May I ask how the feeder transmits the signal?

A, the basic structure and composition of coaxial cable

Coaxial cable is a kind of cable composed of conductor, insulator and electromagnetic shielding layer from the inside to the outside respectively, which is mainly used in the field of communication and broadcasting. Coaxial cable has the advantages of fast transmission speed, small signal loss, strong anti-interference ability, etc., and has become the most important cable in the field of modern communication.

Two, electromagnetic waves in the coaxial cable propagation principle

Electromagnetic waves are formed by the electric and magnetic fields alternately fluctuations, can be propagated through the air, water and metal and other media. In coaxial cable, the propagation principle of electromagnetic wave is different from that in air.

First, the electromagnetic wave will propagate along the conductor inside the coaxial cable. Inside the conductor, the electrons will oscillate under the action of the electric field, and at the same time rotate under the action of the magnetic field, the electric field and the magnetic field will be constantly converted to each other, resulting in the propagation of electromagnetic waves.

Secondly, the electromagnetic wave will be reflected and refracted by the insulator and outer conductor inside the coaxial cable, forming the propagation of electromagnetic field. When the electromagnetic wave reaches the interface between the conductor and insulator, part of the electromagnetic wave will be reflected back, while part of the electromagnetic wave will penetrate the insulator to continue to propagate forward. When the electromagnetic wave reaches the outer conductor of the coaxial cable, it will be reflected back, while part of the electromagnetic wave will propagate outward through the outer conductor.

Three, coaxial cable in the characteristics of electromagnetic waves

Coaxial cable in the characteristics of electromagnetic waves are mainly related to the frequency, time, wavelength and phase of electromagnetic waves. The higher the frequency of the electromagnetic wave, the faster the transmission speed in the coaxial cable, and its wavelength and phase will change. In addition, the electromagnetic wave in the coaxial cable is also subject to reflection, attenuation and other effects, these characteristics will have an impact on the propagation of electromagnetic waves.

Four, summary

Coaxial cable is widely used in communications and broadcasting and other areas of a cable. Electromagnetic wave propagation in coaxial cable is the principle of electromagnetic wave propagation along the conductor inside the coaxial cable, while through the insulator and the outer conductor of the reflection and refraction, the formation of electromagnetic field propagation. The characteristics of electromagnetic waves will change with the frequency, time, wavelength and phase changes, while being affected by reflection, attenuation and other factors.