Page "Path loss" Paragraph 14

Deterministic methods based on the physical laws of wave propagation are also used ; ray tracing is one such method.

These methods are expected to produce more accurate and reliable predictions of the path loss than the empirical methods ; however, they are significantly more expensive in computational effort and depend on the detailed and accurate description of all objects in the propagation space, such as buildings, roofs, windows, doors, and walls.

For these reasons they are used predominantly for short propagation paths.

Among the most commonly used methods in the design of radio equipment such as antennas and feeds is the finite-difference time-domain method.