The dielectric constant of the high frequency PCB substrate must be small and stable. Generally speaking, the smaller the better. The signal transmission rate is inversely proportional to the square root of the material's dielectric constant. A high dielectric constant can easily cause signal transmission delays.

The dielectric loss of the high-frequency PCB substrate material must be small, which mainly affects the quality of signal transmission. The smaller the dielectric loss, the smaller the signal loss.

The impedance of the high-frequency circuit board-actually refers to the resistance and the reactance parameters, because the high-frequency PCB should consider the plug-in installation of electronic components, and the conductivity and signal transmission performance should be considered after the plug-in, so the lower the impedance, the better .

High-frequency circuit board substrates should have low water absorption, and high water absorption will cause dielectric constant and dielectric loss when exposed to moisture.

In order to meet the signal integrity requirements of different applications, the PCB must not only test the S parameters and TDR impedance, but also need to analyze the physical properties of the material itself, the dielectric constant and the dielectric loss. Accurate dielectric constant can not only achieve effective design, but also make the simulation and product's real test results more consistent, and improve the efficiency of design and development. It is of great significance for PCB material suppliers, including PCB production developers.