Stability condition for body-of-revolution finite-difference time-domain method

Although the body-of-revolution finite-difference time-domain method has been successfully applied to solve Maxwell´s equations for rotationally symmetric structures, the stability condition of this method is inferred empirically. A new stability condition is given, which is derived analytically, and it demonstrates that the empirical stability condition is inaccurate. It is shown that the new stability restriction is weaker than the empirical one.