Ground clearance (GC) antennas require that copper be removed from all layers on the PCB.  The importance of this requirement becomes evident as the fundamental operation of these antennas is reviewed. On ground (OG) antennas require a removal of copper area only on the top-most layer, allowing pour and placement of components on the underside of the PCB.  In order to allow for greater radiation efficiency, the OG type PIFA must be physically taller to compensate for this benefit.