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The phased array composed from microstrip radiators is considered. This array can be applied as radiation focusing spiraphase system. The lack of traditional phase shifters ensures good cost, technological and constructive characteristics of spiraphase arrays in a microwave range. Antenna construction and mathematical model are considered. This device permits to realize a focussing of antenna feed field by a microstrip antenna array. The microstrip element shape is arbitrary. The structure contains controlled elements (crystal diodes). These array electrodynamic characteristics are controlled by diodes. The mathematical model is obtained by integral equation method. Microstrip radiators current distribution and radiating properties are investigated. The numerical results can be used to develop antennas with optimum parameters.