We all know that the performance of a PCB circuit board varies with the design of the PCB structure, even for a circuit. With the development of science and technology, electronic products are also rapidly updating, palm electronic products are more popular all over the world, and the RF circuit is becoming a hot product of manufacturers. So how is the RF circuit board designed?
1, the choice of plate
The substrate for printed circuit boards consists of two broad categories: organic and inorganic. The most important properties of the substrate are dielectric constant, epsilon R, dissipation factor (or dielectric loss), tan delta, thermal expansion coefficient CET and moisture absorption rate. Among them, epsilon r affects circuit impedance and signal transmission speed. For high frequency circuits, the dielectric constant tolerance is the most important factor to consider first, and the substrate with small dielectric constant tolerances should be selected.
2 、 PCB board design flow
Schematic design. In order to realize the network connection, in the principle design, the components used must exist in the component library, otherwise, in the SCHLIB should make the necessary components coexist in the storage file. Then, just call the required components from the component library and connect them according to the designed circuit board diagram.After the schematic design is completed, a network table can be formed for use in the PCB design.
Design of PCB
Determination of shape and size of A. PCB. According to the designed PCB board, the shape and size of PCB can be determined according to the position, size and shape of the product and the cooperation with other parts. In the MECHANICAL LAYER layer, draw the shape of the PCB with the PLACE TRACK command.
B. according to the requirements of SMT, make the positioning hole, visual eye and reference point on the PCB board.
Fabrication of C. components. If you need to use some of the components of the library does not exist in the special components, before the layout of the components must be made. The process of making the components in the Protel99 SE is relatively simple, select "DESIGN" menu in the "MAKE LIBRARY" command into the components making design window, then choose "TOOL" menu in the "NEW COMPONENT" commands components. Then just according to the actual components of the shape and size of order PLACE PAD in TOP LAYER layer in certain position draw pad corresponding and edit pad required, and then to PLACE TRACK command in TOP OVERLAYER layer to draw the maximum external components, can take a lead in the name of the component library.
After the completion of D. components, layout and wiring, the two parts discussed in detail below.
E. above process must be checked after completion. This includes checking the wiring board principle and, on the other hand, checking for matching and assembly issues. The inspection of the circuit board principle can be checked manually or automatically checked by the network.
This is the design principle of the internal RF circuit board for sales of hot handheld products. It can be said that it is a leap in technology. I believe that in the continuous development, there will be more and better PCB was designed, PCB circuit board manufacturers will bring better prospects and markets in the electronic market.