An Ultrawideband Conformal Capsule Antenna With Stable Impedance Matching

Bao, Zengdi; Guo, Yong‐Xin; Mittra, R.

doi:10.1109/tap.2017.2741027

Cited by 77 publications

(32 citation statements)

References 18 publications

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“…Many studies exist on the radio link of WCE systems, e.g., [7]- [10], [10]- [13], [13]- [18]. The in-body-to-on-body (IB2OB) link models discussed in [10], [13]- [15] consider frequencies above 1 GHz, leading to higher path loss compared to below 1 GHz.…”

Section: A Review Of Radio Link Studiesmentioning

confidence: 99%

“…The in-body-to-on-body (IB2OB) link models discussed in [10], [13]- [15] consider frequencies above 1 GHz, leading to higher path loss compared to below 1 GHz. Additionally, papers [7]- [13], [18] present IB2OB radio links, where the outside-body antenna is not in contact with the body. Placing the receiving antenna close to the human abdomen instead of further away achieves a smaller path loss [19].…”

Section: A Review Of Radio Link Studiesmentioning

confidence: 99%

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Antenna System Design for Improved Wireless Capsule Endoscope Links at 433 MHz

Miah

Khan

Icheln

et al. 2019

IEEE Trans. Antennas Propagat.

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Wireless capsule endoscopy (WCE) systems are used to capture images of the human digestive tract for medical applications. The antenna is one of the most important components in a WCE system. In this paper, we present novel small antenna solutions for a WCE system operating at the 433 MHz ISM band along with a link budget analysis. The in-body capsule transmitter uses an ultrawideband outer-wall conformal loop antenna, whereas the on-body receiver uses a printed monopole antenna with a partial ground plane. A colon-equivalent tissue phantom and CST Gustav voxel human body model were used for the numerical studies of the capsule antenna. The simulation results in the colon-tissue phantom were validated through in-vitro measurements using a liquid phantom. According to the phantom simulations, the capsule antenna has −10 dB impedance matching from 309 to 1104 MHz. The ultrawideband characteristic enables the capsule antenna to tolerate the detuning effects due to electronic modules in the capsule and due to the proximity of various different tissues in gastrointestinal tracts. The same design methodology was applied to on-body antennas followed by in-vitro and ex-vivo measurements for validation. The on-body antenna exceeds −10 dB impedance matching from 385 MHz to 502 MHz both in simulations and measurements. The path loss for the radio link between an in-body capsule transmitter and an on-body receiver using our antenna solutions, in simulations and measurements, is less than 50 dB for any capsule orientation and location, ensuring sufficient signal level at the receiver, hereby enabling an improved capsule endoscope.Index Terms-Conformal antenna, in-to-on body propagation, wireless capsule endoscope.

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Section: A Review Of Radio Link Studiesmentioning

confidence: 99%

Section: A Review Of Radio Link Studiesmentioning

confidence: 99%

Antenna System Design for Improved Wireless Capsule Endoscope Links at 433 MHz

Miah

Khan

Icheln

et al. 2019

IEEE Trans. Antennas Propagat.

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show abstract

“…Therefore, the radiation efficiency has to be sacrificed [36]- [39]. Bao et al, however, developed a workaround to increase the robustness to environment by designing a wideband slot-loop antenna [2].…”

Section: Antenna Design Approachesmentioning

confidence: 99%

“…Body-implanted devices can monitor physiological parameters, perform treatments, or establish neural interfaces while maintaining mobility and quality of life of a patient [1]. The devices rely on antennas to transmit biotelemetry data or to receive operational and treatment instructions [2]- [5]. Multi-band antennas can integrate both data transmission and wireless power transfer functionality increasing the available space inside an in-body device [6].…”

Section: Introductionmentioning

confidence: 99%

Modeling and Characterization of in-Body Antennas

Nikolayev

2018

2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET)

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Emerging wireless in-body devices pave the way to many breakthroughs in healthcare and clinical research. This technology enables monitoring of physiological parameters while maintaining mobility and freedom of movement of its user. However, establishing reliable communication between an in-body device and external equipment is still a major challenge. The radiation efficiency is constrained by attenuation and reflection losses in tissues. Furthermore, the antennas suffer from impedance detuning issues caused by uncertain electromagnetic properties of body tissues. First, we show that choosing an optimal operating frequency depends on application scenarios and can reduce the losses. Specific designs are then discussed to mitigate the antenna detuning effects due to surrounding biological tissue. Modeling approaches are proposed to lessen the design and optimization complexity. Finally, we present an accurate characterization method of in-body antennas in canonical phantoms using analog fiber optic links.

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“…A wireless in-body device relies on antennas to interface with external systems [4]- [7]. However, the electromagnetic (EM) energy transfer between an in-body device and an external transceiver is generally inefficient.…”

mentioning

confidence: 99%

Impact of Tissue Electromagnetic Properties on Radiation Performance of In-Body Antennas

Nikolayev

Zhadobov

Sauleau

2018

Antennas Wirel. Propag. Lett.

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Abstract-In-body antennas couple strongly to surrounding biological tissues thus resulting in radiation efficiencies well below 1%. Here, we quantify how the permittivity and conductivity, each individually, affect the radiation efficiency of miniature implantable and ingestible antennas. We use a generic pill-sized capsule antenna and a spherical homogeneous phantom with its electromagnetic properties covering the complete range of body tissues. In addition to the phantom surrounded by air, we study the case with a reduced phantom-background contrast (nonresonant case) that allows for decoupling of the obtained results from the phantom shape. The results demonstrate that, for a realistic capsule antenna, the effect of dielectric loading by tissue can partially compensate for the tissue losses. For instance, the gain of the antenna operating in the muscleequivalent medium is about two times (3 dBi) higher than in the fat-equivalent one, even though the conductivity of muscle is one order of magnitude higher than the one of fat. The results suggest that, in majority of cases, in-body devices should be designed for and be placed within higher permittivity tissues with low to moderate losses.Index Terms-biomedical telemetry, implantable, in-body, ingestible, ISM (industrial, scientific, and medical) band.

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An Ultrawideband Conformal Capsule Antenna With Stable Impedance Matching

Cited by 77 publications

References 18 publications

Antenna System Design for Improved Wireless Capsule Endoscope Links at 433 MHz

Antenna System Design for Improved Wireless Capsule Endoscope Links at 433 MHz

Modeling and Characterization of in-Body Antennas

Impact of Tissue Electromagnetic Properties on Radiation Performance of In-Body Antennas

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