Performance Enhancement of MIMO Patch Antenna Using Parasitic Elements

This paper investigates the effects of parasitic elements on the performance of MIMO patch antenna. Multiple square parasitic elements are added in close proximity to each of the rectangular patch elements. These parasitic elements affect the electromagnetic field distribution and consequently reduce the mutual coupling. In addition, wider bandwidth is also achieved. Two MIMO antennas coupled in H-plane and E-plane are designed and measured to demonstrate the proposed concept. The measured results show that both designs have a wide impedance bandwidth of 14% with isolation of more than 20 dB across the whole band (with a small antenna profile of 0.05 lambda(0)). For 40-dB isolation, the H-coupled and E-coupled design achieve a bandwidth of 2.7% and 1.5%, respectively. Compared to other methods, the proposed method has much simpler structure, wider bandwidth and comparable improvement in isolation, with the tradeoff in larger antenna element size.