Mayboroda D. The electrodynamical charachteristics of hybrid metal-dielectric structures with slot discontinuities

The object of investigation: the phenomena of diffraction of eigenwaves by slot discontinuities in HMDS with different shaping. The goal of investigation: developing of electrodynamical models and efficient numerical-analytical algorithms for calculating the characteristics of HMDS with the presence of slot discontinuities; the experimental verification of the key elements of the model. The methods of investigation: by the creation of mathematical models used a common approach, which is based on the method of semi-inversion operator boundary-value problem. Electromagnetic fields in the spectral form are represented as a superposition of plane or cylindrical waves. The diffraction and scattering problems formulated as the problem of determining of the unknown amplitudes of the spatial spectrum of the diffracted and reflected fields. Description of the electrodynamical properties of objects, which include the equidistant discontinuities carried out using a concept of eigenmodes of similar infinite periodic structure. The method of semi-inversion operator boundary-value problem was realized using the operator method. The novelty: for the first time a single approach to solving problems of diffraction problems on complicated electrodynamical objects which have in their composition bounded or semi-infinite sequences of identical equidistant discontinuities was formulated, the correct mathematical model have been built. They allowed to carry out multivariable analysis of the dependences of the electrodynamical characteristics of electromagnetic fields v.s. the geometric dimensions and material constants of the excited volume and radiating structures, frequency-energy and directional characteristics, the frequency spectrum. The character parameters of the scattering of eigenmodes HMDS by a single longitudinal and transverse slot discontinuities in outer screen and by periodic sequences of such discontinuities when the effective radiation is possible have been established. A series of numerical experiments show that the radiation on the main wave type of HMDS is ineffective. It is shown that the effective radiation is appeared or near the cat off frequency of higher order modes, in which the transformation of the main types of waves in one of the leaking types is realized, or by placing in the region of electromagnetic wave propagation a periodic sequence of discontinuities. By measuring the dispersion characteristics and radiation patterns the calculated data on the frequencies at which there is effective radiation patterns were confirmed; the boundary values of the geometric dimensions of the structures and their correlation with the frequency parameter by which the following condition of absence of mutual influence of the scatterers by free space were experimentally established. It is that the period of placement of slots should be comparable with the wavelength. Based on the results of numerical modeling and experimental measurements of HMDS data structures of two radiating units were created. They are defenced by patents of Ukraine. Degree of implementation: the results are using in the learning process and in the Institute of Transport Systems and Technologies of NAS of Ukraine. Field of use: radiophysics and electronics.