Wi-Fi: they improve their connection thanks to a simple sheet of aluminum :

Researchers have shown that it is possible to improve the range of a Wi-Fi connection by using a reflector made by 3D printing and covered with a single sheet of aluminum to guide the transmitted signal by the router. An economical solution that can, as a bonus, help secure the wireless connection.

Tinkering with a damaged or insufficiently powerful radio antenna with a sheet of aluminum foil is a well-known trick. It turns out that this rudimentary technique can also help improve the power of a Wi-Fi signal, and even enhance its protection. A team of researchers from Dartmouth College (USA) found that reflectors of various shapes covered with aluminum foil and placed behind Wi-Fi routers help to improve signal strength in a given space by orienting it in a targeted way.

Currently, the main technical solution for optimizing a Wi-Fi connection in a multi-room environment involves the use of directional antennas to focus the signal. But it is expensive and requires a rather complex configuration. The solution mentioned here, called WiPrint, is much simpler and less expensive.

Reflectors can increase the strength of a 6 dB Wi-Fi signal

Researchers have developed software that simulates the propagation of the radio signal in a space and its interactions with the objects it encounters, as well as an algorithm for creating reflector models with shapes that provide optimized coverage. Once the system has the necessary information (area, footprint, location of Wi-Fi access point, areas to cover and exclude), it takes about twenty minutes to produce a reflector model that can then be manufactured with a 3D printer before being covered with aluminum.

According to tests conducted by the team at the University of Dartmouth, reflectors can increase the strength of a 6 dB Wi-Fi signal and reduce it by 10 dB in areas that need to be excluded. The manufacturing cost is estimated at 35 dollars (about 30 euros at the current price). The researchers plan to go further by exploring the use of alternative materials to plastic that would allow reflectors to be made that can automatically adapt their shape as the environment's configuration changes. They will also study the effectiveness of the device with millimeter waves and visible light.