Illusion cloaks for complex shaped targets combining characteristic mode with transformation optics

Based on scattering cancellation cloaking technology, we developed an illusion cloaking design mechanism for complex-shaped targets of electrically moderate or large sizes, which was achieved by combining transformation optics with the characteristic mode method. Using the transformation optics theory, the electrical size of an object can be reduced under the premise of an identical electromagnetic scattering pattern. Subsequently, a scattering-regulated shroud for the equivalent electrically small object with the same complex shape is designed using the characteristic mode and discrete dipole approximation methods. Finally, the scattering manipulation layer was transformed into the original target. We also derived a theoretical formula for functional coatings that can be used to produce illusion performances for moderate or large complex-shaped targets. The feasibility and efficiency have been demonstrated by numerical simulations.