## 1 Introduction
This implantable system can be utilized in several situations. For instance, in treating a slow heart rhythm, one electrode is placed in the atrium or the ventricle. If the system senses no heart activity, the pacemaker (PM) emits a stimulation pulse of defined parameters. In cases of heart blocks of all degrees, one electrode detects the heart's activity in the atrium, while the other provides delayed ventricular stimulation. Recently, it has become possible to address ventricular desynchrony caused by structural changes (heart failure) by introducing three epicardial electrodes to the left ventricle. An implanted cardioverter-defibrillator (ICD) is used when there is a risk of danger to the patient due to rapid heart rhythm (tachycardia). In this case, we can introduce only one electrode into the right ventricle, or two into the atrium and the other into the ventricle. The three-electrode system for resynchronization therapy of heart failure can also be equipped with a defibrillator (CRT-D). These devices contain sensors for adapting stimulation speed (frequency) according to the patient's needs [PERSON] (2016); [PERSON] (2016). The widespread use of mobile phones in modern society has raised concerns about the potential health risks associated with the radiation emitted by these devices. Many studies have been conducted over the past two decades to assess whether cell phones pose a health risk. Excessive radiation from wireless devices has the potential to affect the human body's biological system [PERSON] (2016); [PERSON] (2016). In the material environment, EMF propagate at a finite speed, which is the maximum speed of light in a vacuum, in the form of waves. Therefore, due to the corpuscular-wave dualism, this propagation can also be described as a flow of particles. In this case, we are referring to radiation. Particularly, because of EM waves, high frequency/radio EMF can penetrate and spread into the human body [PERSON] (2016); [PERSON] (2016); [PERSON] (2016). Even though there has been extensive research on the issue of using mobile phones in a shielded environment, most of this research has been carried out either by numerical calculations or by a theoretical approach; as such, we have the opportunity to enrich the issue with experimental measurements [PERSON] (2016). This study aims to create a series of simulations in the CST Studio Suite software v.2021.05 for different models of the human body, namely for a single-layer, multi-layer, and complex model of an adult woman and a child, as well as to compare the obtained results of the EMF quantities. Most previous studies have predominantly focused on male body models, leaving a significant gap in research dedicated to female and paediatric models. However, women and children are exposed to the same environmental conditions as men, making it crucial to understand how electromagnetic fields (EMF) might interact differently with their bodies. The physiological differences between males, females, and children--such as variations in tissue composition, body size, and developmental stages--can lead to different levels of EMF absorption and distinct effects. To obtain a holistic picture and a relevant assessment of the results of the simulations, let us then carry out a series of experimental measurements for selected pilot simulations of a normal person and a person with a pacemaker in free space. In our research, we also consider the model of a child with a pacemaker, since this intervention is common in paediatric patients with bradycardia or atrioventricular block. These conditions often require the implantation of a pacemaker to ensure an adequate heart rhythm, which emphasizes the study of the effect of EMF on implanted devices for the child organism [20]. Experimental measurements will subsequently provide us with realistic data on EM interactions in simulated conditions, which will create an opportunity to compare and verify the accuracy of our models and simulations in an environment that is close to real conditions.