3D-FDTD characterization of an original low-loss silicon line

Abstract : A numerical and experimental analysis of an original inverted microstrip transmission line on standard Silicon substrate for telecommunication applications is proposed. Simulations have been made using a time domain method such as Finite-Difference-Time-Domain method (FDTD) to obtain results on a large frequency band. However, the main difficulty of the FDTD is due to the absorbing boundary conditions (ABC) which must be perfectly matched to the inhomogeneous media with losses. Indeed, the fine dimensions prescribed by the studied circuit lead to a long computational time. To reduce the FDTD grid but also to simulate inhomogeneous medium with losses, an efficient and broadband ABC has to be implemented because classical ones are not suitable to simulate a lossy substrate. For this reason, a specific uniaxial perfectly matched layers (UPML) is proposed. We compare numerical results obtained with FDTD, HP Momentum and experimental ones to show the validation of the method applied to lossy media.