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Antenna array Complex directional antenna consists of separate near-omnidirectional antennas (radiating elements) positioned in the space and driven by high-frequency … (from 'Glossary' of our website) |
Archives for 2007Paged Saturday, November 24, 2007 at 12:11AM
Asymptotic solution for the diffraction problem on a periodic array of microstrip radiators located above the surface of an infinite generalized cylinder, the curvature radius of which satisfies the condition of slow change along the guide, is considered. By using the matrix reflectivity coefficients, the problem is solved assuming the multilayer isotropic dielectric coating is present. For partial excitation the electric Green tensor function of Maxwell equations is written in closed form, which includes the Airy functions in the Fok definition and their first derivatives.
Friday, November 23, 2007 at 12:11AM
This work considers results of research of characteristics of rectangular printed-circuit radiators in plane phased antenna arrays. The research is conducted by using computer modeling and the mathematical model described in [1].
Thursday, November 22, 2007 at 12:11AM
Based on the asymptotic theory, characteristics of convex cylindrical antenna array consisting of director radiators are studied. To determine the distribution of currents of the radiator vibrators, the numeric projective method is used. Results of numeric computations are presented.
Wednesday, November 21, 2007 at 12:11AM
Based on the asymptotic diffraction theory methods, the problem of determining the near field of the convex cylindrical antenna array composed of aperture radiators is reduced to the boundary value problem in the single cell of the array, which is solved using the Galerkin method. The asymptotic theory is further developed, which provides representation of the radiator diagram in the convex cylindrical array as a sum of the direct wave from the excited radiator, the fast creeping waves and slow creeping waves. Results of numeric computations of the slot elliptical, particularly circular antenna arrays are presented.
Tuesday, November 20, 2007 at 12:11AM
Results of numeric modeling of impedance and polarizational characteristics of single-channel printed-circuit radiator having circular polarization in the base of the antenna array are presented. Possibilities for optimizing the characteristics in the frequency band and scanning angle sector.
Monday, November 19, 2007 at 12:11AM
In this work, a space Hilbert problem is solved, with the boundary condition set on the boundary of the unlimited full bicircular region of class (T∞) or on the boundary of the region Dpq={z∈C2: |z1|p|z2|q<1; p,q∈N}. The main devices used for solving the space Hilbert problem are Temlyakov integrals of second kind.
Friday, November 16, 2007 at 12:11AM
The article presents a critical analysis of possible uses of metamaterials to improve operation of antenna devices and points out directions of necessary studies in the field of metamaterials.
Thursday, November 15, 2007 at 12:11AM
In this work, the theory of boundary value problems is applied to the problem of decomposition of integral functions of two complex variables of the class [n, σD] into quasi-exponential basises (the received result generalizes the result received by G. D. Derevyanchenko and V. A. Kakichev) as well as to the problem of decomposition of functions, holomorphic in logarithmically convex limited full bicircular regions, into quasi-exponential basises.
Monday, November 05, 2007 at 12:11AM
The results of research of characteristics of printed-circuit radiators in a plane phased antenna array is presented, based on the infinite plane antenna array model.
Friday, May 11, 2007 at 12:05AM
Solutions for boundary problems of electrodynamics in tensor form are examined. Equations and boundary conditions for Green tensor functions of general kind are formulated.
Monday, April 23, 2007 at 12:04AM
The optical properties of materials, such as magnetic metals or magnetic semiconductors, having simultaneously negative electrical and magnetic permeabilities are considered. One finds that the refractive index with respect to vacuum is negative; that the Poynting vector and the wave vector of propagating EM waves have opposite signs; that the sign of the Doppler effect is opposite that, for ordinary materials and that the Cherenkov radiation cone is directed backwards rather than forwards. Finally, the question of the mechanical forces arising from EM propagation in materials having a negative refractive index is discussed.
Thursday, April 19, 2007 at 12:04AM
Equations for waveguide, impedance and lens antenna arrays are formulated taking into account excitation conditions and interconnection between radiators. The arrays can be located on flat or curved surfaces.
Wednesday, April 18, 2007 at 12:04AM
General method for determining tensor Green functions corresponding to various classes of solutions for boundary problems is examined.
Thursday, April 05, 2007 at 12:04AM
Analytics inversion of hypersingular operator is derived and based on this, an efficient numerical–analytical method for solving hypersingular integral equations is constructed. Applications of analytical inversion of hypersingular operator in antenna theory are examined.
Monday, March 26, 2007 at 12:03AM
In the paper, the solution method for the problem of electromagnetic waves scattering by cylinder bodies is given. The method is based on 2*pi-periodicity property of functions describing the parameters and distributions of fields and currents on cylinder bodies. The method advantage is the possibility of physical interpretation of results. The example of the proposed method application is given.
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