Broadband Jamming Suppression at Subarray Level for Frequency Diverse Array Antenna

Frequency diverse array (FDA) is a modern and flexible antenna array conception different from the phased array (PA). The FDA utilized a small frequency increment across the antenna elements to achieve a range-dependent beam pattern. Adopting subarray signal processing is one of the critical technologies in new PAs that plays a significant role in clutter and noise jammer suppression. However, it experiences serious performance regression in the case of broadband jamming. This paper proposes a concrete scheme based on FDA subarray signal processing coupled with real-time delay processing to counteract broadband jamming. Therefore, the FDA combines real-time delay processing; the desired target can be distinguished from the clutter and jamming signals at the subarray level. Accordingly, adaptive weights based on space-time finite impulse response (FIR) filter (linearly constrained minimum variance (LCMV) method are applied at all delay outputs of each subarray to achieve optimum performance. The look angle uniquely determines the space steering vector with a different spatial steering vector for each transmitted frequency. The simulation results show that our proposed method is efficient, effective, and practically applicable.