System for positioning antenna under test (aut) with respect to offset feed antennas

A method for measuring at least one far-field characteristic of an antenna under test (AUT) on an AUT positioner in a compact anechoic test range (CATR), the CATR including a plurality of feed antennas and a curved reflector defining a reference focal plane corresponding to a focal point of the curved reflector at a reference position on a transverse axis of the AUT positioner, the method comprising:

• selecting an offset feed antenna of the plurality of feed antennas for receiving a radio frequency (RF) signal, wherein the offset feed antenna is offset from a reference line connecting the focal point of the curved reflector and the reference position on the transverse axis of the AUT positioner, such that an offset focal plane corresponding to the selected feed antenna is angularly offset from the reference focal plane;
• calculating an offset angle φ of the AUT in relation to the selected offset feed antenna, wherein a planar phase front of the AUT is parallel to the offset focal plane of the offset feed antenna at the offset angle φ;
• calculating a transverse offset toff between the reference position of AUT and an offset location of AUT on the transverse axis;
• positioning the AUT on transverse axis in accordance with offset angle φ and transverse offset toff, such that the AUT has a planar phase front parallel to the offset focal plane of the selected feed antenna and is in a center of a quiet zone of the selected feed antenna;
• and
• measuring the at least one far-field characteristic of AUT using selected offset feed antenna.

A system for measuring at least one far-field characteristic of an antenna under test (AUT), the system comprising:

• an AUT positioner configured to move the AUT on a transverse axis of the AUT positioner and to rotate the AUT on an azimuth axis of the AUT;
• a curved reflector defining a reference focal plane corresponding to a focal point of the curved reflector at a reference position on the transverse axis of the AUT positioner;
• a feed antenna configured to communicate a radio frequency (RF) signal with the AUT, wherein the RF signal is reflected by the curved reflector, and wherein the feed antenna is offset from a reference line connecting the focal point of the curved reflector and the reference position on the transverse axis of the AUT positioner, such that an offset focal plane corresponding to the selected feed antenna is angularly offset from the reference focal plane by an offset angle;
• and
• a controller comprising one or more processing units and non-transitory memory storing instructions that, when executed by the one or more processing units, cause the one or more processing units to:
• calculate the offset angle;
• calculate a transverse offset from the reference position to an offset location on the transverse axis of the AUT positioner based on the offset angle;
• and
• control the AUT positioner to move the AUT to the offset angle and the offset location for communicating the RF signal with the AUT, wherein when positioned at the offset angle and the offset location, the AUT has a planar phase front parallel to the offset focal plane of the selected feed antenna and is in a center of a quiet zone of the selected feed antenna.