CRLB based mode selection and enhanced DOA estimation for multifunctional reconfigurable arrays

Abstract

Multifunctional reconfigurable antennas (MRA) with dynamically reconfigurable radiation patterns when used in arrays leads to diverse structures with various radiation and polarization patterns. This variety and degree of freedom in selection of modes for each MRA is exploited for enhanced direction of arrival (DOA) estimation. This paper shows that the Cramer Rao Lower Bound (CRLB) for DOA estimation for an MRA array is highly dependent on the reconfigurable modes of each MRA element and proposes a new computationally effective technique for selection of each antenna mode in an array that minimizes the CRLB. Results show that the MRA array with the proposed mode selection has lower CRLB levels compared to uniform pattern arrays or diverse arrays with random mode selections, hence allowing enhanced estimation of the target DOAs. Furthermore, a multiple signal classification (MUSIC) based DOA and polarization estimation technique suitable for MRAA is proposed and it is shown that the minimized CRLB levels can be achieved by the proposed technique. Further analysis on tracking and surveillance shows the advantages of the proposed technique and the MRA array.