The upgrade of hardware components, and the exponential increase in the number of networking devices and antennas in 5G era have put forward new requirements and challenges for related materials in the industry chain.
Electromagnetic interference can be easily discovered between devices and within the devices themselves. Besides, the harm of electromagnetic interference and electromagnetic radiation also become more and more serious. Meanwhile, with the upgrading of electronics, the power consumption of equipment continues to increase, and the heat emission issue becomes critical.
In the future, the bottleneck of high-frequency and high-power electronic products is the electromagnetic radiation and heat generated by them. In order to solve it, more and more electromagnetic shielding and heat-conducting components will be considered during designing of electronic products. Therefore, the role of electromagnetic shielding and heat dissipation materials and devices will become necessary, and the demand will continue to grow significantly.
Electromagnetic interference shielding(EMI shielding)
After the electronic equipment is energized and started, the internal current generates electromagnetic waves, which will interfere with the signal reception and transmission of other surrounding electronic equipment. Even worse, it enables to interrupt the normal work of other electronic devices.
EMI shielding products use EMI shielding materials to reflect and absorb electromagnetic waves. By blocking the propagation path of electromagnetic waves to achieve isolation and shielding of electromagnetic waves.
Due to the discontinuity of impedance at the interface between air and shielding materials, incident waves will be reflected back. And part of the electromagnetic waves entering the shielding material body will be attenuated and absorbed by the shielding material.
Two ways for electromagnetic interference
There are mainly two methods for EMI shielding of electronic equipment. One is the structural body of electronic device, which is usually made of steel plate, aluminum plate, copper plate or metal plating, conductive coating, etc.
The other is the shielding gasket, which is a conductive EMI shielding product. It is specially used to solve the problem of electromagnetic shielding in the gaps of the structural body. Generally, it is processed from materials such as metal, plastic, silicone and cloth through stamping, forming and heat treatment.
The technical level and development route of EMI shielding components are mainly dominated by the development of electronic shielding materials. Its features like electrical conductivity, magnetic permeability and material thickness are the three basic factors of shielding effectiveness.
The demand for electromagnetic shielding materials will develop in the direction of higher shielding effectiveness, wider shielding frequency and better comprehensive performance in the future.
(1) Common electromagnetic interference shielding products
Currently, the common materials are including conductive plastic devices, conductive silicone devices, metal shielding devices, conductive cloth pad devices, and wave-absorbing devices.
Some new materials are being explored like foamed metal shielding materials, nano-shielding materials and intrinsically conductive polymer materials, relying on their own good conductivity to achieve EMI shielding function. EMI are mainly used in the communication industry, consumer electronics, and automotive electronics, medical, military and electric power and other fields.
(2)Development direction of EMI materials
The future development direction of EMI shielding materials are as follows:
- Filled materials like conductive plastic parts and silicone parts will choose more efficient and low-cost materials;
- Conductive gaskets will use thinner raw material cloth and foam with better performance;
- Conductive coatings using carbon-based conductive powder, etc.
At the same time, various types of electronic devices will be included in the EMC management standards in the future, and the EMC standards will become more stringent.
Thermally conductive factor
Thermal components are usually used to fill the air gap between heating parts and heat dissipation parts, and make good use the performance of thermal components to improve thermal conductivity capability.
By filling the rough and uneven bonding surface, replacing the non-heat-conducting air with a thermal interface material with a thermal conductivity much higher than that of air, the thermal resistance through the thermal interface is reduced, and the heat dissipation efficiency of semiconductor components is improved.
Thermally conductive materials
At present, thermally conductive materials are mainly divided into thermally conductive paste, sheet thermally conductive gap filling material, liquid thermally conductive gap filling material, phase change thermally conductive interface material, thermally conductive gel and graphite film, etc.
Among them, thermally conductive graphite film has gradually become the preferred solution for smart electronic products. However, with the continuous development of technology, electronic products have higher requirements for thermal management solutions, so thermally conductive graphite film materials gain more attention in public. For example, thinner thickness, better thermal conductivity, and the ability to process 3D structural products, or combine with other materials to form composite multifunctional materials, etc.