(1) The PCB board has defects

The manufacturing process of the printed circuit board is very complicated and the process is cumbersome, which leads to the possibility of large defects in the PCB board, and also determines the necessity of difficulty in detecting the defects of the PCB board. The production of PC B board is often in the TOP layer, and the produced board often has the problem that it is not easy to solder because of the installation of the device. There is a large area of copper foil on the PCB, and it is very close to the outer frame, which easily causes the problem of solder resist falling off. At the same time, the electrical ground layer in the PCB board often performs the work of the pad and the connection at the same time, and there is often a problem that the two sets of circuits are short-circuited at the same time, and the connection area is sealed. There will be SMD films on the PCB, large and small characters, covering each other, which is extremely confusing and difficult to distinguish. In addition, PCB boards also have problems such as unclear processing levels, filled blocks drawing pads, too short pads for surface mount devices, overlapping pads, too many pads, and abuse of graphics layers.

(2) The PCB hole has defects

The defects in PCB holes are mainly concentrated on two levels of drilling defects and defects in the holes. Porosity, wrong pore size, offset holes, etc. will cause the metallicity of PCB hole quality. The defects of the PCB holes are closely related to the performance of the equipment and the working environment. Due to the low adaptability of the PCB holes, it is difficult to adapt to the replacement of the equipment and changes in the working environment, resulting in defects. At the same time, PCB holes are easily restricted by the glass transition temperature. When the glass transition temperature is high, the production speed of PCB holes is faster, and when the glass transition temperature is low, the speed is relatively slow. Regarding the defects of PC B holes, there is also the problem of unprofessional drilling process, which is also one of the defects of PC B holes. In addition, there are also defects such as hole position deviation, hole diameter distortion, rough hole wall and more burrs.

The main characteristics of PCB for mobile communication terminals in the 5G era

1. High density

When it comes to the design of mobile terminals, no one millimeter of space is saved in the case, which can create huge value for end customers. Save space, you can use larger, higher-resolution displays, larger batteries, and more sophisticated processors and components. All of these can enhance the functionality of the device while enhancing the overall user experience.

Massive MIMO (Multivariable Control System) antenna configuration and increasingly complex RF front-ends will enable RF lines to occupy more space in 5G smart phones. Among other factors, the terminal will support the processing capacity required for massive 5G data. It may also affect battery capacity and geometry. As a result, despite the increase in input/output requirements, the space available for PCBs in 5G mobile terminals will still be greatly reduced.

5G pcb

2. High frequency and high speed

    With the advent of the 5G era, the obvious change in circuit board performance is high frequency and high speed. As 5G, IOT and other applications will adopt higher frequencies, gradually rising from below 3GHz to 6GHz or even 24-30GHz. Because 5G has a higher inherent frequency, stricter impedance control is required. If it is not formed in an extremely precise manner, the thinner lines of the 5G PCB may increase the risk of signal attenuation and reduce data integrity.

3. High fever

The signal transmission in PCB has "impedance" and "dielectric loss", which increase with the high frequency or high-speed digitalization and high power of the signal, so that the PCB continues to generate heat and heat up. The first stage of my country's 5G commercial frequency band is mainly concentrated below 6GHz, and it will be as high as 24-30GHz in the later stage. As the transmission rate of 5G continues to increase, the data transmission volume will increase greatly, plus the application of 3D video, cloud gaming and wireless charging Appears, these factors soy milk have led to a significant increase in the heat generation of 5G communication terminals compared to the 4G era.