Mathematically speaking, all electromagnetic modeling problems require solving some form of Maxwell's equations subject to certain initial and boundary conditions. Radiation and scattering problems are defined over an unbounded domain. Circuit and device problems are often formulated as shielded structures within finite domains. Aside from a few well-known canonical problems, there are no closed-form solutions available for most electromagnetic problems due to the complexity of their domains and boundaries. Numerical analysis, therefore, is the only way to solve such problems.
[[Image:Info_icon.png|30px]] Click here for a brief review of '''[[A Review of Maxwell's Equations | Maxwell's Equations]]'''.
The numerical techniques used in computational electromagnetics (CEM) are generally divided into three categories:
* '''Quasi-Static Techniques''': These techniques assume static DC or low-frequency conditions, which ignore wave retardation effects. Under these conditions, Maxwell's equations reduce to the electrostatic or magnetostatic forms of Laplace/Poisson equations. These methods are effective in solving lumped devices or structures with small electrical dimensions.
* '''Asymptotic Techniques''': These techniques assume quasi-optical or high-frequency conditions, and solve the asymptotic forms of Maxwell'e equations. These methods are effective in solving structures or scenes with very large electrical dimensions. All the ray tracing techniques like the shoot-and Bounce-Rays (SBR) method fall into this category. Another example is the physical optics (PO) method.
[[Image:Info_icon.png|30px]] Click here for a brief review of '''[[A Review of Maxwell's Equations | Maxwell's Equations]]'''.
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