Ultrawideband characterisation of CPW GaAs monolithic 60 GHz couplers using overlaid structures

Novel Coplanar Waveguide (CPW) coupler structures are proposed and successfully implemented at 60 GHz on a GaAs substrate. The proposed structures use a combination of very small gap, made possible by an advanced e-beam direct-write metal patterning process, and silicon dielectric overlays to achieve a tight coupling. In comparison with a CPW Lange coupler, the proposed couplers provide a smaller size and better performances.