NEC uses a separate method to calculate the contribution of extended planes of material, like a wire mesh reflector. In this case, the plane is considered as a unit and the magnetic contribution is calculated directly and fed back into the calculation once the contributions from the individual wires are considered. Similar integral solutions are used to calculate the effects of the ground plane. Similarly, inductive and capacitive loads, insulated transmission wires above and buried in the ground and other common parts of an extended antenna system are also modeled using simpler numeric methods.