ABSTRACT
A waveguide, in which conducting walls force a wave to propagate in a single direction (say along the z axis), motivates a consideration of a specific dimensional break-up of Green's function for a wave propagating in vacuum with a definite frequency. Furthermore, by deriving alternative expressions for Green's function, one is able to obtain additional mathematical properties of Bessel’s functions. This chapter discusses retarded Green's function satisfying the inhomogeneous Helmholtz equation. An alternative representation for Green's function can be obtained by taking the three dimensional Fourier transform.
