A dual-band metasurface array is presented in this paper for electromagnetic (EM) energy harvesting in the Wi-Fi band and Ku band. The array consists of metasurface unit cells, rectifiers, and load resistors. The metasurface units within each column are interconnected to establish two channels of energy delivery, enabling the transmission and aggregation of incident power. At the terminals of two channels, a single series diode rectifier and a voltage doubler rectifier are integrated into them to rectify the energy in the Wi-Fi band and the Ku band, respectively. A 7 × 7 prototype of the metasurface array is fabricated and tested. The measured results in the anechoic chamber show that the RF-to-dc efficiencies of the prototype at 2.4 GHz and 12.6 GHz reach 64% and 55% accordingly, when the available incident power at the surface is 3 dBm and 14 dBm, respectively.
At present, the sensitivity, accuracy, and stability of terahertz band bio-detection sensors still need to be improved. To meet that demand, a terahertz metamaterial bio-detection sensor was designed and fabricated by introducing a quadruple rotational symmetric microstructure, which can generate strong electromagnetic resonance. The sensor interacts with the incident terahertz wave to generate a magnetic dipole resonance, forming a resonant peak with 98.9% absorption at the resonant frequency of 0.4696 THz. When the refractive index of the analyte increased from 1.0 to 2.0, the resonance peak of the sensor obvious red-shifted, and the absorption of the resonance peak almost exceed 99%. Meanwhile, the sensitivity of the sensor can reach 78.6 GHz/RIU (Refractive index unit, RIU), Q (Quality factor, Q) is up to 55.3, and FOM (Figure of merit, FOM) is up to 9.81. In addition, the quadruple rotation structure unit makes the sensor insensitive to wide incidence angles and polarization. The designed sensor has excellent resonance characteristics and can realize the detection and identi cation of biomolecules with different refractive indices. It also provides new ideas for the design of terahertz band bio-detection sensors and has important applications in medical diagnosis and real-time monitoring.
The rapid development of surveillance technology has driven the research of multispectral stealth. Demand for infrared and microwave radar compatible stealth is becoming increasingly urgent in military applications. Herein, a versatile metamaterial absorber is designed and fabricated to simultaneously achieve ultra-broadband radar scattering reduction, low infrared emission, and high optical transparency. The designed structure consists of an infrared stealth layer, radar absorption layers, and backing ground. The infrared stealth layer employs specifically indium tin oxide (ITO) square patches, while the radar absorption layers can be obtained by stacking different size ITO patterned films of the same structure with high surface resistances, realizing broadband microwave stealth performance in the 1.98 to 18.6 GHz frequency range with an incident angle of 45º. The broad radar stealth and low infrared emissivity of 0.283 are consistent with the simulations and calculations. Furthermore, the designed structure exhibits characteristics such as polarization insensitivity, wide incident angles, optical transparency, and flexibility, allowing for a wide range of applications in various environments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.