Coupled-mode analysis of an ideal microstrip six-port directional coupler on an anisotropic substrate

Abstract

To cite this article: LUKANG YU and BANMALI RAWAT (1997) Coupledmode analysis of an ideal microstrip six-port directional coupler on an anisotropic substrateThe coupled-mode formulation has been applied to simplify the analysis of a symmetrical three-line microstrip coupler (TMC) on an anisotropic substrate. The existence of an ideal six-port directional coupler has been proved under the following conditions: the coupling coe cients of the system are equalized using substrate anisotropy and the lines are matched to their characteristic impedances. The singular behaviour of the normal-mode parameters that occur at the critical equalization point of k l = k c has been examined. The numerical and simulation results con® rm the developed analysis.