Broadband Direction Finding Based on a Three-Element Time-Modulated Array

In this letter, a broadband direction-finding method with a three-element time-modulated array (TMA) is proposed. By combining the differences of baselines, a new phase degree of freedom is introduced to solve the problem of ambiguity caused by the large variation of carrier frequency, which enables the correct estimation of direction within broadband. Furthermore, the mathematical relation between the direction-finding bandwidth and baselines is discussed, which provides the guidance for the design of baselines' distribution to achieve broadband direction finding using TMA within the desired bandwidth. Numerical simulations are provided to demonstrate the validation of the proposed method. A dual-band direction-finding system working at 2.48 and 5 GHz is constructed in the experiment to verify the feasibility of the proposed method.