A method for calibrating an ESA radar to mitigate degradation of its radiation system. The radiation system includes the distribution manifold, the ESA radiating elements and the radome the ESA may be operating through. Sensing of degradation takes place both locally with a switchable matched load to identify individual ESA element characteristics and globally with target based radar return data. The data generated by this sensing of both local and global characteristics is then used to modify available ESA element complex weighting to produce a desired far-field radiation pattern.