Effects of Antenna Radiation Pattern on Airborne SAR Imaging with Sufficient Cyclic Prefix-OFDM
Gaurav Sharma, Arockia Bazil Raj
Abstract
In this paper, we investigate effects of elevation radiation pattern of antenna on the performance of Cyclic Prefix (CP)-orthogonal frequency-division multiplexing (OFDM) based airborne synthetic aperture radar (SAR). It is known that, Inter range cell interference (IRCI)-free SAR imaging is achieved by adding sufficient CP in transmitted OFDM block i.e. the added CP is greater than or equal to the range swath formed by antenna beam in elevation. The receiver of a typical airborne SAR has a dynamic range of 40-50dB so, the targets illuminated by sidelobes of antenna in elevation will also, be processed as targets and form an extended swath resulting into insufficiency of CP. In this paper, we show that for system level implementation, antenna will have a severe impact on imaging of CP-OFDM based airborne SAR. Lastly, simulation results validate that system implemented with a parabolic antenna gives acceptable result for IRCI-free SAR imaging.