Analysis and design of ideal non symmetrical coupled microstrip directional couplers

Ideal directional couplers consisting of coupled asymmetric lines in an inhomogeneous medium have been realized by equalizing the inductive and capacitive coefficients of coupling. Analytical results have been verified numerically by computer simulation of the idealized distributed parameter systems and experimentally by comparing the scattering parameters of directional couplers designed with and without the techniques for improving coupler performance presented. Examples of high-directivity asymmetric couplers consisting of various planar and layered structures and presented together with experimental results for 6-dB couplers on alumina.<<ETX>>