Cross-Pol Pattern Effects of Parabolic Reflector Antennas on the Performance of Spaceborne Quad-Pol SAR Systems

Abstract

The ambiguity performance related to the image quality of a synthetic aperture radar (SAR) system can be categorized into range ambiguity, azimuth ambiguity, and cross ambiguity depending on the cause of the ambiguity signals. The ambiguity performance is affected by the operational method and antenna radiation patterns of an SAR system. In this paper, the effect of the antenna cross-polarization (cross-pol) pattern on the ambiguity performance of a spaceborne quadrature polarimetric (quad-pol) SAR system using an X-band reflector antenna was analyzed. Two methods, conventional quad-pol SAR and hybrid quad-pol SAR systems, have been proposed as quad-pol SAR operational concepts for system performance analysis. We proposed a process to effectively analyze the effect of the antenna cross-pol pattern and showed this through a comparison of several analysis methods. In addition, the difference in antenna radiation patterns according to the size and structure of reflector antennas was compared, and the effects were described in detail. In conclusion, the larger the antenna and the more complex the structure, the greater the effect of the antenna cross-pol pattern, leading to a similar phenomenon as the two quad-pol SAR systems.