How does WiFi signal go through walls?

WiFi signals are a form of electromagnetic radiation, like visible light. Electromagnetic waves with wavelengths in the range of WiFi signals can pass through walls as easily as light passes through glass doors.

One of the most common problems of the modern world is the lack of WiFi, especially when you need it most.

The WiFi signal can reach your device even if the broadcasting router is located quite far away.

However, there are some things about WiFi technology that if you mentioned it a few decades ago, people would think you are crazy. For example, the existence of technology allows you to stream video and connect to the rest of the world without wires!

And yet, the WiFi signal can reach your device even when the broadcasting router is located quite far away. For example, you can browse the web using WiFi even if the WiFi router is in another room, with one or more walls/doors between your phone and the router.

Have you ever wondered: why can't light go through walls, but WiFi signals can? How can that happen?

Electromagnetic radiation and WiFi

You have probably heard about electromagnetic radiation. In fact, it is something that constantly surrounds us. Visible light, Bluetooth signal, WiFi signal, infrared. - electromagnetic radiation exists everywhere. From a technical point of view, it is a form of energy that travels at the speed of light and is divided into groups such as radio waves, microwaves, UV rays. depending on frequency (or wavelength).

Take a look at the photo below:

As you have seen, there are 6 main types of electromagnetic radiation (7, if you count visible light separately).

Radio waves are one of them, and WiFi works on these waves.

WiFi uses radio waves to establish wireless communication between two or more devices. It uses two types of radio frequencies, depending on the amount of data being transmitted - 5GHz and 2.4GHz. The higher the frequency, the greater the amount of data sent per second.

Therefore, 5GHz is used to send large amounts of data through WiFi signals between devices.

How does WiFi signal go through walls?

When an electromagnetic wave (in this case, a WiFi signal) hits a surface, it can do one of three things:

1. Go through (refraction)
2. Reflected back
3. Absorbed

When an object reflects a specific wavelength of visible light, the color associated with that wavelength becomes the color of the object. An apple is red because when light hits its surface, the wavelength of light it reflects the most is the wavelength associated with red.

Now to the next logical question: what causes an object to absorb, reflect, or refract only a specific wavelength of electromagnetic radiation?

That completely depends on the composition of the object. Everything in the universe is made up of microscopic blocks called atoms . It is the size of the atoms and the distance between them (how tightly or loosely they are bound together inside an object) that determine whether the object will absorb a particular wavelength of radiation. electromagnetic radiation, or allow it to pass through.

Take visible light as an example. When you close the bedroom door, the light from outside cannot enter the room. Why?

Electromagnetic frequency band.

Because visible light cannot pass through solid objects, like walls or bedroom doors. However, it can easily pass through certain solid objects, like glass doors. That's exactly why WiFi signals can go through walls or doors.

If for visible light the glass door is a transparent object, then for a WiFi signal (another type of electromagnetic radiation), the wall is a transparent object, by frequency (or wavelength) of the radiation associated with WiFi signals has the ability to penetrate solid objects, but only to a certain extent.

If the wall is too thick, the WiFi signal will not be able to pass through. Also, as WiFi signals travel through the air, they become "diluted", which means they lose some of their power.

That's why if you put the WiFi router in a room surrounded by thick concrete walls, you won't be able to get WiFi when standing outside. Similarly, you will not get a strong WiFi signal on your device if the router is too far away (from 45 - 90 meters).

In a nutshell, for a WiFi signal, the wall is a transparent object, like a glass door in front of visible light. Therefore, the WiFi signal can easily penetrate most types of walls and keep you connected!