Rogers RO4350B high frequency circuit board processing
Optical modules are important components in optical fiber communications, and their signal rates are all high-frequency signals such as 1G, 10G, and 100G. In the application of optical fiber communication, the optical module has the characteristics of small size and large heat generation. Therefore, based on the above-mentioned reasons, the requirements for the PCB material of the optical module are to be able to meet the high speed, and have good electrical and mechanical properties.
The circuit board of the optical module is generally a multi-layer board design. In order to ensure that the signal can still provide sufficient signal amplitude and fidelity after passing through the circuit board, engineers must be particularly careful when designing through holes. When using ordinary FR4 boards, simulation software must be used to carefully confirm to ensure performance. In addition, the transmitted signal of the optical module will be attenuated when it passes through the printed circuit board. Therefore, the printed circuit board using FR4 sheet cannot support the transmission signal above 10G, and the dielectric loss at high frequency is its main defect.
For optical module PCB board materials, we recommend using Rogers' RO4350B hydrocarbon ceramics. This section can well solve the above problems and simplify the design difficulty for engineers. RO4350B is a glass fiber reinforced hydrocarbon/ceramic laminate sheet with a dielectric constant of 3.48 and a loss factor of 0.0031. These features can ensure the transmission of high-frequency signals while reducing signal attenuation during transmission. Its dielectric constant with temperature fluctuation is almost the lowest among similar materials, only 50ppm/ degree Celsius.
The coefficient of thermal expansion (CTE) of RO4350B is similar to that of copper, which can provide excellent dimensional stability, which is very important for multilayer circuit board design. Even in severe thermal shock applications, the low Z-axis thermal expansion coefficient of RO4350B material (only 32ppm/ degree Celsius) can ensure the quality of the through holes in the board.
High frequency board display