Flexible composite electromagnetic wave absorbing material applied to sensing radio frequency identification for internet of things

Abstract

The invention provides a flexible composite electromagnetic wave absorbing material applied to sensing radio frequency identification for internet of things. The flexible composite electromagnetic wave absorbing material comprises the following components in percentage by mass: 60%-95% of composite anti-electromagnetic interference absorbent particles and 40%-5% of an adhesive, wherein the composite anti-electromagnetic interference absorbent particles are formed by mixing, drying and dispersing of 0.1-40 microns of soft magnetic metal particles and soft magnetic levitation liquid, of which the volume ratio is (60%-70%) to (40%-30%); the soft magnetic levitation liquid is formed by stirring and mixing of an organic bridging material which is diluted until the viscosity is within the range of 100-300mPa.s, and surface-activated composite particles; and the volume ratio of the organic bridging material to the composite particles is (90%-95%) to (10%-5%). Through the organic bridging material, the effects on an electronic tag caused by electromagnetic interference under various environments are reduced to the minimal extent; impedance matching of the electromagnetic wave absorbing material and an electronic tag antenna is improved; and the frequency offset phenomenon caused by encapsulation of the wave absorbing material is solved, thus the read reliability of the tag and the compatibility of actual use of the tag are ensured.

Description

technical field [0001] The invention relates to an electromagnetic wave absorbing material, in particular to a flexible electromagnetic wave composite absorbing material used for sensing radio frequency identification of the Internet of Things. Background technique [0002] Radio Frequency Identification (RFID) technology is an important part of the Internet of Things, and Radio Frequency Identification (RFID) technology is essentially an automatic identification technology. Usually, the RFID system consists of three main parts: electronic tags, readers and data management systems. The electronic tag consists of an antenna and an RFID chip, and each chip contains a unique identification code, which is used to indicate the object to which the electronic tag is attached. The reader is used to read and write the information in the electronic tag. The reader communicates with other computers or systems through the network to complete the information acquisition, interpretation ...

AI Technical Summary

Problems solved by technology

[0004] At present, the flexible composite absorbent material available in the market is used for anti-metal electronic tags. When it is used on metal objects, it can guarantee that the effective recognition distance can reach about 40% of the designed recognition distance at most, and the thickness is generally 0.5mm, which cannot meet the requirements of light and thin applications.

At the same time, although the high-permeability sheet-shaped sintered soft ferrite prepared by the tape casting method can ensure that the effective recognition distance reaches about 80% of the designed recognition distance, because it has been sintered at a high temperature of at least 1100 ° C, there are high manufacturing costs, Defects such as fragile products and difficult die-cutting

CN102300446A "An Electromagnetic Wave Composite Absorbing Material for Internet of Things Radio Frequency Identification" describes that the electromagnetic wave composite absorbing material used for Internet of Things radio frequency identification materials is composed of various soft magnetic materials and their mixtures, and its essence has Certain conductivity, although a certain proportion of resin is added, because the absorbent particles are difficult to achieve uniform distribution in the adhesive, contact between adjacent absorbent particles is inevitable, and absorbent particles are inevitably exposed on the surface of the product. When the absorbent particles are in contact with the surface of the metal object, its surface resistivity is also (1.0×105~1.0×106)Ω·m, so when the material is in a high-frequency electromagnetic field, it will generate a certain amount of inductance. When the material is pasted or attached to the electronic tag, the inductance generated by the material will affect the inductance of the inherent design of the tag, thereby changing the inductance of the electronic tag, changing the impedance of the electronic tag, and generating the returned signal frequency point and design signal The frequency point shifts, which affects the exchange of communication signals. In practical applications, it is reflected as: the reading and writing distance becomes shorter or the stability of the reading and writing distance is poor or the label compatibility is poor.