In this Letter, a transmission–reflection integrated programmable metasurface, which achieves quasi-360° phase coverage in the reflection mode and 1-bit phase coding in the transmission mode, is proposed. The steering manipulation of the zeroth-order Bessel beam is investigated over an angular range of 10°–30° in the reflection space, verifying the reconfigurability of the proposed metasurface. Correspondingly, in the transmission space, beam steering is achieved from −10° to −30°, thereby showcasing full-space scanning capabilities. Both numerical simulations and experimental measurements exhibit good consistency, validating the effectiveness of the designed metasurface. The demonstrated capabilities of the proposed metasurface pave the way for adaptive beamforming, intelligent signal routing, and multifunctional wireless systems that demand full-space wave manipulation.
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 1.98–18.6 GHz frequency range with an incident angle of 45°. 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.
22 January 2024 in Journal of Physics D: Applied Physics
The iterative upgrading of the means of warfare has promoted the development of detection technology, and military activities are increasingly demanding target stealth. In this paper, a multifunctional metamaterial absorber is recommended, which simultaneously realizes the integrated stealth functions of ultra-wideband radar wave absorption, low infrared emission, and optically transparent. The structure is composed of an infrared shield, a radar-absorbing layer, and a reflective layer. Simulation results indicate that the absorption bandwidth in the radar band (1.81–20.4 GHz) is more than 90%, and the infrared emissivity is as low as 0.271 in the IR band (3–14 μm). Moreover, it has the features of flexibility, angle stability (0–45°), polarization insensitivity (0–90°), and so on. Furthermore, the electric field current distribution and equivalent circuit model of the structure are analyzed, and a 180 mm*180 mm sample is built and tested; the results show that the simulated and actual measurements are in agreement, and it is expected that such absorbers will be used in areas such as aircraft.
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.