DUAL-FREQUENCY AND DUAL-POLARIZATION MICROSTRIP ANTENNAS FOR SAR APPLICATIONS

This paper discusses various methods of implementing a shared-aperture dual-frequency dual-polarized array antenna for spaced-based syntheti c aperture radar (SAR) applications, After evaluating the use of sever al potential array architecture concepts and radiating elements, a des ign using interlaced C-band microstrip patches and X-band printed slot elements was chosen as the best choice for the present system require ments. Layout considerations far the two arrays and their associated f eed networks are addressed in terms of a practical design. A dual-freq uency (C- and X-band), dual-linear polarized SAR array antenna prototy pe was designed, fabricated, and tested. The principal goal of this ef fort was to demonstrate the viability of the dual-hand dual-polarized array concept, and this has been accomplished. Test results are shown with good correlation between measured and predicted results, validati ng the design approach used. This work demonstrates that a dual-freque ncy dual-polarization SAR antenna within a single aperture is a feasib le approach to meeting user requirements in future SAR spacecraft.