Enhanced Jamming Suppression in Colocated MIMO Radar with Fluid Antenna Array

Beyond traditional solid-state antenna, fluid antennas (FAs) exhibit unparalleled reconfigurability, drawing significant interest for applications in wireless communications and radar. This paper presents a design of FA array (FAA) MIMO radar for improved target detection in the presence of jammers, highlighting the advantages of FAA in sensing scenarios. By utilizing flexible positioning of FAAs, we introduce the antenna position vector (APV) as a design variable, in addition to waveforms, aiming to maximize the signal-to-interference plus noise ratio (SINR) with constraints to maintain waveform unimodularity and avoid FA coupling. The formulated nonconvex problem is tackled by an iterative algorithm based on the block majorization-minimization framework. Each iteration involves solving linearly constrained quadratic programming problems for APV optimization and updating the waveforms via a closed-form solution. Simulation results reveal that the designed APV s of the transmit and receiving FAAs can automatically balance angular resolution and ambiguity, which together with the optimized waveform, significantly enhances the SINR through enhanced jamming suppression. This improvement is attributed to increased flexibility across spatial and frequency dimensions facilitated by the FAAs.