Self-beam steering array antenna by digital beam forming for mobile satellite communications.

With a view to application to array antennas for mobile stations in a mobile satellite communication system, a method is proposed for configuration of a receiving diversity array antenna acquiring a communication beam quickly and tracking with stability by means of the digital beam forming (DBF). In this method, an active array is assumed. The receiving phase difference between the antenna elements is detected by digital complex operation for the received baseband signal. Based on this phase difference, the phases of the antenna elements are made in phase in a relative sense so that equal gain or maximal ratio combining is accomplished. As a result, the main beam can be formed in the direction of the arriving wave. In addition, in the case of maximal ratio combining the radiation pattern is oriented toward the multipath arriving waves so that communication quality is improved as the beams are further combined in phase. In this paper, the effectiveness of the present method is demonstrated by the numerical simulation assuming a mobile communication environment with band-limited QPSK signals. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(10): 88–100, 1997 [ABSTRACT FROM AUTHOR]