thus the descriptive name: absorbing boundary conditions (ABCs). These ABCs were originally constructed based
The complementary operators method (COM) has been shown to be an effective mesh terminator when solving open-region scat-on several principles such as the one-way wave equation, tering and radiation problems. This study presents the theory of asymptotic expansion of the field, or on the pseudo-COM and extends it to include general analytical absorbing bounddifferential operator theory [1][2][3][4][5][6][7][8]. Aside from the perary conditions (ABCs). The COM is applied to the finite difference fectly absorbing boundary condition, which is charactertime domain simulation of electromagnetic problems. The applicaized by nonlocality in space and time, and thus carries tion of COM to elastic and acoustic waves follows in a similar manner. The numerical adaptations of COM to the discretized domain with it tremendous cost in implementation, particularly is then discussed to show that careful numerical adaptation is in time-domain techniques [9, 10], most ABCs take the needed to ensure full complementariness of the discretized equaform of a single partial differential equation enforced at tions. Numerical experiments will be presented to show the effecartificial boundaries. While the single-equation analytical tiveness of COM in predicting accurate time-domain response as ABC has shed considerable insight into the mechanism well as critical frequency domain response. In particular, an experiment is detailed that demonstrates how COM can be effective in by which waves can be annihilated or partially annihilated treating evanescent fields which traditionally have been a major at the boundary, these ABCs have stopped short of challenge for ABCs in general. แฎ 1997 Academic Press delivering a level of accuracy that is necessary in many modern and advanced applications. It is important to note here that even if these classical ABCs were enforced 113