Sparse Nested Arrays With Spatially Spread Orthogonal Dipoles: High Accuracy Passive Direction Finding With Less Mutual Coupling

In sensor array processing, the minimum sensor/element-spacing is usually restricted within a half-wavelength in order to avoid estimation aliasing. This would cause sensor/element mutual coupling when antenna-electromagnetics are considered. Based on the recently proposed nested array (NA) concept, we present a new type of NA called sparse nested spatially spread orthogonal dipole array (SNODA) to realize underdetermined direction finding with less mutual coupling. In SNODA, the sensor/element-spacing can be extended to be much higher than a half-wavelength so that the effect of sensor coupling will be much reduced. The direction estimation ambiguities caused by aperture extension is resolved by combining both spatial and element responses of spread orthogonal dipoles. Matlab code for reproduction of the results is available at https://github.com/jinhesjtu/SNODA-DF.git.