| In 1953, Pierce developed the Coupled Mode Theory utilizing the concept of a single four port device called a transducer. The transducer serves as a region for linear coupling of two uncoupled modes or amplitudes incident on the transducer. It is then possible to get two sets of "coupling" equations from which to generate a simple power relation between the two modes and show how they interact with distance. Application of this theory to a traveling wave tube affords an elegant, simple, and understandable means of generating the determinantal equation using power considerations instead of the more complicated circuit analysis model. It becomes apparent that this concept of coupled modes can be applied to many aspects of electromagnetics where coupling over distance and time takes place. |
