Ten-Element MIMO Array Using Stable Current Nulls for 5G smartphones

A ten-element MIMO array comprised of four two-element building blocks and two gap-coupled loop antennas is proposed. The two-element building block exploited stable current nulls exhibits high isolation (>26 dB), which consists of two loop antennas. Without adopting any decoupling structures, the mutual coupling of the ten-element MIMO array is less than -14.4 dB, which is desirable for future smartphone applications.