Mutual coupling compensation in direction-of-arrival estimation with a linear dipole array

Abstract

Summary form only given. Direction-of-arrival (DOA) estimation is an important feature of smart antenna arrays. Several algorithms have been proposed for DOA estimation, including multiple signal classification (MUSIC), root-MUSIC, estimation of signal parameters via rotational invariance techniques (ESPRIT), matrix pencil (MP), and discrete Fourier transform (DFT)-based methods. These signal processing algorithms have been shown to provide accurate estimates, even under moderate signal-to-noise (SNR) conditions. However, these algorithms generally ignore the mutual coupling among elements of the receiving antenna array. In practice, the elements of the array scatter the incident field to cause mutual coupling, which will compromise the accuracy of these algorithms. Many approaches have been proposed to characterize and compensate for the mutual coupling effect in antenna arrays. For example, the concept of mutual impedance has been used to derive the open-circuit voltages from the received voltages. The open-circuit voltages are claimed to compensate for most of the mutual coupling effects. A MoM-based technique is also proposed and proves effective in suppressing the mutual coupling effects. In this work, the reciprocity theorem is applied to derive a relation between the open-circuit voltages and the receiving voltages, the latter include the mutual coupling effects. MoM techqnique is applied to derive a matrix which relates these two sets of voltages. The proposed decoupling method proves to be able to cancel the mutual coupling effects completely. The ESPRIT algorithm is then use to estimate the DOA's of multiple incident signals. The resolution of incident angle is studied with the proposed method, and other decoupling methods are also used to compare the effectiveness of decoupling on improving the angular resolution.