S shape trace

If it is "S" or similar shape, it is not done for inductance; it is done to equalize path length for delay time matching.

Hi eeh,

PCBs with "S routes" can be done to equalize path lengths for delay time matching, as stated by Robert, but they can also be used to make a RF/microwave printed PCB inductor. When the printed inductor is in the shape of an "S" -- or multiple "S"s -- then it is a "meandering" equivalent inductor used to conserve board space on a PCB (as opposed to just letting the inductor be a staight line). I know the formulas to calculate these values, but I do not personally know of a program to directly calculate them. However, if the meandering inductor's traces are close to each other (which is very common), then you would need an EM simulator -- or a linear simulator using coupled lines -- to find the exact value of the line's inductance (since coupling will affect this value to some degree).

-Bill