## 1 Introduction  
To address the substantial surge in Global Mobile Data Traffic (GMDT), the development of the sixth-generation (6G) network has become imperative. According to Ericsson [1], global data traffic attributed to next-generation networks is experiencing a significant increase compared to the fourth-generation (4G) and other wireless networks, as illustrated in Figure 1.  
The primary objectives of the fifth generation (5G) revolve around meeting heightened user demands, achieving extensive network capacity, and facilitating seamless connectivity for Internet of Things (IoT) applications [2]. In contrast, 6G is anticipated to be designed as an intelligent wireless network that leverages the power of Artificial Intelligence (AI); 6G is envisioned to usher in a paradigm shift toward the Metaverse, a space where reality can be shared between the cyber and real world, connecting and intelligently integrating all things [3]. To accommodate these highly demanding services, 6G is expected to operate at higher carrier frequencies in the millimeter-wave (mmWave) band, ranging from 30 to 300 GHz. This is due to the availability of considerable amounts of unused spectrum resources [4]. However, one crucial aspect that merits attention is the human body's exposure to Electromagnetic Field (EMF) radiation from mmWave base stations, leading to the generation of heat in human body tissues. This thermal effect becomes more pronounced as the frequency shifts from microwave to mmWave bands. Consequently, the mmWave band's limited penetration capability necessitates only a low level of EMF energy to induce heating in human tissues [5]. Efforts such as the LEXNET research initiative [6] aim to minimize the radiation emitted by mmWave networks while upholding the Quality of Service (QoS) standards. Unlike X-rays and gamma rays, mmWave radiation falls under the category of non-ionizing radiation (NIR). This implies that it does not cause mutations or damage to human DNA, therefore posing no direct harm to the user's biological system. However, the main concern remains the elevation of human tissue temperature due to EMF energy absorption [7]. The frequency band ranging from 30 to 300 GHz Is commonly known as \"Extremely High Frequency\" (EHF) or \"millimeter wave band\", whereas the 3 to 30 GHz band is known as \"Super High Frequency\" (SHF) or \"centimeter wave band\". However, since both EHF and SHF have approximately the same propagation characteristics, the collective term \"mmWave band\" is employed, representing wavelengths spanning from 1 to 100 mm within the 3-300 GHz range [4]. For an illustration of the ionizing and non-ionizing spectrum, please refer to Figure 2.  
Figure 1: GMDT growth forecast. Figure 2: Ionizing and non-ionizing radiation spectrum. The utilization of mmWave transmission in commercial applications must adhere to standard exposure guidelines [8; 9]. To assess the exposure of Electromagnetic Field (EMF) energy at frequencies below 6 GHz, the Specific Absorption Rate (SAR) measurement is heavily relied on in the literature [5]. However, at higher carrier frequencies, there is a significant loss of penetration, limiting energy absorption primarily to the skin surface. Consequently, the radiation compliance above 6 GHz is evaluated using Power Density (PD) instead of SAR [5; 6]. The investigation of NIR stemming from mmWave technologies is directly connected to EMF interaction with the biological systems of human beings. This research is of utmost importance due to potential public health concerns and the need to address health and environmental hazards [10; 11]. Moreover, understanding exposure becomes even more crucial when considering mobile networks equipped with high-gain massive Multiple Input Multiple Output (massive MIMO) systems. In the context of telecommunications, massive MIMO, or large-scale MIMO, involves the implementation of a substantial number of antennas at the Base Station (BS) relative to those at the User Equipment (UE).