multiple input and multiple output antenna design for 4g and 5g mobile systems

Todays, with the increasing number of users and demands in the mobile platform industry, users need more transfer rates and more reliable services. In preference to the use of wireless devices at the same time and in a moving medium, they are designed to be portable and need long-lasting power supplies. For this reason, it is desirable that the elements used in the devices have low power consumption, are small in size and capable of meeting the need for high tape. Large bandwidth is always needed for faster and higher quality communication. LTE and LTE-Advanced technologies were introduced on the cellular network side with the increase in the required bandwidths and data transfer. Nowadays, with 5G, it is aimed to provide a much faster and stable data flow than the current technologies. In addition, due to the increase in the number of users, different frequency bands in the frequency spectrum are reserved for telecommunications. Developments in this area with the planning of the application of 5G technology to mobile platforms will make the RF layers of the mobile products in the market more complex and create new solutions that will use the bandwidth most efficiently. In this thesis study, compatible with LTE technology that actualized in Turkey and 5G technology that being developed, supports both 4G and 5G medium frequency (3300 MHz-3800 MHz) broadband multi-antenna is designed. Also the method for increasing the antenna range and efficiency of the designed x antenna are developed. In the thesis that compatible with 4G and 5G multi-input and multi-output antenna design is realized in mobile products, the required high bandwidth is tried to be maximized in antenna which is spread over a wide frequency range and integrated into a small device such as smart phone. The biggest innovation presented within the scope of the thesis is to enable the integration of the developing 5G technology with mobile devices in addition to the 2G - 3G and 4G technologies commonly offered to the user in mobile devices. In addition, the thesis study is the first and only design made in this field so far, considering the main cellular antenna and the secondary antenna that spreads at the same frequencies by working with the MIMO principle and working with broadbands that support both existing technologies and 5G technology in the same system. Keywords: Mobile systems, 4G and 5G compatible antenna, Multi-input and multi-output(MIMO) antenna, High bandwidth, S Parameters, Antenna gain, Antenna efficiency