scholarly journals Near-field radio-frequency imaging by spin-locking with a nitrogen-vacancy spin sensor

2021 ◽  
Vol 130 (2) ◽  
pp. 024503
Author(s):  
Shintaro Nomura ◽  
Koki Kaida ◽  
Hideyuki Watanabe ◽  
Satoshi Kashiwaya
Keyword(s):  
Radio Frequency ◽  
Near Field ◽  
Nitrogen Vacancy ◽  
Spin Locking

scholarly journals Uses of radio emission spectroscopy for non-contact and in situ diagnostics of low pressure radio frequency plasma processing

2021 ◽  
Author(s):  
Rajani K. Vijayaraghavan ◽  
Sean Kelly ◽  
David Coates ◽  
Cezar Gaman ◽  
Niall MacGearailt ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Frequency ◽  
Emission Spectroscopy ◽  
Near Field ◽  
Plasma Processing ◽  
Diagnostic Technique ◽  
Primary Source ◽  
Low Pressure ◽  
Chamber Pressure ◽  
Rf Plasma

Abstract We demonstrate that a passive non-contact diagnostic technique, radio emission spectroscopy (RES), provides a sensitive monitor of currents in a low pressure radio frequency (RF) plasma. A near field magnetic loop antenna was used to capture RF emissions from the plasma without perturbing it. The analysis was implemented for a capacitively coupled RF plasma with an RF supply at a frequency of 13.56 MHz. Real-time measurements are captured in scenarios relevant to contemporary challenges faced during semiconductor fabrication (e.g. window coating and wall disturbance). Exploration of the technique for key equipment parameters including applied RF power, chamber pressure, RF bias frequencies and chamber wall cleanliness shows sensitive and repeatable function. In particular, the induced RES signal was found to vary sensitively to pressure changes and we were able to detect pressure and power variations as low as ~2.5 %/mtorr and ~3.5 %/watt, respectively, during the plasma processing during a trial generic plasma process. Finally, we explored the ability of RES to monitor the operation of a multiple frequency low-pressure RF plasma system (f1 = 2 MHz, f2 = 162 MHz) and intermixing products which suggests strongly that the plasma sheaths are the primary source of this non-linear diode mixing effect.

scholarly journals Design and Development Of Lecturer Attendance System Using Radio Frequency Identification (RFID)

2021 ◽  
Vol 10 (1) ◽  
pp. 15-27
Author(s):  
I Gede Sujana Eka Putra ◽  
Anthony Lee ◽  
I Made Tirta Mahayana ◽  
I Gede Agung Wicaksono Dharmayasa
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Web Application ◽  
Academic Staff ◽  
Near Field ◽  
Literature Study ◽  
Master Data ◽  
Presence Data ◽  
Frequency Identification ◽  
The University

Lecturer attendance record is required by the university to know the presence of lecturers in teaching in class. In general condition, lecturer attendance is recorded on the attendance sheet, or input to web application accessed on a class computer. However, there are some problems in its implementation so that at the end, lecturer presence is carried out using a manual form where the academic staff needs to re-enter the lecturer attendance data into the applications. Based on the above, the authors designed and developed a lecturer attendance information system to record lecturers' attendance using radio frequency identification technology by implementing a near field communication card (NFC Card). The device used to record and read presence data during lectures, by tapping an Mi-fare NFC card to an NFC reader / writer device. The flow of this research method begins with a literature study of NFC card, observe the flow of lecture attendance process and data recorded into lecturer attendance sheet, analyzing the database design, the system design which has compatible with NFC reader and writer devices, designed system interface and continue to develop system. The result is system consists of master data, system attendance, verification and reporting module. The results show that NFC card implementation is more practical for lecturers in conducting lecture attendance and NFC card could be tapped out into an NFC device at a maximum distance up to 7 cm with the reading angle relative to NFC reader/writer with range 00 until 300 can read NFC Card.

scholarly journals High precision epidermal radio frequency antenna via nanofiber network for wireless stretchable multifunction electronics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yufei Zhang ◽  
Zhihao Huo ◽  
Xiandi Wang ◽  
Xun Han ◽  
Wenqiang Wu ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Near Field ◽  
Transmission Efficiency ◽  
Stretchable Electronics ◽  
Information Communication ◽  
Long Distance ◽  
Human Machine Interaction ◽  
Natural Systems ◽  
Content Recognition ◽  
Healthcare Monitoring

Abstract Recently, stretchable electronics combined with wireless technology have been crucial for realizing efficient human-machine interaction. Here, we demonstrate highly stretchable transparent wireless electronics composed of Ag nanofibers coils and functional electronic components for power transfer and information communication. Inspired by natural systems, various patterned Ag nanofibers electrodes with a net structure are fabricated via using lithography and wet etching. The device design is optimized by analyzing the quality factor and radio frequency properties of the coil, considering the effects of strain. Particularly, the wireless transmission efficiency of a five-turn coil drops by approximately only 50% at 10 MHz with the strain of 100%. Moreover, various complex functional wireless electronics are developed using near-field communication and frequency modulation technology for applications in content recognition and long-distance transmission (>1 m), respectively. In summary, the proposed device has considerable potential for applications in artificial electronic skins, human healthcare monitoring and soft robotics.

On the nature of the microwave field emerging from a composite pupil

2020 ◽  
Vol 34 (24) ◽  
pp. 2050247
Author(s):  
Ilaria Cacciari ◽  
Daniela Mugnai ◽  
Anedio Ranfagni
Keyword(s):  
Wave Propagation ◽  
Stochastic Model ◽  
Radio Frequency ◽  
Delay Time ◽  
Microwave Field ◽  
Near Field ◽  
Phase Variation ◽  
Experimental Investigations ◽  
Frequency Signal ◽  
Made In

Further experimental investigations in the microwave field emerging from a composite pupil are reported in order to determine the nature of the wave propagation. The experiments consisted of delay-time measurements as a function of the distance of the detector from the pupil under test, as well as of the phase variation of a radio-frequency signal at 35 MHz that modulated the same microwave carrier at 9.33 GHz. In addition, measurements employing an admittance comparator were made in order to determine the character of the propagation impedance. All results obtained confirmed superluminal behavior in the near field, up to a distance of about 40 cm. These results were then interpreted within the framework of a stochastic model.

scholarly journals Near-field microwave magnetic nanoscopy of superconducting radio frequency cavity materials

2014 ◽  
Vol 104 (23) ◽  
pp. 232603 ◽  
Author(s):  
Tamin Tai ◽  
Behnood G. Ghamsari ◽  
Thomas R. Bieler ◽  
Teng Tan ◽  
X. X. Xi ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Near Field ◽  
Superconducting Radio Frequency

scholarly journals Measurement of induced currents in radio frequency magnetic fields based on near field antenna perturbations

AIP Advances ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 065202
Author(s):  
J. M. Jennings ◽  
A. Kar ◽  
R. Vaidyanathan
Keyword(s):  
Magnetic Fields ◽  
Radio Frequency ◽  
Near Field ◽  
Induced Currents
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