Tips and methods for high frequency PCB design

2. High-performance insulated circuit boards with tightly controlled insulation constant values. This method facilitates efficient management of the electromagnetic field between the insulating material and adjacent wiring.

3. Improve PCB design specifications for high precision etching. Consider a total line width error of +/- 0.0007 inches, manage the undercut and cross-section of the wiring shape, and specify the wiring sidewall plating conditions. Overall management of the wiring (wire) geometry and coating surface is important to address the skin effect issues associated with microwave frequencies and to implement these specifications.

4. There is a tapped inductor on the protruding leads. Avoid using leaded components. In high frequency environments, it is best to use surface mount components.

5. For signal vias, avoid using a via processing on the sensitive board because this process can cause lead inductance at the vias.

6. Provide a rich ground plane. These ground planes are connected using molded holes to prevent the effects of 3-dimensional electromagnetic fields on the board.

7. To select electroless nickel plating or dip gold plating, do not use the HASL method for plating. This plated surface provides a better skin effect for high frequency currents (Figure 2). In addition, this high solderable coating requires fewer leads and helps reduce environmental pollution.

8. The solder mask prevents the flow of solder paste. However, due to the uncertainty of thickness and the unknown nature of the insulation properties, covering the entire surface of the board with the solder resist material will result in a large change in the electromagnetic energy in the microstrip design. A solder dam is generally used as a solder mask. Electromagnetic field. In this case, we manage the conversion between the microstrip and the coaxial cable. In a coaxial cable, the ground plane is annularly interlaced and evenly spaced. In the microstrip, the ground plane is below the active line. This introduces some edge effects that need to be understood, predicted, and considered at design time. Of course, this mismatch can also cause return loss, which must be minimized to avoid noise and signal interference.