Design and Analysis of Four-Element WLAN Band Notched UWB Antenna for MIMO Applications

This article presents a band-notch ultra-wideband (UWB) antenna for multiple-input multiple-output (MIMO) applications. The antenna is designed on FR-4 substrate, with overall dimensions of 70 x 70 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. An inverted U-shaped slot is etched into the feed line to act as an LC notch filter, effectively rejecting the sharp WLAN band (5-5.9 GHz) in each antenna element. Simulation results indicate that the proposed MIMO antenna provides an impedance bandwidth of 107%, ranging from 3.2 to 10.6 GHz, with strong isolation across the entire UWB range. The antenna elements are arranged orthogonally to enhance isolation without the need of additional decoupling structures. It maintained mutual coupling below -24 dB. The antenna achieves a peak gain of 7.3 dBi. Additionally, the MIMO antenna demonstrates excellent diversity performance, with an envelope correlation coefficient (ECC) of less than 0.002, diversity gain (DG) greater than 9.99, mean effective gain (MEG) below -3 dB, and channel capacity loss (CCL) of less than 0.4 bits/sec/Hz, making it well-suited for MIMO applications.