I have a question about return currents. Now, all current needs to travel in a loop. so any charge that leaves a source must return to it (correct me if i'm wrong). usually on a high speed design the return current wants to travel right underneath the trace which is usually the ground plane. when a signal is launched onto a trace, it couples with the plane underneath essentially charging capacitors all it's way down. so electrons on the trace would push out electrons from the plane which return to the negative terminal of the source. say i have a very very badly designed board and have no ground plane but a ground trace that is no where close to the signal trace. would happen if there is no plane and what would it couple with to obtain the return current? Thanks!