V. G. Sargsyan - Ph.D. (Phys.-Math.), Doctoral Candidate, Faculty of Computational Mathematics and Cybernetics of Lomonosov Moscow State University E-mail: vahe_sargsyan@ymail.com A. S. Tadevosyan - Post-graduate Student, Institute for Informatics and Automation Problems NAS of Armenia (Yerevan) E-mail: astadevosyan@gmail.com A. I. Petrosyan - Head of HF Laboratory, Yerevan Telecommunication Research Institute E-mail: asatur@yetri.am

Modern antenna systems in the form of antenna arrays allow to solve problems of electrical scanning in the given direction of space at the same time meeting the requirements for spatial resolution (the beamwidth of the radiation pattern) and the level of jamming immunity (the magnitude of the received signal by sidelobes) [1]. In certain situations (for example, in the existence of significant reflections sources in the radiating near-field region) it is required to achieve a low gain from corresponding directions. The null formation problem needs to be solved for the given directions in such cases. The optimal methods for such patterns are known and require restructuring of all the array elements by rather complicated algorithms [2]. The application of the weight functions is another solution for this problem, where amplitude distribution of currents is determined in the antenna array. In particular, a pattern forming method is considered in [3]. It reduces the transmission level in the given directions by using Hamming weight window function. The problem of null synthesis is solved with approximation by atomic functions in [4]. The method of forming nulls by manipulating the first and last elements in the array is developed in [5]. A number of methods have been developed in terms of [4] in the paper. They present a special type radiation patterns adapted for jamming conditions. The methods use either one or two adjusting coefficients.

 

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