Future spaceborne synthetic aperture radar (SAR) instruments for high resolution mapping of the Earth will require dual polarised phased array antennas with large frequency bandwidths and high efficiencies. A novel type of dual polarized microstrip array antenna has been developed for C or X band SAR application. The radiating element is made of two perpendicular grids which gives a reduced surface area and good port to port and cross-polarisation isolation. An array of these elements working at X-band has been manufactured in flight representative suspended technology. The technology is based on thin dielectric layers suspended in air which reduces losses and surface wave coupling.