Adaptive Beamforming with Imperfect Arrays: Pattern Effects and Their Partial Correction

The effects of various types of imperfections on the radiation pattern of adaptive antenna arrays. using the Applebaum and Frost algorithms, are investigated. The imperfections considered are nonuniform noise figures in the channels, gain and phase shift error, IQ Imbalance, DC offset, finite number of samples when forming the covariance matrix, quantization of the signals and the weights and saturation of the signals. In particular the effects on the resulting sidelobe level, null depth, and gain are studied, and simulated results and analytical expressions for the expected pattern parameters are given. The effects of some methods to partly correct for the imperfections are also investigated. A method to obtain low sidelobe pattern when using the Frost algorithm is also discussed.... Adaptive arrays, Digital beamforming, Error effects, Sampling effects, Error corrections