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What is Dielectric Constant (DK) and Dielectric Loss (DF)?

Suzhou Kying Industrial Materials Co,Ltd.  2022-05-05 09:28:06 作者:SystemMaster
We always see dielectric constant (DK) and dielectric loss (DF) in articles related to high-frequency materials, and these two values are very critical in high-frequency materials, so what are DK and DF?

DK, the abbreviation of Dielectric constant, is called the dielectric constant in Chinese. It is a coefficient that expresses the characteristics of insulating ability and is represented by the letter ε. When an electric field is applied to a medium, an induced charge will be generated and the electric field will be weakened. The ratio of the electric field reduction in the medium to the original applied electric field (in vacuum) is the relative permittivity, also known as the inductive rate, which is related to the frequency. In fact, the dielectric constant is not a constant number, and its dielectric constant is also different under different conditions. Generally, the PCB of digital electronic products attaches great importance to the DK. The lower the DK, the better the quality of the high-speed transmission signal, and the faster the speed. DK is an indicator to measure the ability of a material to store electrical properties. The lower the DK, the faster and stronger the signal transmission speed in the medium.

DF, the abbreviation of Dissipation Factor, the Chinese name is dielectric loss, refers to the phenomenon that the electrolyte itself heats up due to the consumption of part of the electric energy in the alternating electric field. The reason is that the electrolyte contains conductive carriers, and under the action of an external electric field, a conductive current is generated, which consumes a part of the electric energy and turns it into heat energy. It is one of the indicators of the quality of insulating materials (such as insulating oil). Energy loss due to voltage applied to insulating materials such as transformer oil. DF is an index to measure the energy loss of dielectric materials. The lower the DF, the better the integrity of the signal transmission in the medium. The smaller the dielectric loss, the better the quality of the insulating material and the better the insulating performance. Usually measured by the dielectric loss tangent, high-speed products attach great importance to the dielectric loss (DF) of the sheet. Currently, the grades of high-speed materials commonly used in the market are also divided according to the size of the dielectric loss (DF). Different substrate materials are divided into standard loss (Standard Loss), medium loss (Mid Loss), low loss (Low Loss), very low loss (Very Low Loss), ultra low loss (Ultra Low Loss) according to the dielectric loss of the substrate ) corresponding to the five transmission signal loss levels.

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