New dielectric-covered waveguide-to-microstrip transitions for Ka-band transceivers

New dielectric-covered waveguide-to-microstrip transitions at Ka-band have been developed. These transitions are probe-type, but the dielectric material completely covers the waveguide opening in order to provide a moisture barrier and robustness. These transitions are also designed to be less sensitive to fabrication tolerances. The transition structures have been comprehensively analyzed using a 3-D EM software. The resonance phenomena caused by the waveguide-wall discontinuity have been removed by placing vias around the waveguide aperture. These transitions have also been fabricated and measured. The measured insertion loss of the transition is less than 0.4 dB and the return loss is about 15 dB over the entire Ka-band.