H.-O. Ruoss

Numerical study on an equivalent source model for inhomogeneous magnetic field dosimetry in the low-frequency range

A new equivalent numerical source model is proposed for efficient dosimetric investigations in the low-frequency range. This approach allows the reproduction of complicated inhomogeneous magnetic field distributions around electronic appliances with full generality (i.e., supports three-dimensional vector fields). This paper investigates the accuracy of the equivalent source model using the geometry-based numerical reference model of a current loop to simulate the magnetic field distribution of a real electronic appliance. Good agreement between the equivalent source model and the reference is obtained with regard to the magnetic field distribution and the induced electric current density in a homogeneous human body model, respectively.

Hybridisation of MoM and GMT for the numerical analysis of electromagnetic sources radiating in the vicinity of persons with implanted cardiac pacemakers

An iterative combination of the MoM (method of moments) and the GMT (generalised multipole technique) is presented for the analysis of electromagnetic sources radiating close to a human body with implanted cardiac pacemaker. The metallic parts (source and pacemaker) are treated by MoM, while the influence of the smooth dielectric body is taken into account by GMT.

Optimization of Handset Antennas to Reduce Interaction with the User

When using a handset close to the human body a considerable mutual interaction between the antenna and the biological tissue occurs. When investigating this interaction, the main emphasis can be put to either dosimetry or engineering aspects such as the optimization of the antenna. In either case a theoretical and experimental evaluation of the electromagnetic fields is necessary to determine the relevant parameters. These are the specific absorption rate (SAR) in the case of dosimetry and input impedance, radiation patterns, power budget and efficiency when considering the antenna performance. In our work we have developed methods for numerical calculations and measurement techniques in order to design an antenna concept that reduces interaction with the user.

Efficient MOM-based calculation methods to investigate the interaction between complicated antenna structures and biological bodies

In this paper efficient solution techniques are presented which allow a fast and memory economical analysis of complicated antenna structures (e.g. a portable mobile telephone) radiating in the close vicinity of biological bodies. The computation is based on the method of moments, which we combine with physical optics, a special Green’s function expansion for certain layered geometries, and the multiple multipole method. The three different hybrid techniques are discussed and an example is presented to illustrate the application.RésuméCet article présente des procédés de résolution efficaces permettant une analyse rapide et peu coûteuse en mémoire de structures complexes à antennes (notamment de téléphones portables), rayonnant à proximité de corps biologiques. Les calculs sont bases sur la méthode des moments, à laquelle sont combinés les principes de I’optique physique, une extension de la fonction de Green, spéciale pour certaines géométries en couches, ou encore la méthode du multipole multiple. Ces trois procédes hybrides différents sont discuteś et l’application est illustrée à I’aide d’un exemple.