| 摘要 |
PURPOSE:To make the aperture efficiency of the antenna constant over a broad band and to attain the miniaturization by giving the relation of (1/f1-1/l1-1/l2) (1/f2-1/l2-1/l3)approx.=1/l2<2> among equivalent lens focii f1, f2 of the sub reflection mirror and each mirror face distance l1. CONSTITUTION:The mirror face system is replaced into the lens system in the antenna where the cofocus F1 of the sub reflection mirrors 2,3 is placed at the aperture face side of the main reflection mirror 4 and said relation is obtained from the condition that the differentiation coefficient of the beam radius of the main reflection mirror 4 and the beam waist radius of the radiation wave of the aperture with respect to the wavelength of each evaluation equation is made zero. Said differentiation coefficient is decreased by decreasing limitlessly the distance l2 between the sub reflection mirrors 2,3 and the distance is limited to the relation of 0<l2<=0.7m to make the aperture efficiency of the antenna constant. In constituting the antenna system as above, the aperture efficiency of the antenna is made constant over a broad band and the miniaturization is attained.
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