1,721,008 research outputs found
Design of an Integrated Rectenna on Multi-layer High-Resistivity Silicon Substrate
No full textThis paper presents the design of a rectenna integrated on silicon, using a multilayer substrate composed of silicon and air. The rectenna is designed to harvest microwave energy at 2.45 GHz. The substrate structure is composed of three layers of high-resistivity silicon (HRSi, εr = 11.7)
where the central layer presents an air cavity obtained through etching process. The chosen feeding structure for the antenna is based on a planar microstrip feeding line while for the rectifier a planar matching network is adopted to allow the maximum power transfer. The adopted rectifier topology is a voltage doubler, consisting of a pair of Skyworks SMS7630-079LF Schottky diodes. The synthetized low-permittivity substrate is compatible with on-chip systems silicon and assure a 84 % radiation efficiency with a maximum gain of 7.76 dBi, for the patch
antenna. The overall efficiency of the rectenna is 45% for a received power level of 7 dBm
Guest Editorial: Special Cluster on Antennas and Metasurfaces for Advanced Wireless Power Transfer
No full textLa edizione speciale della rivista AWPL si è occupata di soluzioni avanzate di antenne e meta-superficie per scopi di trasmissione wireless di pptenz
Compact, Wearable Antennas for Battery-Less Systems Exploiting Fabrics and Magneto-Dielectric Materials
No full textIn this paper we describe some promising solutions to the modern need for wearable, energy-aware, miniaturized wireless systems whose typical envisaged application could be a Body Area Network (BAN). To reach this goal novel materials are adopted, such as fabrics, in place of standard substrates and metallizations, which require a systematic procedure for their electromagnetic characterization. Indeed the design of such sub-systems represents a big issue, since approximate approaches could result in strong deviations from the actual system performance. To face this problem, we demonstrate our design procedure, which is based on the concurrent use of electromagnetic software tools and nonlinear circuit-level techniques, able to simultaneously predict the actual system behavior of an antenna system, consisting of the radiating and of the nonlinear blocks, at the component level. This approach is demonstrated for the design of a fully wearable tri-band rectifying antenna (rectenna) and of a button-shaped electrically-small antenna deploying a novel magneto-dielectric substrate. Simulations are supported by measurements both in terms of antennas port parameters and far-field results
Smart two-dimensional material-based time modulated array for RFID applications
No full textIn this paper, we present an original way to combine two promising technologies: Time-Modulated Arrays (TMAs) and Two-Dimensional (2D) materials. The potentialities of time-modulated arrays are strongly enhanced by the exploitation of 2D-based radiators, in particular molybdenum disulphide (MoS2). The great ON/OFF ratio of MoS2 under the application of low bias voltages (up to 5 V in the case of monolayer material) would allow creating antenna arrays with switching properties, i.e. selecting just few of the array elements to radiate. This would represent a further degree of freedom in beam-forming for wireless engineering applications. The proposed 2D-TMA finds an application in high-frequency RFID technology combined with wireless sensor networks. Throughout the paper, we will show the benefits coming from merging TMAs and 2D materials technology; furthermore, we will provide some experimental results on multi-layer MoS2 characterization and a theoretical prediction of the link budget performance in a RFID link. Both simulation and material measurement results are encouraging, opening the path to further research in high-performance sensing networks that exploit the most innovative results in the domain of materials engineerin
Metal-Insulator Transition in Monolayer M<inf>o</inf>S<inf>2</inf> for Tunable and Reconfigurable Devices
No full textIn this paper, we show the electromagnetic design of a small patch antenna based on a molybdenum disulphide (MoS2) monolayer, with an area of only 22mm2 , that exhibits high radiation efficiency and large tunability in microwaves at 10GHz thanks to a metalinsulator transition (MIT) induced by electrostatic gating. Furthermore, the MIT in MoS2 is used to reconfigure a tunable carbon nanotube-based filter, conferring it different functionalities: low-pass, high-pass and bandpass around 2GHz, while its carbon nanotube varactors allow tuning the cutoff frequency or central frequenc
Metamaterial-Based Wideband Dual Stop-Band Filters for V-Band Radars
No full textThis paper presents a methodology for designing a compact wideband dual stop-band filter by cascading transmission zeros using Electric-LC (ELC) resonators in coplanar waveguide (CPW) technology on a silicon substrate. Traditional filter design often relies on full-wave simulations and optimization processes, which are computationally intensive. Instead, the proposed approach simplifies the design process by numerically characterizing individual ELC resonator pairs and constructing a database of scattering parameters (S matrices) corresponding to different geometrical configurations. By selecting and cascading appropriate S matrix blocks, both the lower and upper stopbands of the filter can be synthesized with significantly reduced simulation time. Experimental validation was performed on a fabricated filter (with a 61-70 GHz passband), showing good agreement with numerical predictions, despite minor discrepancies attributed to loss effects not fully reproduced in the simulation environment
Large-Area Geometric Diodes Based on Asymmetric and Nonlinear Transport in Patterned Graphene
Full text linkThis contribution reports a comprehensive investigation into the development and validation of optimized models for simulating the electronic properties of large-scale graphenebased geometric diodes. Our study incorporates unique features as, for example, a general treatment for the boundary conditions, that include arbitrary impedance constrains for the diode outputterminals. The observed diode-like rectification behavior has its physical origin to be an intrinsic property of in the nonlinear carrier transport partial differential equations with polarity-dependent coefficients in asymmetric geometries. While atomistic methods offer, in principle, high accuracy at the atomic scale, their computational cost renders them impractical for simulating devices with dimensions exceeding a few nanometers. To address this limitation, we have developed an improved drift-diffusion framework that captures the essential physics of charge transport in the non-ballistic limit. Through extensive numerical simulations and new proposed diode topologies, we have investigated the impact of geometric parameters and external bias on the device characteristics. Direct quantitative comparison of independent results, obtained assuming fully coherent and fully diffusive transport in four-terminal diodes, has also been reported. The present model can be effectively used to preliminarily compare different diode geometries and to design/optimize large multi-terminal structures based on graphene
Graphene Monolayer Nanomesh Structures and Their Applications in Electromagnetic Energy Harvesting for Solving the Matching Conundrum of Rectennas
Full text linkIn this paper, we investigate various graphene monolayer nanomesh structures (diodes) formed only by nanoholes, with a diameter of just 20 nm and etched from the graphene layer in different shapes (such as rhombus, bow tie, rectangle, trapezoid, and triangle), and their electrical properties targeting electromagnetic energy harvesting applications. In this respect, the main parameters characterizing any nonlinear device for energy harvesting are extracted from tens of measurements performed on a single chip containing the fabricated diodes. The best nano-perforated graphene structure is the triangle nanomesh structure, which exhibits remarkable performance in terms of its characteristic parameters, e.g., a 420 Ω differential resistance for optimal impedance matching to an antenna, a high responsivity greater than 103 V/W, and a low noise equivalent power of 847 pW/√Hz at 0 V
Harvesting microwave energy using pyroelectricity of nanostructured graphene/zirconium-doped hafnium oxide ferroelectric heterostructures
No full textIn this work, we present the design, atomistic/circuit/electromagnetic simulations, and the experimental results for graphene monolayer/zirconium-doped hafnium oxide (HfZrO) ultra-thin ferroelectric-based field effect transistors fabricated at the wafer scale, regarding the pyroelectricity generation directly from microwave signals, at room temperature and below it, namely at 218 K and at 100 K. The transistors work like energy harvesters, i.e. they collect low-power microwave energy and transform it into DC voltages with a maximum amplitude between 20 and 30 mV. The same devices function as microwave detectors in the band 1-10.4 GHz and at very low input power levels not exceeding 80μW when they are biased by using a drain voltage, with average responsivity values in the range 200-400 mV mW-1
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