Elimination of direction of arrival estimation ambiguities through the use of non-square coupling matrices

The theory presented here can be useful for antenna arrays operating in two or three dimensions or located close to near-field scatterers. Contrary to common belief where near-field scatterers generally degrade the array performance, it is now possible to take full advantage of their electromagnetic interactions with the array to improve performance and gain additional information about incident signals. The methodology can be applied in smart antennas for parameter estimation as well as beamforming where required element weights can be calculated accurately through the use of the non-square coupling matrix.