Compact and broadband microstrip-to-waveguide transition using antisymmetric tapered probes

A compact and broadband microstrip-to-waveguide transition using antisymmetric tapered probes is proposed. The proposed transition has 47.4% fractional bandwidth for which the return loss is larger than 15%dB, covering the whole frequency range 8-13 GHz. As compared with the microstrip-to-waveguide transition using the tapered CPS probe, the 15%dB fractional bandwidth is increased from 35 to 47.4% along with 44.8% reduction in the transition size. To verify the simulation result, a back-to-back transition has been fabricated and measured, and the measurement result shows good agreement with the simulation result.