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Abstract-The approximate analytical solution of the integral equation concerning the equivalent magnetic current in the narrow slot, coupling two electrodynamic volumes, has been obtained by the averaging method. The formulas and the plots for currents and the coupling coefficients of longitudinal and transverse slots in the common walls of rectangular waveguides are represented. By means of the induced magnetomotive forces method using basis functions of current distribution, obtained by the averaging method, the following electrodynamic structures have been considered: the electrically long longitudinal slot in the common broad wall of rectangular waveguides; two symmetrical transverse slots in the common broad wall of rectangular waveguides; the transverse slots system in the common broad wall of rectangular waveguides. The problem about the resonant iris with the arbitrary oriented slot in the plane of cross-section of a rectangular waveguide has been solved by the averaging method. The problem about stepped junction of two semi-infinite rectangular waveguides with the impedance slotted iris has been solved by the induced magnetomotive forces method. The analytical formulas for the distributed surface impedance of homogeneous and inhomogeneous magnetodielectric coatings of iris surface have been obtained. For a greater number of the considered electrodynamic structures the calculated values are compared with the results, obtained by numerical methods (also using commercial programs) and the experimental data.

Abstract-The problem of excitation of electromagnetic fields by a material body of finite dimensions in presence of coupling hole between two arbitrary electrodynamic volumes is formulated. The problem is reduced to two-dimensional integral equations for the surface electric current on a material body and the equivalent magnetic current on a coupling hole. A physically correct transition from the initial integral equations to one-dimensional equations for the currents in a thin impedance vibrator which, in general case, may have irregular geometric parameters, and a narrow slot is justified. A solution of resulting equations system for the transverse slot in the broad wall of rectangular waveguide and a vibrator with variable surface impedance in it was found by a generalized method of induced electro-magneto-motive forces. The calculated and experimental plots of electrodynamic characteristics of a vibrator-slot structure in a rectangular waveguide are presented.

Abstract-The problem of electromagnetic waves radiation into a space outside a perfectly conducting sphere through a narrow slot, cut in an end-wall of a semi-infinite rectangular waveguide, excited by a fundamental wave of H 10 type is solved using a rigorous self-consistent formulation. The starting point for the analysis is the one-dimensional integral equation for the equivalent magnetic current in the slot, obtained by using the effective thickness of the slot. The asymptotic solution of the equation was found by the generalized method of induced magnetomotive forces (MMF). The physical adequacy of the constructed mathematical model to the real physical process is confirmed by experimental data. Influence of the sphere radius upon energy characteristics of the slot radiator was investigated numerically. It was shown that at any frequency of waveguide single-mode range, the radiation coefficient of a spherical antenna can be made close to one by choosing the slot length, the sphere radius and the waveguide height. Conditions for correct application of infinite screen approximation for spherical scatterers with sufficiently large radii are formulated.

Abstract-The authors suggest the generalized method of induced electromotive forces (EMF) for the investigation of the characteristics of single and systems of thin impedance vibrators at their arbitrary excitation and distribution of the surface impedance on the ground of the made analysis in the proposed paper. The distinctive peculiarity of this method is the use of the functional distributions, obtained as a result of the analytical solution of the integral equation for the current by the asymptotic averaging method before, as the basic approximations for the current along the impedance vibrator.

A problem of electromagnetic waves radiation and scattering by a structure, consisting of a narrow transverse slot cut in the broad wall of a rectangular waveguide and two vibrators with a variable surface impedance located inside the waveguide and interacting with one another, is solved. A solution of integral equations for electric currents at the vibrators and equivalent magnetic current in the slot is derived by using the generalized method of induced electro-magneto-motive forces (EMMF). Conditions needed to achieve maximum slot radiation coefficient are defined. Computed and experimental graphs of electrodynamic characteristics of the vibrator-slot structure for different vibrator locations and for the various surface impedance distributions along the vibrators are presented.

Abstract-The problem of electromagnetic waves radiation by a vibrators system with variable distributed surface impedance along their axes located in free space is solved by the generalized method of induced electromotive forces (EMF). The distinctive peculiarity of this method is the use of the functional distributions, obtained as a result of the analytical solution of the integral equation for the current by the asymptotic averaging method before, as the basic approximations for the currents along the impedance vibrators. The multi-parameter characteristics of three-element and multi-element antennas with variable impedance vibrators are calculated.