Bio Electromagnetics

Inhomogeneous Human Model in FEKO
Head with hand and phone

Highly Inhomogeneous Bodies

Volume discretisation techniques such as the Finite Difference Time Domain (FDTD) or Finite Element Method (FEM) are most suitable, and therefore popular, for the analysis of highly inhomogeneous dielectric bodies.

The hybrid MoM/FEM as implemented in FEKO, is particularly suitable for cases where there is a free space region of arbitrary size between the antenna and the dielectric body. The advantage offered by the MoM/FEM hybrid is that the free space between the MoM region (antenna) and the FEM region (dielectric body) does not have to be discretised leading to a reduction in memory and runtime requirements.

Partly homogeneous dielectric bodies, which can also be nested within each other (e.g. eyes and a brain inside a head volume), can be solved using the Surface Equivalence Principle (SEP). The SEP is however not efficient for highly inhomogeneous models and the FEM should therefore be used.

Homogeneous Bodies

For many applications it is not essential to take the inhomogeneous nature of the dielectric body into account (for example radiation patterns and input impedance calculations). SAR (Specific Absorption Rate) compliance measurements are also normally done in phantoms filled with a homogeneous liquid simulating the human head. Simulations should therefore be done using a homogeneous body in order to have proper comparison between the measurement and simulation environments.

In FEKO homogeneous dielectric bodies can be simulated using either the MoM (SEP) or the FEM, where all tetrahedral volume elements are assigned the same dielectric properties.

Specific Applications

• Mobile phone and other mobile device design, e.g. PDA, blue tooth applications.
• Mobile phone base station compliance analysis.
• Calculation of RF fields inside automobiles.
• Biomedical applications, e.g. pacemakers.

Specific Absorption Rate (SAR) Extraction

FEKO has been thoroughly verified through measurements as well as comparisons to other CEM codes for field calculations inside dielectric volumes. Special routines have been implemented for the extraction of maximum SAR according to the ICNIRP compliance regulations. Spatial peak SAR searching can also be done using parallel processing.

FEKO Models of human body, head and hand

Surface Equivalence Principle (SEP)
Articulated (parametric) Human (SEP and FEM) Articulated Hand (SEP) IEEE Head (SEP)

Finite Element Method (FEM)
Visible Human Full Model (Inhomogeneous FEM) Visible Human Head and Shoulders (Inhomogeneous FEM) Visible Human Head (Inhomogeneous FEM) IEEE SAM (Homogeneous FEM) Hugo 4 organs (FEM)