When the distance from the disturbance area to the capacitor reaches λ/4, the phase of the compensation current is π, which is exactly 180 degrees away from the phase of the noise source, that is, completely out of phase. At this time, the compensation current no longer works, the decoupling function fails, and the compensation energy cannot be delivered in time. In order to effectively transfer the compensation energy, the phase difference between the noise source and the compensation current should be as small as possible, preferably in the same phase. The closer the distance, the smaller the phase difference and the more compensation can be transmitted.