scope:

This paper is the product of a discussion in the MIMO Study Working Group responsible for the IEEE PC63.26 draft standard on testing of transmitters used in licensed services. One topic that needs to be addressed is to determine the adequate measurement distance for the purpose of compliance demonstration of devices including antennas and antenna arrays. This paper focuses on measurements of the EIRP and TRP for intentional radiators, with particular considerations on AAS, where the antennas and transceivers are integrated, and no antenna ports can be accessed. Nevertheless, the concepts and methodologies detailed herein are also applicable when a radiofrequency port is accessible and for other quantities of interest such as the gain, directivity, and half-power beamwidth (HPBW), as defined by the IEEE Std 145™-2013 [1].¹ Although the testing of wireless devices as per IEEE Std C63.10™-2020 or draft 2 of IEEE PC63.26 requires evaluations at specific test distances, guidance on how to reduce the measurement range length and still yield acceptable measurement accuracy can be expanded in the standards. Procedures to practically increase the measurement accuracy in test sites with limited range lengths are also unavailable. Another challenge is the qualification and mitigation of uncertainty contributions in such measurements.

This paper aims to respond to the specified challenges by providing a revision of state-of-the-art far-field (FF) assessment, through the definition of an effective FF range length that is shorter than the FHD yet appropriate to derive the quantities of interest with a given certainty. It also provides brief insight into major measurement uncertainty contributions at such distances, as well as methods to characterize and mitigate them.

¹ Numbers in brackets correspond to the list of sources in Section 7.