Broadband absorption in mid-infrared metamaterial absorbers with multiple dielectric layers

Kim

et al. 2018

Sci Rep

An integrated model utilizing external parasitic capacitors for a dual-band metamaterial perfect absorber (DMPA) is proposed and demonstrated in the UHF radio band. By adjusting the lumped capacitors on a simple meta-surface, the thickness of absorber is reduced to be only 1/378 and 1/320 with respect to the operating wavelength at 305 and 360.5 MHz, respectively. The simulations and the experiments confirm that the DMPA can maintain an absorption over 91% in a wide range of incident angle (up to 55°) and independent of the polarization of incident radiation. Additionally, we examine the integrated model for smaller dual-band absorber and absorption performance at higher frequencies (LTE band). Finally, we consolidate our approach by fabricating an ultrathin triple-band perfect absorber miniaturized to be only 1/591 of the longest operating wavelength. Our work is expected to contribute to the actualization of metamaterial-based devices working at radio frequency.

Section: Design Results and Discussionmentioning

confidence: 99%

Ultra-subwavelength thickness for dual/triple-band metamaterial absorber at very low frequency

Kim

et al. 2018

Sci Rep

“…3(a) 233233. L 1 and L 2 are the effective inductances of the top quarter of meta-surface and the via interconnect located at each quadrant of the unit cell, respectively.…”

Section: Design Results and Discussionmentioning

confidence: 99%

Miniaturization for ultrathin metamaterial perfect absorber in the VHF band

Yoo

et al. 2017

Sci Rep

An efficient resolution for ultrathin metamaterial perfect absorber (MPA) is proposed and demonstrated in the VHF radio band (30–300 MHz). By adjusting the lumped capacitors and the through vertical interconnects, the absorber is miniaturized to be only λ/816 and λ/84 for its thickness and periodicity with respect to the operating wavelength (at 102 MHz), respectively. The detailed simulation and calculation show that the MPA can maintain an absorption rate over 90% in a certain range of incident angle and with a wide variation of capacitance. Additionally, we utilized the advantages of the initial single-band structure to realize a nearly perfect dual-band absorber in the same range. The results were confirmed by both simulation and experiment at oblique incidence angles up to 50°. Our work is expected to contribute to the actualization of future metamaterial-based devices working at radio frequency.

“…Therefore, the absorption frequency can be quantitatively defined by the equivalent inductor-capacitor (LC) circuit model, which has been reported elsewhere. 35,36 The equivalent circuit of our MPA is presented in Fig. 3(a) (the resistor element is ignored for simplicity in this case).…”

Section: Resultsmentioning

confidence: 99%

Size-efficient metamaterial absorber at low frequencies: Design, fabrication, and characterization

Journal of Applied Physics

Dũng

et al. 2015

Articles you may be interested inA novel ultrathin and broadband microwave metamaterial absorber J. Appl. Phys. 116, 094504 (2014); 10.1063/1.4894824Bandwidth-enhanced polarization-insensitive microwave metamaterial absorber and its equivalent circuit model Integrating non-planar metamaterials with magnetic absorbing materials to yield ultra-broadband microwave hybrid absorbers Appl. Phys. Lett.We numerically and experimentally demonstrated a metamaterial perfect absorber (MPA) in MHz region based on a planar sandwiched metal-dielectric-metal structure. First, the single-peak perfect absorption was obtained at 400 MHz. The ratios of the periodicity of unit cells and the thickness to the absorption wavelength are 1/12 and 1/94, respectively. The advantage of structural design and the mechanism for the low-frequency MPA are described in detail by the comparison between calculation, simulation, and experiment. Influence of the incident angle of electromagnetic (EM) wave for both transverse-electric (TE) and transverse-magnetic (TM) polarization on absorption was also investigated, and the absorption was maintained to be above 95% at incident angles up to 30 . Finally, we propose a self-asymmetric structure, which induces the dual-band perfect absorption in the same range of frequency. The EM behavior of the excitation modes and the mechanism of the dual-band MPA are clearly explained. Especially, when two resonance modes are finely controlled to be close enough, the bandwidth (full width at half maximum) of MPA is enhanced to be nearly wider twice than that in case of single-peak perfect absorption. The enhanced bandwidth is still well preserved by varying the incident angle up to 30 for both TE and TM polarization. The results were also confirmed by both simulation and experiment. Our work is promising for potential practical applications in the radio range, such as radio-frequency shielding devices, single/dualfrequency filters, and switching devices. V C 2015 AIP Publishing LLC.