A system and method are provided to determine at least one of equivalent isotropic radiated power (EIRP) or effective isotropic sensitivity (EIS) of an antenna under test (AUT) in a test chamber, the AUT including an antenna array with an array phase center that is offset from a center of a quiet zone of the test chamber. The method includes performing a local beam peak direction scan of an antenna pattern of the AUT using a probe antenna located at laterally offset positions at a near-field distance from the AUT to determine a beam peak direction; performing EIRP and/or EIS near-field measurements of the AUT in the determined beam peak direction using the probe antenna located at near-field distances from the AUT in a radial direction; deriving a far-field equivalent of the EIRP and/or EIS near-field measurement along the determined beam peak direction; and deriving the beam peak direction of the AUT.