Design and Optimization of Sparse Planar Antenna Arrays for Wireless 3-D Local Positioning Systems

In this paper the design and measurement verification of optimized planar sparse arrays for use in wireless localization applications are presented. Existing literature on array optimization has mainly been concerned with arrays intended for imaging applications. As the array requirements for 3-D localization in multipath environments are essentially different, we made an analysis of the array parameters important for this specific application. The set of challenging practically relevant requirements for the optimization of the planar array layout was defined, including a restriction to a small number of antennas and minimal interelement distance bigger than $\lambda /2$ . An adapted multi-objective particle swarm optimization stochastic algorithm was employed to optimize array for the robust and precise direction of arrival of a single source inside a wide angular scan range up to ±60° in azimuth and elevation planes. Two optimized receive arrays consisting of eight patches were manufactured and measured to present the trade-off achieved under the desired requirements. The effects of optimized array parameters on the performance of 3-D positioning are validated by angle measurements in an anechoic chamber and different indoor scenarios.