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arXiv · 1911.01033

Ultra-wideband Reflection-type Metasurface for Generating Integer and Fractional Orbital Angular Momentum

Ling-Jun Yang·Sheng Sun·Wei E. I. Sha
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Abstract

Vortex beams carrying orbital angular momentum are extensively studied owing to its potential to expand channel capacity of microwave and optical communication. By utilizing the Pancharatnam-Berry phase concept, an ultra-wideband single layer metasurface is proposed to realize the conversion from incident plane waves to reflected vortex beams covering a considerable bandwidth from 6.75 to 21.85 GHz . An equivalent circuit model combined with broadband phase shift network is developed to effectively design the meta-atoms in metasurface. It is the first time to design wideband metasurfaces with the phase-based characteristics. To verify the proposed model, some deformed square loop meta-atoms are proposed to construct the metasurfaces with broadband OAM characteristic. Moreover, the vortex beams with the integer (l = -3), fractional (l = -1.5), and high-order (l = -10) OAM mode are generated respectively. Based on an OAM spectral analysis, the mode purity of the generated vortex waves is discussed in detail. The experimental results achieve a good agreement with those obtained from the simulation, thus proving the effectiveness and practicability of the proposed method.

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Ling-Jun Yang, Sheng Sun, Wei E. I. Sha. 2019-11-04. Ultra-wideband Reflection-type Metasurface for Generating Integer and Fractional Orbital Angular Momentum. https://doi.org/10.1109/tap.2019.2948711

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