An Efficient and Low-Profile MIMO Antenna for 5G-WiFi Interference Rejection: Design and Analysis

The interference between 5G and Wi-Fi within the ultra-wideband (5.1 GHz–5.85 GHz) is a major concern for wireless communication. This overlap causes reduced data rates, increased latency, and overall diminished network efficiency. As more devices and networks use these frequencies, managing this interference becomes critical for maintaining optimal performance. Addressing the issue requires advanced antenna designs and effective spectrum management. This paper proposes a highly efficient and reconfigurable multiple input multiple output (MIMO) antenna to mitigate the effects of this interference. To achieve this, we design an array of quad-element MIMO antennae on an FR-4 substrate for the frequency range of (3.1 to 10.6) GHz. Next, we add a U-shaped notch to reject the 5 GHz band of frequencies centered at 5.5 GHz. The antenna's configuration allows it to function as both orthogonal and back-to-back structures, making it an ideal choice for MIMO-based portable devices. At the rear end of the substrate, a parasitic element in the shape of a mechanical chain strip line serves as a decoupling and isolation structure. The thickness of the strip line structure is configured to be 0.035 mm for optimal isolation, and the total dimension of the antenna is configured to be 58×58×1.6 mm². We simulate the proposed design and find that it achieves a stable diversity gain of 10 dB, with an efficiency correlation coefficient of less than 0.01 dB. The proposed design makes it a decent contender for non-planar or compact 3-D structures.