A modified complex-envelope (CE) alternatingdirection-implicit (ADI) finite-difference time-domain solver for electromagnetic (EM) fields is presented. Like the conventional ADI scheme, the modified scheme is based on splitting the time step into two halves. In each substep, Maxwell's equations are solved implicitly in one direction and explicitly in the perpendicular direction. The new scheme is a combination of the conventional CE-ADI scheme and the leapfrog ADI scheme that was recently reported. The main features are a more compact form of the tridiagonal equations and greater flexibility in the application of boundary conditions. The boundary conditions on the six faces of the solution box are general and can be specified either as perfect conductor, symmetry boundary conditions, cavity modes, or arbitrary external specification. The new compact CE-ADI scheme is unconditionally stable; thus, the time step can be larger than the one imposed by the Courant-Friedrichs-Lewy (CFL) condition. Fast stable EM simulations of a planar slow-wave structure are demonstrated, with time steps exceeding the CFL limit by two orders of magnitude.
Bibliographical noteFunding Information:
Manuscript received October 15, 2009; revised January 11, 2010; accepted February 19, 2010. Date of publication May 17, 2010; date of current version June 9, 2010. This work was supported by the U.S. Office of Naval Research. M. Botton is with the Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel (e-mail: email@example.com). S. J. Cooke, A. N. Vlasov, and B. Levush are with the U.S. Naval Research Laboratory, Washington, DC 20375 USA (e-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org). T. M. Antonsen, Jr., is with Science Applications International Corporation (SAIC), McLean, VA 22102 USA, and also with the Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742-3511 USA (e-mail: email@example.com). I. A. Chernyavskiy is with SAIC, McLean, VA 22102 USA (e-mail: firstname.lastname@example.org). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TPS.2010.2047274
- Alternating direction implicit (ADI)
- Slow-wave structure
- Vacuum electronics