Mutual scattering mode for LTE MIMO antennas and its application to correlation reduction

A - mutual scattering mode -is introduced in this paper as a novel method to reduce the correlation for the LTE MIMO antenna arrays. This mode is mainly based on the increase of the Q factor for the closely-positioned MIMO antenna elements. With the increased Q factor, each element becomes a scatter for the other elements. Consequently, without adding any structure in the MIMO system, the radiation patterns will be separated to achieve a low correlation (even close to zero) in LTE 700 MHz bands. In practice, this high Q factor is realized through better impedance matching, which makes this mode quite easy to excite. When the effective MIMO element distance is larger than a certain value, better matching (higher Q factor) can not only reduce the correlation but also improve the efficiency (even though the mutual coupling becomes stronger).