###### Abstract
The antenna also has large dimensions of 110 mm \(\times\) 55 mm \(\times\) 1.6 mm. A compact antenna with an overall size of 12.5 mm \(\times\) 12.5 mm \(\times\) 0.8 mm and peak gain of 6 dBi is reported in [26]. The antenna consists of small size and is operational over high gain, but offers low value of other MIMO performance parameters. A two-port MIMO antenna with geometrical dimensions of 60 mm \(\times\) 100 mm \(\times\) 0.965 mm and operating over a bandwidth of 27.6-28.3 GHz and ECC of 0.134. This work has the advantage of simplified geometry, but the demerit of large dimensions, narrow bandwidth, and low value of ECC [27]. A compact MIMO antenna with dimensions of 18.5 mm \(\times\) 18.5 mm is reported in [28]. The antenna is compact in size and offers a wideband of 4 GHz, but complex geometry due to the multi-layer structure. Another compact antenna with an overall size of 48 mm \(\times\) 31 mm \(\times\) 0.254 mm is reported in [29]. The antenna has the advantage of compact size and offers a wideband of 26-31 GHz, but the demerit of high isolation of \(-\)21 dB; [30] reports a broad and strong gain. The antenna provides a high gain of 12 dBi and a wideband of 23-40 GHz. This design's setback is substantial, measuring 80 mm by 80 mm by 1.57 mm. The dimensions of a small, high-gain, broadband antenna that operates throughout the frequency range of 25.5 to 30 GHz and has a peak gain of 8.75 dBi are given in [31]. The antenna is small, wideband, and high-gain; however, the authors failed to mention the importance of ECC, and its shape is complicated. It can be observed from the above discussion and the rest of the literature that the MIMO antenna configuration of the patch antenna is adopted due to its numerous advantages and applications. The ratch antenna with MIMO configuration has an application in smart mobile phones [32] with a high performance parameter and simple geometry, and also in wearable applications when the radiator is placed over flexible substrate material [33]. To obtain the good results and requirements for 5G applications, various techniques are adopted to improve the performance of the MIMO antenna [34; 35]. The most important parameter is mutual coupling between MIMO elements, and some design meta-material is inspired to improve the mutual coupling [36]. The decoupling structure, also called parasitic patch, is loaded between antenna elements to improve isolation [37]. The corner-fed technique [38] and multi-feeding method [39] are also used to get the desired results operational over the 5G spectrum. Moreover, a low-cost MIMO antenna configuration operating over wideband is also adopted for IoT applications [40]. In addition to the patch antenna, Yagi antenna with MIMO configuration is also adopted in the literature for 5G applications [41]. From the above literature review, it is clear that there is still a research gap to design an antenna with compact size, a low profile, and simplified geometry. The antenna should operate over a wideband and offer high gain and radiation efficiency. In this article, the antenna is presented to overcome the demands of a 5G wireless communication system. The antenna offers ultra-wideband and high peak gain. The MIMO parameters also lie according to requirements of any MIMO system. In the rest of the paper, the single element design of the antenna is studied along with results in the form of a S-parameter, gain verses frequency plot, radiation pattern, and radiation efficiency. Afterwards, the MIMO configuration is analyzed, and comparison is performed between measured and simulated results. Last, the comparison table is added to compare the results of proposed antenna with literature along with conclusion and references. The novelty of proposed work is:  
* The compact size and simplified geometry;
* Wide operational band and high gain;
* Low mutual coupling between MIMO elements;
* Good values of MIMO parameters, such as, ECC, CCL, DG, and MEG.