Knowledge of flexible absorbing material

With the development of modern science and technology, the impact of electromagnetic wave radiation on the environment is increasing. In airports, planes and flights are delayed due to electromagnetic interference; in hospitals, mobile phones often interfere with the normal operation of various electronic medical instruments. Therefore, to control electromagnetic pollution and find a material that can resist and weaken electromagnetic wave radiation, flexible absorbing material, has become a major subject of wave absorbing material science.


Electromagnetic radiation causes direct and indirect damage to the human body through thermal effects, non-thermal effects and cumulative effects. Studies have confirmed that ferrite absorbing materials have the best performance, and it has the characteristics of high absorption frequency band, high absorption rate, and thin matching thickness. The application of this material in electronic equipment can absorb leaked electromagnetic radiation and achieve the purpose of eliminating electromagnetic interference. According to the law that electromagnetic waves propagate in the medium from low magnetic to high magnetic permeability, high-permeability ferrite is 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.


The main structure of flexible absorbing material:

  1. The principle of flexible absorbing material is to convert electromagnetic waves emitted by electronic equipment into heat energy through insulation loss, magnetic loss, impedance loss, etc. to reduce electromagnetic radiation. It has the characteristics of high magnetic permeability and wide optional frequency band, and can be developed for specific frequency bands.
  2. The flexible absorbing material has good absorption characteristics in the range of 10MHz~6GHz, which can avoid electromagnetic interference or leakage caused by secondary reflection. The products are mainly absorbing patches, and can also be processed into various shapes according to customer requirements. The flexible absorbing material can be used in the cavity of electronic equipment such as notebook computers, mobile phones, and communication cabinets.
  3. The flexible absorbing material has good electromagnetic wave absorption effect and wide absorption frequency. It can be customized according to the frequency band required by customers. It is thin, cost-effective, and has a wide range of uses and applications.
flexible absorbing material
flexible absorbing material

Application of absorbing material products:

  1. It can be used in the cavity of electronic equipment such as notebook computers, mobile phones, and communication cabinets.
  2. It can be used to reduce the radiation and noise of various electronic devices.
  3. It can reduce the coupling conduction radiation interference and low frequency echo interference between low frequencies.
  4. Internal EMI (resonance and crosstalk) in the barrier frame can be reduced.
  5. Apply it between the chip and the cooling module.
  6. Apply EMI/RFI: Literally translated as Electromagnetic Interference. There are three elements of electromagnetic interference: interference source, interference propagation path, and sensitive equipment. The source of interference refers to the electronic equipment or system that generates electromagnetic interference, and the propagation path of the interference includes cables, space, etc. Sensitive equipment refers to electronic equipment or systems that are susceptible to electromagnetic interference. Radio Frequency Interference (RF Interference): Radio frequency is a high-frequency alternating current, also known as electromagnetic waves. Radio frequency interference is interference caused by electromagnetic waves. For example, two electromagnetic waves with similar frequencies will be received by the receiver at the same time, causing interference. There will be harmonic interference near the transmitting station, which will interfere with other receiving equipment. Emitting electromagnetic waves of the same frequency can interfere with radio stations.


The absorbing mechanism of flexible absorbing material

The flexible absorbing material is that the electromagnetic energy is absorbed when the electromagnetic wave passes through, so that the incident electromagnetic energy is converted into other forms of energy such as heat energy, and these energy will be lost. This article takes you to understand the absorbing mechanism of absorbing materials.


1 The basic conditions for materials to absorb electromagnetic waves are:

1) When an electromagnetic wave strikes a material, it can enter the material’s interior (matching properties).

2) Electromagnetic radiation entering the material can decay rapidly. This can be achieved by applying boundary conditions, requiring materials with high electromagnetic losses.

Radar waves have impedance when they pass through free space, and they are projected vertically to the surface of the medium with half the impedance and will be reflected. Therefore, in order to prevent radar waves from being reflected, it must be in an ideal state. Various absorbing materials have different reflection coefficients due to different absorbing mechanisms, internal structures, shapes, incident angles, and polarization modes. In order to achieve a good absorbing effect, material selection and specific design are required.

Absorbing sheet emi shielding sheet

2 Binder

Absorbent coatings are mainly composed of binders and absorbers. The binder is the film-forming substance of the coating, and it is the main substance that makes the coating firmly adhere to the surface of the coating to form a continuous film. The absorber with specific electromagnetic parameters is the key to the absorbing coating, which determines the absorbing performance of the absorbing coating.

The selection of binder should follow the following principles:

1) There is a lot of absorbent and the specific gravity is low.

2) excellent adhesion, flexibility, and impact resistance;

3) High temperature and chemical resistance;

4) It has the same dielectric constant as the absorber. Judging from the current research progress, adhesive systems with good comprehensive performance and stable process mainly include chlorosulfonated polyethylene, epoxy resin and polyurethane.


As a professional supplier of wave absorbing materials, PH Functional Materials has independently developed a number of series of absorbing materials, NFC absorbing materials, flexible absorbing materials, flexible whiteboards, soft ferrite magnetic powder, electromagnetic shielding coatings, etc. The leading level of electromagnetic functional materials in China. We have advanced production technology and excellent product quality, if you need, please contact us.

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