Modeling and Characterization of Biotelemetric Radio Channel From Ingested Implants Considering Organ Contents

Abstract

The paper introduces numerical and experimental investigations of biotelemetry radio channels and wave attenuation in human subjects with ingested wireless implants. The study covers commonly used frequencies in telemedicine applications: ultrahigh frequencies at 402 MHz, 868 MHz and the industrial, scientific and medical (ISM) band frequency at 2.4 GHz. Numerical electromagnetic analysis is applied to model in/on-body radio propagation channels and the resulted parameters demonstrated the importance of digital phantom accuracy in ccharacterization of wave absorption and attenuation with regards to organ contents, specifically for the digestion system. Path gain variations of biotelemetry radio channels, in the close vicinity of the subject, with wireless implants were measured using a near field scanner. Simulation results were verified with measurement in good agreement.Index Terms-Biotelemetry radio channel, electromagnetic time-domain numerical technique, ingested medical implants, wave propagation.

Experimental Path Loss Models for In-Body Communications within 2.36-2.5 GHz

“…However, no mathematical formulas for the path loss were provided in that study. On the other hand, numerical and experimental path loss investigations with ingested wireless implants in 402 MHz, 868 MHz, and 2.4 GHz were presented in [26]. A logdistance path loss formula as a function of the propagation distance, d, was introduced for the in-body to on-body channel scenario.…”

In Vivo Communications: Steps Toward the Next Generation of Implantable Devices

“…The parameters for anatomical regions are provided in [13] and electromagnetic properties such as, conductivity, relative permittivity, loss tangent, penetration depth can be derived using these parameters and Eq. tissues for experimental and numerical investigation [9]. They can be classified as homogeneous, multi-layered and heterogeneous phantom models.…”

“…However, performing experiments on a living human is carefully regulated. Therefore, anesthetized animals [14], [15] under anesthesia or physical phantoms [9], [16] are often used for experimental investigation.…”

Extraction of antenna gain from path loss model for in-body communication

“…This need arises as the human body is a lossy medium which considerably attenuates the electromagnetic waves traveling from the transmitter (Tx) to the receiver (Rx). Up to now, in literature various PL models have been proposed for in-body propagation but the gains of the Tx and Rx antennas are always included in the models, limiting the general usability [1]. In this letter, we make for the first time in-body path loss (PL) independent of the antenna by extracting the antenna gains from the PL for two different types of antennas within homogeneous lossy human muscle and head tissue.…”