Modeling radar power and phase antenna patterns and the evaluation of dual-polarization antenna performance [presentation]

Many radars are adopting the simultaneous transmission of horizontal (H) and vertical (V) polarized waves in order to achieve dual polarization measurements. Crosscoupling of the H and V waves can bias the dual polarization measurements (Hubbert et al. 2010a,b). Antenna polarization errors are one cause of such cross-coupling and it is desirable to minimize the antenna polarization errors. One figure of merit for performance of an antenna is ICPR (Integrated Cross-Polarization Ratio) defined as the LDR (Linear Depolarization Ratio) when the radar beam is filled with small spherical scatterers (Chandrasekar and Keeler 1993). Typically, only antenna power patterns are available and the phase patterns are unknown, especially for crosspolar antenna patterns. Thus, the upper bound of ICPR (ICPRub) is evaluated from the antenna power patterns. It is now possible to accurately model the complex antenna patterns if the antenna reflector surface can be measured and the antenna pattern of the feedhorn is known. In this paper the performance of the SPol (NCAR’s S-band polarimetric radar) antenna is evaluated using a GRASP (General Reflector Antenna Software Package) software.