Feko is a comprehensive electromagnetic solver with multiple solution methods that is used for electromagnetic field analyses
involving 3D objects of arbitrary shapes.
EDITFEKO is used to construct advanced models (both the geometry and solution requirements) using a high-level scripting language
which includes loops and conditional statements.
One of the key features in Feko is that it includes a broad set of unique and hybridised solution methods. Effective use of Feko features requires an understanding of the available methods.
Feko offers state-of-the-art optimisation engines based on generic algorithm (GA) and other methods, which can be used
to automatically optimise the design and determine the optimum solution.
Feko writes all the results to an ASCII output file .out as well as a binary output file .bof for usage by POSTFEKO. Use the .out file to obtain additional information about the solution.
The MRI application macro computes , , their ratio and the intrinsic signal-to-noise ratio (ISNR) for magnetic resonance imaging (MRI) investigations in POSTFEKO.
The radiation phase centre is a useful quantity to calculate, especially for reflector antennas. The phase centre calculation
is not available in Feko by default, but a stand-alone application macro is available that can be used to calculate the phase centre of a calculated far field.
This POSTFEKOapplication macro can be used to plot all the standard parameters that are available after a characteristic mode analysis simulation
was performed.
This application macro is used for calculating mean effective gain (MEG) and envelope correlation coefficient (ECC) for a MIMO antenna configuration.
The MEG ratio can also be plotted.
The Multiport post-processingapplication macro allows you to calculate results for changes in the port loading without rerunning the Solver. Results that are supported are far fields, near fields, currents and specific port parameters, for example,
the voltage, current and S-parameters of each port.
A Lua implementation of the transient Pennes bioheat equation using finite differences and explicit time stepping for calculating
thermal results in POSTFEKO.
The characteristic mode synthesis and design application macro is a post-processing application macro that can be used to calculate a weighted sum for the currents, near fields, and far fields requests for specific
characteristic modes of interest. The application macro uses a modified version of the modal weighting coefficient (MWC) to use the radiating phase when synthesising
the results with the macro.
CADFEKO and POSTFEKO have a powerful, fast, lightweight scripting language integrated into the application allowing you to create
models, get hold of simulation results and model configuration information as well as manipulation of data and automate
repetitive tasks.
A Lua implementation of the transient Pennes bioheat equation using finite differences and explicit time stepping for calculating
thermal results in POSTFEKO.
The example focuses on the thermal analysis of a hip implant in an MRI
system.
During an experimental safety test setup, an implant is placed in an ASTM-2009 phantom
designed according to the ASTM F2182-09 standard.1 The
phantom is filled with a gel that has averaged material properties similar to those of
human tissue. The implant is positioned near the edge of the phantom, where the field
gradients are high to emulate a potential worst-case scenario. The phantom with the
implant is placed in an MRI scanner and the temperature rise is monitored.
The specific absorption rate (SAR) results at 64 MHz when the MRI coil accepts a power of
38 W of which 30 W is absorbed in the phantom gel, shows the implant has a strong
influence on the fields. Localised peaks in the SAR distribution can be seen at the tips
of the implant.
1 Standard F2182–09, “Standard Test
Method for Measurement of Radio Frequency Induced Heating Near Passive Implants
During Magnetic Resonance Imaging”, ASTM International, http://%E2%81%A0www.astm.org.