Polarization sensitive PARAFAC beamforming for near-field/far-field signals using co-centered orthogonal loop and dipole pairs

A parallel factor analysis (PARAFAC) based beamformer using a polarization sensitive array of co-centered orthogonal loop and dipole (COLD) vector antennas is proposed for near-field or far-field source signals. While joint suppression of the interferences in the direction, polarization, and range domains is achieved, the beamformer needs only one of the following source knowledge (maybe inaccurate) about signal of interest (SOI): direction, polarization, and range. The beamformer is robust to the error in the sample estimates of SOI steering vector and array covariance matrix via eigenvalue smoothing regularization. A minimum mean squared error criterion for choosing adaptively the regularization factor in eigenvalue smoothing is also presented for noncircular SOI. Simulation results are included to illustrate the performance of the proposed beamformer.