scholarly journals Listening to NFC at higher harmonic frequencies

Radiotekhnika ◽  
2021 ◽  
pp. 99-104
Author(s):  
V.G. Kryzhanovskyi ◽  
S.P. Serhiienko ◽  
D.V. Chernov ◽  
V.V. Kryzhanovsky
Keyword(s):  
Information Exchange ◽  
Electromagnetic Waves ◽  
Near Field ◽  
Harmonic Signal ◽  
Field Zone ◽  
Third Harmonic ◽  
The Third ◽  
Narrow Bandwidth ◽  
Simulation And Experiment ◽  
High Level

The widespread use of the NFC technology (Near Field Communication) arouses interest to various security aspects. There are known examples of information exchange with card at a distance greater than standard 5-10 cm. It is also interesting to use signals of higher harmonics, which potentially may be radiated in the form of electromagnetic waves, rather than exists as a magnetic field of scattering. In this work, the radiation of third harmonic by card of standard ISO 14443-3А with the fundamental frequency 13.56 MHZ for various excitation modes using the RFID-RC522 reader, smartphone Sony Xperia Z5 Premium, and continuous 10% amplitude modulated 13.56 MHz signal from generator with the subcarrier of imitated smart card response 847.5 kHz was investigated. The card response at third harmonic was simulated in circuit analysis software. Both simulation and experiment proved, that the third harmonic with its side frequencies 40,68 ± 0,8475 MHz have the highest level after the fundamental. To receive the third harmonic signal, the resonant loop antenna in the form of ring vibrator loaded on capacitor was used. This allows the sizes of the received system to be reduced, but the problem of complex field structure in the near-field zone remains. Due to narrow bandwidth of the receiver antenna, the registration of card response signal was complicated. The experiments with three methods of signal generation proved, that third-harmonic signal is registered at the distance more than 1.5m, which may pose a threat for contactless smart-cards transactions security. At the same time, the influence of high level of noise at such a distance may cause difficulties to decode the short-duration signals, which requires further study.

Nonlinear Optics of Linear Conjugated Polymers

1992 ◽  
Vol 247 ◽  
Author(s):  
D. Guo ◽  
S. Mazumdar ◽  
G. I. Stegeman ◽  
M. Cha ◽  
D. Neher ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Dipole Moments ◽  
Harmonic Signal ◽  
Oscillator Strengths ◽  
Experimental Investigations ◽  
Transition Dipole ◽  
Third Harmonic ◽  
The Third ◽  
Transition Dipole Moments ◽  
Spectral Ranges

The third order nonlinear optical properties of conjugated polymers have been considered promising since the 1970s when Sauteret et al reported large non-resonant values in PTS.[1] Although it is well-understood that the physical origin of the nonlinearities is due to the delocalization of the π-electrons, the details, and how best to calculate them have been the focus of a continuing theoretical dialogue. Until recently, experimental investigations of nonlinearities have been limited to only a few wavelengths. Now third harmonic generation (THG), which accesses only the electronic nonlinearities, can be performed over wide spectral ranges, for example from 500 to 2000 nm. The resulting third harmonic wavelength typically spans the electronic molecular transitions associated with the nonlinearities. By measuring the spectral distribution of both the amplitude and phase of the third harmonic signal, the dominant transitions (between the“essential states”) contributing to the nonlinearity can be identified. Such information is most useful for comparing with theories in which the oscillator strengths (transition dipole moments) for the various molecular transitions are calculated.

scholarly journals Особенности нелинейного СВЧ-отклика многозонных сверхпроводников на основе ферроселенида натрия-калия (Na-=SUB=-0.3-=/SUB=-K-=SUB=-0.7-=/SUB=-)-=SUB=-x-=/SUB=-Fe-=SUB=-2-y-=/SUB=-Se-=SUB=-2-=/SUB=-

2018 ◽  
Vol 60 (11) ◽  
pp. 2116
Author(s):  
Е.Е. Пестов ◽  
Ю.Н. Ноздрин ◽  
А.И. Елькина ◽  
Ю.C. Ерин ◽  
М. Лю ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Near Field ◽  
Sodium Potassium ◽  
Third Harmonic ◽  
The Third ◽  
Microwave Microscopy ◽  
Temperature Dependences ◽  
Harmonic Power

Abstract —Temperature dependences of the third-harmonic power for the (Na_0.3K_0.7)_ x Fe_2 – _ y Se_2 sodium–potassium ferroselenide single crystals have been investigated by nonlinear near-field microwave microscopy. The temperature dependence of magnetic susceptibility at a frequency of 100 kHz for this compound has been measured. The experimental results suggest a double-gap structure of the (Na_0.3K_0.7)_ x Fe_2 – _ y Se_2 superconductor.

scholarly journals Virtual Singular Scattering of Electromagnetic Waves in Transformation Media Concept

2012 ◽  
Vol 1 (1) ◽  
pp. 38
Author(s):  
M. Y. Barabanenkov ◽  
Y. N. Barabanenkov ◽  
S. A. Nikitov
Keyword(s):  
Green Function ◽  
Free Space ◽  
Electromagnetic Waves ◽  
Scattering Amplitude ◽  
Near Field ◽  
Empty Space ◽  
Resonance Scattering ◽  
Field Zone ◽  
Left Handed ◽  
Veselago Medium

If a scatterer and an observation point (receive) both approach the so-called near field zone of a source of electromagnetic waves, the scattering process becomes singular one which is mathematically attributed to the spatial singularity of the free space Green function at the origin. Starting from less well known property of left-handed material slab to transfer the singularity of the free space Green function by implementing coordinate transformation, we present a phenomenon of virtual singular scattering of electromagnetic wave on an inhomogeneity located in the volume of left – handed material slab. Virtual singular scattering means that a scatterer is situated only virtually in the near field zone of a source, being, in fact, positioned in the far field zone. Such a situation is realized if a scatterer is embedded into a flat Veselago’s lens and approaches the lens’s inner focus because a slab of Veselago medium produces virtual sources inside and behind the slab and virtual scatterer (as a source of secondary waves) from both slab sides. Considering a line-like dielectric scatterer we demonstrate that the scattering efficiency is proportional to product of singular quasistatic parts of two empty space Green functions that means a multiplicative quasistatic singularity of the Green function for a slab of inhomogeneous Veselago medium. We calculate a resonance value of the scattering amplitude in the regime similar to the known Mie resonance scattering.

scholarly journals Особенности нелинейного отклика структуры сверхпроводник-нормальный металл с большим отношением удельных сопротивлений

2019 ◽  
Vol 61 (9) ◽  
pp. 1589
Author(s):  
Е.Е. Пестов ◽  
Ю.Н. Ноздрин ◽  
В.В. Рогов ◽  
И.Ю. Пашенькин ◽  
Д.Ю. Водолазов
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Proximity Effect ◽  
Near Field ◽  
Perpendicular Magnetic Field ◽  
Third Harmonic ◽  
The Third ◽  
Microwave Microscopy ◽  
Harmonic Power

Using the method of near-field microwave microscopy, we investigated the temperature dependence of the third harmonic power P3ω (T) of superconductor – normal metal MoN / Al structures with proximity effect. The presence of an additional (low-temperature) maximum and vanishing in the dependence P3ω (T) for the MoN / Al structure, which disappear when a weak perpendicular magnetic field is applied.

Terahertz Coherent Scanning Probe Microscope

2010 ◽  
Vol 5 (4) ◽  
pp. 151-153
Author(s):  
Valeriy N. Trukhin ◽  
Nikolay N. Zinov’ev ◽  
Aleksandr V. Andrianov ◽  
Leonid L. Samoilov ◽  
Aleksandr O. Golubok ◽  
...  
Keyword(s):  
Scattered Radiation ◽  
Electromagnetic Waves ◽  
Near Field ◽  
Harmonic Signal ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
Signal Demodulation ◽  
Probe Microscope

We present the terahertz (THz) scanning probe microscope which combines a THz coherent spectrometer and a scanning probe microscope. It detects forward-scattered radiation and employs harmonic signal demodulation to extract the signal of near-field contribution to scattering of THz electromagnetic waves

Der Einfluß der Inaktivitätsosteoporose auf die szintigraphische Darstellung knöcherner Verletzungen im Bereich des Handgelenks

1989 ◽  
Vol 28 (04) ◽  
pp. 124-128 ◽  
Author(s):  
J. Spitz ◽  
N. Clemenz ◽  
K. Tittel ◽  
H. Weigand
Keyword(s):  
Bone Scintigraphy ◽  
Plaster Cast ◽  
Scaphoid Bone ◽  
X Ray ◽  
The Third ◽  
High Level ◽  
Clinical Conditions ◽  
Rate Of Accumulation

In addition to its established oncological indications the sensitivity of bone scintigraphy is of steadily increasing significance in traumatology. Inactivity- induced osteoporosis plays a major role during the immobilization period in the plaster cast. In the region of the joints remodelling intensity may reach such a high level that the non-injured bone shows a higher rate of accumulation than the fracture. This process already begins between the third and fourth week of immobilization. The highest uptake is found after fracture of the scaphoid bone at the end of twelve weeks of immobilization. Control scintigraphies at intervals of several days are indicated to differentiate between various clinical conditions (pseudoarthrosis, activated osteoarthrosis, algodystrophy in case of doubtful x-ray results).

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