This bachelor's thesis thoroughly investigates the key factors that have a major impact on the propagation of electromagnetic waves in complex urban environments. Focusing on electromagnetic waves as carriers of signals in communication, the paper analyzes the concept of electromagnetic wave polarization, investigates its importance in the context of propagation, and investigates various phenomena such as reflection, refraction and transmission that are resulting from the process of wave propagation. The role and characteristics of the propagation of antennas are also studied, just as the basic mechanisms of propagation of electromagnetic waves over different surfaces and over obstacles, which is explored in depth. The specifics of radio wave propagation within densely populated urban areas are also the subject of research, especially when it comes to absorption losses and the occurrence of multipath propagation. By analyzing these phenomena, this paper helps to understand the complex challenges that arise when it comes to communicating in urban environments. In order to better understand these phenomena, two important propagation models are analyzed: the Okumura-Hata model and the Cost-231-Hata model. Through the analysis of these aspects, this paper provides a comprehensive insight into the various mechanisms of electromagnetic wave propagation within complex urban environments. Propagation models such as OkumuraHata and Cost-231-Hata models contribute significantly to the proper planning and optimization of communication systems within demanding urban environments. Taking into account the changing factors of signal propagation, these models become key tools for ensuring stable communication and signal quality within urban environments