Microstrip antennas for SAR applications

This paper discusses various methods of implementing a shared-aperture dual-frequency dual-polarized array antenna for spaced-based synthetic aperture radar (SAR) applications. After evaluating the use of several potential array architecture concepts and radiating elements, a design using interlaced C-band microstrip patches and X-band printed slot elements was chosen as the best choice for the present system requirements. Layout considerations for the two arrays and their associated feed networks are addressed in terms of a practical design. A dual-frequency (C- and X-band), dual-linear polarized SAR array antenna prototype was designed, fabricated, and tested. The principal goal of this effort was to demonstrate the viability of the dual-band dual-polarized array concept, and this has been accomplished. Test results are shown with good correlation between measured and predicted results, validating the design approach used. This work demonstrates that a dual-frequency dual-polarization SAR antenna within a single aperture is a feasible approach to meeting user requirements in future SAR spacecraft