A compact two element MIMO antenna with improved isolation for wireless applications

This paper presents a compact 55× 20 mm² wideband multi-input-multi-output (MIMO) antenna. The proposed structure consists of two antenna elements excited using CPW feeding technique and is printed on a low cost and easily available FR4 substrate. In the proposed MIMO design, the first antenna at port 1 is fixed in its position and orientation while, the second antenna at port 2 is placed in six different orientations by keeping the overall dimension constant. The observation is made on the variation in the insertion loss as the orientation of the second antenna is altered. With this analysis, the orientation of second antenna element giving the least interference and insertion loss is proposed, and all the parameters are studied. The proposed design exhibits an average peak gain greater than 2.8 dBi, envelope correlation coefficient (ECC) less than 0.0001, insertion loss less than -38 dB and stable radiation patterns over the entire wide bandwidth. The antenna operation (i.e. |S₁₁| and |S₂₂|<-10 dB) ranges from 4.1 to 6.4 GHz at port 1 and 4.35 to 6.5 GHz at port 2, thereby making the antenna suitable for Wireless Local Area Network (WLAN) and Wireless Fidelity (Wi-Fi) applications.