## 4 Results and Discussion
Although our research has shown promising new results, we must be aware of potential research limitations, such as the following:  
* Degree of Generalizability: The measurements were taken in a specific urban area, which may not reflect conditions in other urban areas or different geographical locations. Therefore, the generalizability of the findings to broader populations or regions may be limited. * Controlled Environment: This experiment focused on two specific scenarios: when the car was in an open space without a direct line of sight to a base station antenna, and when the car was in an underground parking area. Although these scenarios provided valuable insight, they represent controlled environments with specific characteristics. The findings may not fully capture the variability and complexity of real-world conditions in which wireless devices are used. * Interference and External Factors: The experiment did not explicitly address potential interference or the presence of external factors that could affect the E-field measurements. Various elements, such as nearby buildings, other wireless devices or environmental conditions, may introduce noise or distortions to the measurements, leading to potential inaccuracies or limitations in the conclusions drawn. * Specific Application Scope: This experiment focused on the potential use of EMFs emitted by wireless devices in a car as an energy source for battery-less wearable or IoT devices. Although the findings support this hypothesis, the scope of the application may be limited to specific scenarios or devices. Further research is necessary to explore the applicability and feasibility of such energy-harvesting systems in diverse real-world environments and for different types of wearable or IoT devices. Figure 9: Power as a function of the electric field at: (**a**) 2.40 GHz, (**b**) 2.45 GHz, and (**c**) 2.50 GHz. * Long-Term Effects and Health Considerations: This experiment primarily focused on potential energy-harvesting applications and did not directly address the long-term effects or health considerations associated with exposure to EMFs emitted by wireless devices. To fully understand the implications of using these EMFs as an energy source, it is crucial to consider potential health risks and conduct thorough studies to ensure the safety and well-being of users. The results of our experiment can be useful to the developers of future RF energy-harvesting systems. Even if we consider a small-scale experiment that involved a controlled location, and that the range of the direct application of the energy harvested inside a vehicle is limited to devices that can be useful for people taking a trip with the car, the results are promising and open a path to the future testing of the energy-harvesting process in different microenvironments. In summary, the research results add value to the existing scientific literature by providing a comprehensive dataset specific to the car environment, offering a comparative analysis, exploring emerging technologies, analyzing variations and supporting the hypothesis of using EMFs for energy harvesting. These contributions expand the knowledge base, inform future research directions and enhance the understanding of the potential applications of EMFs in the context of energy harvesting and wearable/IoT device powering.