In memoriam: Oleg Alexandrovich Tretyakov

Oleg Alexandrovich Tretyakov (Figure 1), the Chair of Commission B of the URSI National Committee of Ukraine since 1993, a member of the IEEE, and Professor Emeritus of the Department of Theoretical Radiophysics, V N. Karazin Kharkiv National University (KhNU), Ukraine, passed away on January 25, 2022, in Istanbul, at the age of 83. He died shortly after he was hospitalized and diagnosed with lung cancer on December 29, 2021.