Design of a two symetrical F-shaped MIMO antenna for Wi-MAX and WLAN applications

In this work, an F-shaped planar-monopole two antennas operating in Wi-MAX and WLAN standards with isolation is proposed. The system contains of two symmetrical F-shaped antennas that are placed parallel on the top face of an FR-4 substrate. We added a T-shaped junction on the upper layer to connect the two F-monopoles each other and the ground plane in order to improve the isolation at the operating band. On the bottom side of the substrate, we etch two rectangular open ended slots as well as a ring-shaped slot in order to improve the isolation and the impedance bandwidth. The MIMO antenna is designed to resonate at 2.5 GHz, and 5.8 GHz to meet the requirements for the Wi-MAX and, WLAN applications respectively. The measured results show that the proposed MIMO antenna has high isolation of more than 20 dB at 2.5 and 5.8 GHz bands. Meanwhile, the envelope correlation coefficient (ECC) is lower than 0.001 and the proposed structure has impedance bandwidths of 440 MHz (2.17-2.61 GHz) and 340 MHz (5.53-5.87 GHz), making it suitable for Wi-MAX and WLAN applications.