Layering it All: Stripline-to-Waveguide Transitions for Corrugated Horns at W-band

Feeding horn antennas from a printed circuit board (PCB) is crucial at millimeter-waves for competitive system realization. At millimeter-waves the transition becomes lossy or bulky or both. This paper introduces a novel realization concept for a W-band stripline-to-rectangular waveguide transition, based on a polyimide PCB combined with a stacked corrugated horn antenna. The transition comprises a probe orthogonal to the H-plane of a waveguide port, processed using a polyimide substrate. The corrugated horn is realized by alternately stacked laser-cut aluminum sheets of 100 and 400 µm thickness. Simulations of the horn show a maximum gain of 19.7 dBi at 95 GHz, a reflection below -20 dB from 80 to 110 GHz, and a side-lobe level of -31.8 dB at 90 GHz. The measurements of the combined structure correspond well with the simulation: the reflection is in the range of -10 dB. This new approach can be predicted very well using simulations, offering cost efficiency and rapid production.