A dual-band compact L-Quad antenna array for radio localization

This paper presents a dual-band compact antenna array for radio localization. The proposed antenna includes two single-band L-Quad subarrays (1710 - 1785 MHz and 2400 - 2480 MHz), each of them comprises three full-polarimetric antennas arranged in an equilateral triangle. One of the main advantages of the antenna investigated is the feature of having two polarizations. With it, it is possible to eliminate some errors and improve the algorithm for direction finding. The angular field-of-view of the array is approximately ±60°. The radio emitter localization is achieved in terms of Direction of Arrival (DoA) estimation and the figure of merit that this work focuses on is the Cramér-Rao Lower Bound (CRLB). This paper addresses mutual coupling (with the aim of designing compact arrays) via an eigen-analysis in which a modal decomposition is performed and modal radiation efficiencies are computed. Results for the CRLB and the eigen-efficiencies demonstrate the performance of the antenna both in terms of direction finding and mutual coupling. Finally, a comparison is drawn between the six-element dual-band antenna array and a six-element single-band antenna array.