## 1 Introduction  
The world is going to experience 5G technology very soon with the highest broadband speed and minimum latency. To ensure widespread coverage and support for all services covered by the previous technology, it needs to work with three frequency ranges. These are Sub-1 GHz, 1-6 GHz, and above 6 GHz. The Sub-1 GHz band is used for providing widespread coverage in the cities, suburban, and village areas and help to support the Internet of thing services. On the other hand, the 1-6 GHz band provide both capacity and coverage advantages. The band above 6 GHz fulfills the requirements of an ultra-high broadband speed of 5G. According to the report by Global mobile Suppliers Association (GSA), a substantial number of countries are considering, planning, or in the process of auctioning the band around 3.5 GHz. However, to meet the requirement of high broadband speed of up to 20 Gb/s, there will be a need to utilize millimeter wavebands starting from 24 GHz. GSMA recommended 26 GHz (24.25 GHz-27.5 GHz), 40 GHz (37.5 GHz-43.5 GHz), and 67 GHz-71 GHz bands for the mobile. For this reason, auctions will take place in the following years in many countries to license the 5G mid-bands and millimeter wavebands. The operators could also utilize the unlicensed bands to extend the 5G user experience by aggregating it with the licensed one. So for the 5G mid-bandof 3.5 GHz, the unlicensed band can be of 6 GHz frequency which is similar to the Wi-Fi bands of 2.4 GHz and 5 GHz; the 2.4 GHz band is used for the coverage, and 5 GHz is used for the high data rate. Similarly, the 3.5 GHz band could be used to cover coverage and capacity, i.e., it will handle the increasing number of subscribers, and the unlicensed 6 GHz band could be used to provide high data rate. So, designing patch antennae resonating in these frequency bands will be a prudential step [1; 2]. In addition, designing antennae for 5G communications should consider some key requirements of 5G technology. First of all, to experience the fastest 5G services, regulators should assign at least 100 MHz per operator in the 5G mid-band and 1 GHz in millimeter wavebands. So, the designed antenna should resonate over a wider bandwidth covering the whole license band but avoid the frequency bands that are already in use for 4G. Secondly, to get the benefits of services like autonomous car driving, augmented reality, virtual reality, and tactile internet which are highly demanding services of 5G communication, continuous strong connections with minimum latency are required. To fulfill this requirement, the antenna should possess high gain. Last of all, because the beginning of the 5G technology will experience a massive number of small IoT, a compact antennae design for these tiny devices will be essential [3]. Defected Ground Structure (DGS) is one of the popular techniques that is used to enhance the patch antenna performance by increasing the gain and bandwidth, lowering cross-polarization, and coupling in the case of the array antenna. The DGS structure is similar to a unit cell or a periodic configuration which is placed directly under the transmission line [4; 5]. But recent research has shown that the placement of this structure at a sliding displacement from the underneath position of the feed line can also lead to a good parametric output. Some methods are used to reduce cross-polarization [6; 7; 8], and some others have focused on the improvement of other parameters like gain, bandwidth, and return loss [9; 10; 11; 12; 13]. Good isolation between the co- and cross-polarization (XP), as well as reduced XP levels in the H-plane, have been achieved by implementing symmetric and non-proximal DGS shapes in [6], but a slight gain reduction was observed. Whereas the proximal position of a composite type of DGS structure leading to a reduction of XP and also a reduction in the back radiation was achieved in [7]. On the other hand, two circular slots were used to reduce XP in [8].