Isolation and frequency reconfigurable compact MIMO antenna for wireless local area network applications

In this study, to design a compact four-port multiple-input-multiple-output (MIMO) antenna for dual-band wireless local area network applications, both frequency and isolation between antennas are made as reconfigurable. Both antenna element and decoupling network shown in this study are designed using meander line concept. The frequency reconfigurable capability of the antenna is achieved by incorporating positive-intrinsic-negative (PIN) diodes in the meander line resonator. By making PIN diodes ON and OFF, four antenna elements switch their operating frequency in between 2.4-2.5 and 5.1-5.8 GHz bands. Isolation between the antenna elements also made as reconfigurable by placing PIN diodes in the decoupling network. In ON state, isolation is found in 2.4-2.5 GHz band, whereas in OFF state, isolation is achieved in 5.1-5.8 GHz band. Overall, in both the bands, excellent isolation (more than 15 dB) between the antenna elements has been achieved. The proposed antenna design is printed on the FR-4 substrate and its overall area is 38 x 38 mm(2). Each antenna element is in polarisation diversity with the adjacent antenna element which makes the proposed design suitable for achieving good MIMO performance.