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.