Quaternion-Capon beamformer using crossed-dipole arrays

Adaptive beamforming using a crossed-dipole array is addressed in the hypercomplex framework. A new variant of Capon beamformer, called Quaternion-Capon (Q-Capon) beamformer, is herein proposed to fulfill the linearly constrained minimization operation in the quaternion domain. Simulation results show that the Q-Capon beamformer has a better convergence performance than the standard "long-vector" Capon beamformer, and is more robust than the latter to the uncertainty in signal\´s steering vector especially under the scenario of high signal to noise ratio values.