Before revision:  The boundary conditions are enforced weakly through the numerical flux of DG. Numerical results show that the proposed DG-based unit-cell scheme models the device accurately but is significantly faster than the DG scheme that takes into account the whole device  .
After revision:  The boundary conditions are enforced weakly through the numerical flux of DG. Numerical results show that the proposed DG-based unit-cell scheme is significantly faster than the DG scheme that takes into account the whole device .