A reflective textile metasurface for indoor signal coverage enhancement

The design of a reflective metasurface solely based on flexible textile material is presented for indoor signal coverage enhancement in a specific scenario – reflecting and reallocating radio frequency energy that would have leaked through a large window area. The proposed reflective metasurface design, reflective metasurface is composed of layers of square conductive textile patches and dielectric textile substrates. For the unit cell design, a reflective phase difference of up to 90° can be achieved via varying the size of the conductive patches. Meanwhile, a phase difference of up to 180° can be achieved by the alignment of conductive patches on different textile substrate layers, which is an ideal design philosophy for textile material. The proposed metasurface, consisting of 12 × 12 unit cells, can achieve a main reflected beam pointing in the direction of ±35° and a secondary reflected beam at ±63°. Simulated results show that the reflected beams remain relatively stable under the crumpling conditions often seen for curtains. A prototype of the design was fabricated and tested in a real-world scenario. A maximum signal strength enhancement of 15 dB and an average enhancement of 5.97 dB in a wide range of directions can be achieved with the reflective metasurface applied.