Mutual Coupling
Understanding Mutual Coupling
Mutual coupling modifies each element's input impedance from its isolated value, creating scan-dependent impedance variations in phased arrays. The coupling magnitude depends on element spacing, polarization, and the array environment.
Coupling effects include scan blindness at specific angles, gain reduction, pattern distortion, and impedance mismatch. Array designers must account for mutual coupling in element matching, beamforming weights, and calibration procedures.
Frequently Asked Questions
How does mutual coupling affect array performance?
Mutual coupling changes element impedances with scan angle, distorts radiation patterns, and creates scan blindness at angles where strong surface waves are excited.
How is mutual coupling characterized?
Coupling is measured as S-parameters between array elements (S12, S13, etc.) and is typically specified as coupling coefficient in dB.