Inspired by the idea to minimize the return path, I am thinking about the two possible improvements of the design, how to connect the signal source to consumer. In short, there are lots of high frequency lines going from the source to consumer and then sharing the return path into the ground. I have produced a separate example because my original circuit is too complex. Let's assume we need the following connectivity:
The source that is an IC chip puts the VCC voltage in pulses at high frequency into consumer. The consumer that is the LED array passes the current through into the ground. I assume, the ground should be the return path for the signals.
Seeking to minimize the length of the loop, the two ideas come to mind:
Put large copper area into the second layer that is now ground only. I have seen multiple recommendations in the literature to do so. However I am not sure about the exact shape of the "return path" of my signals. If they choose to go the shortest way right to the ground pin of the chip, this will not be the smallest area covered by the signal loop.
Provide individual ground routing for the signals in the parallel layer. In this way I hope that the return path would largely match the signal path on the opposite layer. However it cannot go all way together because they still have the different destination.
Here is the routing of the three possible designs (left – the current version, middle – ground plane, right – individual ground that still obviously must join somewhere).
Which of these designs (left, middle, right) would provide the least inference?