Field superposition method and system

Abstract

Disclosed is a method of wireless communication between a vehicle base station and a transponder, the method comprising: i) driving first and second antennae on the vehicle by the vehicle base station using first driving currents, the first antenna being separated from the transponder by a portion of a vehicle in which the vehicle base station resides; ii) detecting three separate mutually orthogonal vector components of the respective fields emitted by the first and second antennae and received at the transponder; iii) calculating superposition factors for the first and second antennae based upon the separate vector components; iv) concurrently driving the first and second antennae using the same phase, respectively using the first driving currents multiplied by the calculated superposition factors; v) detecting three mutually orthogonal vector components of a superposed signal including signals from both antennae received at the transponder; vi) determining whether two of the three detected vector components are above a threshold noise level; vii) if fewer than two of the three detected vector components are above the threshold noise level, repeating step iv) with one of the first and second antennae being driven by the first driving current multiplied by the calculated superposition factors and by an adjustment factor; and viii) if two of the three detected vector components are above the threshold noise level, authenticating the transponder in response to the detected superposed vector components being within an error-based range of the sum of the separate vector components for each of the first and second antennae as multiplied respectively by the superposition factors for the first and second antennae.