Progress In Electromagnetics Research C, Vol. 116, 1–12, 2021 Design and Realization of Dual Band Notch UWB MIMO Antenna in 5G and Wi-Fi 6E by Using Hybrid Technique Hamza El Omari El Bakali 1, * , Alia Zakriti 2 , Abdelkrim Farkhsi 1 , Aziz Dkiouak 2 , and Mohssine El Ouahabi 2 Abstract—In this paper, a novel design of a small printed Ultra-Wideband (UWB) Multi-Input Multi- Output (MIMO) antenna with a wide impedance bandwidth from 3.05 GHz to 11.65 GHz is introduced. The newly designed UWB MIMO antenna has an isolation enhancement of more than −15 dB between the two elements. This isolation is achieved by inserting a three-line stub on the ground plane between the two radiating elements. In addition, these parallel lines improve the impedance matching and the bandwidth of this structure. Dual band notched characteristics are achieved for the 5G band (3.6GHz) and Wi-fi 6E application (6 GHz), by etching a complementary split ring resonator (CSRR) in both the truncated square patch elements and by loading the split ring resonator (SRR) on the ground plane at the back of antenna, respectively. The SRR and its complement are metamaterials structures, showing the behavior of an LC resonator circuit. The hybrid technique improves impedance matching, bandwidth, minimizes the mutual coupling in UWB frequency range, and delivers dual-notch characteristics. The simulation and measurement results of the proposed antenna with a good agreement are presented. The proposed structure exhibits high performances in terms of envelope correlation coefficient (ECC), diversity gain (DG), efficiency, total active reflection coefficient (TARC), and channel capacity loss (CCL) except the notched band. 1. INTRODUCTION Today’s modern wireless communications sector is very demanding and requires both high data transmission speed and good quality of service. For a wide range of applications, including short-range radar, imaging systems, and broadband wireless applications, UWB is a very attractive technology due to its low cost, low power level, and high data rate [1,2]. However, besides all these positive characteristics, UWB system is also affected by transmission problems such as multipath fading. The integration of MIMO technique in UWB systems is seen as the key to increasing channel capacity and reducing multipath fading without the need for additional power [3–6]. Increasing attention has been paid to the design of a compact UWB MIMO antenna suitable for portable wireless devices. However, the placement of multiple antenna elements on the receiving terminal in a limited space causes considerable problems such as mutual coupling between the adjacent antenna elements [7]. Therefore, several recent techniques and procedures have been suggested in the literature to overcome this limitation by maintaining the overall size of the MIMO such as the use of parasitic elements between the antennas on both sides of the substrate which yields an insertion loss lower than −20 dB in the operational frequency band [8], In Ref. [9], an arc-shaped Defected Ground Structure (DGS) is embedded in the ground plane to reduce the mutual coupling effect between the Received 7 August 2021, Accepted 15 September 2021, Scheduled 9 October 2021 * Corresponding author: Hamza El Omari El Bakali (h.elomari@uae.ac.ma). 1 Department of Physics, Information Systems and Telecommunications Laboratory, Faculty of Science, Abdelmalek Essaadi University, Tetuan, Morocco. 2 Department of Civil and Industrial Sciences and Technologies, Laboratory of Sciences and Advanced Technology, National School of Applied Sciences, Abdelmalek Essaadi University, Tetuan, Morocco.