Efficient Mutual-Coupling Aware Fault Diagnosis of Phased Array Antennas Using Optimized Excitations

Antenna fault diagnosis for phased antenna arrays is an important research area since faulty elements deteriorate the expected field pattern, leading to degraded performance in various applications. While several compressive sensing-based techniques have been proposed, they rely on a simplified array factor formula, ignoring mutual coupling effects among antennas. We show that this assumption can lead to poor diagnosis in the presence of significant mutual coupling by using two popular models-the average embedded element pattern and a port-level coupling matrix approach. Also, we optimize the antenna excitations to minimize the mutual coherence of the system measurement matrix, leading to a reduced number of measurements required for fault diagnosis. Our simulation results indicate that accounting for the effect of mutual coupling results in a far more reliable diagnosis. In addition, our framework is executed using a single measurement probe fixed in space, thus making a step toward practical fault diagnosis techniques that can be deployed on antenna array systems.