Antenna size versus sea clutter rejection: A new analysis of coastal radar performances and optimization

In the field of coastal surveillance radar, and more generally in maritime environment, the overall radar performance for the detection and tracking of small target is primarily linked to the capability of the radar to reject the sea clutter. Sea clutter is the radar signal return of the sea surface illuminated by RF waves and can often be a strong as the target radar return. A conventional method to counter sea clutter is to use very large antennas providing high angular resolution trying to optimize the signal to clutter ratio in the radar processing by defining the smallest possible illuminated cell of sea surface. This paper provides an in depth analysis of the pro and cons of large slotted waveguides antennas and shows that bigger is not better : Parasitic effects, correlated to antenna dimensions, in the beam forming process of big antennas tends to degrade the antenna performance and leads to the conclusion that the optimal antenna size is often smaller than the one currently used on existing coastal surveillance radars.