M. Ivashina

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In recent years, Compressive Sensing has attracted considerable attention in various areas of antennas and electromagnetics, including the synthesis of sparse array antennas. The CS synthesis of arrays achieves higher accuracy than analytical methods and allows for the fast and deterministic design of large complex arrays, without resorting to(More)
We discuss how to evaluate SKA technology options with regard to science output quality. In this work we will focus on polarimetry. We review the SKA specification for polarimetry and assess these requirements. In particular we will use as a illustrative case study a comparison of two dish types combined with two different feeds. The dish types we consider(More)
The Jacobi-Bessel (JB) series representation for modeling reflector antenna patterns is proposed to be used as a reference tool to assess and improve the pattern shape of multi-beam wide-scan radio telescopes. After expanding each beam in JB functions, the number of dominant JB functions per beam not only serves as an indication of the beam calibratability(More)
A dual-mode antenna design, utilizing a combination of differential- and common-mode excitations, is presented. This antenna offers the possibility to complex-combine both modes in order to obtain a near-hemispherical Field of View (FoV) coverage. A Single-Ended (SE) to Mixed-Mode (MM) transformation model is introduced to determine the MM radiation(More)
This paper describes a numerical approach for the analysis of a reflector antenna system which is fed by a Phased Array Feed. This approach takes mutual interaction effects into account between the antenna array and the low noise amplifiers in the evaluation of the system sensitivity and optimization of the beamformer weights, and can be used when several(More)
—The design of a push-broom multi-beam radiometer for future ocean observations is described. The radiometer provides a sensitivity one order of magnitude higher than a traditional conical scanning radiometer, and has the big advantage of being fully stationary relative to the satellite platform. Thanks to a dense focal plane array and a dedicated(More)
The performance of a dual-polarized quad-mode antenna, representing a potential array antenna element for wide scan-angle applications, is assessed. This analysis is carried out by investigating the utilization of the four available Transverse Electromagnetic (TEM) excitation modes, when beamforming for maximum gain, Signal-to-Noise ratio (SNR), and(More)
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We consider the application of the Characteristic Basis Function Pattern (CBFP) method to calibrate for direction-dependent gain effects of the LOFAR Low Band Antenna (LBA) array. The use of array-based calibration models, as opposed to element-based calibration models, is proposed in order to reduce the number of solvable beam model parameters.