This paper provides an alternate interpretation about the existence of complex modes in lossless perfectly conducting closed structures. It is shown that for a homogeneous source free region, the classical waveguide modes which are the solutions to source free Helmholtz equation are indeed complete. However, when there are some sources of discontinuities or some form of inhomogeneity in the structure modes with complex propagation constants appear in lossless perfectly conducting closed structures. The complex modes are needed to form a complete set for modal expansion of the fields. One of the objectives of this paper is to show that these complex modes are the solutions of the inhomogeneous wave equation and that they can be derived from the classical waveguide modes which are solutions to the source free wave equation.
|Original language||English (US)|
|Number of pages||7|
|Journal||AEU. Archiv fur Elektronik und Ubertragungstechnik|
|State||Published - May 1 1994|
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering