Jonathan Bringuier

Electromagnetic Wave Propagation in Body Area Networks Using the Finite-Difference-Time-Domain Method

A rigorous full-wave solution, via the Finite-Difference-Time-Domain (FDTD) method, is performed in an attempt to obtain realistic communication channel models for on-body wireless transmission in Body-Area-Networks (BANs), which are local data networks using the human body as a propagation medium. The problem of modeling the coupling between body mounted antennas is often not amenable to attack by hybrid techniques owing to the complex nature of the human body. For instance, the time-domain Greens function approach becomes more involved when the antennas are not conformal. Furthermore, the human body is irregular in shape and has dispersion properties that are unique. One consequence of this is that we must resort to modeling the antenna network mounted on the body in its entirety, and the number of degrees of freedom (DoFs) can be on the order of billions. Even so, this type of problem can still be modeled by employing a parallel version of the FDTD algorithm running on a cluster. Lastly, we note that the results of rigorous simulation of BANs can serve as benchmarks for comparison with the abundance of measurement data.

Modeling and Design of Wideband Antennas For Body Area Networks (BANs)

Recently, there has a growing interest in the development and implementation of body area networks. These systems are intended to operate in a similar fashion to wireless land area networks (WLAN) with exception that they are strictly confined to the human body. This type of technology has risen in demand due to the growing abundance of portable computing devices. However, the human body creates a challenging environment for the design of wearable antennas that can communicate efficiently. As a result, a detailed study of the on body communication channel is required. Lastly, many of these systems are intended to operate over a very wide frequency band. Therefore, the design of ultra wide band antennas (UWB) is a pertinent area of research in this technology

Modeling of interaction between body-mounted antennas

As wearable electronic devices continue to become popularized, there is an increasing demand for these components to provide the capability of exchanging data wireless with high capacity. Currently, there is strong motivation for the development of body-centric link networks. The efficiency of these networks relies heavily on the propagation characteristics of radiated energy in the presence of the user. To properly design such systems, a careful study of this behavior and the appropriate choice of the antenna are necessary. In this paper, the authors have addressed both the coupling of antennas mounted on the body and the design of ultra-wide-band antennas (UWB) which meet the required capacity of such systems.

Spectral evaluation of stirring effect in a reverberation chamber

The spectral field data on the observation planes inside a mode stirred chamber have been computed by using the FDTD method. They can describe the directional dependence in the reverberation chamber. Correlation coefficients have been found to evaluate the stirring effects. The correlation coefficients were obtained and compared for three different sizes of stirrers and statistical uniformity was investigated.

Full-wave simulation of Body Area Networks using the FDTD method

In this paper the authors provide a rigorous full-wave simulation of Body Area Networks (BANs) using the FDTD. Some relevant statistical parameters for path loss are presented for different body-phantom models.

Some novel techniques for size reduction of microstrip patch antennas

In this article, we detail the design of a size-reduced antenna that can be conveniently fabricated by using the LTCC process, and present some examples of a modified design that enables us to further reduce the size of the antenna than that achievable by using the side-loading approach alone. The additional size-reduction is realized by routing the current distribution on the patch along a circuitous path to effectively increase its resonant length.

Closely coupled booster radiators to improve OTA performance of 4G mobile handsets

Two independent CPL (Compound Planar Loop) antennas are integrated inside a plastic phone case. Significant OTA (Over-the-Air) performance enhancement of the mobile device is observed by applying this phone case onto the device. The coupled energy will then induce the characteristic compound EM field due to the unique structure of CPL antenna design and re-radiate into the farfield. Higher gain with desired radiation pattern and polarization can be achieved with optimized CPL design. While improving the radiated performance of the device, reduced SAR (Specific Absorption Rate) performance is also observed with the CPL re-radiator structure.

A numerically efficient approach to metamaterial (MTM) modeling

Ever since the existence of negative refraction by metamaterial prisms was demonstrated by Pendry, Smith and others about a decade ago, the subject has received a tremendous amount of attention from many researchers around the world. A special class of MTMs, namely double negative or DNG type of artificially synthesized materials, has been used not only to design superlenses, but to also enhance the directivity of antennas, such as microstrip patch antennas (MPAs) [1–2]. In the process, the terms MTMs and DNGs have become almost synonymous; it is not uncommon to find them being used interchangeably with one another in the literature.

Efficient analysis of frequency selective surfaces using the Ewald transform

A novel approach to analyze FSS structures is used whereby the Ewald transform technique, in conjunction with a particular choice of basis function, is shown to reduce the complexity of the problem formulation and greatly improve the convergence rate of the MoM solution for periodic structures. In particular, we consider wire-type geometries, which need not be confined to a single plane configuration, to demonstrate the effectiveness of this method.

An approach for solving the time domain electric field integral equation (TD-EFIE) utilizing a novel basis function

In this paper we present a novel technique for solving the time domain electric field integral equation (TD-EFIE). This approach is based on a new choice for the basis functions in the time domain that have closed-form representations and are causal.