I.Y. Kolchugin - Deputy Head of Department, JSC «Concern «Automation». E-mail: kiy@oao-avtomatika.ru

Describes how to build tunable beam-forming system (BFS) for the transmitting circular HF-band antenna array. Justified the need for circular antenna arrays (CAA) with operational control of spatial and polarization characteristics. Proposed solution to build BFS for transmitting CAA based on controlled power dividers (PD) and controlled phase shifters (PS). The structure of BFS proposed, including binary PD structure and PSs in the final layer. Reasonable solutions for parts of BFS based on discrete tunable lumped element are motivated. The calculative ratios are received and the basic characteristics are calculated. Is shown that the PD and PS provide sufficient broadbandness. The method of synthesis is designed for the realization of required amplitude-and-phase distribution at CAA radiators, including the procedure for determining of PD division coefficients and phase shifts in PS. Noted that values of parameters of elements, corresponding with each of the required patterns, may be stored in databases of server equipment of the automated radio station, which essentially reduces the time for transmitting equipment switching to another frequency, azimuthal and meridional radiation direction or another type of polarization of the radiated waves.