Textile Reflectarray Antennas Integrated Within Electroluminescent Textile Displays

Integrated designs of textile reflectarrays and electroluminescent textile displays are proposed in this paper. The proposed designs efficiently utilize the same areas on textiles to display and improve signal coverage, which has several advantages such as size reduction and concealed implementation of reflectarrays. To the best of the authors’ knowledge, it is the first design that deeply integrates textile antennas within textile displays. Firstly, the mechanism of the textile display is explained and display materials are characterized by modified measuring methods to improve simulation accuracy. Secondly, additional requirements due to antenna-display integration are clarified, and two techniques that reuse the display control lines for phase tuning are proposed. Using these techniques, three types of unit cells—single-polarized, dual-polarized and quad-pixel—are designed. Equivalent circuits based on the transmission line method are proposed for unit cell analysis. With these unit cells, three 15×15 textile reflectarray antennas in displays (TRAiD) are designed to operate at 5.8 GHz with different polarization characteristics and different pixel densities. The simulated gains and aperture efficiencies are comparable to those of the textile reflectarray without displays. For ease of verification, three 5×5 TRAiDs are simulated, fabricated and measured. All TRAiDs can simultaneously work as an antenna and a display. The simulated gains of the 5×5 TRAiDs are 12.9 dBi, 13.4 dBi and 12.8 dBi, while the measured ones are 14.4 dBi, 12.8 dBi and 11.8 dBi.