A Broadband Microstrip-to-Waveguide Transition with Tapered CPS Probe

A novel microstrip-to-waveguide transition utilizing tapered coplanar strip probe and microstrip-to-slotline transformer is presented. The transition is highly compatible with MIC technology and can be easily integrated with rectangular waveguides. Design of X-band and Ka-band transition demonstrates more than 35% bandwidth with return loss less than -15 dB. The transition has the advantages of broad bandwidth, compact size, easy assembly, and low fabrication cost.