Multiphysics Sensitivity Analysis in FDTD Based Electromagnetic-Thermal Simulations

We present a new framework for multiphysics sensitivity analysis with the Finite-Difference Time-Domain (FDTD) method and apply it to joint electromagnetic-thermal simulations. Electromagnetic field and temperature derivatives with respect to uncertain input parameters, such as the complex permittivity of a biological tissue, are computed in a single FDTD simulation. Instead of finite-difference based derivative computations, we use the complex-step derivative approximation, which is robust as free of subtractive cancellation errors and straightforward to integrate with existing FDTD codes for first and higher order derivatives.