ANTENNA PERFORMANCE MEASUREMENT DEVICE AND ANTENNA PERFORMANCE MEASUREMENT METHOD

摘要

PURPOSE: To install a collimation antenna at a near distance by driving a sub reflecting mirror so as to correct a phase deviation due to the path difference between a center and an end of a main reflecting mirror for a radio wave from the collimation antenna. ;CONSTITUTION: When the distance R between an antenna system 1 and a collimation antenna 2 is small, wave fronts 3a, 3b, 3c of a radio wave from the antenna 2 have a path difference ΔR between a center and an end of a main reflecting mirror 11 to cause A phase difference. On the other hand, radio wave optical path lengths FP₁A₁, FQ₁G₁B₁ and FR₁H₁C₁ from the system 1 are constant. In order to eliminate the path difference ΔR, a sub reflecting mirror drive mechanism 13 equipped to the sub reflecting mirror 12 of the system 1 drives the sub reflecting mirror 12 up to a position 12a by ΔZ apart from the main reflecting mirror 11. As a result, an equi-phase face OC₁B₁A₁ of a radio wave on the aperture of the main reflecting mirror 11 is changed on a circular ark like an arc face OC₂B₂A₂ and the ΔR is decreased to approach the wave front 3a of the radio wave from the antenna 2. Thus, the sub reflecting mirror 12 has only to be driven so that the arc face OC₂B₂A₂ most approaches the wave front 3a.;COPYRIGHT: (C)1994,JPO