Abstract: An array antenna mounted on a spacecraft in its stowed state. After the spacecraft is launched in a predetermined position or on a predetermined orbit, the array antenna is extended to a flat plate form or a curved surface form. The array antenna has a structure that a plurality of subarrays are connected by plate springs or the like. The array antenna is extended in a kite form by using cables for connecting a spacecraft body and the subarrays or is extended by using an extension pole mounted on the spacecraft body. Each subarray includes a variable phase shifter to switch a shape and a direction of a directivity beam. A feeder line, a power supply line, a control signal line and the like connect the spacecraft body and each subarray.