In this article, a slot-antenna array with wideband and high-isolation for multiple-input multiple-output (MIMO) systems is presented that can be used in fifth-generation new radio (5G NR) communication. The MIMO antenna system is realized by loading six identical antennas (Ant1-Ant6) into an FR4 substrate to form a six-port array for a 6×6 MIMO system. Each antenna element is a slot antenna type that is composed of a T-shaped open slot and an L-shaped 50 Ω microstrip line. Each T-shaped slot is formed by inserting an I-shaped open branch in the center of the ground plane's U-shaped slot. The L-shaped microstrip line is placed on the upper surface of FR4 to enable coupling feeding in the 3.3 to 5.10 GHz frequency range to cover the 5G NR bands N77/N78/N79. The isolation is increased to more than 18.1 dB by etching the T-shaped slot between the radiation elements on the metal plate. The proposed antenna system was fabricated and tested. The experimental results indicate that the MIMO system can cover the frequency range of 3.20-5.15 GHz with a return loss of 6 dB and provides isolation greater than 16.2 dB. Additionally, a total efficiency greater than 50% and envelope correlation coefficient of less than 0.02 are obtained. The performance under hand-on scenarios is also good. Simulated and measured results indicate that the stated results are consistent. The test results indicate that the antenna satisfies the 5G communication requirements.
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