Improved reactance domain unitary propagator algorithms for electronically steerable parasitic array radiator antennas

In this study, the authors propose four algorithms for directions of arrival (DoAs) estimation of multiple incoming narrowband plane waves onto electronically steerable parasitic array radiator antennas. The constraints on the proposed algorithms are the same as those imposed onto the classic subspace methods allowing superior high-resolution and localisation capabilities even for correlated sources scenarios but with more reduced computations load and processing time than existing schemes. We also demonstrate that estimating the propagator operator through both introduced real-valued orthogonal decompositions techniques not only yields to a faster DoAs estimation with a reduced computational complexity, but also it improves the robustness of the developed algorithms to noise as compared with the classic propagator algorithm. The Cramer-Rao bound on the variance of the estimated DoAs by the proposed algorithms is analysed. The achieved performance by the developed methods is studied and compared with conventional antenna arrays. The simulation results confirm that high-resolution DoAs estimation can be achieved with the developed algorithms and prove the validity of the proposed approach.