Agile and efficient MIMO system for smart phone terminals

The paper proposes a novel multi-input multi-output (MIMO) system architecture that covers most of the high LTE bands. The system is comprised of four small loop antennas. Each antenna has two ports, one for communication and one for control. The control port is used for tuning the loop antenna where impressive frequency agility using a single capacitor is obtained. A good level of inherent isolation among the four loop antennas is maintained over the different frequency bands. The MIMO performance of the proposed system is evaluated through its spectral efficiency versus frequency. Finally, the information bandwidth of the MIMO system can be defined by comparing its spectral efficiency against the spectral efficiency of three ideal MIMO antennas.