Comment on "Radial dependence of radiation from a bounded source" by Kirk T. McDonald

Abstract

The purpose of this note is to point out that McDonald's criticism of our work \cite{r1} is based on a circular argument. In order to show that the field of a bounded source falls off as $f(\theta,\phi)/r$ in the far zone, McDonald uses a Huygens-Kirchhoff diffraction integral whose derivation (from Maxwell's equations) already entails assuming a fall-off of this form for the field at infinity \cite{r2}. ($r$, $\theta$ and $\phi$ are the spherical polar coordinates centred on a point within the source, and $f$ is a factor independent of $r$.