A. A. Nikitin - Post-graduate Student of Department of Physics and Technology of Optical Communication, Nizhny Novgorod State Technical University n.a. R.E. Alekseev E-mail: physics@nntu.nnov.ru N. A. Novoselova - Ph.D. (Eng.), Associate Professor of Department of Physics and Technology of Optical Communication, Nizhny Novgorod State Technical University n.a. R.E. Alekseev A. S. Raevskij - Dr.Sc. (Phys.-Math.), Professor, Head of Department of Physics and Technology of Optical Communication, Nizhny Novgorod State Technical University n.a. R.E. Alekseev S. B. Raevskij - Honored Scientist of RF, Dr.Sc. (Eng.), Professor of Department of Physics and Technology of Optical Communication, Nizhny Novgorod State Technical University n.a. R.E. Alekseev

The article deals with improper waves of open guiding structures described by solutions of semihomogeneous nonself-adjoint boundary electrodynamic problems, which are divided into self-consistent and nonself-consistent. In the first case the boundary value problem becomes attached to the Helmholtz equation, the right side of which is a function that is a solution of the homogeneous boundary value problem; in the second case - on the homogeneous one. And in either of the cases the outer boundary is supposed free, which corresponds to the semi-homogeneous boundary value problem. As open guiding structures we consider an open dielectric waveguide, a corrugated conductive cylinder, an open dielectric waveguide placed into the dissipative medium, a dielectric sphere in the inhomogeneous dielectric medium. In the first three cases, the waves propagate along the z coordinate and their fields are written in the cylindrical coordinate system. In the latter case the waves propagate along a spherical surface and their fields are written in the spherical coordinate system. The discussed open guiding structures are described by the electrodynamic nonself-adjoint operators. Solutions of boundary value problems in the absence of the zero boundary condition as r corresponds to the improper waves. This is either leaky waves or slow improper ones. And in either of the cases field increases along the transverse coordinate when moving away from the guiding structure. And they both really exist only near the source where their fields are localized. Descending of fields of the specified (improper) waves in the direction of their propagation is explained by radiation into open space. Interest in the improper modes is called by possibility of construction on the open structures antenna feeds and various kinds of cross-radiation sensors.

 

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