A wideband waveguide slot array antenna element for high-resolution SAR application

For the synthetic aperture radar (SAR) systems, there is an increasing demand for achieving resolutions of 0.2 m times 0.2 m. As the range resolution and system bandwidth are inversely proportional, the system bandwidth are expected to be larger than 1 GHz. Thus an antenna with wider band must be developed. Waveguide slot antenna has been implemented on several SAR satellites due to its inherent advantages such as high efficiency and power handling capacity, but its bandwidth is limited. To avoid the manufacture difficulties of the ridge waveguide, which can be used to broaden the bandwidth of the slot antenna, a novel antenna element with conventional waveguide is designed, fabricated and tested. The bandwidth of VSWR les1.5 is greater than 1 GHz at X- band, which can meet the specifications of the system. The radiation pattern and gain agree well with the simulated results.