To obtain a multi-beam characteristic up to a sufficiently small separation angle and to make a optical path length difference between respective beams negligibly small by installing respectively specific plane mirrors and aberration correction mirror planes in a symmetrical form symmetrically with respect to a center axis.
The antenna is provided with plane mirrors 4 arranged at a beam waist position of a radio wave from a sub reflecting mirror 2 and aberration correction mirror planes 5 correcting wave front aberration caused in a main reflecting mirror 1 and the sub reflecting mirror 2 to convert the received wave into a spherical wave. Then a light beam 6 of a beam 1 and a light beam 7 of a beam 2, a minimum separation angle of the beams 2Θmin an aperture diameter D of the main reflecting mirror 1, and an aperture diameter Dp of each plane mirror 4 are shown in figure. In this case, the two sets each of the plane mirrors 4 and the aberration correction mirror planes 5 arranged at both sides of a center axis 3 are arranged in a symmetrical form symmetrically with respect to the center axis 3. Thus, the movable multi-beam characteristic is obtained up to a sufficiently small separate angle and the optical path length difference of two beams is made negligibly small because of the symmetry of the mirror face system provided corresponding to each beam thereby compensating phase fluctuation in the air.
MIYAHARA NORIO
URASAKI SHUJI
SHIMAWAKI YUTAKA
MATSUMOTO SOICHI
