A transition from rectangular waveguide to coplanar waveguide on membrane

Several transitions from coplanar waveguide on thin dielectric membrane to rectangular waveguide have been investigated. The optimum transition structure turned out to consist of a coplanar-to-microstrip transition on membrane followed by a triangularly shaped microstrip probe performing the transition from microstrip line to rectangular waveguide. The taper between the coplanar and the microstrip transmission line as well as the shape of the microstrip probe has been optimized for D-band operation.