A novel MIMO antenna with DGS for high isolation

A novel four port multiple-input-multiple-output (MIMO) antenna at 2.4 GHz ISM band is designed in this paper. The MIMO antenna includes an octangular patch surrounded by a square ring patch. The overall system dimension is 60 × 60 × 1.6 mm
³
. The antenna operates in a 50 MHz bandwidth centered at 2.44 GHz. A defected ground structure (DGS) for improving the isolation between four ports is proposed. Isolation improvement by 10 dB is achieved and mutual coupling values as low as -23.6 dB are obtained between antenna elements.