Radar-infrared Bi-stealth Vortex Beam Generator Using Hybrid Metasurface

Multispectral stealth technology has been a research hotspot and is pivotal importance and also challenging due to its ability of avoiding detectors at multiple wavelengths simultaneously. This is especially true for achieving multifunctional devices with both multi-mechanism stealth and sophisticated wavefront control. Among various functions, vortex beams with orbital angular momentum show potential applications in radar detection, imaging, and secure communication. Herein, a transmission vortex beam generator based on bi-stealth hybrid metasurface is presented using a polarization-selective metasurface, combined with an infrared (IR) camouflage layer and a microwave absorbing layer. Such a metadevice is designed to generate vortex beam with a topological charge of l = +1 along +z direction by cascading three super-thin flexible printed circuit boards and two 3D-printing substrates. Meanwhile, radar cross section is effectively reduced in both x- and y-polarizations within 8 ∼ 18GHz when electromagnetic wave is incident along −z direction. Moreover, our designed hybrid metasurface shows low emission performance in IR band (3 ∼ 14µm) due to the high filling ratio of ITO square films on top layer. To validate the effectiveness of our strategy, a proof-of-concept prototype is simulated, fabricated, and measured. Numerical and experimental results coincide well, and both validate desired functions and exhibit high efficiency. Our proposed methodology provides a solid platform for integration of multifunctions and multispectral stealth.