A self-steering array and its application to phase synchronization

A self-steering array which automatically tracks the receiver of an aircraft powered by microwave energy sent from the ground and its applications are discussed. The original system adjusts phase shifters by plusmn90deg based on its altitude and the reception intensity on the ground. A newly revised system which does not require an altimeter and converges faster is proposed. This system changes the phase shifters by 0deg and 180deg in addition to the plusmn90deg shifts. When a system is so large, the array would be composed of a lot of units. The system is too large to distribute a reference signal generated by a single reference oscillator. Although the beam steering is possible in each unit by a retrodirective system, a beam radiated from units could cancel each other depending on the phases of their reference signals. Although their frequency can be synchronized, it would be difficult to adjust the phases. The phase of each reference oscillator could be adjusted using the present self- steering technique.