A uniquely shaped MIMO antenna on FR4 material to enhance isolation and bandwidth for wireless applications

This paper presents a CPW fed wideband four element multiple input multiple output (MIMO) antenna. The MIMO structure is developed from the analysis of a single wideband CPW fed antenna with −10 dB bandwidth of 1700 MHz. After which a two antenna element structure is analyzed having the same bandwidth range with isolation below −50 dB. Finally, the proposed four element MIMO structure is designed with isolation less than 30 dB between the antenna elements with an Envelope Correlation Coefficient (ECC) below 0.003, measured gain between 2.4 dBi & 5.9 dBi and the radiation efficiency is well above 90% over the entire operating range. The targeted applications lie between 4.3 and 6.0 GHz under the C band spectrum for WLAN and Wi-Fi. The proposed design is printed on a uniquely shaped FR4 substrate to achieve low insertion loss and greater isolation between the antenna elements. The edge-to-edge distance between the adjacent antenna elements is 15 mm keeping which the antenna elements are placed on the arms of the substrate pattern. This also further helps in increasing the number of antenna elements just by extending the armed pattern with constant edge-to-edge distance. The important parameters of the MIMO system such as ECC with a value as low as 0.0002, Diversity Gain (DG) of 9.998 dB, Total Active Reflection Coefficient (TARC), Mean Effective Gain (MEG) measuring the ratio < 3 dB and Channel Capacity Loss (CCL) of 0.0635 bits/s/Hz are observed at the center frequency of 5 GHz. All the necessary simulations are carried out in Ansys HFSS.