Field superposition system and method therefor

Wireless communications between a vehicle base station and a transponder are authenticated. Interior and exterior antennas are respectively driven using first driving currents, the interior antenna being separated from the transponder by a portion of a vehicle in which the vehicle base station resides. Separate vector components of the respective fields emitted by the interior and exterior antennas are received and detected at the transponder. Superposition factors are calculated for the interior and exterior antennas based upon the separate vector components. Each of the interior and exterior antennas is concurrently driven using the same phase, respectively using the driving currents multiplied by the superposition factors. Superposed vector components are detected for a superposed signal including signals from both antennas received at the transponder. The transponder is authenticated based on the detected superposed vector components for the superposed signal being within a noise-based range of the sum of the separate vector components for each of the interior and exterior antennas as multiplied respectively by the superposition factors for the interior and exterior antennas.