###### Abstract
With the etched T-shape, an MC of less than \(-\)20 dB was obtained. In most of these studies, the other performance of the antenna was slightly affected. In [27], researchers use defected ground structures to reduce the MC between UWB MIMO antennas. The proposed structure only covers 3.0 to 10 GHz with an antenna size of 60 \(\times\) 35 mm\({}^{2}\). Similar to the studies in [27], a defected ground structure on a monopole antenna was loaded with U-stub for mutual coupling reduction in an UWM MIMO antenna as proposed by [28]. The frequency coverage was slightly increased from 3.18 to 11.50 GHz with an antenna size of 40 \(\times\) 40 mm\({}^{2}\) and an isolation of less than 18 dB. In [29], a good isolation \(>\)20 dB was achieved within a very low frequency between 3.34 to 3.87 GHz with an antenna size of 20 \(\times\) 35 mm\({}^{2}\). Studies in [30] utilizes a uniplanar EBG exhibiting multiple stop bands to achieve a MC of \(-\)18 dB within a large frequency band between 3.6 to 17.6 GHz but with large antenna size of 46 \(\times\) 27.2 mm\({}^{2}\). [PERSON] and [PERSON] [31] use a double-sided EBG for MC reduction among the quad port of UWB MIMO antenna to achieve an isolation \(<\)\(-\)20 dB and an antenna size of 30 \(\times\) 30 mm\({}^{2}\) within a 3-11 GHz frequency range. In [32], the proposed methods cover an extremely low frequency band between 2 to 7 Ghz to achieve 20 dB isolation with an antenna size of 49 \(\times\) 26.2 mm\({}^{2}\). More recently, [PERSON] et al. [33] proposed a novel approach for low MC reduction for UWB wireless applications. In this study also, an isolation of \(-\)19 dB was achieved with an improved antenna size of 46 \(\times\) 27.2 mm\({}^{2}\) and was able to cover 4 to 12 GH. Considering these studies, we observed that an improved isolation for the full UWB range is not achieved. Aside from covering a small bandwidth, the antenna size becomes too large, which limits its use for handheld wireless applications. In this paper, a modified electromagnetic band gap was used as a decoupling structure between the radiating elements of a MIMO antenna operating within the UWB frequency band. The decoupling capability of the MEBG structure was examined and analyzed. In addition, the performance of the antenna was assessed when the MEBGwas introduced and compared to the reference antenna without the MEBG decoupling structure. In view of this, the contribution of this paper is as follows. * We propose an improved mutual coupling reduction method that achieves a relatively high isolation of \(-23\) dB that covers a broadband of frequencies. * The MC reduction method was designed in a way that we achieved a small antenna size \(19\times 24\) mm\({}^{2}\) when compared to previous studies. Unlike previous methods and studies used for MC reduction, the method introduced for MC reduction does not degrade the performance of the antenna. A modified EBG was employed in symmetrical order for mutual coupling reduction, unlike the other EBGs with mushroom patterns [21; 22]. The remainder of the paper is structured as follows: Section 2 presents the process involved in the UWB patch antenna design; Section 3 presents the design of the UWB MIMO antenna and the performance evaluation metrics; Section 4 presents the results and discussions; Section 5 presents a comparative analysis of the performance of this method with previous related studies in the literature; Section 6 concludes the paper.