PCB Tech - High frequency circuit board

When 5G is commercialized on a large scale, millimeter-wave technology guarantees better performance: extremely wide bandwidth, available spectrum bandwidth of 28GHz frequency band up to 1GHz, available signal bandwidth of 60GHz frequency band up to 2GHz per channel.

The corresponding antenna has high resolution, good anti-interference performance and can be miniaturized.The propagation attenuation in the atmosphere is fast, and the close range secure communication can be realized.

In order to meet the requirements of high frequency and high speed, as well as the problems of poor penetration and fast attenuation of millimeter wave, 5G communication equipment has the following three requirements for PCB performance:

1. Low transmission loss;

2. Low transmission delay;

3. Precision control with high characteristic impedance.

There are two ways to high-frequency PCB, one is the PCB processing process requirements higher, the other is the use of high frequency CCL - to meet the high frequency application environment of the substrate material called high frequency copper clad plate.There are mainly dielectric constant (Dk) and dielectric loss factor (Df) to measure the performance of high frequency copperplate materials.The smaller the Dk and Df, the more stable the performance of the high frequency and high speed substrate is.

In addition, as for rf plates, PCB plates have larger area and more layers, requiring higher heat resistance (Tg, high temperature modulus retention rate) and stricter thickness tolerance of the substrate. Common circuit board main high frequency and high speed materials have several kinds: hydrocarbon resin, PTFE, LCP liquid crystal polymer, PPE/PPO, etc.