Scientific REPORTS | (2018) 8:4423 | DOI:10.1038/s41598-018-22163-6
Thermally Tunable Ultra-wideband
Metamaterial Absorbers based on
, Jieqiu Zhang
, Yongqiang Pang
, Lin Zheng
, Jiafu Wang
, Hua Ma
Distilled water has frequency dispersive characteristic and high value of imaginary part in permittivity,
which can be seen as a good candidate of broadband metamaterial absorbers(MAs) in microwave.
Here, an interesting idea based on the combination of water-substrate and metallic metamaterial in
the three-dimensional construction is proposed, which can achieve outstanding broadband absorption.
As a proof, the distilled water is lled into the dielectric reservoir as ultra-thin water-substrate, and
then the water-substrates are arranged on the metal backplane periodically as three-dimensional
water-substrate array(TWA). Simulation shows that the TWA achieves broadband absorption with
the eciency more than 90% from 8.3 to 21.0 GHz. Then, the trigonal metallic shbone structure
is introduced here between the water-substrate and the dielectric reservoir periodically as three-
dimensional water-substrate metamaterial absorber(TWMA). The proposed TWMA could achieve
ultra-broadband absorption from 2.6 to 16.8 GHz, which has increase by 64.8% in relative absorption
bandwidth. Meanwhile, due to the participation of distilled water, the thermally tunable property also
deserves to be discussed here. In view of the outstanding performance, it is worth to expect a wide
range of applications to emerge inspired from the proposed construction.
Metamaterials, stemming from a pursuit of exotic electromagnetic property, have been equipped with more
diversied performances for light modulation, such as electromagnetic wave absorption, abnormal refraction,
and destructive scattering. With the continuous innovation in metamaterials, a lot of well-chosen materials were
introduced here for the construction of new articial media, such as all-dielectric ceramic
, phase-change mate-
, and graphene
. e according metamaterial would achieve more improvement as well as the desired
electromagnetic property, such as high-temperature-tolerance character, thermally switchable property, and elec-
trically recongurable performance.
For the electromagnetic wave absorption, the first MA based on the three-layered construction of
metal-dielectric-metal was proposed in microwave frequency
. e strong resonance inspired by the metal-
lic electric resonator worked together with the suitable loss from Fr4 substrate, which contributed to near per-
fect absorption at a certain frequency. en, with the emerging of metamaterials, single-, dual-, and multi-band
absorbers can be exibly gained
. However, it should be pointed out that the highly eective absorption was
always accompanied with narrow band characteristic, which has always been an obstacle for the application
requirements. To acquire broadband MA, the spatial arrangements of multi-unit with contiguous resonances
were rstly proposed
. e varied MA units can be assembled together not only on the same plane
along incident wave vector
. However, the aforementioned MAs eectively broadened the absorption band-
width at the sacrice of high absorbing eciency, ultra-thin thickness or lightweight characteristic. Meanwhile,
frequency dispersive materials can also be designed as resonators
in MAs, which also con-
tributed to the broadband absorption. However, the fabricated frequency dispersive materials are not easy to meet
the required values of the eective permittivity/permeability.
College of Science, Air Force Engineering University, Xi’an, Shaanxi, 710051, People’s Republic of China.
of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, 710049, People’s Republic of
China. Correspondence and requests for materials should be addressed to Y.S. (email: firstname.lastname@example.org) or S.Q.
Received: 3 October 2017
Accepted: 13 February 2018
Published: xx xx xxxx