Criteria for physical dimensions of MIMO OTA multi-probe test setup

This paper discusses requirements for physical dimensions of an anechoic chamber and fading emulator based MIMO over the air (OTA) test set-up. The purpose is to find an answer to the question of how large devices can be measured with certain accuracy for given dimensions of a ring of OTA antennas and a given range of frequencies. Criteria for physical dimensions are developed based on field strength stability across the test zone and phase stability across the test zone. As a reference also the CTIA minimum measurement distance criteria are presented. It is found that the ratio of the radius of a test area and the radius of a ring of OTA antennas has to be 0.1 or lower on a frequency range of 0.5 to 6 GHz.