High resolution millimetre wave measurement radars for ground based SAR and ISAR imaging

An experimental radar operating simultaneously at 10 GHz, 35 GHz, 94 GHz and 220 GHz has been developed, which is capable to deliver an instantaneous bandwidth of 4000 MHz at the lower frequency bands and 8000 MHz at 220 GHz. The radar is of FM-CW type and uses a chirp modulation. Two types of application have been envisaged, both to determine the scattering centre distributions of targets, one using a tower-turntable ISAR and the other a ground based SAR approach. For the first method data are sampled over a full turn of 360deg, for the second approach only a limited aspect angle section can be evaluated. The paper describes the radar set-up and the evaluation algorithm and compares typical results for both methods.