Previously, electromagnetic shielding was not widely used, but now it is widely used and plays a significant role. In electronic devices, electromagnetic interference energy is generally transmitted through two ways: conductive coupling and radiative coupling. When designing, filtering methods are usually used to suppress conductive coupling; For radiation coupling, electromagnetic shielding measures are used to control it.
Electromagnetic waves are the main mode of electromagnetic energy propagation. When high-frequency circuits work, they radiate electromagnetic waves outward, causing interference to adjacent equipment. On the other hand, various electromagnetic waves in space can also be induced into the circuit, causing interference to the circuit. The function of electromagnetic shielding is to cut off the propagation path of electromagnetic waves, thereby removing interference. Among many methods to solve electromagnetic interference problems, electromagnetic shielding is fundamental and useful. The use of electromagnetic shielding to solve electromagnetic interference problems will not affect the normal operation of the circuit, so there is no need to make any modifications to the circuit.
Electromagnetic shielding is one of the important means to solve the electromagnetic compatibility problems of electronic devices. Most electromagnetic compatibility problems can be solved through electromagnetic shielding, especially with the increasing frequency of circuit operation, relying solely on circuit board design often cannot meet the requirements of electromagnetic compatibility standards. There are many differences between the shielding design of electrical equipment and the traditional structural design. Generally, if the shielding problem is not considered in the structural design, it is difficult to meet the requirements of electromagnetic compatibility. So, when designing electronic products, electromagnetic shielding issues should be considered from the beginning. Electromagnetic shielding is mainly used to prevent the influence of high-frequency electromagnetic fields, thereby controlling the radiation propagation of electromagnetic waves from one area to another. The basic principle is to use conductor materials with low resistance values to generate shielding effects by utilizing the reflection of electromagnetic waves on the surface of the shielding body, absorption within the conductor, and losses during transmission.
The purpose of electromagnetic shielding is to suppress the propagation of electromagnetic noise, so that instruments in an electromagnetic environment do not generate electromagnetic interference while avoiding it. Usually, materials with good conductivity and magnetic conductivity are used to isolate the required shielding area from the outside by several meters. For users who have not engaged in or used related products, these are relatively unfamiliar, but if they read more relevant knowledge in the future, it is also easy to understand the principles in this regard.
