Active microwave absorber with the dual-ability of dividable modulation in absorbing intensity and frequency

Metasurfaces are artificially structured thin films with unusual properties on demand. Different from metamaterials, the metasurfaces change the electromagnetic waves mainly by exploiting the boundary conditions, rather than the constitutive parameters in three dimensional (3D) spaces. Despite the intrinsic similarities in the operational principles of metasurfaces, there is not a universal theory available for the understanding and design of these devices. In this article, we propose the concept of metasurface waves (M-waves) and provide a general theory to describe the principles of such waves. Most importantly, it is shown that the M-waves share some fundamental properties such as extremely short wavelength, abrupt phase change and strong chromatic dispersion, which making them different from traditional bulk waves. We show that these properties can enable many important applications such as subwavelength imaging and lithography, planar optical devices, broadband anti-reflection, absorption and polarization conversion. Our results demonstrated unambiguously that traditional laws of diffraction, refraction, reflection and absorption can be overcome by using the novel properties of M-waves. The theory provided here may pave the way for the design of new electromagnetic devices and further improvement of metasurfaces. metasurface, subwavelength structure, diffraction limit, flat lens, perfect absorption PACS number(s): 42.25.Gy, 42.79.Wc, 78.67.Pt, 78.68.+m Citation:

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“…Such critical materials include semiconductors and phase-changing materials, as demonstrated in many recent articles [104][105][106][107].…”

Section: Smart Metasurfacementioning

confidence: 98%

Principles of electromagnetic waves in metasurfaces

Luo

2015

Sci. China Phys. Mech. Astron.

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460

323

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“…Furthermore, most current metadevices are static, and their performance is not reconfigurable once fabricated. Although some techniques such as the incorporation of semiconductors and phase‐change materials could offer some tunability, deeper understanding of the time‐domain response and control strategy is still urgently required. Furthermore, specific design packages should be developed to accelerate the design speed and consider the engineering‐related parameters such as optical aberration, system integration, and environmental adaptability .…”

Section: Conclusion and Outlooksmentioning

confidence: 99%

Subwavelength Optical Engineering with Metasurface Waves

Luo

2018

Advanced Optical Materials

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167

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Figure 3. Plasmonic superlens and hyperlens. a) Plasmonic EYI effect in structured metal film. Adapted with permission. [46] Copyright 2004, American Institute of Physics (AIP). b) Schematic of the optical system for the demonstration of thin film superlens. Adapted with permission. [49] Figure 11. Multifunctional metasurfaces. a) The far-field intensity distribution of wave-fronts with positive (red) and negative (blue) helicities emerging from segmented, interleaved, and harmonic response metasurfaces composed of gap-plasmon nanoantennas (inset). Adapted with permission. [167] Copyright 2016, AAAS. b) Schematic of the generation of a solid and a hollow spot at two wavelengths and the calculated intensity distribution in the focal plane. Adapted with permission. [12]

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“…The MA enjoys the features of light weight and low profile, but suffers from narrow and fixed absorbing frequency bandwidth. [6][7][8] Since MA is realized through artificial design of the unit cell structure, one unique advantage of MA is that more functions than absorbing waves can be combined into MA, such as absorbing frequency tuning, [9][10][11][12] absorbing intensity tuning, 13 polarization independent absorbing, 14-16 multiple band absorbing, [17][18][19][20] wide incident angle absorber. 21,22 Tunable absorbers are particularly useful components in wideband wireless communications systems, including the emerging system of cognitive radio networks and the intelligent radar system.…”

Section: Introductionmentioning

confidence: 99%

A frequency and bandwidth tunable metamaterial absorber in x-band

Yuan

Zhu

Feng

2015

Journal of Applied Physics

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Smart control is an attracting and important function for modern electromagnetic wave absorber. This paper presents the design, fabrication, and measurement of a frequency and bandwidth tunable metamaterial absorber (MA) in X-band. The unit cell of the MA consists of a microstrip resonator loaded with the varactors. Simulation and measurement results show that by tuning the bias voltage on the varactors, the peak absorption frequency can be tuned by 0.44 GHz with the peak absorption greater than 95%. Field and circuit model analysis is conducted to reveal the working mode and predict the absorbing frequency. After that, by specially designing the bias circuit so as to adjust the bias voltage on neighboring unit cells separately, dual resonance and absorption peaks occur, and the overall absorption bandwidth can thus be tuned conveniently by controlling the difference of the two resonance frequencies. The center absorbing frequency can also be tuned. Simulation and experiment results show that the 75% absorption (À6 dB reflection) bandwidth can be tuned from 0.40 GHz to 0.74 GHz, which is a two-fold tuning range. This work is believed to improve the state-of-the-art smart metamaterial absorber. V C 2015 AIP Publishing LLC.

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Active microwave absorber with the dual-ability of dividable modulation in absorbing intensity and frequency

Cited by 42 publications

References 22 publications

Principles of electromagnetic waves in metasurfaces

Principles of electromagnetic waves in metasurfaces

Subwavelength Optical Engineering with Metasurface Waves

A frequency and bandwidth tunable metamaterial absorber in x-band

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