Design of C-Band Low-Profile and Lightweight Spaceborne SAR Antenna

In order to meet the urgent requirement of miniaturized spaceborne SAR Antenna in small-scale satellite platform, a C-band low-profile lightweight waveguide slot array antenna is designed in this paper. The antenna has an overall dimensions of 6m×l.2m, and considering the limited space in satellite platform, the whole array is divided into five identical small arrays which are foldable, and each small array is further divided into ten planar sub arrays. The sub array is comprised of a number of linear waveguide slot antenna arrays where slots are open in the broad side. The connection between the waveguide antenna array and the T/R module is realized by adopting a coaxial vertical transition directly instead of using cables, hence the T/R module, which is the main heat source, can be tightly stick to the metal waveguide antenna, and the antenna itself helps to dissipate most of the heat. What's more, the other RF components including the delayed module, active devices, feeding network, and calibration network are all integrated at the back of the antenna panel, making the antenna system very compact and low profile. The height of the antenna system decreases to 40mm and the density reduces to less than 30kg/m2, which is of significance meaning in spaceborne SAR antenna on small size satellite platform where size and weight are important considerations.