Abstract: A stripline patch antenna having a slot plate which is capable of obtaining higher antenna gain, while reducing the loss due to the feed lines. The antenna includes at least one radiating element for transmitting and receiving radio waves; a feed line for transmitting signals to and from the radiating element; a dielectric substrate for supporting the radiating element means and the feed line means; a grounding conductor located below the dielectric substrate; and a slot plate located above the dielectric substrate, having a plurality of slots more numerous than the radiating element. The triplate substrate can be adapted to this antenna. A plurality of antenna units so constructed can be arranged in array such that at least one of the slots of each antenna unit is shared with a neighboring antenna unit.

Abstract: Attitude control is implemented by detecting the phase difference between signals received by at least two antennas and detecting the angle of deflection between the direction of arrival of radio signals and the antenna beams. By using antennas that are separately driven, within the plane of rotation in which the deflection angle is to be detected, the phase of the received signals can be shifted equivalently to when the antennas are driven as a consolidated unit. Also, when at least three antennas are used in an orthogonal arrangement for detecting the deflection angle in two directions, the antennas are divided into two groups which are individually driven. This reduces the inertia of the moving parts and enables the size and weight of the drive mechanisms to be reduced.