A direct transition from microstrip to waveguide for millimeter-wave MMICs using LTCC

A direct transition from microstrip line to rectangular waveguide compatible with millimeter-wave MMICs is presented. The transition is based on an aperture fed microstrip patch antenna radiating into the waveguide. The microstrip feed line and slot is patterned on the MMIC part and a novel approach using LTCC is presented for realization of the patch antenna and an extension of the waveguide using via walls. By this approach several transitions can be realized simultaneously and freely placed on one or more MMICs. The loss typically encountered going to a separate waveguide probe substrate is thus avoided. The design and simulation results for an LTCC-based transition at W-band is described and measurements on a test transition at G-band is reported.