AntennaDesign.wikiAntenna design, explained

How does the finite element method simulate antennas?

From Antenna Design Wiki · By the · Published · Last reviewed · How we research

The finite element method (FEM) solves the vector wave equation in a volume around the antenna that is meshed into tetrahedra, using vector (edge) basis functions and a sparse matrix solved at each frequency. Adaptive mesh refinement driven by error estimates, as in Ansys HFSS, gives high accuracy for complex geometries and materials; the volume is terminated by absorbing boundaries or perfectly matched layers.[1][2]

Why are edge elements used?

Nodal elements for vector fields generate spurious non-physical solutions. Edge (Nédélec) elements assign unknowns to tangential field components along element edges, naturally enforcing tangential continuity and eliminating spurious modes.[1]

How is the open region handled?

The mesh must be truncated: absorbing boundary conditions placed typically at least λ/4 away from radiators, perfectly matched layers, or hybrid FEM–boundary-integral formulations that are exact at the boundary. Far fields are computed from equivalent currents on a surface enclosing the antenna.[1][3]

When is FEM preferred?

Antennas with intricate dielectric parts, ceramic loading, waveguide feeds, horns, filters integrated with antennas and resonant structures where single-frequency accuracy is key. Wideband sweeps use interpolating or fast frequency sweeps based on model-order reduction.[1][4]

Frequently asked questions

Is FEM slow for wideband antennas?

Each frequency requires a solve, but fast and interpolating sweeps make wideband results practical.

What drives FEM memory?

The number of tetrahedra and matrix fill from the sparse factorization.

Does FEM handle anisotropic materials?

Yes, naturally, through tensor material properties per element.

References

Online sources accessed October 21, 2026; printed works cited by edition. See all sources.

  1. “The Finite Element Method in Electromagnetics, 3rd ed.”. J.-M. Jin, Wiley. 2014.
  2. “Ansys HFSS (finite element method 3D electromagnetic simulator)”. Ansys, Inc.. product documentation.
  3. “A Perfectly Matched Layer for the Absorption of Electromagnetic Waves”. J.-P. Berenger, Journal of Computational Physics, vol. 114, no. 2, pp. 185-200. October 1994.
  4. “Antenna Engineering Handbook, 4th ed.”. J. L. Volakis (ed.), McGraw-Hill. 2007.
Categories: Simulation