Wide-band radar front-end calibration for imaging SAR experiments with conformal antenna array

If specifically designed, one of the advantages of conformal antenna arrays is their large field of view (LFOV) which can be significantly larger than the one of planar arrays. This property was successfully exploited in a radar experiment generating SAR images with an array scanning angle of 70°. For that purpose a conformal antenna array was connected to a radar front-end that provided means for wide-band beam scanning. In an iterative off-line calibration process based on repetitive radiation pattern measurements the settings of all antenna channels were determined to generate special array radiation patterns for three specific scanning directions with maximum gain in the transmit and a prescribed side-lobe level in the receive mode. Special care was given to the wide-band stability of the array patterns.