This paper presents a novel self-decoupled 10-element multiple input and multiple output (MIMO) antenna for mobile terminal applications. High isolation between the elements is achieved by using a novel pattern diversity technique. Overall MIMO consists of two antennas of type A, four antennas of type B, and four antennas of type C, with each one, operating at 5.5 GHz. Antennas-A, B, and C are of slotted pattern, arranged in the system circuit board and two small substrates. The two small substrates having dimensions of 7.4 mm × 150 mm are vertically placed along the long side edges of the system circuit board. The overall size of the system ground plane is assumed to be 150 mm x 75 mm. The designed MIMO antenna is suitable for 5.5 GHz WiMAX operation at the mobile terminal. The MIMO elements show isolation> 15 dB over the common bandwidth (BW) of three antennas i.e. between 5.37-5.7 GHz (5.9 %) with VSWR is 3:1. © 2022 The Institute of Electronics Information and Communication Engineers (IEICE) of Japan.