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The problem of creation of antenna feeder devices (AFD) for telemetric systems of launchers for commercial starts of spacecrafts on different ascent trajectories is considered. The principles of AFD creation on the basis of use of the controlled antenna arrays of meter and decimeter frequency bands and features of switching antennas are stated.
The optimal algorithm of multiband spatio-temporal radiometric signal processing is synthesized. Analytical expressions both for the potential fluctuation sensitivity of the system designed according to the algorithm and for the ambiguity function of multiband radiometric systems are deduced. An example of the theory application is demonstrated.
A method for forming the space-time waveforms with rectangular envelope using a multi-frequency antenna array is proposed. A comparative analysis of structural and correlation features of multi-frequency space-time waveforms with rectangular envelope is carried out.
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.
A new method of directivity calculations for rectangular arrays composed of subarrays is proposed. The method is based on representation of a double integral on angular coordinates in the form of series of squared Bessel functions. As a result of application of the developed technique, an empirical formula for calculation of aperture efficiency for the beams of a multibeam array is obtained.
This paper describes a new method proposed for obtaining a special form radiation pattern. The main idea of this method is to use a combination of straight and incline diffraction gratings in a planar diffraction radiation antenna. A comparison of radiation characteristics of straight and inclined gratings was made. The radiation pattern of antenna with a combined grating confirms the correctness...
Two kinds of planar center-fed leaky-wave antenna arrays for millimeter wave systems are presented. The antenna arrays consist of a printed one-dimensional periodic metal strip grating on a grounded dielectric waveguide and designed for broadside radiation. The first antenna array has a hybrid structure with a feeding device for the planar dielectric waveguide, represented by a center-fed linear slot...
A review of modern optimal and quasi-optimal algorithms for radiometric signal processing, which provide images with a high spatial resolution is given. It is shown that the high resolution is achieved with ultra-wideband or multi-band time or space-time signal processing. Analytical expressions for the limiting error of image estimation, ambiguity functions and potential fluctuation sensitivity of...
NenuFAR is both a giant extension of the LOFAR and a large standalone instrument in the low-frequency range (10–85 MHz). It was designed in Nançay with national and international collaboration. Antenna radiators were modeled on the LWA antenna design whereas preamplifiers were designed in France. Antennas will be distributed in 96 mini-arrays of 19 dual-polarized elements, densely covering a disk...
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