What material is commonly treated as base for high frequency circuit PCB?
The 5g mobile communication terminal adopts the high frequency board technology to deal with the challenge. First of all, the dielectric constant of the high frequency board determines the transmission speed of the electrical signal in the medium. The lower the dielectric constant, the faster the signal transmission speed. Therefore, high-frequency PCBs need to choose low-dielectric constant dielectric materials. High-frequency PCBs need to choose a dielectric material with a low dielectric constant. As the frequency increases, the loss in the substrate is no longer negligible, and the loss of signal transmission energy is proportional to the loss factor and frequency.
Therefore, in order to meet the requirements of high frequency, high speed, high density, high dielectric constant (DK≤3), low loss factor (DF≤0.005), glass transition temperature (TG>165℃), and good dimensional stability (low CTE) , CAF resistance (conductive anode wire) and good processability require mobile terminal boards. The base material of the hard board is preferably fluorinated resin (PTFE, polytetrafluoroethylene), and the base material of the soft board is preferably modified polyimide (MPI) or liquid crystal polymer (LCP).
In order to meet the high heat dissipation requirements caused by high heat generation, it is recommended to add materials with good thermal conductivity (such as ceramic powder such as alumina and silica) to the selected dielectric materials. When conditions permit, it is best to use metal-based copper clad laminates (such as Aluminum base board) for PCB circuit boards in high-heating functional areas. The conductor layer is covered on the insulated aluminum base, and the heat generated in the conductors in the board quickly passes through the aluminum plate. Communicate it to achieve efficient heat dissipation.
