MIMO multiband antenna system combining resonant and nonresonant elements

Multi-input and multi-output (MIMO) technology will enable high-data rates in wireless devices to allow speech and video calls to streaming media and web browsing all over a common platform. MIMO technology needs M antennas both in transmission and reception. Because the space in a wireless device is limited, including M antennas is a challenge. To face such challenge, a MIMO antenna system is proposed, which comprises a multiband monopole antenna (35 × 15 mm²) and two small nonresonant elements, each one operating in a particular frequency region: 824-960 and 1710-2170 MHz. The size of each of the nonresonant elements is only 5 × 5 × 5 mm³. The proposed MIMO system is analyzed in terms of bandwidth, efficiency, correlation, and multiplexing efficiency. MIMO capacity is measured in a reverberation chamber considering a free-space Rayleigh scenario and also including the effect of a phantom-head and hand. The results reveal that the proposed MIMO system provides capacity close to the ideal bound, whereas having a small size and able to operate at several 2G, 3G, and 4G (long-term evolution) standards. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1076-1084, 2014