Microwave is electromagnetic wave with frequency from 300MHz to 300GHz and it is a finite frequency band of the entire electromagnetic wave spectrum. According to the microwave transmission feature, microwave can be viewed as plane wave. Along the transmission direction, the plane wave has no longitudinal components of electric field and magnetic field. Both electric field and magnetic field are vertical to the transmission direction. Thus, the plane wave is called transverse electromagnetic wave and marked as TEM wave. For the application of each frequency band in the microwave spectrum
Above Figure VHF and LF are ground wave which is very capable of diffraction and can diffract hundreds of kilometers; they are mainly used in radio and navigation. MF is used in broadcast and is less capable of diffraction than VHF and LF. HF is not ground wave, and it is reflected to the ionosphere. VHF and UHF are used in TV. Though UHF is used in TV, (that is, the microwave is involved) it is not called microwave. After the microwave, it is optical wave which is also a type of electromagnetic wave.
Digital microwave communication refers to a type of communication mode which uses microwave (frequency) to carry digital information through the electric wave space, transmit independent information and conduct regeneration. Microwave is weak in diffraction and it is only line-of-sight communication, therefore, it has a limited transmission distance. In long-distance transmission, relay is needed to connect sites. Thus, it is called microwave relay communication.
Microwave communication uses microwave as the carrier of signals, which is similar to optical fiber communication that uses light as the carrier of signals. Simply speaking, transmitting module and optoelectronic inspection module used for receiving in the optical fiber transmission system are similar to the transmitting and receiving antenna. Compared with the optical fiber communication with wire channels, microwave channel is wireless and microwave communication is much more complicated.
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| Each frequency band in the microwave spectrum |
Above Figure VHF and LF are ground wave which is very capable of diffraction and can diffract hundreds of kilometers; they are mainly used in radio and navigation. MF is used in broadcast and is less capable of diffraction than VHF and LF. HF is not ground wave, and it is reflected to the ionosphere. VHF and UHF are used in TV. Though UHF is used in TV, (that is, the microwave is involved) it is not called microwave. After the microwave, it is optical wave which is also a type of electromagnetic wave.
Digital microwave communication refers to a type of communication mode which uses microwave (frequency) to carry digital information through the electric wave space, transmit independent information and conduct regeneration. Microwave is weak in diffraction and it is only line-of-sight communication, therefore, it has a limited transmission distance. In long-distance transmission, relay is needed to connect sites. Thus, it is called microwave relay communication.
Microwave communication uses microwave as the carrier of signals, which is similar to optical fiber communication that uses light as the carrier of signals. Simply speaking, transmitting module and optoelectronic inspection module used for receiving in the optical fiber transmission system are similar to the transmitting and receiving antenna. Compared with the optical fiber communication with wire channels, microwave channel is wireless and microwave communication is much more complicated.
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