Mode conversion at GCPW-to-microstrip-line transitions

Mode conversion at the transition between grounded coplanar waveguide (GCPW ) and microstrip line is demonstrated, Experimental results show the effect of overmoding in a conductor-backed coplanar waveguide on the transition b ehavior. A simple micromachining solution is used to cancel the parasitic m odes triggered by the transition in the GCPW feed line. This results in an insertion loss of 0.3 dB and a return loss better than -18 dB from 75 to 11 0 GHz. The transition can prove very useful for millimeter-wave packaging a nd interconnects.