Calibration techniques for very large arrays

Phased array antenna systems are growing in use within military systems. These arrays of thousands of elements need precise control of the aperture distributions to meet requirements for gain, sidelobes, etc. Errors in these phase and amplitude distributions over time will degrade the performance of these apertures. FIRST RF favors simple concepts with little or no hardware impact that fully characterize the entire phased array system. These methods make maximum use of existing hardware, and allow background calibration tasks to be run during normal operation. Accurate, unobtrusive methods for continuous calibration of large phased arrays produce savings during fabrication by relaxing the tight requirements on mounting structures and temperature stable RF components. In some field environments where the full array is assembled for the first time on site, factory calibration is not practical, and these approaches offer accurate means for system verification. FIRST RF proposes a set of novel calibration methods that are unobtrusive to system architecture and operations, while providing accurate, fast, and continuous calibration of the phased array in the field. The proposed concepts will find application in commercial markets like automotive and aerospace through the cost benefits of life-cycle calibration that operates from fabrication through replacement.