Arbitrarily oriented microstrip lines coupled through an inclined slot in the common ground plane

An analysis of arbitrarily oriented microstrip lines coupled through an inclined slot in the common ground plane is presented. The method of analysis is based on the spectral domain approach and reciprocity theorem. Computed scattering parameters are compared with other available measured and computed data for the case of parallel microstrip lines, showing good agreements. It is found that for arbitrarily oriented microstrip lines, by varying slot inclination angle, coupling level can be widely controlled and there exists maximum coupling for a certain value of slot inclination angle. Effects of slot length on coupling and losses are also investigated.