Probe movement system for spherical near-field antenna testing

摘要

A probe movement apparatus for spherical near-field antenna testing moves a probe (22) over a spherical measurement surface or path by two bent cantilevered arms (14 and 18). A positioner (12 or 16) rotates each arm (14 and 18). An elevation positioner (16) is mounted on the tip of an azimuth arm (12) The azimuth positioner (12) is mounted on a base (10). The rotation axes of the two positioners (12 and 16) intersect and are orthogonal. The axes intersection point defines the center of the measurement sphere. The antenna (32) is mounted within the measurement sphere on an anti-spin bearing (26) on the azimuth arm (14) centered above the azimuth positioner (12). A shaft (28) connects to the anti-spin bearing, extends down though the azimuth arm (14) and positioner (12) and connects to an anti-spin positioner (30). The anti-spin positioner (30) attaches to the base (10) and holds the antenna (32) stationary. Optionally, the anti-spin positioner (30) may rotate the antenna (32) to check for and minimize the effect of radio frequency reflections.