To help illustrate the critical requirement for the on-ground (OG) antenna design to be physically taller, the electric field (E) simulated here shows most of the current energy is on the top of the antenna itself with very little of the energy forced onto the ground plane itself. The strongest field occurs across the top of the element itself. Since the ground return path is through the board, the effective distance from the underside of the antenna to the next ground layer will have the largest impact on the center frequency tuning of this antenna. It is for this reason all ground layers must be cleared out until the final ground pour on the bottom of the antenna.