Wrapping aluminum foil around your router's antennas to increase speed isn't pseudoscience, it actually works. Research from Xia Zhou, an assistant professor of computer science at Dartmouth College, has found a customized aluminum reflector on a router's antennas increases speed and makes a connection more secure.
Speed is typically impaired because routers will send wireless signals in all directions over a certain range. While beamforming has helped the situation, speed is still impaired and security could be better.
Addressing both concerns requires judicious control over how wireless signals propagate in an environment. Specifically, we aim to strengthen the signal in regions where high performance is desired, and weaken the signal in regions where malicious third-parties could potentially be eavesdropping, - Zhou
Zhou's WiPrint technology would 3D print a custom reflector that'll boost signals in the right direction. The reflector is "computationally optimized" using an algorithm. Zhou's team verified the efficacy of this solution by adding reflectors made of glossy metals like aluminum to a series of WiFi access points.
With a simple investment of about $35 and specifying coverage requirements, a wireless reflector can be custom-built to outperform antennae that cost thousands of dollars, - Zhou