Commutating Feed Assembly.

The principal activities performed during the Commutating Feed Assembly contract include development of a stripline feed network and non-contacting loop couplers for low-loss transfer and distribution of RF energy. The commutator described not only has superior electrical performance over that of an electronic system, but also offers improvements in reliability and life-cycle cost. It can be accessible located where maintenance actions are more easily carried out than in an electronically-scanned system or a conventional rotating antenna. Non-contacting loop couplers achieve low-loss transfer and distribution of RF energy, with precise control of amplitude and phase that is needed to realize low sidelobe levels. This method of coupling is preferable to the capacitive coupling used in existing electromechanical commutating feeds, where illumination flutter results in unacceptable MTI performance. To obtain multiple beam groups in elevation, two or more commutators may be stacked on a common drive shaft.