Broadband Transition Design From Microstrip to CPW

This letter presents a broadband transition between microstrip and CPW located at the opposite lawyer of the substrate. Basically, the transition is based on two couples of microstrip-to-slotline transitions. In order to widen bandwidth of the transition, a short-ended parallel microstrip stub is added. A demonstrator transition has been designed, fabricated and measured. Results show that a frequency range of 2.05 to 9.96 GHz (referred to return loss of 10 dB) is obtained.