Microwave transmission is not only widely used in mobile networks, but is also favored by fixed network operators. It is widely used and can be used in broadcast television, security video surveillance transmission, and control. China also has a national backbone microwave link.
Wireless microwave transmission characteristics
1. Linear transmission in line of sight
Since the short wavelength of the microwave, so it can not be transmitted along the Earth's surface as that wave, because the ground absorbed quickly put it; it can not be transmitted to the reflecting surface as far away as through the ionospheric shortwave Because it can escape into the space through the ionosphere. Because the surface of the earth is a curved surface, microwaves can only be transmitted in a straight line within the line-of-sight range, thus determining that the transmission distance between two microwave stations cannot be very long, generally around 70 km, otherwise no more stable transmission characteristics can be obtained. .
2. Multipath transmission
In the actually used microwave communication line, an antenna with very strong directivity is always used, and the receiving and transmitting antennas are aligned so that the receiving end receives a strong direct wave.
However, due to the limited directivity of the antenna, there will always be a part of the electromagnetic waves transmitted to the ground surface, after reaching the surface of the reflector antenna receiving end, or scattered into space; secondly, due to the unevenness of the gas present in the atmosphere, will causing refraction and absorption of electromagnetic waves, part of the energy is lost; Further, since the solid matter can not pass through the microwave transmission line, so that the solids on the transmission route, especially tall buildings, it will cause diffraction of the microwaves and Level loss. Therefore, microwave communication has both straight-line transmission characteristics and multi-path transmission characteristics.