NTT DOCOMO announced the first field test of an active antenna system that achieves a 4 dB reduction in electrical loss compared to conventional antennas. This promises to help enlarge the coverage range of base stations 1.7-fold.
The active antenna system, which was developed by Tokyo-based Nihon Dengyo Kosaku Co., integrates multiple antenna elements, each equipped with a small transceiver, which enables installment in confined spaces and assures continued coverage if one or more of the transceivers fails.
https://www.nttdocomo.co.jp/english/info/media_center/pr/2014/0221_00.html
