Propagation characteristics of meter waves, decimeter waves, and centimeter waves

1. Meter waves (30MHz - 300MHz)

Meter waves are often called high frequency (HF) bands, and their wavelengths range from about 1 meter to 10 meters. These bands have strong ground wave propagation capabilities, that is, the ability to propagate along the surface of the earth. In addition, meter waves can also propagate through reflection from the ionosphere, which is called sky wave propagation. This propagation mode allows signals to be transmitted over long distances and even enables global communication. However, due to changes in ionospheric conditions, this propagation mode is not as stable as line-of-sight propagation, especially at night or when solar activity is strong, when changes in the state of the ionosphere affect the reflection effect of the signal.

2. Decimeter waves (300MHz - 3GHz)

Decimeter waves, also known as ultra-high frequency (UHF) bands, have wavelengths between 10 centimeters and 1 meter. Compared with meter waves, decimeter waves have stronger penetration capabilities, propagate farther in urban environments, and are suitable for large-scale coverage. This is because decimeter waves are relatively less affected by atmospheric absorption and can be reflected around buildings and other obstacles, although their diffraction capabilities are not as good as those of low-frequency bands. Decimeter waves are commonly used in applications such as broadcasting, television, and mobile communications (such as 2G and 3G networks).

3. Centimeter waves (3GHz - 30GHz)

Centimeter waves, also known as part of microwaves, have wavelengths ranging from 1 cm to 10 cm. Centimeter waves are commonly used in satellite TV, Wi-Fi, radar systems, and other applications that require higher bandwidth. Centimeter waves have good balance and adaptability and can propagate effectively in a variety of environments. They are suitable for medium and long-range wireless signal transmission because they can provide sufficient bandwidth to support high-speed data transmission and can resist the influence of environmental factors to a certain extent. With the advancement of technology, especially in 6G research, centimeter waves have attracted much attention because they provide good coverage and large bandwidth in the 7-15GHz range.