Active Cloaking of a Non-Uniform Scatterer.

Area of Science:

• Electromagnetic theory
• Metamaterials and cloaking technology
• Antenna arrays and wave manipulation

Background:

• Active cloaking utilizes radiating sources to cancel electromagnetic scattering, offering potential advantages over passive methods.
• Experimental validation for active cloaking complex geometries remains limited, hindering practical applications.
• Existing research primarily focuses on simple uniform scatterers, leaving complex targets unaddressed.

Purpose of the Study:

• To design and experimentally demonstrate a low-profile, active cloak for complex, metallic, polygonal targets.
• To validate the feasibility of active cloaking for objects with flat surfaces and edges.
• To assess the performance and bandwidth of the developed active cloak.

Main Methods:

• A surface conformal array of monopoles was employed as radiating sources.
• A parallel-plate waveguide apparatus was used to create a quasi-2D environment for experiments.
• The cloak's performance was evaluated by measuring the reduction in scattering cross-section under frontal and oblique incidence of a 1.2 GHz cylindrical wave.

Main Results:

• The active cloak reduced the target's scattering cross-section by an average of 7.2 dB at frontal incidence and 8.6 dB at oblique incidence.
• The cloak demonstrated a functional bandwidth of 14% and reconfigurability for single-frequency operation from 0.8-1.8 GHz.
• Experimental results confirm the feasibility of active cloaking for complex scatterers with flat surfaces and edges.

Conclusions:

• The study successfully demonstrated the practical application of active cloaking for complex geometries.
• The developed active cloak offers significant scattering reduction and operational flexibility.
• This work paves the way for advanced cloaking applications in real-world scenarios.