The measured performance of a 170 GHz remote steering launcher

It has been assumed that the square or rectangular corrugated waveguide propagates ideal HE/sub n1/ modes independent of polarization. Since higher order HE/sub n1/ modes are only excited in the plane of steering, and those modes are much more sensitive to the corrugation depth and surface flatness with E perpendicular to the corrugated surface, it seemed likely that the details of the corrugations are the source of the behavior. We therefore have implemented a method to produce, even in copper, highly reproducible corrugations. In the present work, we describe the results of measurements made using square waveguide of inside dimension 45.7 mm having all four walls corrugated with a 0.66 mm pitch and with a variation in corrugation depth of < /spl plusmn/0.006 mm.