Contoured-beam reflectarray for improving angular coverage in DVB-S passive radars

Main advantages of employing DVB-S as Illuminator of Opportunity for passive radar are high availability and possibility of radar imaging. In this article, detection, tracking and radar imaging of ground targets are considered, focussing in the design of surveillance antennas capable of fulfilling the requirements defined by the DVB-S passive radar. High gain antenna is required due to low scattered power from the targets but, simultaneously, a wide azimuth beamwidth is mandatory to generate interesting cross-range resolutions from Inverse Synthetic Aperture Radar images relying on the target translation motion. To tackle this challenge, a dual-feed reflectarray generating two simultaneous overlapping beams, with a common phase center and different pointing directions, is proposed. This solution, by means of the sum-pattern of both beams, improves detection, tracking and radar imaging performances. As an added value, it allows the implementation of monopulse techniques.