Global modeling of microwave applications by combining the FDTD method anda general semiconductor device and circuit simulator

This paper presents the coupling of two commercially available simulation c odes: DESSIS-ISE, a multidimensional semiconductor device and circuit simul ator, and EMLAB-ISE, an electromagnetic-field solver based on the finite-di fference time-domain (FDTD) method. Full-wave electromagnetics and nonlinea r devices are simulated in a coupled self-consistent way using the lumped-e lement approach [1], [2], The active region of the del ice is represented a s a lumped element within the FDTD grid, while the packaging and waveguidin g structures are modeled in their physical dimensions. For the nonlinear de vice, multidimensional semiconductor device simulation, as well as standard SPICE models, may be applied, Several examples show the capability of comp rehensive analysis of microwave applications and the versatility in the sim ulation of the active elements. The coupling formalism is explained in deta il, including time-step adjustment and biasing of active devices.