The scattering of a plane wave by a microstrip line is formulated under the most general conditions, including the finite conductivities of the metal strip, substrate and ground plane, in order to determine accurately the absorption of energy by the microstrip structure. It is shown that a new class of modes in the metal is needed for a formulation of the microstrip structure as a rigorous boundary-value problem by the method of mode matching.
S. T. Peng,
Robert T. Kinasewitz,
"Scattering Of Plane Wave By Microstrip Lines", Proc. SPIE 1039, 13th Intl Conf on Infrared and Millimeter Waves, (18 November 1989); doi: 10.1117/12.978474; https://doi.org/10.1117/12.978474