The Biot-Savart law gives the exact field distribution (in the absence of magnetic materials) for both the near and far fields, for any current path, or for any current path segment. The Biot-Savart law as applied to a circular wire loop in the XY plane is shown in Fig. 1.36 (Note that Eqs. (1.346) to (1.348) may be used to approximate the far field, R > a).
