RT Journal Article ID 3ae506d217aaacfa A1 Borulko, V. F. A1 Vovk, S. M. T1 PRINCIPLE OF MINIMUM EXTENT IN SPATIAL SPECTRUM EXTRAPOLATION PROBLEMS OF COMPLEX-VALUED SOURCES JF Telecommunications and Radio Engineering JO TRE YR 2013 FD 2013-04-12 VO 72 IS 7 SP 581 OP 592 K1 spectrum extrapolation K1 radiation sources K1 minimum spatial extent AB This paper considers a problem of spatial spectrum extrapolation for complex-valued sources, whose position is a priori unknown. This problem was solved using the principle of minimum spatial extent of the radiation source. The quasi-extent functional is being considered in its scalar and vector form, which allowed to formulate the respective problems of non-linear optimization. The gradient optimization approach is suggested as a solution. Numerical simulation was performed for a single and five complex-valued sources PB Begell House LK https://www.dl.begellhouse.com/journals/0632a9d54950b268,3ec7deeb5e01313f,3ae506d217aaacfa.html