scholarly journals Demonstration of Thermally Tunable Multi-Band and Ultra-Broadband Metamaterial Absorbers Maintaining High Efficiency during Tuning Process

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5708
Author(s):  
Nanli Mou ◽  
Bing Tang ◽  
Jingzhou Li ◽  
Yaqiang Zhang ◽  
Hongxing Dong ◽  
...  

Metamaterial absorbers (MMAs) with dynamic tuning features have attracted great attention recently, but most realizations to date have suffered from a decay in absorptivity as the working frequency shifts. Here, thermally tunable multi-band and ultra-broadband MMAs based on vanadium dioxide (VO2) are proposed, with nearly no reduction in absorption during the tuning process. Simulations demonstrated that the proposed design can be switched between two independently designable multi-band frequency ranges, with the absorptivity being maintained above 99.8%. Moreover, via designing multiple adjacent absorption spectra, an ultra-broadband switchable MMA that maintains high absorptivity during the tuning process is also demonstrated. Raising the ambient temperature from 298 K to 358 K, the broadband absorptive range shifts from 1.194–2.325 THz to 0.398–1.356 THz, while the absorptivity remains above 90%. This method has potential for THz communication, smart filtering, detecting, imaging, and so forth.

2021 ◽  
Vol 8 ◽  
pp. 4
Author(s):  
Peng Xu ◽  
Wei Xiang Jiang ◽  
Xiao Cai ◽  
Yue Gou ◽  
Tie Jun Cui

In this paper, we propose, design and fabricate a kind of ultrathin and high-efficiency circularly polarization converter based on artificially engineered surfaces in the transmission mode. The converter is composed of double-layer periodic surface structures with cross slots. The top and bottom layers are printed on both sides of the F4B substrate and connected by metallic via holes. The proposed converter can transform the right-handed circularly polarized incident electromagnetic (EM) wave to a left-handed circularly-polarized one with near-unity efficiency in the transmission mode, or vice versa. We explain the conversion mechanism based on numerical simulations and equivalent circuit (EC) theory. The measured result has a good agreement with the simulated one in the working frequency band. Such ultrathin polarization converters can be used in wireless microwave communication, remote sensing, and EM imaging where circularly polarization diversity is needed.


2021 ◽  
Author(s):  
Yuanyuan Jiang ◽  
Man Zhang ◽  
Weihua Wang ◽  
Zhengyong Song

Abstract Utilizing the phase transition characteristic of vanadium dioxide, we present a metamaterial configuration to achieve both reflective and transmissive cross-polarization converters. When vanadium dioxide is metal, the design behaves as a reflective cross-polarization converter. It consists of metallic grating, topas spacer, and vanadium dioxide film. Polarization conversion ratio is more than 90% in the frequency range from 4.80 THz to 13.13 THz. When vanadium dioxide is insulator, the design behaves as a transmissive cross-polarization converter using cascaded metallic gratings with rotation angle . High-efficiency broadband cross-polarization wave conversion is achieved in the frequency band of 0.50-4.75 THz. The effects of oblique incidence on reflective and transmissive modes are studied on polarization conversion. The results tell that cross-polarization conversion is better when incident angle is in the range of -. The designed metamaterial may have a certain inspiration for the research of terahertz multifunctional polarization converter.


Author(s):  
Adamu Y. Iliyasu ◽  
Mohamad Rijal Bin Hamid ◽  
Mohamad Kamal A. Rahim ◽  
Noor Asmawati Samsuri ◽  
Mohd Fairus Bin Mohd Yusoff

2016 ◽  
Vol 30 (11) ◽  
pp. 1650186 ◽  
Author(s):  
Cumali Sabah

The design and characterization of perfect metamaterial absorbers (MAs) based on simple configurations including square- and triangle-shapes, which operate in X-band frequency region are numerically and experimentally investigated. The proposed MAs provide perfect absorption with the polarization angle independency. In X-band waveguide, the absorption rates are 99.69% and 99.97% at the resonance frequencies of 10.57 GHz and 10.93 GHz for the square- and triangle-shaped MAs, respectively. In addition, the same configurations are numerically tested under free space boundary conditions to compare and discuss the obtained results. The suggested MAs enable myriad potential application areas for security and stealth technologies in X-band including wireless communication.


2019 ◽  
Vol 6 (5) ◽  
pp. 055809 ◽  
Author(s):  
Yixin Fan ◽  
Yixian Qian ◽  
Shan Yin ◽  
Dongxia Li ◽  
Mingzhu Jiang ◽  
...  

2008 ◽  
Vol 93 (2) ◽  
pp. 024101 ◽  
Author(s):  
T. Driscoll ◽  
S. Palit ◽  
M. M. Qazilbash ◽  
M. Brehm ◽  
F. Keilmann ◽  
...  

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