Measurements and simulations for on-body antenna design and propagation studies

Hu, Zhong; Gallo, M.; Bai, Qing; Nechayev, Y.I.; Hall, P.S.; Bozzetti, M.

doi:10.1049/ic.2007.1067

Cited by 7 publications

(7 citation statements)

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“…In recent years, body-centric wireless communications become an active area of research due to their various applications such as e-healthcare, support systems for specialized occupations, and personal communications [1][2][3][4][5][6][7]. Since the candidate frequencies for body-centric wireless communications widely range from MHz to GHz, dielectric properties of the human body tissues, relative dimensions of the human body to wavelength, and the propagation channels around the human body extremely vary with frequencies.…”

Section: Troductiomentioning

confidence: 99%

Electric field distributions around the human body with a small antenna in the frequency range of 2.5 MHz to 2.5 GHz

Ito

Haga

Takahashi

et al. 2009

2009 IEEE International Workshop on Antenna Technology

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In recent years, body-centric wireless communications become an active area of research due to their various applications such as e-healthcare, support systems for specialized occupations, and personal communications. Since the candidate frequencies for body-centric wireless communications widely range from MHz to GHz, dielectric properties of the human body tissues, relative dimensions of the human body to wavelength, and the propagation channels around the body extremely vary with frequencies. In this paper, to bring objective and unified idea on the frequency characteristics of body-centric wireless communication channels, electric field distributions around the human body wearing a small antenna in a wide frequency range of 2.5 MHz to 2.5 GHz are numerically calculated. The results show that behavior of the electric field distributions around the human body could be broadly divided into two ranges; below 100 MHz and above 250 MHz. I TRODUCTIOIn recent years, body-centric wireless communications become an active area of research due to their various applications such as e-healthcare, support systems for specialized occupations, and personal communications [1-7]. Since the candidate frequencies for body-centric wireless communications widely range from MHz to GHz, dielectric properties of the human body tissues, relative dimensions of the human body to wavelength, and the propagation channels around the human body extremely vary with frequencies. Therefore, we have to focus on certain frequency bands in most cases. For example, in a frequency range below several MHz, of which wavelength is longer than the human body, the physical propagation mechanism is unclear yet; thus, the electromagnetic phenomena are often explained by using lumped-parameter equivalent circuit that the devices and the human body are electrostatically coupled [2]. However, an equivalent circuit is sometimes not enough, and upper limit of frequency that such explanation is capable is still unclear. In this paper, to bring objective and unified idea on the frequency characteristics of body-centric wireless communication channels, electric field distributions around the human body wearing a small antenna in a wide frequency range of 2.5 MHz to 2.5 GHz are numerically calculated. These data would be useful to choose appropriate frequency range for specific applications. UMERICAL MODELI G OF A TE A A D HUMA BODYSince extremely wide frequency range is used in this calculation, an antenna should remain as simple and identical as possible over the range. From this requirement, a typical top-loaded monopole antenna shown in Fig. 1 is used. The antenna has low-profile dimension (5 mm thick) and has no matching structure (e.g. shorting posts); thus, impedance matching is not considered here. However, its radiation pattern is omnidirectional for any frequency over the range. Moreover, its ground plane partially simulates an electrode mounted to HF-band devices. Fig. 2 shows a whole-body block model with the antenna. The model has homogenous dielectric...

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Section: Troductiomentioning

confidence: 99%

Electric field distributions around the human body with a small antenna in the frequency range of 2.5 MHz to 2.5 GHz

Ito

Haga

Takahashi

et al. 2009

2009 IEEE International Workshop on Antenna Technology

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“…Indeed, it has been experimentally confirmed that the onbody link loss between a pair of monopole antennas attached to the human body is lower than that between some other types of antennas (i.e., loop antennas, patch antennas, patch array antennas) [8]. However, since a quarter-wavelength monopole antenna is impractical, antennas with other basic structures, such as planar inverted-F antennas (PIFAs) and top-loaded monopole antennas have also been investigated [11]. In addition, PIFAs have been reported to be relatively immune to fading during dynamic changes in body posture because of their nondirectivity and multipolarization [9].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Cavity Slot Antenna for Body-Area Networks

Haga

Saito

Takahashi

et al. 2009

IEEE Trans. Antennas Propagat.

125

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Antennas and the propagation characteristics for body-area networks have become an active area of research. In this paper, a cavity slot antenna is proposed for onbody communications at 2.45 GHz. First, the antenna characteristics (input impedance, radiation pattern, and efficiency) are calculated by the finite-difference time-domain method. The results show that the proposed antenna has a relatively high efficiency of more than 50% even in the vicinity of the human body. Next, the onbody radio wave-propagation characteristics are investigated through numerical simulation and experimental measurements of the electric-field distributions around a phantom with a simplified shape of a human arm. Both sets of results are then compared and discussed. Finally, good agreement between the measured and the calculated results is confirmed.Index Terms-Body-area network (BAN), body-centric wireless communications, cavity slot antennas, onbody communications.

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“…It is evident that particular areas of the body have unique characteristics, thereby affecting the performance of the radio channel [1]. Furthermore, external perturbations, such as human mobility [3] and operation in cluttered backgrounds [4], result in a complex environment for the propagation characteristics of body-worn sensors. Usually, these are comprised of low-power microcontrollers, tiny radio frequency (RF) transceivers and compact antennas that have low gain and narrow bandwidth (low-profile antennas).…”

Section: Introductionmentioning

confidence: 99%

Exploring Physiological Parameters in Dynamic WBAN Channels

Munoz

Foster

Hao

2014

IEEE Trans. Antennas Propagat.

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On-body radio propagation in the 2.45 GHz ISM frequency band (2.40-2.48 GHz) was investigated during three different activities, jogging, rowing and cycling. Four different links were examined, from the waist to the wrist, ankle, chest and back; it was observed that the channel behavior could be related to the repetitive nature of the activities. Furthermore, combinations of the wrist, ankle and chest channels could potentially be used to identify the activity, whilst the waist-back channel show little variation between activities (roughly 2 dB, compared to 6-15 dB for the other links).The results also show that dynamic on-body radio channels contain rich biomechanical information, such as motion pattern, heartbeat and breathing process. It is demonstrated that physiological and kinetic features can, therefore, be extracted through some known signal processing techniques. For example, the repetitive nature of the activities introduces harmonics into the signal via the fading, which correspond to the speed of motion. In addition, the mechanical motion of the torso during respiration and cardiac activity also introduce harmonics due to changes in the path loss, albeit with low magnitudes. The detection of such signals is discussed.

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Measurements and simulations for on-body antenna design and propagation studies

Cited by 7 publications

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Electric field distributions around the human body with a small antenna in the frequency range of 2.5 MHz to 2.5 GHz

Electric field distributions around the human body with a small antenna in the frequency range of 2.5 MHz to 2.5 GHz

Characteristics of Cavity Slot Antenna for Body-Area Networks

Exploring Physiological Parameters in Dynamic WBAN Channels

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