A Voxel Vascular Structure-based Mannequin-like Arm Electromagnetic Model for Radio Frequency Biomedical Sensors.

Radio Frequency (RF) sensor is widely used to monitor physiological signals. Generally, RF sensor simulation is mostly done using a layered model, which sometimes cannot model the accurate properties in the real world. A voxel vascular structure-based mannequin-like arm electromagnetic model (VVS-MaM) is proposed to evaluate the RF sensor, which mainly gathers the real physiological signal. This model is built with high-precision Magnetic Resonance Imaging (MRI), and it can finish fast simulation while there is also a voxel-like part in it which means it has the advantages of both the layered model and the real human model. After modelling, both simulation and in-vivo experiments are designed to test this sensor. In the simulation, the simulated standard resonant frequency of the equivalent model is 1.8137 GHz, and the relative error of the VVS-MaM is 0.012 GHz, which is closer to the standard value than the layer model result of 0.049 GHz. Meanwhile, in the in-vivo experiments, an RF sensor based on a composite right/left-handed transmission line (CRLH-TL) and complementary split resonator rings (CSRRs) are fabricated, and the measurements from the real experiments are gathered and stored to compare with that of the simulation. The comparison shows that the relative error of the VVS-MaM (0.08804 GHz)is closer to the in-vivo measurements than that of the layer model (0.09891 GHz), which validates the performance of VVS-MaM.Clinical Relevance-Radio Frequency, magnetic resonance imaging, scattering parameter, composite right/left-handed, complementary split resonator ring.

Modeling and characterization of different channels based on human body communication.

Human body communication (HBC), which uses the human body as a transmission medium for electrical signals, provides a prospective communication solution for body sensor networks (BSNs). In this paper, an inhomogeneous model which includes the tissue layers of skin, fat, and muscle is proposed to study the propagation characteristics of different HBC channels. Specifically, the HBC channels, namely, the on-body to on-body (OB-OB)channel, on-body to in-body (OB-IB) channel, in-body to on-body (IB-OB) channel, and in-body to in-body (IB-IB)channel, are studied over different frequencies (from 1MHz to 100MHz) through numerical simulations with finite-difference time-domain (FDTD) method. The results show that the gain of OB-IB channel and IB-OB channel is almost the same. The gain of IB-IB channel is greater than other channels in the frequency range 1MHz to 70MHz. In addition, the gain of all channels is associated with the channel length and communication frequency. The simulations are verified by experimental measurements in a porcine tissue sample. The results show that the simulations are in agreement with the measurements.

Characterization and analysis of dynamic implant communication channels based on inhomogeneous model.

Implant communication plays an important role in achieving information exchange among implantable devices in personal health care. In this paper, the characteristics of dynamic implant communication channels (ICCs) are studied by using a set of 30 inhomogeneous human body models (frames) which corresponded to one period of a walking motion. The gain variations of three different ICCs (from belly to head, right wrist, and right ankle) are investigated at 21MHz, 403.5MHz, and 2.45GHz, respectively. The results show that the ICC gain may be affected by body posture, body shadowing effect, multipath fading, and earth ground. In addition, compared with the ICC gain at 403.5MHz and 2.45GHz, the ICC gain at 21MHz is motion-insensitive in implant communication.