Матеріали конференцій
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Item Numerical and experimental research of helical antennas for GPS applications(Видавництво Національного університету "Львівська політехніка", 2009) Dubrovka, F. F.; Dolzhenko, D. S.; Sushko, A. Ju.The results of research and development of helix and spiral antennas for producing both narrow and wide radiation patterns specified for GPS applications are presented.Item Cross-polar radiation of a dual-band coaxial feed horn with partial dielectric loading(Видавництво Національного університету "Львівська політехніка", 2009) Dubrovka, F. F.; Dubrovka, R. F.; Ovsianyk, Yu. A.Cross-polar radiation of a novel dual-band coaxial hybrid-mode feed horn with partial dielectric loading for single and dual reflector antennas has been investigated. In comparison to dual-band corrugated horns this horn has higher crosspolar level, but provides larger band separation (e.g., 6.6:1 in the paper) and rather good electrical performances over a wide frequency range (20% and more) within each operational frequency band. Furthermore, the main concept of the coaxial feed system can be easily extended for multi-band cost-effective applications.Item A novel broadband coaxial orthomode transducer with high port isolation(Видавництво Національного університету "Львівська політехніка", 2009) Dubrovka, F. F.; Vasylenko, D. O.A novel compact design of a broadband orthomode transducer with circular coaxial waveguide input and two orthogonal highly isolated rectangular waveguide outputs is presented. A neural-genetic algorithm is used to optimize the inner architecture of the OMT. Within the operational frequency band 3.4–4.2 GHz input return loss is less than –20 dB and isolation between ports is better than 30 dB. The TEM mode in coaxial structure is not excited due to the special design of the OMT.Item Radiation characteristics of a novel “ring-in-cone” antenna(Видавництво Національного університету "Львівська політехніка", 2009) Dubrovka, F. F.; Bankowsky, V. L.Results of numerical investigations of radiation characteristics of the finite "ring-onrod" antenna and a novel combined "ring-in-cone" antenna are presented.Item Accuracy estimation of cross polar radiation prediction of open-ended thin-wall circular waveguide by Approximate methods(Видавництво Національного університету "Львівська політехніка", 2009) Dubrovka, F. F.; Piltyay, S. I.Approximate methods and exact factorization method have been used to predict peak crosspolar of radiation levels of open-ended thin-wall circular waveguides. The ranges of minimal discrepancy with factorization method are estimated for each approximate method. Optimal diameters that minimize peak crosspolar levels in front half-space, back half-space and the whole space have been defined.Item A new approach to analysis of curvilinear conducting surface radiators(Видавництво Національного університету "Львівська політехніка", 2009) Dubrovka, F. F.; Tolkachov, O. V.We present a new approach to analysis of curvilinear perfect conducting surface radiators. The feature of this approach is a formulation of boundary value problem as a system of integral equations in regard to the complex electrodynamic vector potential and the scalar potential and simultaneous solution of this system for unknown distributions of current density vector and charge density using technique of parametrical mapping for representing curvilinear surface and the Galerkin’s method with boundary elements. Advantages of the approach in comparison with the Harrington integral equation on example of surface current distributions at the third order surface (Ferguson’spatches) are demonstrated.