Design and analysis of coplanar Lange coupler for millimetre-wave applications up to 90 GHz

This paper presents the first millimetre-wave coplanar Lange couplers which operate at 32 GHz and 65 GHz with a 40 percent bandwidth. Detailed design and analysis using the HP-Momentum EM simulator have been carried out to compute the even- and odd-mode impedances and effective dielectric constant of the coupler. The comparison of simulated and measured S-parameters up to 90 GHz shows the validity of the design approach and the capability of integrated coplanar Lange couplers.