The University of Electro-CommunicationsUEC Research Portal

Video ProfilesResearch

January 2023 Issue

Bioelectromagnetics: interaction between human body and electromagnetic waves

Dairoku Muramatsu
Associate Professor at the Department of Mechanical and Intelligent Systems Engineering

Dairoku Muramatsu’s research integrates electronics and bionics in an area known as “bioelectromagnetics”. “The human bodies is composed of many biological tissues, such as skin, muscle, fat, bone, and different types of organs,” explains Muramatsu. “These tissues and organs are electrically unique materials that interact with electromagnetic waves in a complex manner. The goal of my research is to clarify this complex interaction and utilize it for communication with digital gadgets, medical and healthcare devices, human interfaces, and even for food industry.”

In this video, Muramatsu describes two specific applications in the areas of wireless communication and healthcare.

Human body communication is one of the areas of wireless communication technologies. Amazingly, it is possible to use human bodies as signal transmission paths for sending digital data. Once an electrical signal goes inside the body via electrodes, the signal propagates mainly through the human body and the space around the body.

The animation in the video illustrates how the electric field is distributed around the human body when a radio frequency signal is excited at the wrist. Notably, the electric field is distributed only around the body and propagates along the body's surface. This communication principle enables both highly secure and low-power communications.

As an application example of human body communication, Muramatsu implemented an LED color control system where a user selects color information from an app on a smartphone. This information is sent to the transmitter and modulated to a radio frequency signal. The signal is input to the hand through the electrode and subsequently distributed as an electric field around the user’s body as described above. The receiver detects the electric field as a radio frequency signal, which is demodulated and used to control the color of the LEDs. “The important point is that the information is transmitted only when the user directly touches the transceiver electrodes,” says Muramatsu. “So, human body communication can be used as an intuitive touch interface in e-money transactions, such as a using railway networks.

In the medical healthcare field, Muramatsu is working on non-invasive blood glucose monitoring. The current number of diabetic patients around the world is over 500 million, and that is estimated to 700 million in the next 20 years. Daily monitoring of blood glucose is vital for managing diabetes to prevent serious complications. The current monitoring method requires invasive blood sampling from a patient's fingertip. However, blood sampling with needle puncturing is uncomfortable, vulnerable to infection, and can be high in cost of consumables. To address such drawbacks and to improve patients’ quality of life, Muramatsu proposed a non-invasive blood glucose monitoring based on bioelectromagnetics.

“Our method utilizes changes in a patient’s bioimpedance as an indicator of blood-glucose concentration,” says Muramatsu. “Patients put a wearable device such as a smart watch on the wrist and the device inputs electricity to the patient’s body, and detects the bioimpedance from the sensing electrodes on its backside. Then, we estimate the blood glucose level from the patient’s bioimpedance. In this way, we can realize non-invasive monitoring without blood samples, infection risk, and any consumables.”
These were two examples of bioelectromagnetics. It is a multidisciplinary area of research that uses complex human-electricity interaction to develop practical applications that would not be possible through engineering alone.

“We need the cooperation of researchers in a wide range of expertise,” says Muramatsu. “So, we are always open to collaboration and exchange.”

References and further information

1. D. Muramatsu, K. Arai, K. Higuchi, “A Study on Floor Ground Contribution in Semi-Passive Human Body Communication”, IEICE Commun. Express, Vol.11, pp.39-45, 2022.

2. R. Takamatsu, K. Higuchi, T. Suzuki, D. Muramatsu, “Electrical Properties of Fresh Human Blood at 10 kHz–100 MHz”, IEEJ Trans. Electr. Electron. Eng., Vol.17, No.4, pp.614-616, 2022.
https://doi.org/10.1002/tee.23549

3. D. Muramatsu, K. Sasaki, “Noise Reduction Using a Triple-layer Electrode in Conductive/Capacitive Hybrid Electrocardiogram Measurement”, Sens. Mater., Vol.33, pp.4105-4111, 2021.
https://doi.org/10.18494/SAM.2021.3591
D. Muramatsu, “NaCl-Based Blood Phantom Analysis for In Vitro Bioimpedance Measurement”, AIP Advances, Vol.11, No.8, pp.1-5, 2021.
https://doi.org/10.1063/5.0055949

4. D. Muramatsu, K. Sasaki, “Transmission Analysis in Human Body Communication for Head-Mounted Wearable Devices”, Electronics, Vol.10, No.10, pp.1213-1227, 2021.
https://doi.org/10.3390/electronics10101213

5. Y. Nishida, K. Sasaki, K. Yamamoto, D. Muramatsu, F. Koshiji, “Equivalent Circuit Model Viewed from Receiver Side in Human Body Communication”, IEEE Trans. Biomed. Circ. Sys., Vol.13, No.4, pp.746-755, 2019.
https://doi.org/10.1109/TBCAS.2019.2918323

Dairoku Muramatsu website
https://mdairoku.com