scholarly journals Effect of Earth Ground and Environment on Body-Centric Communications in the MHz Band

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Katsuyuki Fujii ◽  
Yasuyuki Okumura
Keyword(s):  
Electric Field ◽  
Human Body ◽  
Open Circuit Voltage ◽  
Electronic Devices ◽  
Wearable Devices ◽  
Open Circuit ◽  
Closed Circuit ◽  
Area Network ◽  
Current Increase ◽  
The Earth

Body area network (BAN) research, which uses the human body as a transmission channel, has recently attracted considerable attention globally. Zimmerman first advocated the idea in 1995. Illustrations of the electric field streamlines around the human body and wearable devices with electrodes were drawn. In the pictures, the electrodes of the wearable devices constitute a closed circuit with the human body and the earth ground. However, analysis of the circuit has not been conducted. In this study, we model the human body shunted to earth ground in a radio anechoic chamber to analyze the electric field strength around it and clarify the effect of earth ground during BAN run time. The results suggest that earth ground has little influence on the human body and wearable devices. Only when the human body is directly grounded, the electric field near the feet area will decrease. The input impedance of the transmitter is approximately the same, and the received open-circuit voltage and current of the receiver are also the same. In addition, we elucidate that stable communications can be established by developing a closed circuit using earth ground as return path. When the external electronic devices and human body are shunted to earth ground, the received open-circuit voltage and current increase.

Study of Anode Modification and Bias Voltage Treatment on Organic Solar Cells with Rubrene/ C60 Heterojunctions

2011 ◽  
Vol 295-297 ◽  
pp. 506-510
Author(s):  
Bing Wu ◽  
Peng Yi Liu ◽  
Zi Guo Chen ◽  
Jing Cao
Keyword(s):  
Solar Cells ◽  
Electric Field ◽  
Power Conversion Efficiency ◽  
Bias Voltage ◽  
Organic Solar Cells ◽  
Open Circuit Voltage ◽  
Power Conversion ◽  
Open Circuit ◽  
Device Performance ◽  
Anode Modification

The organic solar cells with a structure of ITO/Rubrene(35 nm)/C60(35 nm)/BCP (6 nm)/Al(150 nm) was fabricated and the influence of anode modifying layer(MoO3) and 3V bias voltage treatment on device performance were investigated. The experiment results show, inserting anode modifying layer, the open-circuit voltage and the power conversion efficiency were almost increased by a factor of 5.3 and 11.3, respectively. The anode modifying layer can effectively enhance the built-in electric field and improve dissociation and transport excitons. The bias voltage treatment can improve the performance of defective devices by burning partial defects, but there is little effect for too few defective devices.

NITRIDE BASED SCHOTTKY-BARRIER PHOTOVOLTAIC DEVICES

2007 ◽  
Vol 1040 ◽  
Author(s):  
Balakrishnam R Jampana ◽  
Omkar K Jani ◽  
Hongbo Yu ◽  
Ian T Ferguson ◽  
Brian E McCandless ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Barrier Height ◽  
Annealing Temperature ◽  
Open Circuit Voltage ◽  
Short Circuit ◽  
Schottky Contact ◽  
Open Circuit ◽  
Photovoltaic Devices ◽  
Current Increase ◽  
Uv Illumination

AbstractSchottky-barrier photovoltaic devices are fabricated by selective metal deposition on p-GaN. A 1.25 V open-circuit voltage is observed for the best device. Devices were optimized by annealing in forming gas at temperatures ranging from 550°C to 700°C. Annealing time and forming gas flow rate are used to control the metal-semiconductor Schottky barrier formation. Optimum fabrication parameters are achieved based on photovoltaic response from the devices under UV illumination. Barrier heights (0.47 eV - 0.49 eV) were used as basis to compare the device response. The Schottky-barrier height is very sensitive to processing conditions, for example a 2.5% increase in barrier height is observed when Schottky contact annealing temperature is changed from 600 °C to 650 °C. Under UV illumination, the open-circuit voltage and short-circuit current increase with increasing annealing temperature while the series resistance decreases under such conditions.

Effects of Carbon Grading at the p/i Interface on the Open Circuit Voltage of p-i-n and n-i-p Amophous Silicon Solar Cells

1987 ◽  
Vol 95 ◽  
Author(s):  
N. T. Tran ◽  
F. R. Jeffrey ◽  
D. J. Olsen
Keyword(s):  
Solar Cells ◽  
Electric Field ◽  
Amorphous Silicon ◽  
Buffer Layer ◽  
Open Circuit Voltage ◽  
Electron Tunneling ◽  
Open Circuit ◽  
Silicon Solar Cells

AbstractCarbon grading in the buffer layer at the p/i interface increases the open circuit voltage of both p-i-n and n-i-p amorphous silicon solar cells. We propose that carbon grading enlarges the electric field and reduces the electron tunneling at the p/i interface.

scholarly journals Ηλεκτρομαγνητική μελέτη υπόγειων αγωγών

2013 ◽  
Author(s):  
Κωνσταντίνος Ράλλης
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Finite Length ◽  
Current Distribution ◽  
Time Domain ◽  
Electronic Devices ◽  
Lightning Stroke ◽  
Mutual Impedance ◽  
The Earth ◽  
Improper Integrals

The aim of this doctoral thesis is to study electromagnetic compatibility problems dealing with field couplings to underground transmission lines, communication systems or electronic devices. As an overview: (i) we develop expressions for the accurate computation of mutual impedances between two underground conductors of finite length, (ii) we use a modern technique to solve the well-known Pollaczek and Carson formulas for the evaluation of the earth-return impedance for underground and overground conductors, (iii) we present a method for calculating the electromagnetic field generated by a lightning stroke for studying the problem of induced over-voltage on lines and electronic devices both in power and telecommunication systems, (iv) we deal with the computation of the current distribution along a vertical grounding rod. In all cases, our approach is purely electromagnetic with the use of the elementary electric dipoles technique. More specifically: In the first chapter we provide the expressions for the field generated by a vertical or horizontal elementary electric dipole placed in air or in ground. We form the boundary problem of the system dipole and air-ground interface for the calculation of the Hertz vector components generated by the dipole and the calculation of the electromagnetic field. We also provide tables with the cylindrical components of the produced field. In the second chapter we study the problem of the mutual impedance between two underground conductors of finite length and arbitrary position. With the use of the elementary dipoles technique we derive expressions for the accurate calculation of the mutual impedance that have the form of double infinite improper integrals and we evaluate them by using advanced integration algorithms. We then follow an alternative approach which involves the computation of the equivalent Sommerfeld type integrals by using the Discrete Complex Image Method (DCIM). This method allows the transformation of the Sommerfeld integrals to semi-infinite integrals with known analytical solutions. This is possible by approximating the integrand by a sum of complex exponentials. We finally give results of the mutual impedance and carry out comparisons in order to validate our expressions. In the third chapter we deal with the computation of the current distribution along a vertical grounding rod. We derive the mathematical model by applying the elementary dipoles technique and then we use the Method of Moments for solving the electric field integral equation. For the validation of the developed model, we solve the problem with the FEM method by using the software package COMSOL. In the fourth chapter we evaluate the well-known Pollaczek and Carson formulas for the earth-return impedance for underground and overground conductors. The integrals are solved by using again the DCIM method. For the approximation of the integrand with a sum of exponentials we use the Generalized Pencil of Function (GPOF) method (one and two level). The results of the impedance are compared with results derived with numerical integration of the Pollaczek integral and the analytical solution of Carson’s integral. In chapter five we evaluate the electromagnetic field generated by the lightning stroke in an observation point above and underground. The knowledge of the field is very important when we study couplings with power lines or telecommunication conductors. The expressions for the lightning field have the form of semi-infinite improper integrals in frequency domain, and their numerical computation poses a computational challenge. The problem is more demanding in the case of time domain response, were a large number of computations for a frequency range is required, in order to carry out the required inverse Fourier transform. We propose an efficient method for calculating the lightning integrals, based on their numerical calculation along a deformed path of integration. The method is combined with an interpolation technique in order to reduce the number of frequencies required in the Fourier synthesis of the time domain electric field. The result is a very fast and straightforward tool for the calculation of the underground and overground lightning field, without the use of specially developed numerical algorithms or analytical approximations.

scholarly journals Transmission Analysis in Human Body Communication for Head-Mounted Wearable Devices

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1213
Author(s):  
Dairoku Muramatsu ◽  
Ken Sasaki
Keyword(s):  
Electric Field ◽  
Human Body ◽  
Hearing Aids ◽  
Wearable Devices ◽  
Transmission Mechanism ◽  
Signal Frequency ◽  
Head Model ◽  
Transmission Characteristics ◽  
Field Distributions ◽  
Human Body Communication

As society ages, wireless body area networks (WBANs) are expected to increasingly improve the quality of life of the elderly and disabled. One promising WBAN technology is human body communication (HBC), which utilizes part of the human body as a transmission medium. Communication between head-mounted wearable devices, such as hearing aids, is a potential HBC application. To clarify the HBC transmission mechanism between head-mounted wearable devices, this study analyzes the input impedance characteristics of the transceiver electrodes, transmission characteristics, and electric field distributions around and through a detailed head model. The investigation was performed via an electromagnetic field simulation. The signal frequency had less effect on the transmission characteristics and electric field distributions at 10, 20, and 30 MHz. However, the transmission mechanism between the head-mounted wearable devices was influenced by the number of electrodes in the transceiver. Moreover, the transmission characteristics between two-electrode transceivers were improved by impedance matching. Finally, the availability of the proposed system was evaluated from power consumption and human safety perspectives.

Effect of C60 on the Photovoltaic Properties of Polypyrrole-C60 Heterojunctions

2010 ◽  
Vol 663-665 ◽  
pp. 828-831
Author(s):  
Fu Fang Zhou ◽  
Qing Lan Ma ◽  
Zhuo Ran She ◽  
Yuan Ming Huang ◽  
Chun Xu Pan
Keyword(s):  
Open Circuit Voltage ◽  
Short Circuit ◽  
Power Conversion ◽  
Photovoltaic Cells ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Photovoltaic Properties ◽  
Current Increase ◽  
Good Material ◽  
Slight Amount

We report here a series of polypyrrole/C60-H3PO4 two-layer photovoltaic cells fabricated by varying the C60 ratio with regard to polypyrrole. It is found that a slight amount of C60 can remarkably improve photovoltaic properties by four orders of magnitude; with C60 ratio the open-circuit voltage and short-circuit current increase, and at higher C60 ratio the photovoltaic working threshold is lowered too, the cell can even work efficiently in dark, more approaching the efficiency under strong illumination. The optimized device yields 1.2 V open-circuit voltage and 14 μA/cm2 short-circuit current, and a power conversion efficiency 0.01%. Our results show that polypyrrole is a potentially good material for photovoltaic cells. The effect of C60 in combination with polypyrrole is discussed.

scholarly journals Touch-Based Dual-Band System Combined Human Body Communication and Wireless LAN for Wearable Devices

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 335
Author(s):  
Kunho Park ◽  
Jong Baek ◽  
Se Kim ◽  
Min Jeong ◽  
Youn Kim
Keyword(s):  
Human Body ◽  
High Speed ◽  
Local Area Network ◽  
Band System ◽  
Transparent Electrode ◽  
Wearable Devices ◽  
Physical Contact ◽  
Dual Band ◽  
Area Network ◽  
Human Body Communication

A touch-based dual-band system (TBDB), in which human body communication (HBC) and wireless local area network (WLAN) are combined to provide an intuitive service, is proposed. The proposed system can connect the network between devices using HBC, and the data is transmitted via WLAN. The network setup is configured within 100 ms through HBC by simply touching the devices to be connected. Subsequently, data is transmitted at high-speed through the WLAN at a data rate of 54 Mbps. Security is advantageous as HBC technology transmits data through physical contact. The TBDB system can provide a system suitable for wearable devices by combining the advantages of HBC with intuitive service and WLAN at a high transfer rate. A transparent electrode that is adaptable to various display panels is used instead of a metal electrode. The proposed TBDB system using the transparent electrode demonstrates a reliable and intuitive video streaming service between a server and a client, simply by touching the devices. The proposed system can be used between most electronic devices, such as smartphones, tablet PCs, and TVs, owing to the intuitive network connection by touch.

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