PCB Tech - The importance of selecting high frequency materials

With the progress of electronic design technology and manufacturing technology, electronic products are gradually developing towards high density, high functionality, thin and short, and high transmission rate. In addition, with the rapid development of chip miniaturization and the increase of data transmission quantity, the working frequency of the system is also higher and higher. To be an excellent electronic product, we need not only excellent circuit design, but also good manufacturability, because good manufacturability can reduce the problems in mass production, shorten the product development progress, reduce the design cost, so as to improve the product competitiveness. Therefore, it is very important for product design engineers to choose PCB materials when designing electronic products.

When the working frequency of the circuit is in the radio frequency band, the range of boards that the design engineer can choose will be greatly reduced. The special formulation of Rogers ro4835 high frequency plate improves oxidation resistance. When used at a certain temperature for a long time, it can provide special stable electrical properties, while maintaining the processing advantages of FR4 thermosetting resin. At the same time, the dielectric constant (DK) is 3.48, the dielectric loss (DF) is 0.0037 at 10 GHz, and the z-axis thermal expansion coefficient (CTE) is low, which ensures the reliability of metal through-hole under various processing and operating conditions. The x-axis and y-axis expansion coefficients of the material are similar to those of copper, and have excellent dimensional stability.

With the communication technology from 2G, 2.5G, 3G to 4G and the current 5G, the data transmission throughput is increasing, the bandwidth required is wider and wider, and the frequency is higher and higher; the miniaturization of equipment is also one of the development trends in the future, and once the equipment becomes smaller, PCB is required to have higher thermal conductivity and higher dielectric constant. High frequency circuit board materials are mainly used in high power amplifier, base station antenna, global positioning system, weather radar and weather satellite, automobile radar and sensor.

The main parameters of PCB material are DK and DF. In high frequency circuit board, the stability of DK value is the guarantee of board reliability; DF value should be as small as possible to reduce signal loss. And, in some high-speed, large-scale data transmission system will also use some high-frequency plate.