Microwave Tech - High-Frequency Microwave Printed Board manufacturing technology

High-Frequency Microwave Printed Board refers to a microwave device produced on a specific microwave substrate coppery clad board by ordinary rigid printed board manufacturing methods. In PCB wire high-speed signal transmission line, at present can be divided into two categories: one is the high-frequency signal transmission class electronic products, this kind of product is associated with the electromagnetic wave of radio, it is a sine wave to transmit signal products, such as radar, radio and television and communications(mobile phone, microwave communications, optical fiber communications, etc.); The other is the high-speed logic signal transmission class of electronic products, this kind of products are digital signal transmission, also related to the square wave transmission of electromagnetic waves, this kind of products began mainly in computers, computers, and other applications, has been rapidly promoted to home appliances and communication electronic products.

To achieve high-frequency microwave transmission, there are definite requirements on the electrical characteristics of microwave printed board substrate materials. In terms of improving high-speed transmission, the substrate materials with small dielectric constant and medium loss Angle tangent must be selected to achieve low loss and delay of the transmission signal.

High-speed transmission of substrate materials, generally ceramic materials, glass fiber cloth, PTFE, other thermosetting resins, etc.

High-Frequency Microwave Printed Board

The characteristics of microwave printed board manufacturing are mainly shown in the following aspects:

1, substrate diversification:

For a long time, because of its single variety and poor dielectric uniformity, it has been less and less suitable for some occasions requiring high performance. In the 1990s, RT/Duroid series and TMM series microwave substrate plates produced by Rogers company in the United States have been gradually applied, mainly including glass fiber reinforced PTFE coppered plate, ceramic powder filled PTFE coppered plate and ceramic powder filled thermosetting resin coppered plate. Although the price is expensive, it is excellent dielectric properties and mechanical properties still have a considerable advantage over domestic microwave PCB substrate.

2, the design requirements of high precision:

The graphics manufacturing precision of microwave printed board will gradually improve, but due to the limitation of the manufacturing process of the printed board itself, the improvement of the precision can't be unlimited and will enter a stable stage after a certain degree. And the microwave board design content will be very rich. In terms of type, there will be not only a single panel, double panel, but also microwave multilayer panels. Higher requirements will be put forward for the grounding of microwave plate, such as the general solution to the hole metallization of PTFE base plate, the solution to the grounding of microwave plate with aluminum substrate. Further diversification of plating will be required and particular emphasis will be placed on the protection and plating of aluminum substrates. In addition, higher requirements will be put forward for the overall three-proof protection of microwave plate, especially for the three-proof protection of Teflon base plate.

3. Computer control:

Computer technology is rarely used in traditional microwave printed board production, but with the extensive application of CAD technology in the design, and the high precision and large quantity of microwave printed board, computer technology has become an inevitable choice in high-frequency microwave printed board manufacturing. High precision microwave printed board template design and manufacturing, shape CNC processing, as well as high precision microwave printed board batch production and inspection, has been inseparable from computer technology. Therefore, it is necessary to connect CAD, CAM, and CAT of microwave printed board. Through data processing and process intervention of CAD design, corresponding NC machining files and NC testing files are generated, which can be used for process control, process inspection, and finished product inspection of microwave printed board production.

4, high precision graphics manufacturing professional:

Compared with the traditional rigid printed board, the high-precision graphics manufacturing of microwave printed board is developing towards a more specialized direction, including the production and process control technology of high-precision template manufacturing, high-precision graphics transfer, high-precision graphics etching, and other related processes, as well as the reasonable manufacturing process route arrangement. According to different design requirements, such as whether the hole is metalized or not, the type of surface plating, and so on, the reasonable manufacturing process method is formulated. After a lot of process experiments, the process parameters of each related process are optimized, and the process allowance of each process is determined.

5. Diversification of surface plating:

With the expansion of the application range of microwave printed boards, the environmental conditions of its use are also complicated. At the same time, due to the extensive application of aluminum substrate, the surface coating and protection of microwave printed board is put forward higher requirements based on the original chemical precipitation silver and tin-cerium alloy. First, the plating and protection of the surface of microstrip graphics should meet the welding requirements of microwave devices. The process technology of nickel plating gold is adopted to ensure that the microstrip graphics will not be damaged in a harsh environment. In addition to the solderable coating on the surface of the microstrip pattern, the most important thing is to solve the three protection technology which can effectively protect and not affect the microwave performance. The second is the protection and plating technology of aluminum liner. If the aluminum liner is not protected, it will be corroded quickly when exposed to a wet and salt spray environment. Therefore, with the application of aluminum liner in large numbers, its protection technology should be paid enough attention.

6, shape processing numerical control:

The shape processing of microwave printed board, especially the 3d shape processing of microwave printed board with aluminum lining board, is a key technology to be solved in the batch production of microwave printed board. In the face of thousands of microwave printed boards with aluminum lining boards, the traditional shape processing method can not guarantee the manufacturing accuracy and consistency, nor can guarantee the production cycle, but must use the advanced computer-controlled NUMERICAL control processing technology. However, the shape processing technology of microwave printed boardswith aluminum lining is different from the processing of metal and non-metal materials. Due to the co-existence of metal and non-metal materials, its processing tools, processing parameters, and processing machine tools have great particularity, but also a large number of technical problems need to be solved.

7. Batch production and inspection equipment:

Microwave printed board is different from ordinary single and double panel and multilayer board. It not only plays the role of structural and connecting parts but also plays the role of the signal transmission line. That is to say, for the transmission of high-frequency signals and high-speed digital signals with microwave printed board electrical testing, not only to measure the line (or network) "on "off" and "short circuit" and other requirements but also should measure the characteristic impedance value is in the specified qualified range.

In addition, high-frequency microwave PCB has a large number of data to test, such as graphics accuracy, position accuracy, coincidence accuracy, coating thickness, shape three-dimensional dimension accuracy, and so on.