Chang-hee Hyoung

Effects of ground electrode on signal transmission of human body communication using human body as transmission medium

In this paper, the measurement results on the effects of ground electrode according to the transmission distance are presented. A biological tissue-equivalent phantom has been used in the measurement of a previous paper, but a real human body is used in this paper. Also, the measurement results are analyzed by EM simulation. In the previous papers K. Fujii et al. (2003)-(2002), the simulation model for human body has been composed of only muscle tissue. In this paper, a more accurate model composed of muscle and other tissues is used during the simulation. Finally, the method by which a ground electrode can be used more efficiently is proposed based on the measurement results

A Method of Increasing Data Rate for Human Body Communication System for Body Area Network Applications

Human body communications (HBC), which have been standardized in IEEE 802.15.6 standard for wireless body area networks (WBAN), provides a maximum data rate of 1.3125 Mbps through frequency selective digital transmission (FSDT). This paper reviews FSDT and proposes a modified FSDT (MFSDT). By exploiting the efficient modification of the FSDTs transmitter structure, MFSDT achieves a maximum data rate of 3.9375 Mbps, and the decoding complexity of MFSDT increases linearly with an increase in the data rate. In addition, FSDT and MFSDT performance are investigated with respect to the effects of the transmit filter provided to meet transmit spectral mask requirements, and a human body channel modeled as a finite impulse response filter.

An Energy Combiner for a Multi-Input Energy-Harvesting System

An energy combiner for delivering electrical energy harvested simultaneously from individual energy harvesters (EHs) to a single energy storage device such as a battery is presented. It is designed as a modular architecture to be handled as a subsystem and supports an arbitrary number of EHs, which can be connected to the energy combiner in a hot-pluggable form. With the adaptive connection flows of a novel control algorithm, the energy harvested from each EH can be transmitted to an energy storage device without interfering with each other. An evaluation system is implemented, including the energy combiner circuit fabricated in a 0.13-μm CMOS process. The experimental results show that the energy combiner, with a low power consumption of 1.55 μW, achieves a maximum energy-combining efficiency of up to 95% for three input sources.

A Feasibility Study on the Adoption of Human Body Communication for Medical Service

A feasibility study on the adoption of human body communication (HBC) for medical service is presented. The electrical specifications of HBC for medical service were reviewed. The ratio of the leakage current into the heart to the output current of a capsule-type transmitter and the propagation loss in the channel were simulated using an anatomical body model. The in-body to on-body channel loss for HBC was provided by electromagnetic simulation from the capsule-type transmitter in the stomach to receiving electrodes on the abdominal region. An analog front end with a sensitivity of 37 μVpp was developed, which showed an improvement of 21 dB against the best report. The 14 mm × 26 mm capsule-type transmitter was implemented, and preclinical experiment was conducted using a live pig. The proposed system successfully transferred data from the capsule-type transmitter in a stomach to the electrodes on the butt and the low jaw of the pig at a high rate of 2 Mb/s at a distance of 90 cm without packet error.

Effect of load impedance on the signal loss of human body communication

In this paper, the effect of load impedance was presented and analyzed based on the lumped model for human body communication. The signal loss decreased as the load impedance increased, but it was saturated gradually because of the leakage impedance.

Reverse effect of ground electrode on the signal loss of human body communication

In this paper, we analyzed the effects of the ground electrode, especially the reverse effect in which the signal loss increases by the ground electrode. We measured how the signal loss varies in relation to the ground electrode. Furthermore, we simulated the current distribution to analyze the effects of the ground electrode. In other papers, the body has an artificial posture in which two arms and a shoulder formed a straight line. In our approach, we measured the signal loss of a person with a natural posture for actual human body communication; that is, the persons two arms and shoulder did not form a straight line. Also, we reflected the modified posture of the body in the simulation model.

Analysis of signal interference in human body communication using human body as transmission medium

In this paper, the measurement results on the signal interference of human body communication are presented. A real human body is used in the measurement. Also, the measurement results are analyzed by EM simulation. Finally, the frequency band where the human body communication can be used without the interruption by signal interference is proposed based on the measurement and simulation results

Receptive properties of the human body of emitted electromagnetic waves for energy harvesting

This paper investigates the receptive properties of the human body of emitted electromagnetic waves as part of an investigation into the possibility of energy harvesting from the electromagnetic waves using the human body. Voltages received as the human body functions as an antenna were measured and compared with simulation results. The received voltages in a general electromagnetic environment were also estimated.

Performance evaluation of human body communication system for IEEE 802.15 on the effect of human body channel

The root mean square (RMS) delay spread and coherence bandwidth are examined based on measurement for a wide band human body channel. Using the results, the relation between these two wideband channel parameters is evaluated. The inter-symbol interference (ISI) effect on the performance of the frequency selective digital transmission (FSDT) is investigated by modeling the time dispersive human body channel as a finite impulse response (FIR) filter. Then, the compatible required transmitter power is computed for a reliable FSDT communication link.

Effects of transmitter’s location on the signal loss of the human body communication

When the transmitter is held in the hand, the signal loss is larger than when it is attached to the wrist. When it is held in the hand, the coupling to the ground plane becomes strong because the palm is located on the coupling path to the ground plane. Therefore, much current near transmitter is distributed in the opposite direction of the receiver and less current flows to the receiver.