Ferro-nano-carbon split ring resonators a bianisotropic metamaterial in X-band: Constitutive parameters analysis

193

112

As cutting-edge emerging electromagnetic (EM) wave-absorbing materials, the Achilles’ heel of graphenes is vulnerable to oxidation under high temperature and oxygen atmosphere, particularly at temperatures more than 600 °C. Herein, a graphene@Fe3O4/siliconboron carbonitride (SiBCN) nanocomplex with a hierarchical A/B/C structure, in which SiBCN serves as a “shield” to protect graphene@Fe3O4 from undergoing high-temperature oxidation, was designed and tuned by polymer-derived ceramic route. The nanocomplexes are stable even at 1100–1400 °C in either argon or air atmosphere. Their minimum reflection coefficient (RCmin) and effective absorption bandwidth (EAB) are −43.78 dB and 3.4 GHz at ambient temperature, respectively. After oxidation at 600 °C, they exhibit much better EM wave absorption, where the RCmin decreases to −66.21 dB and EAB increases to 3.69 GHz in X-band. At a high temperature of 600 °C, they also possess excellent and promising EW wave absorption, for which EAB is 3.93 GHz, covering 93.6% range of X-band. In comparison to previous works on graphenes, either the EAB or the RCmin of these nanocomplexes is excellent at high-temperature oxidation. This novel nanomaterial technology may shed light on the downstream applications of graphenes in EM-wave-absorbing devices and smart structures worked in harsh environments.

Section: Introductionmentioning

confidence: 99%

Graphene Shield by SiBCN Ceramic: A Promising High-Temperature Electromagnetic Wave-Absorbing Material with Oxidation Resistance

Luo

Tian

et al. 2018

193

112

“…Despite the promises of passive RFID technology, these devices remain fragile to adverse environments and relatively expensive because of the silicon integrated circuit chip used to provide a unique ID. , Alternatively, resonators are chipless devices (ID provided without the assisted integrated circuit chip) and passive and allow for contactless communication. Among resonators, split-ring resonators (SRRs) can be inkjet printed on plastic or paper substrates, converted in high-performance sensing devices, and have the potential to operate wirelessly by integrating an antenna in the device. − Furthermore, gas sensing can be achieved with SRRs by introducing an intermediary material that exhibits dielectric property variation in the presence of specific gases, leading to a change in transmission parameters of the overall circuit and enabling gas detection and identification. , Thus, this technology is promising for the development of low-cost, passive, and robust wireless sensors . Nevertheless, the applicability of wireless sensing platforms necessitate meeting stringent criteria in terms of devices’ sensing performance, temperature operability, response time, and selectivity, while offering small size and low energy consumption.…”

Section: Introductionmentioning

confidence: 49%

Highly Sensitive and Contactless Ammonia Detection Based on Nanocomposites of Phosphate-Functionalized Reduced Graphene Oxide/Polyaniline Immobilized on Microstrip Resonators

Tanguy

Wiltshire

Arjmand

et al. 2020

Ammonia is a key compound in a variety of industrial sectors, including automotive, chemical, and food. Its hazardous effects on the environment and human health require the implementation of proper safety guidelines and monitoring techniques. An attractive approach is to add sensing functionality to low-cost wireless communication devices to allow for the monitoring/mapping of the chemical environment across a large area. This study outlines a highly sensitive contactless ammonia gas sensor with the potential for continuous and wireless mapping of ammonia emissions by integrating an antenna on the device. The devices were fabricated by casting a novel advanced sensing nanocomposite, polyaniline (PANI), and phosphate-functionalized reduced graphene oxide (P-rGO) on split-ring resonators (SRRs). P-rGO incorporation in PANI produced a positive-sensing synergistic effect to multiply the sensing response severalfold to ammonia and dimethylamine gases. Furthermore, we identified that the modification of the semiconductive behavior of the nanosheets, achieved via phosphate functionalization, is the key factor to the positive-sensing synergy observed in the nanocomposites because of the formation of localized heterojunctions. The prepared SRRs exhibited remarkably a low detection limit, ∼1 ppm, to ammonia gas, as well as good stability and selectivity, which paves the path for a novel generation of wireless, chipless, potentially fully printable, and passive sensor platforms.

“…Invisible cloaking is one of the most fascinating advancements in modern electromagnetic research associated with the development of metamaterials and transformation optics (TO). − Besides the high-frequency operation in microwaves or visible light, it is equally essential to investigate similar functions for low-frequency regimes where uncoupled electrical or magnetic counterparts have been explored before. − From the practice, the latter one seems more attractive as a magnetic field has been widely involved in various instrumentations, such as metal probing or nuclear magnetic resonance (NMR) imaging. In the quasi-static approximation, the bilayer cloak consisting of a ferromagnetic (FM)–diamagnetic composite has been mostly adopted to design a magnetic invisible device based on the algorithm of field “scattering” cancellation.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin Conformal Magnetic Invisible Cloak for Irregular Objects

Zhan

Zhou

et al. 2021

Magnetic invisible cloaking has been previously demonstrated but only limited to objects with rotational geometries either in spherical or cylindrical shapes, for which the classic analytical bilayer scheme could be strictly applied to design the hiding coat. In this work, we show that a quasi-static cloaking effect could be achieved for irregular objects, e.g., metals with sharp edges, using a numerical optimization scheme. In the quasi-static limit, it is unambiguously proved that the disturbance of the irregular geometries could be well compensated by the inhomogeneous distribution of the soft ferromagnetic (FM) layer either in permeability values or in shapes under the framework of a bilayer cloak. An FM mesh coat with a constant thickness of 0.5 mm was successfully engineered to meet the specific requirements. Experimentally, good cloaking performance with a field disturbance of less than 0.5% has been achieved for a 2 × 2 × 5 cm3 brass bar in a wide frequency range from ∼10 to 250 kHz. A commercial metal scanner was also applied to verify the practical potential. The general strategy to hide almost arbitrary objects was discussed in the end. In principle, the numerical conformal coat engineered by the composite material proposed here could be broadly extended for objects with various geometries.