Compact dual-element inverted-F MIMO antenna system with enhanced isolation

A compact multiple-input-multiple-output (MIMO) inverted-F antenna system for time division-long term evolution (TD-LTE) E band, 3.50-GHz worldwide interoperability for microwave access, and 5.20-GHz wireless local area network with enhanced isolation is proposed. The proposed MIMO antenna system consists of two identical inverted-F antenna elements operating in the 2.32-2.37/3.40-3.62/5.12-5.29 GHz frequency bands at the reflection coefficient level below -10 dB. The edge-to-edge distance between the two antenna elements is only 0.1 mm. The high isolation is achieved by mirror symmetrical orientation of the two antenna elements on the different side of the FR4 substrate and replacing part of the substrate with pieces of copper to connect the ground planes together to form a common ground. The size of the proposed antenna system has the dimensions of 53.00 mm x 10.95 mm. The measured isolation between the two antenna elements exceed 19.23 dB, 14.56 dB and 23.74 dB at the aforementioned operation bands, respectively. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:363-368, 2016