Electromagnetic wave generation processes in the hybrid log-periodic microstripe antenna on the dielectric substrate integrated with field-effect transistor are experimentally studied in the frequency range of 6 — 20 GHz. The possibility of synchronization and power combining in the array consisting of antenna-coupled oscillators placed on the common dielectric substrate is investigated. It is shown that the considerable increasing the generation efficiency and power combining can be obtained by using the external synchronization signal or quasi-optical design of the array.