Dual band multiple input multiple output textile antenna design for wearable applications

Multiple Input - Multiple Output (MIMO) antenna technology refers to an antenna structure that has more than one radiator at both the receiving and transmitting ends. The antenna in question is designed to obtain multiple channels occupying the same bandwidth in a multipath environment, in order to increase the data rate in wireless communication systems. The main disadvantage with Multiple Input - Multiple Output antenna technology is the coupling that occurs between the radiating elements. If the coupling between the radiating elements is high, the Multiple Input - Multiple Output antenna system only acts as an antenna array. Therefore, a strong decoupling between the radiating elements must be provided to reap the benefits of this technology. The main aim of this thesis is to investigate and apply wearable dual band printed Multiple Input - Multiple Output textile antenna geometry for WLAN and 5G applications. Antenna performance characteristics; scattering parameters are reported in terms of envelope correlation coefficient (ECC), diversity gain (DG), antenna efficiency, antenna peak gain and antenna radiation patterns. In this thesis, two antenna elements formed by mirroring the nested spiral ring-shaped resonator, an L-shaped slit placed on a complete ground structure of both antennas, and a vertical beam that cuts the ground structure in half to provide strong decoupling between the antenna radiation elements are presented. Multiple Input - Multiple Output textile antenna design consisting of slits has been realized. In order to improve the performance of the proposed antenna, a parametric study based on numerical analysis was conducted. The experimental findings of the antenna were compared with the numerical results obtained simultaneously from HFSS (High Frequency Structure Simulator) and CST (Computer Simulation Technology) simulation programs. The antenna in question is designed as a dual-band 2×2 Multiple Input - Multiple Output antenna operating in the 5G (4.80 - 5.00 GHz) and WLAN (5.75 - 5.85 GHz) frequency bands for wearable textile applications. In order to obtain the Antenna, the optimum design of the dual-band single antenna structure was carried out first in the 5G (4.80 - 5.00 GHz) and WLAN (5.75 - 5.85 GHz) frequency bands. It is planned to use a woven conductive fabric made of copper and nickel-plated nylon for the manufacture of the antenna resonator and the ground part. The antenna was produced, but electromagnetic measurements could not be taken due to the formation of short and open circuits in the radiator part, despite the zünd mechanical cutting, which is the most precise cutting technique known.