Enhanced Isolation 4×4 MIMO Antennas on Cross-Substrate for Vehicular Communications

To improve the isolation in a multiple-input-multiple-output (MIMO) antenna, this work presents the use of a cross-shaped substrate, instead of a traditional square substrate. Two 4×4 MIMO antennas operating in the dedicated short-range communication band (5.850-5.925 GHz) for vehicular communication are designed and tested. It is found that the isolation can be improved to a large extent by using a cross-shaped substrate without compromising other antenna performance parameters. Facilitated by the substrate shape, the antenna size is reduced and loaded with complementary split ring resonators for further enhancement in isolation.