Impact of the Antenna-Body Distance on the WBAN Channel Characteristics

Särestöniemi, Mariella; Kissi, Chaïmaâ; Raez, Carlos Pomalaza; Hämäläinen, Matti; Iinatti, Jari

doi:10.1109/ismict.2019.8743894

Cited by 15 publications

(8 citation statements)

References 9 publications

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“…For these on-body antennas, the optimal antenna matching is obtained with antenna-body distance 30 mm, which however is not considerable for practical applications. Besides, in [16] it was found that although the antenna matching is weaker with antennabody distance 4 mm, there are not significant differences in the propagation depths between the antenna-body distances 30 mm and 4 mm. For the Ring antenna, within the frequency range of interest, i.e., 3.75 -4.25 GHz, path loss is smallest, approximately 60 dB, as the capsule is located on the middle of SI.…”

Section: A On-body Antenna Locationmentioning

confidence: 93%

WBAN Channel Characteristics Between Capsule Endoscope and Receiving Directive UWB On-Body Antennas

et al. 2020

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This paper presents a study on the ultra wideband (UWB) radio channel characteristics between a capsule endoscope and a directive on-body antenna in different parts of the small intestine. The study is conducted using a finite integration technique (FIT) based electromagnetic simulation software CST Studio Suite and four of its anatomical voxel models. The capsule endoscope model is set inside different areas of the small intestine of the voxel models. A recently published directive on-body antenna designed for in-body communications is used in the evaluations. The obtained frequency and time domain channel characteristics are compared with previously published results with another directive on-body antenna designed for capsule endoscopy communications. Power flow presentations are used to understand differences obtained with two on-body antennas. Different rotation angles of the capsule are also considered in this study. It is found that channel characteristics vary remarkably depending on the antenna location in the small intestine and location of the on-body antenna. Thus, the on-body antennas should be located carefully to ensure coverage over the whole intestine area. Path loss does not only depend on the distance between a capsule and the on-body antenna but also on the tissues between the capsule and on-body antennas. Obviously, the antenna patterns have clear impact on the received signal's strength. Furthermore, orientation of the capsule affects also strongly impact when linearly polarized antennas are used. INDEX TERMS Abdominal monitoring, capsule endoscopy, directive antenna, ultrawide band, wireless body area networks.

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Section: A On-body Antenna Locationmentioning

confidence: 93%

WBAN Channel Characteristics Between Capsule Endoscope and Receiving Directive UWB On-Body Antennas

et al. 2020

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“…Especially in the abdomen area, tilt angles may vary significantly depending on the shape of the abdomen area. Furthermore, as presented in [8], the impact of antenna and body distance can have significant impact on the channel characteristics. Simulation based studies of [8] show that only 2mm difference can cause even 8 dB difference to the level of the main peaks.…”

Section: A Antenna Location 1 Side-by-side Casementioning

confidence: 99%

“…Furthermore, as presented in [8], the impact of antenna and body distance can have significant impact on the channel characteristics. Simulation based studies of [8] show that only 2mm difference can cause even 8 dB difference to the level of the main peaks. Hence, the thickness of the cloth may affect significantly on the measurement results.…”

Section: A Antenna Location 1 Side-by-side Casementioning

confidence: 99%

Measurement and Simulation Based Study on UWB Channel Characteristics on the Abdomen Area

Särestöniemi

Kissi

Raez

et al. 2019

2019 13th International Symposium on Medical Information and Communication Technology (ISMICT)

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This paper presents a comprehensive simulation and measurement data based study on the UWB on-body radio channel characteristics on the human abdomen area. The main target is to evaluate channel characteristics with several different antenna location options using a recently published ultra wideband (UWB) antenna designed for inbody communications, e.g. for capsule endoscope localization. For the simulations, we use two voxel models and two layer models. Measurement data consists of channel data for seven volunteers having different body size and body composition. The simulation and measurement data is compared and the reason for the differences is discussed. Furthermore, it is shown that the on-body channel characteristics vary significantly depending on the body size and shape of the volunteer if the antenna separation distance is large. With smaller antenna distances, the difference is minor.

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“…As these antennas operate in the proximity of lossy body tissues, their performance is greatly affected by the user. Based on measurements [8]- [10] and Electromagnetic (EM) simulations [11]- [13], the antenna efficiency is reported to be strongly impacted by the body for separations below 8 mm, while this impact is negligible when the antenna is more than 15 mm away from the body. Moreover, different body types [10], [14] and on-body antenna locations [15]- [19] have a clear impact on the radiation characteristics.…”

Section: Introductionmentioning

confidence: 99%

User Influence on Polarization Characteristics in Off-Body Channels

et al. 2020

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This paper investigates the impact of the user's body on wearable antenna radiation characteristics and the consequent effects on the off-body channel, with the focus on the polarization aspect. The impact on antenna gain and polarization is analyzed for different antenna placements and separations from the body, based on electromagnetic simulations with numerical phantoms at 3, 4 and 5 GHz. Results show a strong influence of the body on the antenna efficiency, gain, and polarization. The excess losses due to body-shadowing suppress the antenna radiation behind the body by more than 20 dB, while its polarization changes from vertical in free space, to an elliptical one when placed on the body. The obtained radiation characteristics are then employed for off-body channel simulations using a geometrybased polarized channel model, which employs an analytic mobility model for wearable antennas based on Fourier series. The antenna rotation due to changes in user's posture is seen as one of the main sources of offbody channel degradation. The polarization mismatch losses imposed by antennas' physical misalignment, are observed to yield periodic fades of the Line-of-Sight component, with more than 30 dB drops in the received power level.

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Impact of the Antenna-Body Distance on the WBAN Channel Characteristics

Cited by 15 publications

References 9 publications

WBAN Channel Characteristics Between Capsule Endoscope and Receiving Directive UWB On-Body Antennas

WBAN Channel Characteristics Between Capsule Endoscope and Receiving Directive UWB On-Body Antennas

Measurement and Simulation Based Study on UWB Channel Characteristics on the Abdomen Area

User Influence on Polarization Characteristics in Off-Body Channels

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