semba-fdtd

In a nutshell, semba-fdtd capabilities are

• Cluster working capabilites through MPI.

• Multiple threads per processor through OpenMP.

• Closed/symmetric problems by means of PEC and PMC conditions.

• Open problems by means of PML boundary conditions (CPML formulation) or by Mur ABCs.

• Non-uniformly meshed domains by means of rectilinear (or graded) meshes.

• Bulk lossless and lossy dielectrics.

• Materials with frequency dependent relative permittivity and/or permeability, with an arbitrary number of complex-conjugate pole-residue pairs.

• Bulk anisotropic lossless and lossy dielectrics.

• Equivalent models of multilayered skin-depth materials.

• Branched multiwires.

• Multiconductor transmission lines networks embedded within 3D FDTD solvers.

• Coupling with SPICE solvers (ngspice).

• Junctions of wires of different radii.

  1. Junctions of multiwires.
  2. Wire bundles.
  3. Loaded with p.u.l resistance and inductance wires.
  4. Grounding through lumped elements.

• Plane-wave illumination with arbitrary time variation.

• Multiple planewaves illumination for reverberation chamber modeling.

• Hertzian dipole sources.

• Equivalent Huygens surfaces.

• Low frequency thin composites and lossy surfaces.

• Thin slots.

• Time, frequency and transfer function probes.

• Near-to-far field transformation.

Usage

Running from prebuilt binary releases

Prebuilt binares are available at releases.

In windows, you need to install intel oneapi runtime libraries.

Compilation

It is important to point out the repository has dependencies which are available as submodules. It is necessary to run git submodule init and git submodule update from the root folder before running any cmake or build commands.

If you use intel oneapi compiler, make sure to run

  source /opt/intel/oneapi/compiler/latest/env/vars.sh
  export FC=ifx
  export CC=icx
  export CXX=icpx

Compilation options

HDF5 Libraries

HDF5 precompiled libraries for ubuntu are used by default (see precompiled libraries cmake script).

You can compile HDF5 for your specific platform downloading the latest sources from this link. Extract to a folder and build and install with the following commands

  cmake -S . -B build-ifx --fresh -DHDF5_BUILD_FORTRAN=YES
  cmake --build build-ifx -j 
  cmake --install build-ifx --prefix ~/hdf5-installed 

A specific HDF5 library can be set with the option -DHDF5_ROOT=<path-to-library>, e.g.

  cmake -S . -B build -DCMAKE_BUILD_TYPE=Release -DHDF5_ROOT=~/hdf5-installed -DHDF5_USE_STATIC_LIBRARIES=TRUE --fresh 
  cmake --build build -j

MTLN and ngspice

MTLN depends on lapack and ngspice. Precompiled versions are included for windows (intelLLVM) and ubuntu (intelLLVM and GNU). For other platform/compilers these will need to be compiled.

Compiling ngspice

In linux, when using some of the provided scripts you may find problems with carriage returns. These can be fixed with:

sed -i -e 's/\r$//' compile_linux.sh
sed -i -e 's/\r$//' autogen.sh
find . -name \*.m4|xargs dos2unix\nfind . -name \*.ac|xargs dos2unix\nfind . -name \*.am|xargs dos2unix

the ngspice static library can be compiled doing the following:

1. Edit configure.ac, to AC_SUBST([STATIC], [-static])
2. Edit compile_linux_shared.sh, to

libngspice_la_CFLAGS = -static

libngspice_la_LDFLAGS = -static -version-info @LIB_VERSION@

MPI

If you use intel oneapi, make sure to load the mpi environment variables:

  source /opt/intel/oneapi/mpi/latest/env/vars.sh

Testing

Tests must be run from the root folder. python wrapper test assumes that semba-fdtd has been compiled successfully and is located in folder build/bin/. For intel compilation it also assumes that the intel runtime libraries are accessible.

Running cases

semba-fdtd uses the following format as input files. These can be run with

  semba-fdtd -i CASE_NAME.fdtd.json

License

This code is licensed under the terms of the MIT License. All rights reserved by the University of Granada (Spain)

References

• Miguel Ruiz Cabello, Maksims Abalenkovs, Luis Diaz Angulo, Clemente Cobos Sanchez, Franco Moglie, Salvador Gonzalez Garcia, Performance of parallel FDTD method for shared- and distributed-memory architectures: Application to bioelectromagnetics. PLOS ONE. 2020. https://doi.org/10.1371/journal.pone.0238115
• Luis Diaz Angulo, Miguel Ruiz Cabello, Jesus Alvarez, Amelia Rubio Bretones, Salvador Gonzalez Garcia, From Microscopic to Macroscopic Description of Composite Thin Panels: A Road Map for Their Simulation in Time Domain. IEEE Transactions on Microwave Theory and Techniques. 2018. https://doi.org/10.1109/TMTT.2017.2786263.
• Miguel Ruiz Cabello, Luis Diaz Angulo, Jesus Alvarez, Ian Flintoft, Samuel Bourke, John Dawson, A Hybrid Crank–Nicolson FDTD Subgridding Boundary Condition for Lossy Thin-Layer Modeling. IEEE Transactions on Microwave Theory and Techniques. 2017. https://doi.org/10.1109/TMTT.2016.2637348.
• Miguel Ruiz Cabello, Luis Diaz Angulo, Amelia Rubio Bretones, Rafael Gomez Martin, Salvador Gonzalez Garcia and Jesus Alvarez, A novel subgriding scheme for arbitrarily dispersive thin-layer modeling, 2017 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO), Seville, Spain, 2017. https://doi.org/10.1109/NEMO.2017.7964255.
• Guadalupe Gutierrez Gutierrez, Daniel Mateos Romero, Miguel Ruiz Cabello, Enrique Pascual-Gil, Luis Diaz Angulo, David Garcia Gomez, Salvador Gonzalez Garcia, On the Design of Aircraft Electrical Structure Networks, IEEE Transactions on Electromagnetic Compatibility. 2016. https://doi.org/10.1109/TEMC.2016.2514379.