An analytical array scanning method for field computations of sources within a periodic structure

In the past, there is little work on field analysis of source interaction with periodic structures. This paper describes a numerically exact method for both near and far fields of sources (anomalies) within periodic structures. The problem is first converted into numerical modeling of infinite phased array of artificial sources. Analytical array scanning of the infinite array fields results in the desired field solutions. The examples of a line-source within a corrugated parallel-plate waveguide, a line-source within a dielectric-strip grating structure, and a dipole on an artificial periodic substrate are given to illustrate this general numerical approach. A contribution of this work is that it identifies the mode-conversion mechanism from plane-waves to periodic waves, and it also provides fundamental understanding of field theory of sources within two- or three-dimensional periodic (photonic band-gap) media.