Solving inverse electromagnetic problems using FDTD and gradient-based minimization
Article first published online: 11 APR 2006
Copyright © 2006 John Wiley & Sons, Ltd.
International Journal for Numerical Methods in Engineering
Volume 68, Issue 6, pages 650–673, 5 November 2006
How to Cite
Abenius, E. and Strand, B. (2006), Solving inverse electromagnetic problems using FDTD and gradient-based minimization. Int. J. Numer. Meth. Engng., 68: 650–673. doi: 10.1002/nme.1731
- Issue published online: 25 SEP 2006
- Article first published online: 11 APR 2006
- Manuscript Accepted: 24 FEB 2006
- Manuscript Revised: 20 FEB 2006
- Manuscript Received: 20 MAY 2005
- Parallel and Scientific Computing Institute
- Swedish Foundation for Strategic Research
We address time-domain inverse electromagnetic scattering for determining unknown characteristics of an object from observations of the scattered field. Applications include non-destructive characterization of media and optimization of material properties, for example, the design of radar absorbing materials. Another application is model reduction where a detailed model of a complex geometry is reduced to a simplified model.
The inverse problem is formulated as an optimal control problem where the cost function to be minimized is the difference between the estimated and observed fields, and the control parameters are the unknown object characteristics. The problem is solved in a deterministic gradient-based optimization algorithm using a parallel 2D FDTD scheme. Highly accurate analytical gradients are computed from the adjoint formulation.
The inverse method is applied to the characterization of layered dispersive media and the determination of parameters in subcell models for thin sheets and narrow slots. Copyright © 2006 John Wiley & Sons, Ltd.