A multiple input-multiple output antenna assembly with high isolation between the antennas is disclosed. The antenna assembly includes a substrate with a ground layer at its surface. Two antennas are disposed opposing each other on the substrate. A meandering slot is interposed between the first and second antennas on the ground plane. A first signal port is provided for applying a first signal to excite the first antenna and a second signal port is provided for applying a second signal to excite the second antenna. The meandering slot provides isolation that inhibits electromagnetic propagation between the first and second antennas. A third signal port is provided for applying a third signal to excite the meandering slot to act as another antenna for multiple input, multiple output operation.