Waveguide-to-microstrip transitions for millimeter-wave applications

Design and test data are presented for waveguide-to-microstrip probe transitions that cover millimeter-wave frequencies from 26 to 110 GHz. The broadband design provides a good transition for full-waveguide bandwidth (40%). Because of the compact structure, the measured insertion loss contributed by the transition is less than 0.1 dB in Ka-band, less than 0.2 dB in Q-band and V-band, and less than 0.35 dB in W-band. These transitions are useful for the device and circuit characterisation of millimeter-wave MICs and MMICs.<>