First of all, look at the mobile phone signal jammer itself. The mobile phone jammer emits radio frequency signals that specifically target mobile phone signals. When it encounters a wall in the transmission path, some of the signals will be reflected back, and some of the signals can directly penetrate the wall, but the signal strength will have a certain attenuation. 

And facing different walls, the attenuation degree of mobile phone jammers is also different. For example, the wall is a reinforced concrete wall or a brick concrete wall. With a reinforced concrete wall and a brick concrete wall with two consecutive sides, the interference signal emitted by the mobile phone signal jammer is basically no longer attenuated, which means it cannot be used through the wall. Therefore, the signals emitted by mobile phone signal jammers usually cannot pass through walls. After all, the shielded signal (wireless signal) is not X-ray and does not have the ability to penetrate directly. It also has certain refraction and reflection when encountering walls.

Different wall materials have different attenuation levels for mobile phone interference devices. For example, if the wall is made of lightweight steel keel gypsum board, its attenuation will be small, as will glass and wooden doors. In addition, if the signal of the mobile phone jammer also refracts through the open space of the door or window, or through the reflection and refraction of the wall, it will have some impact on the mobile phone signal behind the wall, which makes people feel that the mobile phone jammer has the illusion of penetrating ability.

Of course, the ability to penetrate walls is also related to the transmission power of the various frequency bands of the mobile phone jammer. Generally speaking, the higher the transmission power, the stronger the penetration ability. It is the same as listening to the sound from another wall. If the sound from the next wall is loud, you can hear it clearly. If the sound from the next wall is small, you will almost never hear it.