With the advent of 5G millimeter-wave (mmWave) devices of various sizes and applications, each requiring different architectures and sizes of mmWave antennas, it’s critical for test engineers to understand the differences in over-the-air (OTA) test chambers and test techniques. Direct far field (DFF) and compact antenna test range (CATR) are two types of OTA test methods supported by the 3GPP TR 38.810 Study on Test Methods for 5G FR2 (mmWave bands) devices.
Since CATR OTA chambers can cost up to 10 times more than DFF chambers, a test engineer must decide which one is best suited for the intended application and test requirements. Here, we will explain the differences between DFF and CATR chambers and the tradeoffs in cost and path-loss performance between the two types of chambers.
5G mmWave devices operating above 24 GHz incorporate millimeter-sized antenna arrays or dipole antennas, which become an integral part of the device module packaging. Thus, the only way to characterize and test the performance of the antennas as part of the final product is via OTA testing.