# Characteristic Mode Analysis

Characteristic mode analysis (CMA) is the numerical calculation of a weighted set of orthogonal current modes that are supported on a conducting surface. The sets of characteristic near fields and far fields associated with these characteristic currents can provide insight into the radiating properties of structures, allowing for a systematic approach to antenna design and placement.

Characteristic modes are obtained by solving a particular weighted eigenvalue equation that is derived from the method of moments impedance matrix. Feko has a built-in solver that calculates these modes, with no need for post-processing by the user. The eigen values, modal significance, characteristic angles, currents, near fields, and far fields can be visualised in POSTFEKO.