But we don't 100 percent think you actually need to do this.
Wi-Fi signals are ubiquitous, but even though they're invisible to
us, the materials they interact with still affect them. These
electromagnetic waves can travel through wood, glass, or concrete, but
not water, so—pro tip—don’t put a fish tank in front of your router.
Then there’s metal: it reflects the waves, a fact you can even take
advantage of to shape the Wi-Fi signal in your home.
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That’s the key point behind research from Dartmouth College that
describes a way to fashion a 3D-printed reflector you can place near
your router’s antennas. The reflector needs to be covered with aluminum
foil, and if designed and positioned correctly, it can amplify the
signal in the direction in which you want it to be strong, and diminish
it in others (like towards a neighbor’s apartment).
“The idea is really based on the reflection of Wi-Fi signals,” says
Xia Zhou, an assistant professor of computer science at Dartmouth, and
the senior scientist behind the new research. Their algorithm lets them
fashion a curvy reflector to tailor the Wi-Fi signal for different
environments. “For instance, if you want stronger signals in the study
room, or weaker signals in the restroom,” Zhou says, with a chuckle.
Think of it like a reflector behind a flashlight bulb, concentrating
the beam where you want it to go. Metals like aluminum, copper, and
silver all do the job. Zhou says they did their tests with a Netgear
R700 router, and that the method works on both frequencies that a
typical two-band router emits: 2.4 GHz and 5 GHz. (Theoretically, it
should work better as the frequency increases and the wavelengths
shorten.)
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Ultimately, Zou says she hopes this research will help “lower the
barrier” so that everyday people can control how their Wi-Fi blankets
their home. After all, routers—those devices that emit that unseeable
signal our devices are all thirsty for—are somewhat mysterious to most
of us. You can learn more about their research here or check out a recent paper they authored.
Experts say the technique basically should work. The idea “makes
perfect sense” in principle, says Swarun Kumar, an assistant professor
of electrical and computer engineering at Carnegie Mellon University,
noting that like light, Wi-Fi signals are reflected by metals. And Eric
Siu, a senior product development manager at Linksys, who focuses on
wireless routers, agrees. “In general, it does sort of work,” he says.
The antennas you see on routers tend to be omnidirectional, Siu says,
so their waves go out in all directions. And if you want to visualize
that signal, imagine a donut. The signal shape has holes towards the top
and bottom of the antenna, but radiates out from the sides. A metal
filing cabinet next to a router will reflect those waves, and mirrors
can cause problems, too.
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But Siu is reluctant to tell people to actually 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 U.S., 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 other words: tinker at your own risk. And feel free to put on a tinfoil hat while you’re at it, just for fun.
