# How does a capacitor behave if the voltage potential at the top plate is different at each point?

Let's say we have two large, square parallel copper planes separated by a dialectric.

Then let's say that there is an AC current running between two opposite ends of the top plane and the bottom plane is connected to ground.

Since the voltage potential is different at each unit of space within the top plane, how does this affect the effective capacitance and more importantly, the signal current of the capacitive coupling? The voltage potential across the top plane will increase/decrease as it moves along the plane.

• Capacitance is not a function of the applied voltage but of the geometry of the configuration, i.e. only on the distance between the plates, the area of the plates and the dielectric constant of the insulator. Commented Jan 30, 2022 at 13:02
• So the signal current at the bottom plane will be the same as if the top plane had a constant voltage cross it? Commented Jan 30, 2022 at 13:10