Unfurlable reflector SAR antenna at P-band

Array-fed unfurlable reflector antennas in the 12 m class can be can be a viable alternative to large direct radiating arrays, for low frequency SAR applications. In this paper several architectural solutions for a P-band (435 MHz) SAR antenna relying on the current technology of a 12 m EQM reflector developed within a previous ESA program, are described. The proposed illumination system is based on a patch array where a doublet in stripline technology is employed as building brick. It has the capability to cancel the high cross-polar level generated by the offset reflector geometry at reduced F/D (~0.5), through a suitable simple integrated network. This feature is of primarily importance to the dual linear polarization SAR functionality in full polarimetry imaging. The complete feed array ranges from two to four such doublets allowing providing a lot of flexibility in SAR operative modes.