• To develop the analytical theory of the wave diffraction and transformation by a finite periodic sequence of certain complex planar heterogeneities. The basis element of the sequence are: a thick grate of perfectly conducting strips, a grate of rectangular bars and cylinders, a resistive film and magnetodielectric layers, which are placed inside a waveguide or open transmission line.
• To develop the theory of artificial dielectric medium that includes thick grate of perfectly conducting strips.
• To investigate the process of Gaussian beam scattering on the sequence of perfectly conducting bar gates.
• To investigate the electromagnetic properties of bounded periodical structures with different types of periodicity defects.

       Periodical structures are the basis of wide class of devices. Improving of operating performances of known devices and developing a new one are connected with their composition complicating, new functional components imbedding. The important stage of periodical sequence investigations is finding the scattered fields of the device composite elements. This requires of appropriate models and effective algorithms of their solving.

       Periodical structures are the basis of wide class of devices. Improving of operating performances of known devices and developing a new one are connected with their composition complicating, new functional components imbedding. The important stage of periodical sequence investigations is finding the scattered fields of the device composite elements. This requires of appropriate models and effective algorithms of their solving.        The model must be invariant to the basic element structure, waveguide type, nature and topology of excitation fields. The result of the investigation must be presented in the form that is convenient to physical analysis, optimization and new devises synthesis. The method that is based on the circuit theory and the matrix polynomial technique is suitable for solving these problems.

       A generalized electromagnetic model of microwave multifunction system is proposed. The closed-form formulas convenient for both physical analysis and engineering design are worked out by a complex method, which combines both direct and approximate mathematical methods.

The frequency dependences of the reflecting coefficient magnitude for the sequence of cylindrical grates

The frequency dependences of the scattering and transformation coefficient magnitudes for the rectangular waveguide that included sequence of thick grates.

       Analytical theory of wave diffraction and transformation by a finite periodic sequence of certain complex planar heterogeneities is developed. The interrelations between character of eigenwave propagation for those structures and the parametric dependences (i.e. in frequency, in spacing parameters, etc.) of diffraction coefficients are established taking into account intertype field transformation.
       The closed-form expressions are presented for the effective permittivity and permeability of non-resonant magnetodielectric layers with thick grates of perfectly conducting strips. On this basis, the conditions of artificial medium synthesis are determined. The dynamics of scattered fields of the spatial wave-beam at different incidence angles and structure parameters are investigated.
       The influences of structure periodicity defects on the scattered and transformed fields are examined.