Characteristics of Electromagnetic Absorber
The electromagnetic absorber is a functional composite material that mainly absorbs electromagnetic waves. It can eliminate the back and forth reflection of electromagnetic waves in the shielding cavity, reduce the interference of clutter to its own equipment, and effectively prevent electromagnetic wave radiation from harassing and harming surrounding equipment and personnel. It is an advanced means of eliminating electromagnetic wave pollution.
In addition, the electromagnetic absorber with high magnetic permeability can play the role of focusing magnetic flux and provide an effective solution to the problem of RFID reading and writing interference.
The working principle of electromagnetic absorber
- According to the law of electromagnetic waves propagating in the medium from low magnetic permeability to high magnetic permeability, high permeability absorbents are used to guide electromagnetic waves, and through resonance, a large amount of radiation energy of electromagnetic waves is absorbed, and then the energy of electromagnetic waves is converted into heat energy through coupling. Thereby reducing or eliminating electromagnetic wave interference and radiation hazards.
- During the RFID identification process, because the electronic tag is susceptible to the interference of the metal eddy current close to it, the actual effective reading and writing distance of the tag is greatly shortened or no response occurs at all, resulting in a complete failure of data reading and writing. RFID absorbing materials have high magnetic permeability and can play the role of focusing magnetic flux, providing an effective solution to such interference problems.
Electromagnetic waves have excellent characteristics, and their application fields cover military, civil and other fields and frequency bands. One of them is to efficiently absorb the space electromagnetic wave energy incident on its surface, that is, electromagnetic wave absorbers, which are used in conventional wave absorbing materials. opened up a new research direction in the field. With the deepening of electromagnetic wave absorber research, people are not only satisfied with the pursuit of the superior performance of the planar structure electromagnetic absorber, but also hope to apply the electromagnetic absorber to a wider and more complex environment.
Electromagnetic Absorber Application
Electromagnetic Absorber are widely used in fields that require electromagnetic wave absorption, and can suppress electromagnetic wave interference and radiation of electronic equipment in a wide frequency range, and are widely used in the following fields:
- Mobile phone, GPS and other wireless communication products;
- Notebook computers, digital cameras, digital video cameras, flat panel displays (PDP) and other digital products;
- RFID radio frequency identification technology, such as NFC mobile phone, handheld POS machine, ETC system, access control, anti-counterfeiting and card readers such as water, electricity and coal;
- Frequency conversion equipment such as wireless chargers;
- High-precision electronic equipment such as medical and health care equipment;
- Electronic circuit boards (PCB), integrated circuits and other functional modules.
As far as the current research and production levels are concerned, it is unrealistic to use a single material as an absorber to achieve broadband absorption, and it cannot solve the problem of non-reflection. In practical applications, a single material and direct use are generally less used, but in the form of electromagnetic absorber.
The electromagnetic absorber is a structured electromagnetic absorbing material for the best electromagnetic wave absorption effect, and it can appear in the form of commercial products. Internationally, composite and structural design methods are used to solve the absorption problem of a certain frequency band, and it is the first to be applied in military applications.
The research on electromagnetic absorber is based on the research on absorbing materials. At present, the practical absorber structures are as follows:
- Single-layer structure: It is a single-coating and single-layer absorber that behaves as a composite material.
- Multi-layer structure: It consists of a wave-transmitting layer, an impedance matching layer, an absorbing layer and a reflective backing. In the design, the mutual cancellation technology of the incident wave and the reflected wave is often used. Although the corresponding absorption peak will appear at this time, the absorption bandwidth will be affected.
At present, the United States, Japan, and Western European countries are in the world’s leading position in the research of electromagnetic absorber, and they have respectively developed civil electromagnetic wave absorbers with a thickness of millimeters. The most advanced absorber structure is the electromagnetic absorber structure used in military stealth aircraft in the United States. This structure can reduce the reflection of radar waves by 7-10dB in a wide frequency band.
PH Functional Materials specializes in the production of electromagnetic absorbers, our products have strict quality control standards, stable quality, and meet global supply standards. Besides, our products also include emi shielding film, Wireless charging ferrite and emi suppressor sheet, etc. If you need these products, please contact us, we will provide you with the best service.
