1. Introduction to the properties and principles of ferrite absorbing materials
Ferrite absorbing material is a kind of high-tech functional composite material that mainly absorbs electromagnetic waves, and its reflection, scattering and transmission are very small. When the wave is inside the material, it promotes the transition between the energy levels of the ions and electrons in the constituent material molecules, resulting in conductance loss, high-frequency dielectric loss and hysteresis loss, etc., so that the electromagnetic energy is converted into heat energy and dissipated to the space to disappear, thereby producing Absorption. Does not cause secondary pollution due to reflection, main features: thin thickness, good flexibility, high strength, high absorption rate, anti-aging (the carrier is a silicone rubber material), stability (-50----180℃), low frequency characteristics (10MHZ----10GHz), it has good absorption characteristics for both specular wave and surface wave.
Second, the application of ferrite sheet
The ferrite sheet can be applied to handheld devices such as payment mobile phones. The main function of electronic tags is to reduce the absorption of the signal magnetic field by metal materials, and increase the magnetic field strength to effectively increase the sensing distance. The payment method for payment mobile phones (NFC) is Through 13.56MHz; RFID radio frequency identification system realized. The RFID smart label of this application is affixed to the back cover of the mobile phone, which can save space to a certain extent. In handheld electronic devices such as mobile phones, electronic tags need to be integrated or attached to the electronic device to function as a component of the device. Often due to limited space, it is inevitable to attach RFID tags (usually passive) to metal, etc. The surface of the conductive object or the place where there are metal devices nearby. In this way, the alternating electromagnetic field induced by the tag under the action of the signal sent by the card reader is easily attenuated by the metal eddy current, which greatly weakens the signal strength, leading to the failure of the reading process. Therefore, in order for the product to be able to better use the card reader, it is necessary to add a microwave absorbing material to the product. Ferrite sheets have begun to be widely used in small payment mobile phones and radio frequency fields.
In addition, it is also widely used in electromagnetic compatibility, electronic instrument equipment, high-frequency equipment, shielding boxes, radio-frequency shielding boxes, shielding cabinets, test fixtures, microwave anechoic chambers, and in the absorption and shielding of industrial microwave energy equipment to prevent microwave leakage, communication and navigation systems Anti-interference and radiation protection of high-frequency electronic and electrical equipment. Suppress electromagnetic interference, improve the antenna pattern, and improve the accuracy of radar direction finding and ranging; prevent electromagnetic interference, electromagnetic wave radiation and waveform shaping of microwave devices and equipment; microwave anechoic chamber, electromagnetic compatibility room, absorption load, attenuator, radar wave RCS reduction Wait.