This paper presents a study on the power distribution within the tissues for abdominal monitoring and implant communications systems. This study is carried out using finite integration technique based simulations with an anatomical voxel model as well as with recently introduced directive on-body antennas designed for in-body communications. The investigation is conducted by evaluating 2D power flow on the cross-cut of the abdomen area to illustrate the propagation inside the different abdominal tissues. Additionally, power values in different parts of the abdomen area, such as in different parts of the small intestine (SI), colon, stomach etc., are calculated. The main purpose is to examine power distribution in the abdominal area with different antenna location options suitable for abdomen monitoring systems. Furthermore, channel characteristics between an endoscope capsule and an on-body antenna are evaluated in two different areas of the SI tract: close to the on-body antenna and further from the on-body antenna. Power distribution information is useful when designing the medical and health monitoring devices for the abdomen area, such as capsule endoscope, gastrointestinal activity monitoring systems, etc.

A novel UWB antenna working in the 805.15.6 Low-UWB region is proposed in this paper. The antenna is targeted for Wireless Capsule Endoscopy (WCE) localization. Simulation results show that the antenna performs well at 4 GHz with a 500 MHz bandwidth which is complaint with the IEEE 802.15.6 standard for Body Area Networks (BAN). A preliminary study on the single antenna performance is presented first, followed by the introduction of the boxshaped cavity version of the antenna structure. Both types of antenna are directional with high gain. To investigate WCE applications, the cavity antenna in proximity of a multi-layer model emulating human body tissues properties at 4 GHz was also simulated.

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.

This paper presents a study on the radio channel characteristics between an endoscope capsule and an on-body antenna in different parts of the small intestine with different onbody antenna location options. The study is conducted using finite integration technique based electromagnetic simulation software CST and one of its anatomical voxels. An endoscope capsule model with a dipole antenna is set inside different areas of the small intestine of the voxel model. A recently published highly-directive on-body antenna designed for on-in-body communications is used in the evaluations. Different rotation angles of the capsule are also considered both with a layer model and a voxel model. It is found that radio 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. However, the 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 onbody antennas. Furthermore, orientation of the capsule has also strong impact when linearly polarized antennas are used.

This paper presents a study of the radio channel characteristics between a capsule endoscopy and a multi onbody antenna system on ultra wideband wireless body area networks (UWB-WBAN). Multiple on-body antennas are required to provide reliable communication link between the capsule and the on-body device, but also essential for capsule localization. The main aim is to study the variation of the frequency and time domain channel characteristics for the selected on-body antennas in different capsule locations, including the most challenging capsule locations deep inside the tissues or far away from most of the antennas. This study also evaluates whether five of selected type directive on-body antennas is enough to cover the intestine area thoroughly. The study is conducted with CST Studio Suite simulations and one of its anatomical voxel models. A simplified capsule model and a directive on-body antenna designed for low-band UWB inbody communications are used in this study. It is found that five of this type directive on-body antennas provide sufficient coverage over the intestine area even in the most challenging capsule locations. In certain capsule locations, the variation between the channel attenuations can be significant, over 40 dB within the frequency range of interest, if the capsule is located deep inside the tissues without smooth access to outer fat layer through which the signal could travel easily to different on-body antennas. Instead, if the capsule is located close to the subcutaneous fat layer, the channel attenuation is moderate even for the antennas which are located far from the capsule.