Wireless MIMO Base Station Near and Far Field Measurement Challenges

Wireless communication systems use Multiple Input Multiple Output-antenna techniques to increase coverage, data throughput and spectral efficiency. Often beam forming techniques are used to provide additional antenna gain relative to Single Input Single Output systems. Regulatory compliance radiated emissions tests for wireless devices are performed using a single measurement antenna at a specified measurement distance. Radiated measurements above 1 GHz at 3 meters test distance create further complications because long conductors and slots generate near-field radiation conditions beyond 3 meters. This paper examines of near and far-field conditions for MIMO antenna system and suggests how radiated emissions testing could be improved.