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Radio astronomy deals with the weakest signals received by a radio electronic device, and, as a result, it is very complicated problem to maintain appropriate SNR while transferring signal from the antenna output to receiver's input. In this paper, a system for delivering the radio astronomical signals from dipole terminals to ADC input of Giant Ukrainian Radio Telescope (GURT) is described. Examples...
Advantages of the diamond dipole antenna as an active antenna are presented. Such an antenna is like an inverted bow-tie antenna, but the former has some advantages over the ordinary bow-tie antenna. It is shown that the diamond dipole antenna may be an effective element of a new antenna array for low-frequency radio astronomy as well as a communication antenna.
Transient radiation of a dipole corresponds to excitation of a spherical harmonic wave in some conical line from an evanescent wave domain. The governing equation contains a cut-off frequency that depends on radius. Using high refraction index material the cut-off frequencies for the radiating mode can be significantly reduced. This can lead to “tunneling” energy from the evanescent region and consequently...
A new technique for calculation of a diffracted field excited by a half-wave dipole on the edges of a finite size rectangular screen, at any observation point of a near zone is described. The technique is based on the laws of the geometric theory of diffraction with using the uniform diffraction factors obtained from the exact solution of a diffraction problem of the field of an arbitrarily oriented...
An algorithm is considered for calculating the EM field of dipole in case of arbitrary spacing between the point of dipole location and the point of its field observation, as well as arbitrary distance of points from the boundary of dielectric half-spaces. The algorithm is adapted to the height of mentioned points above the boundary and allows to reduce significantly calculation time while providing...
Forming ultrawideband (3.2∶1) end-fire radiation mechanism of a low profile dipole-slot antenna backed by a ground plane at wavelengths close to the distance of 0.5λ from the plane are considered. It has been shown that at this frequencies the dipole-slot radiation differential phase shift in forward-backward directions is close to 180°. Therefore, the radiation of the dipole-slot antenna is summarized...
The angle dependence of near field radiated of Hertzian dipole excited by transient current is investigated. The more precise approximation in the solution for near field of the dipole is obtained in time domain by means of vector potential technique. As an example, the quickly decreasing excitation current case is considered.
Antennas with rotational symmetry - flat and volume self-complementary antennas, consisting of several metallic and slot radiators of identical shapes and dimensions, are considered. Methods of calculating mutual capacitances between individual radiators or groups of radiators, based on conformal transformations and reduction of three-dimensional problems to the planar ones, are presented. Various...
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