Microwave Tech - Briefly on the matters needing attention in the production of high-frequency microwave panels

I. Introduction
With the continuous development of science and technology, especially information technology, the process technology of PCB board production is correspondingly improved to meet the needs of different users. In recent years, the fields of communications, automobiles, etc. have developed very rapidly, and some changes have taken place in the demand for printed boards, and the demand for high-power printed boards and high-frequency microwave boards has increased. Many bosses of printed circuit board manufacturing companies are optimistic about this growth point, but how to do a good job of high-frequency microwave boards, companies must practice their internal skills. Based on the problems I encountered in the production, I briefly described the matters that should be paid attention to in the production of high-frequency microwave panels.
Second, the basic requirements of high-frequency microwave panels
1. When designing the substrate, the telecommunications engineer has selected the specified dielectric constant, dielectric thickness, and copper foil thickness according to the actual impedance requirements. Therefore, when accepting the order, it must be carefully checked and the design requirements must be met.
2. The production accuracy of transmission lines requires the transmission of high-frequency signals, and the characteristic impedance requirements of printed wires are very strict, that is, the production accuracy of transmission lines is generally ±0.02mm (the transmission line with ±0.01mm accuracy is also very common). The edges should be very neat, and tiny burrs and gaps are not allowed.

3. The coating requires the characteristic impedance of the high-frequency microwave board transmission line to directly affect the transmission quality of the microwave signal. The characteristic impedance has a certain relationship with the thickness of the copper foil. Especially for PCB high-frequency boards with hole metallization, the plating thickness not only affects the total copper foil thickness but also affects the accuracy of the wire after etching. Therefore, the plating thickness The size and uniformity should be strictly controlled.
4. Requirements for mechanical processing: First, the material of the high-frequency microwave board is very different from the epoxy glass cloth material of the printed board in terms of machining; secondly, the processing accuracy of the high-frequency microwave board is higher than that of the printed board. Many, the general shape tolerance is ±0.1mm (high precision is generally ±0.05mm or 0~-0.1mm).
5. The requirement of characteristic impedance. I have already talked about the content of characteristic impedance. It is the most basic requirement of high-frequency microwave board. It cannot meet the requirement of characteristic impedance. Everything is in vain.