Single-channel multiple baseline interferometer DF with time modulation

This article proposed a direction-of-arrival(DOA) estimation method using multiple baseline phase interferometer in the framework of single channel based on time-modulated array (TMA) theory, which overcomes the problem of amplitude and phase inconsistency and system complexity caused by multiple radio frequency(RF) channels in traditional phase interferometer. The method proposed in this article uses single pole multi throw switch to turn on each antenna unit of multi baseline phase interferometer periodically, and estimate the phase differences, which is generated by multiple groups of baselines, from the harmonic characteristics generated by received signal. This article analyzes the limitations of traditional multi baseline phase interferometer in DOA estimation, and then proposed a method of single channel multi baseline phase measurement base on TMA theory. After that, a four-baseline phase interferometer is designed for simulation combined with the requirements of broadband direction finding(DF) in 2−8 GHz. The result of simulation shows that the DF error can be reduced to lower than 0.1° in the range of 2−8 GHz, which indicates the effectiveness of the proposed method.