For ultrawideband (UWB) applications, a compact multiple-input-multiple-output (MIMO) antenna prototypes are proposed. The first prototype is with a dimension of 40 × 40 mm2. The design consists of seven squares surrounding a center square in which the ground plane is partially implemented. In the second prototype, a compact multiple-input-multiple-output (MIMO) antenna having a size of 36 × 40 mm2 is proposed. To achieve good isolation two planar-monopole (PM) antenna elements are placed perpendicular to each other. On one side of the substrate antenna elements with microstrip-fed is printed. On the other side of the substrate two ground planes are connected via a short ground strip and two inverted U-shape stubs are added to the ground. This arrangement provides good isolation and increase impedance bandwidth. Using High Frequency Structure Simulator Software the results are simulated. © 2016 IEEE.