Superresolution effects in broadband antenna arrays

The problem of finding the angular 3-dB beamwidth for a wideband Griffiths-Jim adaptive beamformer is discussed. Approximate analytic expressions are presented and their relation to the Cramer-Rao bound (CRB) is considered. Results on the CRB in direction of arrival estimation for a sinusoidal signal are extended to narrowband and broadband signals, together with simple interpretations of their behavior. Superresolution results with a five-element array for three target signal bandwidths (400-2000, 800-1600, and 1120-1280 Hz) are presented.<
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