Radio waves have the ability to partially penetrate walls and other obstacles, which is why they are commonly used for wireless communication. However, the extent to which radio waves can pass through walls depends on several factors, including the frequency of the radio waves and the material composition of the walls.
Lower frequency radio waves, such as those used for AM (Amplitude Modulation) and FM (Frequency Modulation) radio, have relatively longer wavelengths. These longer wavelengths allow them to better penetrate through obstacles like walls and buildings. As a result, you can often receive radio signals indoors, even if the transmitter is located outside the building.
On the other hand, higher frequency radio waves, like those used for Wi-Fi, Bluetooth, and some cellular networks, have shorter wavelengths. While they can still penetrate walls to some extent, their ability to do so is reduced compared to lower frequency waves. As a result, you might experience weaker Wi-Fi or cellular signals when you are inside a building with thick walls or other barriers.
Metal and concrete walls are particularly effective at blocking radio waves, regardless of their frequency. This is why you might notice that your Wi-Fi signal becomes weaker or non-existent when you're inside a building made of these materials.
To address this issue, engineers use various techniques like installing multiple access points or using signal repeaters to extend and enhance the wireless coverage inside buildings.
In summary, radio waves can penetrate walls to a certain degree, but the effectiveness depends on the frequency of the waves and the material composition of the walls. Lower frequency waves have better penetration capabilities, while higher frequency waves may experience more significant signal attenuation when encountering obstacles like walls.