the leaky-wave radiator with the side-lobe level of radiation pattern less -20 dB. The solution of the problem of the excitation by the longitudinal slot of waveguide with the dielectric insert of finite length under the slot is obtained. The method of induced magnetomotive forces is developed and the solutions of boundary-value problems are obtained for a number of the structures such as the systems of the closely spaced slots, waveguide-slot leaky wave arrays, two-dimensional waveguide-slot arrays, multifrequency slot arrays with the combined aperture on the multimode waveguide. The numerical solution of a problem of determining of distribution of the near electromagnetic field radiated by the slots of any length and systems of such radiators in the dielectric medium with losses is obtained. The extent of application: the results are applied in the training process. The field of application: radiophysics and electronics.