Synthesizing Low-Bandwidth Far-Field Antenna Patterns from High-Bandwidth Near-Field Measurements.

For the characterization of multi-mode Synthetic Aperture Radar (SAR) antenna, Far-field patterns are generated based on Near-Field measurements for each chirp-bandwidth mode, which is a time-intensive process. In this paper, we present a method and its validation for RISAT-1A payload of ISRO to derive low bandwidth mode radiation pattern from high bandwidth near-field measurements. The results confirm that only one measurement in highest bandwidth mode would suffice the complete antenna characterization requirements for different bandwidths.