scholarly journals Transparent hybrid anapole metasurfaces with negligible electromagnetic coupling for phase engineering

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexey V. Kuznetsov ◽  
Adrià Canós Valero ◽  
Mikhail Tarkhov ◽  
Vjaceslavs Bobrovs ◽  
Dmitrii Redka ◽  
...  
Keyword(s):  
Electromagnetic Coupling ◽  
Near Field ◽  
New Paradigm ◽  
Dielectric Substrates ◽  
Field Coupling ◽  
Magnetic Components ◽  
Wavefront Shaping ◽  
The Individual ◽  
Magnetic Resonances ◽  
Phase Engineering

Abstract All-dielectric nanophotonics has become one of the most active fields of research in modern optics, largely due to the opportunities offered by the simultaneous resonant control of electric and magnetic components of light at the nanoscale. In this rapidly evolving scenario, the possibility to design artificial Huygens sources by overlapping electric and magnetic resonances has established a new paradigm in flat optics, bringing devices closer to efficient wavefront shaping with direct phase engineering at the level of the individual meta-atoms. However, their efficiency is fundamentally limited by the near-field coupling between the constituents of the metalattice. In this work, we challenge this well-conceived notion and propose an alternative concept to achieve phase control and full transmission in metasurfaces, based on the unusual properties of the nonradiating sources known as hybrid anapoles (HAs). We analyze theoretically an array of such sources and demonstrate that HAs are characterized by negligible coupling with their neighbors. Therefore, in contrast to Huygens particles, the proposed sources can operate as individual meta-atoms even in highly compact designs, becoming robust against strong disorder and preserving its characteristics when deposited on dielectric substrates. Remarkably, the phase of the transmitted wave can be modulated with negligible reflection. To illustrate the capabilities of our platform, we also utilize a disordered HA array to implement a controlled phase modulation to an ultrafast Gaussian pulse. The results of our study represent a departure from the currently established designs and open an avenue toward the realization of new devices for flat optics with unprecedented efficiency.

Influence of High-Frequency Near-Field Coupling Between Magnetic Components on EMI Filter Design

2013 ◽  
Vol 28 (10) ◽  
pp. 4568-4579 ◽  
Author(s):  
Ruxi Wang ◽  
Handy Fortin Blanchette ◽  
Mingkai Mu ◽  
Dushan Boroyevich ◽  
Paolo Mattavelli
Keyword(s):  
High Frequency ◽  
Filter Design ◽  
Near Field ◽  
Field Coupling ◽  
Magnetic Components ◽  
Emi Filter

scholarly journals Vibrational coupling in plasmonic molecules

2017 ◽  
Vol 114 (44) ◽  
pp. 11621-11626 ◽  
Author(s):  
Chongyue Yi ◽  
Pratiksha D. Dongare ◽  
Man-Nung Su ◽  
Wenxiao Wang ◽  
Debadi Chakraborty ◽  
...  
Keyword(s):  
Near Field ◽  
Optical Control ◽  
Vibrational Modes ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Vibrational Coupling ◽  
Field Coupling ◽  
Plasmon Hybridization Theory ◽  
Low Energies ◽  
The Individual

Plasmon hybridization theory, inspired by molecular orbital theory, has been extremely successful in describing the near-field coupling in clusters of plasmonic nanoparticles, also known as plasmonic molecules. However, the vibrational modes of plasmonic molecules have been virtually unexplored. By designing precisely configured plasmonic molecules of varying complexity and probing them at the individual plasmonic molecule level, intramolecular coupling of acoustic modes, mediated by the underlying substrate, is observed. The strength of this coupling can be manipulated through the configuration of the plasmonic molecules. Surprisingly, classical continuum elastic theory fails to account for the experimental trends, which are well described by a simple coupled oscillator picture that assumes the vibrational coupling is mediated by coherent phonons with low energies. These findings provide a route to the systematic optical control of the gigahertz response of metallic nanostructures, opening the door to new optomechanical device strategies.

scholarly journals Design of Multi Standard Near Field Communication Outphasing Transmitter with Modulation Wave Shaping

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 188
Author(s):  
Žiga Korošak ◽  
Nejc Suhadolnik ◽  
Anton Pleteršek
Keyword(s):  
Radio Frequency Identification ◽  
High Efficiency ◽  
Near Field ◽  
Cmos Technology ◽  
Near Field Communication ◽  
Differential Delay ◽  
Fully Differential ◽  
Delay Locked Loop ◽  
Modulation Wave ◽  
The Individual

The aim of this work is to tackle the problem of modulation wave shaping in the field of near field communication (NFC) radio frequency identification (RFID). For this purpose, a high-efficiency transmitter circuit was developed to comply with the strict requirements of the newest EMVCo and NFC Forum specifications for pulse shapes. The proposed circuit uses an outphasing modulator that is based on a digital-to-time converter (DTC). The DTC based outphasing modulator supports amplitude shift keying (ASK) modulation, operates at four times the 13.56 MHz carrier frequency and is made fully differential in order to remove the parasitic phase modulation components. The accompanying transmitter logic includes lookup tables with programmable modulation pulse wave shapes. The modulator solution uses a 64-cell tapped current controlled fully differential delay locked loop (DLL), which produces a 360° delay at 54.24 MHz, and a glitch-free multiplexor to select the individual taps. The outphased output from the modulator is mixed to create an RF pulse width modulated (PWM) output, which drives the antenna. Additionally, this implementation is fully compatible with D-class amplifiers enabling high efficiency. A test circuit of the proposed differential multi-standard reader’s transmitter was simulated in 40 nm CMOS technology. Stricter pulse shape requirements were easily satisfied, while achieving an output linearity of 0.2 bits and maximum power consumption under 7.5 mW.

scholarly journals A theoretical and numerical approach for selecting miniaturized antenna topologies on magneto-dielectric substrates

2015 ◽  
Vol 7 (3-4) ◽  
pp. 369-377 ◽  
Author(s):  
Alex Pacini ◽  
Alessandra Costanzo ◽  
Diego Masotti
Keyword(s):  
Near Field ◽  
Dielectric Materials ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Microwave Range ◽  
Dielectric Substrates ◽  
Full Wave ◽  
Miniaturized Antenna ◽  
Wavelength Radiation ◽  
Definition Of

An increasing interest is arising in developing miniaturized antennas in the microwave range. However, even when the adopted antennas dimensions are small compared with the wavelength, radiation performances have to be preserved to keep the system-operating conditions. For this purpose, magneto-dielectric materials are currently exploited as promising substrates, which allows us to reduce antenna dimensions by exploiting both relative permittivity and permeability. In this paper, we address generic antennas in resonant conditions and we develop a general theoretical approach, not based on simplified equivalent models, to establish topologies most suitable for exploiting high permeability and/or high-permittivity substrates, for miniaturization purposes. A novel definition of the region pertaining to the antenna near-field and of the associated field strength is proposed. It is then showed that radiation efficiency and bandwidth can be preserved only by a selected combinations of antenna topologies and substrate characteristics. Indeed, by the proposed independent approach, we confirm that non-dispersive magneto-dielectric materials with relative permeability greater than unit, can be efficiently adopted only by antennas that are mainly represented by equivalent magnetic sources. Conversely, if equivalent electric sources are involved, the antenna performances are significantly degraded. The theoretical results are validated by full-wave numerical simulations of reference topologies.

scholarly journals Transnational sustainability certification for the bioeconomy? Patterns and discourse coalitions of resistance and alternatives in biomass exporting regions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas Vogelpohl
Keyword(s):  
Empirical Studies ◽  
General Pattern ◽  
New Paradigm ◽  
Public And Private ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Political Economies ◽  
The Individual ◽  
Sustainability Standards ◽  
Discourse Coalitions

AbstractThe bioeconomy is nowadays widely proclaimed by governments and corporations around the world as a new paradigm for a sustainable economy. Essentially, it broadly denotes the promotion, development and establishment of the use of biogenic resources in diverse kinds of industrial technologies, production processes and products. Yet, in order for the bioeconomy to be sustainable, it has to be assured that these biogenic resources are sourced sustainably. In the last 30 years, transnational sustainability certification (TSC) has established itself as a popular instrument in this context, for example in the case of European biofuels sustainability regulation. In the last decade or so, however, TSC initiatives in several biomass production sectors like palm oil, soy, fruits, aquaculture or fisheries—mostly initiated by non-governmental organizations (NGOs) and corporations from the Global North—are increasingly met with resistance from actors from the resource-producing countries, mostly located in the Global South. Issues brought up in this context concern their lack of legitimacy and respect for national regulatory sovereignty and conflicting priorities in terms of sustainable development. Consequently, governmental and corporate actors from the resource-producing countries have developed sustainability standards that now at least partly compete with TSC. Against this background, this contribution investigates this apparent dilemma of biomass certification by taking stock of existing TSC initiatives and territorial responses to them in several sectors of the bioeconomy in order to discover general patterns and dynamics of transnational biomass sustainability certification. This analysis is based on a review of existing empirical studies on these issues as well as on conceptual literature on discourse coalitions and transnational hybrid governance for the classification of the different aspects and developments in the individual sectors. Results show that TSC is indeed challenged in all sectors around story lines of sovereignty and sustainability, employed by closely associated state and industry actors in the specific context of the prevalent state-industry relations and the practices and institutions of the respective international political economies. Beyond this general pattern, these alternative systems take on different shapes and complex relations between transnational and territorial sustainability governance emerge that are not always antagonistic, but also exist in parallel or even complementarily and involve various hybrid configurations of public and private actors. Overall, this casts some doubt on the potential of TSC as an instrument to safeguard the sustainability of the bioeconomy and shows one of its potential pitfalls, which is reflected upon in the conclusion.

Reconstruct the PWM Signal of Switching Power Supplies from the Near Field Radiation

2013 ◽  
Vol 718-720 ◽  
pp. 1792-1796
Author(s):  
Zhong Qun Li ◽  
Kai Xie ◽  
Ying Hao Ye ◽  
Rong Bin Guo ◽  
Xu Fei Wang
Keyword(s):  
Pulse Width Modulation ◽  
Signal Reconstruction ◽  
Near Field ◽  
Buck Converter ◽  
Power Supplies ◽  
Switching Converters ◽  
Switching Power ◽  
Magnetic Components ◽  
Field Radiation ◽  
Switching Power Supplies

A non-contact testing method is proposed for encapsulation treated or insulation coated switching power supplies, which is implemented by reconstructing the pulse width modulation (PWM) signal of switching converters from the near field radiation of magnetic components. The radiation pattern of a buck converter is investigated, and the magnetic field sensing probe and PWM signal reconstruction circuit are also illustrated. The reconstruction testing is carried out on a buck converter; the duty cycle error of the reconstructed PWM signal is less than 0.2%, which validates the proposed method.

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