Detection of a radar signal reflected from a phase-modulated surface

The conditions under which a target, protected by a phase-modulated surface, might be detected by a radar system are reviewed and it is shown that fairly minor modifications to the radar receiver front end can lead to detection when simple switching strategies are employed. More complex switching strategies based on pseudo-random binary codes are then reviewed and examples of efficacious codes are given. Even though designed with simple pulse radar systems in mind, these codes are shown to be equally effective in shielding a target from other types of radar system.