Cognitive Techniques for a Wideband Phased Array Radar

The need for ultra wideband phased array radar is growing in the areas of ground, naval and avionic radar systems. However, the design of a multifunction radar system creates new needs for frequency allocations to radiolocation services. This is in contrast with the growth of activities in the area of civil communications, which aim to threaten the availability of frequency spectrum for multifunction radar systems. One promising solution for the design of a cognitive radar operating in spectrally dense environments is to adopt frequency notching at the frequency channels occupied by the primary user of the network by modifying the instantaneous phase of the radar pulse. The scope of this paper is to evaluate the impact of the phase modulation of the cognitive frequency notching technique on the beamforming performance. The performance is evaluated considering the phase misalignment introduced by the notching technique in a phased array architecture based on a modern wideband tiled antenna concept.