Wideband transition from conductor-backed coplanar waveguide to modified coplanar stripline using multiple substrates

The authors present a wideband and low-loss transition from conductor-backed coplanar waveguide to a modified, conductor-backed coplanar strip transmission line. The measured insertion loss is less than 1 dB up to 4.8 GHz and the return loss is greater than 12 dB. To reduce undesired modes, two dielectric layers are used between the circuit and the conductor backing.