W2344EP Datasheet, PDF (4/10 Pages) Keysight Technologies – 3D Electromagnetic Modeling

EMPro Simulation Capabilities
There are several different technical approaches to EM simulation, each with their own advantages in certain application
areas. The most established 3D EM simulation technologies are FEM and FDTD. Both of these technologies are available
in EMPro.
Finite element method
FEM is a frequency-domain technique that can handle arbitrary shaped
structures such as bondwires, conical shape vias and solder balls/bumps where
z-dimensional changes appear in the structure. FEM solvers can also simulate
dielectric bricks or finite-size substrates.
FEM is based on volumetric meshing where the full problem space is divided
into thousands of smaller regions and represents the field in each sub-region
(element) with a local function. The geometric model is automatically divided
into a large number of tetrahedra, where a single tetrahedron is formed by four
equilateral triangles. This collection of tetrahedra is referred to as the finite
element mesh. The Keysight Technologies, Inc. FEM simulator includes both
direct and iterative solvers, and both linear and quadratic basis functions, to
solve a broad range of problems. The same FEM simulator is available in both
EMPro and ADS. EMPro supports remote simulation and distributed frequency
sweeps for FEM.
Finite difference time domain
As with FEM, the FDTD method is based on volumetric sampling of the electric
and magnetic fields throughout the complete space. Whereas FEM meshes
consist of tetrahedral cells, FDTD meshes are typically built from rectangular
(Yee) cells. The FDTD method updates the field values while stepping through
time, following the electromagnetic waves as they propagate through the
structure. As a result, a single FDTD simulation can provide data over an ultra-
wide frequency range.
Because of its simple, robust nature and its ability to incorporate a broad range
of linear and nonlinear materials and devices, FDTD is used to study a wide
range of applications, including: antenna design, microwave circuits, bio/EM
effects, EMC/EMI problems, and photonics. FDTD is an inherently parallel
method and therefore lends itself very well to the processing capabilities of the
most recent advances in CPU (general-purpose processors) and GPU (graphics
processors) hardware. EMPro also supports remote simulation and distributed
port simulations for FDTD.
Table 1. Summary comparison of FEM versus FDTD
FEM
FDTD
Frequency domain method
Time domain method
Tetrahedral mesh cells
Good for high-Q structures
Rectangular mesh cells
Good for broadband applications, physical transitions
Fast for multi-port simulations
Each port requires additional simulation
Based on solving matrix equations; best for electrically small
problems
Based on iterative time stepping; less memory intensive for
electrically large problems
Multi-threaded; problems can be divided and run in parallel on Highly multi-threaded; problems can be divided and run in
multi-core CPUs
parallel on multi-core CPUs and on large GPU cards
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