2023 International Conference on Emerging Technologies for Communications (ICETC 2023)
1

Electric Field Attenuation of Wireless Medical Telemeters by
Hospital Structures
Isao KAYANO†a), Member, Yumina KAGAWA†, and Seiichi MOCHIZUKI†, Nonmembers

1. Introduction

3. Results and Discussions

Wireless medical telemeters, which transmit patientbioinformation with radio waves, have been introduced athigh pace recently, resulting in the fact that over 80%
hospitals installed telemeters in 2020. However, most
hospitals are facing technical problems in radio waves being
disturbed by building structures, medical equipments, bedsand others[1]. In this study, we thus simulated theattenuation phenomena of electric fields emitted fromtelemeters based on the finite difference time domain(FDTD) method and performed validation by comparing
with the actual measurement data.

Fig.2 shows the simulation result of the electric fields in theXY plane. It was found that the electric fields graduallybecame smaller, indicated as the gradual change from red toblue. The field was also found to be attenuated nearly
concentrically from the radiation source, while became
extremely weak behind the building pillars. In Fig.3, the line
segments of (a) and (b) in Fig.2 were indicated as red andblue, respectively. The vertical axis represents the electricfield intensity, while the horizontal axis the distance in the x
direction. Here, yellow indicates the actual measurement
data. Both the simulated and measured data are in good
agreement, demonstrating the validity of the simulation. Itwas also shown that the electric field attenuation due to theinfluence of the metal pillars is about 20 dB at maximum.

2. Methods (FDTD simulation and measurements)
A schematic diagram of this simulation model is shown inFig.1. Hospital rooms assume to consist of mortar, plasterboards, window glass, and metal pillars. The dimension ofeach room was X=3775-4500 mm, Y=6505 mm, and
Z=2605 mm (Fig.1). Eight rooms of this size were locatedin the simulation model. A radiation source which is a 50 Ω
micro dipole antenna with 1 mW and 420 MHz was placedin the center of one of the eight rooms (Z=500 mm), and ahorizontal electric field [dBV/m] was simulated at a heightof 500 mm. In an actual model structure of the same
dimension as the simulation model, a radiation source(Fukuda Denshi; LX-5230) was installed, and the electricfields were measured at eight locations using a spectrum
analyzer (Micronix; MSA538E).

Fig. 2 Simulated electric fields

Fig. 3 Attenuated electric fields (observed on lines (a) and (b) in Fig.2)

4. Conclusion
It was suggested that the attenuation of the electric fields
emitted from wireless medical telemeters is affected only
slightly by window glasses and plaster boards while greatly
by metal pillars.
Acknowledgments

Fig. 1 A schematic of the simulation modelThis work was supported by JSPS KAKENHI Grant
Number 22H03324.
References†The author is with Kawasaki University of Medical Welfare,Kurashiki-shi, Okayama, 701-0111 Japan.
a) E-mail: kayano@me.kawasaki-m.ac.jp[1] Isao KAYANO, et al., “Novel Channel Management of Wireless
Medical Telemeters Based on Simulation and Actual Measurementof Electromagnetic Environment in a Hospital”, JSMI, 91(5), pp.411421, 2021.

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