This master's thesis explores the evolution of mobile networks, starting from 2G technology and advancing to the latest 5G systems. At the outset, an overview of 5G networks and their purposes is provided, highlighting key requirements for antenna systems. Chapter 4 presents fundamental concepts of electromagnetic waves and propagation, while Chapter 5 discusses the requirements of 5G antennas, including high data transfer rates, extensive network capacity, connectivity of a large number of devices, and low latency and reliability. MIMO (Multiple-Input Multiple-Output) technology, crucial for 5G systems, is described in Chapter 6, along with its advantages and signal processing algorithms. Chapter 7 examines beamforming techniques, encompassing digital and analog beamforming, as well as MIMO beamforming to enhance network capacity. Lastly, in Chapter 8, CST Studio is explored as a tool for designing and simulating antenna systems in 5G networks. The practical aspect of the program includes the design of four different antennas operating at different frequencies. The thesis provides an in-depth understanding of antenna systems, particularly in the context of 5G technology, and connects them with advanced techniques such as MIMO and beamforming to enhance the performance of mobile networks.