Make Wi-Fi Signal Strong Using Aluminium Foil

By | November 27, 2017

Even after being omnipresent and invisible to us, Wi-Fi signals are yet affected by the materials they interact with. Though these signals can pass through many common materials such as wood, glass, or concrete but it can’t pass through water, thus, putting a fish tank in front of your router is not a good idea. Then there is metal which can reflect the waves and you can use it to your advantage to shape the trajectory of the Wi-Fi signal waves.

And this is also the key idea behind a research from Dartmouth College, which demonstrates how a 3D-printed reflector placed nearby your router’s antenna can amplify the signal. It says that the reflector should be covered with Aluminium foil, and if designed and placed properly, it can boost the signal in whichever direction you want and diminish it in other directions.


“The idea is really based on the reflection of Wi-Fi signals,” says Xia Zhou, who is an assistant professor of Computer Science at Dartmouth, and also the senior scientist behind this research. Their custom algorithm helps them fashion a curvy reflector to shape the wave’s trajectory in different environments. “For instance, if you want stronger signals in the study room, or weaker signals in the restroom,” Zhou says and chuckles.

One can think of it as a reflector behind a flashlight bulb that concentrates the beam wherever you want it to go. Reflective metals such as Aluminum, Copper and Silver –all can get the job done. Zhou performed the test with a Netgear R700 router and the method worked for both the frequencies that a typical two-band router emits: 2.4 GHz and 5GHz. (Additional info: Theoretically, the reflector should be more efficient at higher frequencies when wavelength decreases)

According to expert the technique should work. Swarun Kumar, assistant professor of Electrical and Computer Engineering at Carnegie Mellon University says “The idea ‘makes perfect sense’, noting that like light, Wi-Fi signals are reflected by metals.” Eric Siu, who is a senior product development manager at LinkSys, with specialty in Wireless Router, agrees. “In general, it does sort of work,” he says.

The antennas you see on routers tend to be omnidirectional, Siu says, so the waves travel equally in all the directions. To visualize this signal just think of the signal as a donut. The shape of signal has holes towards the top and bottom of the antenna, but sides radiate the signals. If there’s a metal filing cabinet next to the router then the signals will reflect and even a mirror can cause problems.

However, Siu is reluctant to advise people to fashion their own aluminum foil Wi-Fi enhancers. “I can’t really advise people to use tinfoil or any sort of reflector, mainly for regulatory reasons,” he says. “In the US, the FCC actually governs the output power, so they have limitations as to what’s the maximum power level your wireless router can radiate a signal in any particular direction.”In simpler words, try it at your own risk. And try putting a tinfoil hat while you’re at it for fun.

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