Omnidirectional surface wave cloak using an isotropic homogeneous dielectric coating.

Transformation optics has introduced cloaking as a key concept, but achieving free-space cloaking in three dimensions remains challenging due to material constraints. Approximations for fabrication often lead to poor performance. Surface wave systems offer an alternative approach, leveraging surface curvature for simpler solutions. Prior research has shown that cloaking in surface wave systems can be achieved with less complex material requirements. However, a gap remains in demonstrating practical cloaking for surface wave distortions. This paper addresses that gap by exploring a novel cloaking method for surface wave fronts. The study builds on established knowledge of surface wave behavior and refractive index manipulation. No prior work had resolved cloaking for curved surfaces in microwave regimes. This paper introduces a new approach to surface wave cloaking.

The aim of this study is to demonstrate a surface wave cloaking technique that operates in the microwave regime. The specific problem addressed is cloaking a bump on a surface while maintaining wave front integrity. The motivation stems from the limitations of free-space cloaking methods and the potential of surface wave systems. The researchers propose using an isotropic homogeneous dielectric coating to correct wave front distortion. The study seeks to validate the feasibility of this approach through fabrication and testing. The focus is on achieving omnidirectional operation in surface wave cloaking. The researchers aim to provide a practical solution that avoids the complexities of free-space cloaking.

The study employs transformation optics principles to design a surface wave cloak. The approach involves correcting wave front distortion caused by surface curvature. A refractive index profile is calculated to compensate for the bump's effect. The cloak is fabricated using a metallic-backed homogeneous dielectric waveguide. The waveguide's thickness varies to achieve the desired refractive index profile. The design leverages surface curvature to simplify the cloaking mechanism. The method does not require anisotropic or metamaterial components. The fabricated device is tested in the microwave regime to assess performance.

The fabricated surface wave cloak successfully cloaks a bump in the microwave regime. The device exhibits omnidirectional operation across a range of angles. The refractive index profile effectively corrects wave front distortion. The waveguide's thickness variation aligns with the calculated refractive index profile. The device's performance is evaluated using microwave measurements. The results confirm that the cloaking effect is maintained regardless of the incident angle. No significant degradation in wave propagation is observed. The study demonstrates the practicality of the proposed cloaking method.

The authors conclude that the proposed surface wave cloak is a viable solution for cloaking surface irregularities. The device's omnidirectional operation supports its effectiveness in the microwave regime. The use of a homogeneous dielectric coating simplifies fabrication compared to free-space cloaking methods. The refractive index profile successfully compensates for surface curvature effects. The study confirms that the cloaking mechanism works as proposed. The results suggest that surface wave cloaking can be achieved without complex material requirements. The authors propose that this approach could be extended to other surface wave systems. The findings support further exploration of surface wave cloaking techniques.