ABSTRACT
Determination of the scattering parameters of a waveguide junction requires in general the solution of a boundary-value problem for Maxwell’s equations, often by numerical methods that are outside the scope of this chapter. Rather than describe the mode-matching technique in full generality, the authors illustrate its use for a particular class of waveguide junctions. They consider only the case of transverse magnetic (TM) modes. A simple example of a one-port equivalent circuit is provided by the open-ended two-wire transmission line. The authors readily argue that the admittance of this open end must be capacitive rather than inductive, based on the behavior of the fields near the end of the line. In order to achieve significant densities of circuit elements in integrated optics, ways have to be found to allow dielectric waveguides to cross each other without undesired crosstalk or radiation loss.
