Compact Multimode Multielement Antenna for Indoor UWB Massive MIMO

In this paper, we present a concept for a compact ultra-wideband multielement antenna (MEA) for massive MIMO indoor base stations. The antenna concept is based on the simultaneous excitation of different characteristic modes on each element of the MEA. This enables an effective 484 port antenna using only 121 physical antenna elements. Thereby, a size reduction of 54% compared to a generic MEA based on crossed dipoles is achieved. The antenna operates in the ultra-wide frequency band of 6-8.5 GHz with a reflection coefficient of s
_ii
<; -10 dB and the interelement and intraelement mutual coupling of the antenna ports is s
_ji
≤ -20 dB.