| 摘要 |
PURPOSE:To extract only a normally rotated direct wave of a circular polarized signal through a small-sized antenna, by separating a circular polarized signal into the normally rotated direct wave and a normally rotated reflected wave and a reversely rotated reflected wave through a hybrid coupler, and synthesizing both reflected waves same amplitude in reverse phase. CONSTITUTION:A normally rotated direct wave of a circular polarized wave 1 of normal optical activity from a communication satellite for the ship, a normally rotatated reflected wave of circular polarized wave 2 and a reversely rotated reflected wave of circularly-polarized wave 3 reflected from the sea surface 8 are received by a small-sized antenna 6 on a vessel 7. The received signals are inputted to a hybrid coupler 14 to obtain said wave 3 at its output terminal 13, and while an attenuator 17 and a phase shifter 18 are so adjusted that the wave 3 has the same amplitude as the reflected wave 2 at the output terminal 20 and a phase difference in 180 deg., both signals are synthesized by a synthesizer 19. Thus, only a normally rotated direct wave of circular polarized wave appears at an output terminal 20, and the signal free from phading is obtained. |
