Accurate Electromagnetic simulation of dielectrics in device structures using Neptune

Abstract

Dielectric materials play an important role in many classes of vacuum electronic device, but they present unique challenges to simulate accurately using time-domain Electromagnetic Particle-in-Cell (EM-PIC) codes. Results for previously published embedded boundary (or `cut-cell') algorithms typically do not exhibit true 2nd-order convergence with respect to grid cell size when curved interfaces must be resolved, particularly when the ratio of dielectric constants across an interface is large. We demonstrate here a new algorithm for time-domain simulation of structures that successfully addresses this challenge and provides accurate results in a broad range of geometries. We have implemented the algorithm within the Neptune EM-PIC code to execute efficiently on fast GPUs or multicore CPUs, and will present results for specific device simulations.