DFF – Direct far field

An over-the-air (OTA) test method used in 5G that involves  mounting the device under test (DUT) on a positioner that  rotates in azimuth and elevation. This process enables  measurement of the DUT at any angle on the full 3D sphere.

The DFF method can perform the most comprehensive tests  measuring multiple signals and requires a larger test chamber  for mmWave devices.