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A study of the diffraction of an electromagnetic wave on a dielectric coating with a diaphragm over an infinite waveguide antenna array has been carried out. The metal diaphragm is located at some distance from the surface of the antenna array. The influence of the geometric dimensions of a metal diaphragm and its distance from the grating surface on the modulus of the reflection coefficient of the incident wave in waveguides is investigated. Dielectric coatings with different values of the dielectric constant are considered.

The calculation of the non-reflective connection in the coaxial line is performed by the integral equation method. The connection of coaxial lines with a significant difference in geometric dimensions is considered. A system of equations is obtained that allows calculating the reflection coefficient of the T-wave from such an inhomogeneity. This technique makes it possible to calculate a multistage coaxial waveguide in order to minimize the reflection coefficient from inhomogeneities.

It is known that electromagnetic radiation affects the functional systems of living beings, in particular, the endocrine and cardiovascular systems and directly the heart cells and their functioning. In this case, the influence of electromagnetic radiation significantly affects the properties of the cardiovascular system and changes physiological processes in it. Moreover, sensitivity to signals is higher for biosystems with a higher level of organization. The method of simulating hypothyroidism for rats makes it possible to develop an experimental model for analyzing morphogenetic changes in the rat heart. Under conditions of hypothyroidism modeling, destructive changes in muscle fibers are observed in the myocardium after thyroidectomy, but after microwave irradiation with an exposure of 45 minutes, a regenerative-compensatory reconstruction of the structural components of the myocardium of the heart wall occurs. After thyroidectomy and microwave irradiation with an exposure of 120 minutes, an increase in degenerative and destructive processes in the heart myocardium was observed. For the first time, a comparative ultramicroscopic study using electron microscopy was carried out. It showed that after electromagnetic irradiation with an exposure of 45 minutes, the general structure of the mitochondrial apparatus does not change. Irradiation with an exposure of 120 minutes causes the destruction of subsarcolemal and paranuclear organelles, edema and degradation of intermyofibrillar mitochondria. After exposure to electromagnetic radiation with the exposure of 45 minutes in a hypothyroid state, a compensatory restructuring of the energy apparatus of the contractile cardiomyocytes of the left ventricle occurs due to the formation of mitochondria and an increase in their contact interaction. After exposure to radiation for 120 minutes, the development of destructive-degenerative processes in the mitochondrial apparatus of left ventricular cardiomyocytes, deepening of damage to intermitochondrial contacts was observed. The most significant increase in the relative volume of the endothelium in the areas of the rat heart myocardium was observed for the case of microwave irradiation only (without experimental hypothyroidism) with exposure duration of 45 minutes. Immunohistochemical study both for the case of microwave irradiation only and for the case of microwave irradiation under conditions of experimental hypothyroidism allows us to conclude that morphogenetic transformations are highly active in the myocardium of the heart when the duration of exposure is 45 minutes. This study will make it possible to develop recommendations for persons with thyroid diseases on the duration of daily exposure of staying in electromagnetic field emitted by devices with characteristics similar to the case under study.

The stepwise transition in the coaxial waveguide is calculated by the integral equation method. To solve the problem, the entire region of field definition is conditionally divided into three partial areas for which the field components are recorded. A system of equations is obtained that allows one to calculate the reflection coefficient of a T-wave from this homogeneity. The geometric dimensions of the waveguide, which provide the minimum value of the reflection coefficient, are given.

An electrodynamics calculation is performed for an infinite waveguide antenna array in the form of open ends of waveguides, in the near zone of which a metal-dielectric structure is located. This metal-dielectric structure is located in the "Floquet channels" and is a combination of a dielectric coating over the antenna array and horns. In this case, the horns are not a continuation of the waveguides, but are located at some distance from them. The space between the waveguides and the horns is filled with a dielectric. A system of equations that allows calculating the reflection coefficients of incident waves in waveguides is obtained.

A general methodology for calculating antenna arrays with layered dielectric is considered. To demonstrate the proposed methodology, we consider the solution of the problem of radiation of linear waveguide array. Plane-parallel waveguides have a finite wall thickness. Antenna array scans in E and H planes. This problem is solved using Fredholm integral equations of the second kind. To solve the problem, the entire domain of the electromagnetic field is divided into partial intersecting regions An example of constructing Green’s functions of selected partial regions with allowance for their dielectric filling is considered. The formulation of the boundary-value problem for the antenna array in the form of Fredholm integral equations of the second kind using the technique of dividing the determination domain into partial regions with Green’s functions allows us to solve the following problem: calculations of the antenna array with dielectric plugs in the waveguides and with a dielectric coating over the antenna array. This technique allows optimization of dielectric parameters with the aim of aperture matching of the antenna array. The calculation results of the dependence of the reflection coefficient on the phase shift between waveguides in the H-plane are presented. The calculations are performed for different values of the dielectric constant of the plugs in the waveguides and the dielectric constant of the dielectric layer above the antenna array. The influence of the geometric dimensions of the plugs in the waveguides and the dielectric coating above the array is studied.

The method of improving the interference protection of axisymmetric antennas is considered. An experimental study of the focusing properties of a zonal antenna is carried out in this work. Such a zonal antenna acts as a shading screen and is located in the aperture of an axisymmetric antenna. The combination of a shading screen with an axisymmetric antenna can significantly reduce the level of side lobes in the anterior semi-space, and as a result, significantly improve the immunity of the antenna system. A zonal antenna for 40 GHz frequency is manufactured. The field distribution along the axis of symmetry for different numbers of rings in the antenna is experimentally investigated. The number of rings varied from 1 to 5. The focusing properties of the zonal antenna are studied at the change of operating frequency. The position of the focus is investigated when the working frequency changes in relation to the calculated frequency. It is established that the experimentally found focal point does not coincide with the focal point found by geometric optics. For a zonal antenna with three rings, the difference between the experimentally found focus and the focus found by the law of geometric optics is 0.1%. The distribution of the field in planes perpendicular to the focal line is investigated. It is established that an increase in the number of rings in a zonal antenna to more than five leads to diffraction effects which impair the focusing properties of the zonal antenna. At the same time there is a "deliquescence" of the wave beam in the focus. These studies allow us to determine the boundaries of the working frequency of a complex antenna system.

The features of the use of finite waveguide antenna arrays in the structure of modern smart antenna systems are considered. The paper deals with the problem of diffraction of an electromagnetic wave on a finite waveguide antenna array scanning in the E-plane. Antenna array consists of five radiating elements. The open ends of the waveguides are surrounded by a metal screen. The resonator coupling region was chosen as matching elements. The solution of the problem is carried out by the integral equation method on the basis of the selection of overlapping regions. The problem reduces to solving the Fredholm integral equation of the second kind. An array of infinitely thin plates and that of waveguides with a finite wall thickness are considered. The main regularities for choosing the optimal geometric dimensions of the antenna array are established. Studies were carried out for arrays with a number of elements from five to fifteen. The analysis of edge effects in the final antenna array is carried out. It is shown that the introduction of a resonator region into a five-element lattice makes it possible to expand the sector of the radiation angles and avoid the effect of blinding. It is shown that this statement is valid not only for five-element lattices, but also for arrays with a large number of radiating elements. The radiation patterns are calculated. The coefficients of mutual coupling in an array with five elements are investigated. General recommendations for choosing optimal sizes of the resonator coupling region of radiators are considered.

Context. The problem of the regional television channel transition from analogue broadcasting to digital broadcasting has been solved. Objective is to identify and overcome the difficulties of the local transition to digital television standard DVB-T2 on the example of the usual regional television company. Method. A two-level transition of the regional TV channel from analog to digital broadcasting is proposed. The first level includes the election of the best video format for broadcasting in the DVB-T2 standard and HDTV, as well as two options for replacing the television equipment that can provide digital terrestrial second generation digital terrestrial television and high definition television. The two options for replacing equipment are due to the limited funds that can allocate TV company for a short time interval on the technical re-equipment. At the second level, the city level to calculate the real range of coverage of digital broadcasting and the proposed methods of achieving it. Results. In this example, the technique of the transition from analogue to digital broadcasting for usual regional television companies is shown. Calculations carried out on the example of TV Private TV Dnipro – «Channel 9», the city Dnipro showed that the existing analogue system fixing, processing and transportation of the video on the regional TV channel will require the complete replacement of the equipment. Depending on the volume of finances allocated for modernization, two ways of replacing equipment are suggested. Calculations showed that minimally satisfactory coverage of digital TV in the city Dnipro provided at a distance of about 65 km. However, the quality of digital television on the verge of coverage is not provided in full by poor field strength at the point of maximum distance from the TV center. Conclusions. The method of transition of the regional TV channel from analogue broadcasting to digital broadcasting has been developed. It can be recommended for use in practice, considering local conditions in other regional channels in Ukraine.

The problem of electromagnetic wave diffraction by the metal objects has been solved using integral equation technique. The diagrams of backward scattering have been plotted for four different objects. Based on the feature vector, which has been constructed by applying wavelet packet signal decomposition, a neural network has been trained. We have performed the testing of ability of the neural network to recognize the object depending on the noise level. Various methods of the feature vector forming have been considered.

Linear Energy Transfer (LET) is the main physical parameter to compare charged particles to photons and predict the higher biological effectiveness of the former radiation. Cytogenetic damage complexity governs cellular radioresponse and reflects the peculiar manner with which energy is deposited by ions as described by the Bragg curve, and is therefore likely to change along ion penetration depth and with its track structure. Hence, ion beams of different Z but similar LETs may differ radiobiologically and construction of ???biological??? Bragg curves may improve modeling of this type of radiation. Moreover, there are still uncertainties on charged-particle non-cancer effects of relevance in cancer hadrontherapy. In fact, most experimental data are almost exclusively on tumour cell lethality and on the Spread-Out Bragg Peak (SOBP), overlooking sub-lethal damage induction on normal cells at various positions along the Bragg curve. Further, very little is known on non-targeted effects (NTE) by ion-irradiated normal cells expressing long-term sub-lethal damage. We studied the onset of Stress-Induced Premature Senescence (SIPS) by ???-galactosidase assay and the induction of chromosome aberrations (CA) by whole-chromosome FISH painting and mFISH along the Bragg curve for several ion beams on three normal cell lines (AG01522 fibroblasts, MCF-10A breast epithelial cells and endothelial HUVEC cells). Occurrence of NTE by medium-transfer design from irradiated prematurely senescing cells was studied at different time points after irradiation on unirradiated MCF10A and breast cancer epithelial MCF7 cells. End-of-track effects of up to 20 MeV 12C and 16O beams were studied at the 3-MV Tandem accelerator, Department of Physics, Naples; 60 MeV/u 16O and 20Ne beams were used at INFN-LNS cyclotron, Catania, to explore changing biological effectiveness along the Bragg curve. Data show SIPS being very effectively induced by ion irradiation, with a qualitative and quantitative dependence on ion type and Bragg curve position, persisting for up to 2 months post exposure. CA data also indicate a similar dependence: the elevated incidence of complex-type rearrangements as revealed by mFISH well agrees with these aberrations being a cytogenetic signature of high-LET radiation. However, the overall incidence of CA and SIPS point to a significantly greater efficiency of ion beams compared to x-rays even at very high LETs, contrary to the notion of a close-to-unity RBE above 200 keV/???m. The onset of SIPS at ion beam entrance may have important implications for hadrontherapy cancer patients. Finally, we observed a significant bystander effect by senescing cells manifesting itself with an increase in tumour cell proliferation, in agreement with in vivo reports of a Senescence-Associated Secretory Phenotype. Monte-Carlo modeling by Geant4 code is under way to correlate ion-track structure with such results.

L'efficacia radiobiologica nell'induzione della senescenza cellulare prematura, come effetto subletale di interesse per gli effetti tardivi da esposizione a particelle cariche, è stata studiata in linee cellulari umane normali per vari fasci di ioni accelerati. Esistono pochi dati sperimentali al riguardo; in aggiunta, il Linear Energy Transfer (LET), solitamente utilizzato per predire gli effetti generati dalle particelle cariche, non tiene conto delle possibili dipendenze dallo Z e varia significativamente lungo la profondità di penetrazione dello ione. E' pertanto possibile che l'efficacia nell'induzione di tale effetto vari lungo la curva di Bragg. I risultati preliminari sembrano confermare tale dipendenza.