| 摘要 |
PURPOSE:To obtain a prescribed direction characteristic and frequency characteristic by using a feeding circuit including an amplitude and phase compensating circuit so as to feed an antenna system comprising four radiation elements arranged on a circle in a radius R at an equal interval and a center element arranged at the center of the circle. CONSTITUTION:The antenna system 1 has the center element E0 arranged at the center of the circle in a radius R and radiation elements E1-E4 arranged on the circle at an equal interval. The feeding circuit 2 consists of the 1st coupler group H1-3rd coupler group H3 comprising 3dB couplers H11-H34, an amplitude/phase compensating circuit group AP comprising amplitude compensating circuits A1-A4 and phase compensation circuits P1-P4, hybrid couplers Halpha1-Hbeta2, a four-distributor 4, an attenuator 5 and 90 deg. delay devices 61, 62 or the like. Thus, the radiation level in + or -90 deg. in the direction of main lobe is brought into <=-10.5dB and the ratio of the upper limit frequency to the lower limit frequency obtaining an excellent characteristic is >= nearly nine times. |
