Tightly Coupled Array Design Based on Phase Center Contour for Indoor Direction Findings in Harsh Environments

A new model for accurate direction findings is presented, and the superiority of the proposed model is demonstrated over the existing models for real system requirements. The proposed model is constructed based on the phase center contour of each element in the array. It is also shown that the accuracy of the proposed model will remain for tightly coupled arrays while other models fail. A novel algorithm according to this new model is also proposed. The proposed algorithm is proved by both simulations and measurements to be a viable solution for indoor applications where strong multipath interferences exist in the environment. Furthermore, a detailed explanation of accurate direction finding in harsh environments is presented using ultra-miniaturized tightly coupled arrays. In general, the direction-of-arrival estimation accuracy deteriorates using such miniaturized arrays, whereas we have shown that an excellent estimation accuracy is achieved using the proposed model and the detection algorithm. This statement is substantiated for any environments regardless of the strength of interference. To validate the developed model and theory, several practical prototypes of tightly coupled arrays are fabricated using the typical FR4 printed-circuit-board (PCB) fabrication process. The prototypes are measured in several indoor scenarios at the presence of multipath. The results are studied in detail.