Piecewise-uniform bends in rectangular waveguide

A new configuration of improved rectangular-waveguide bend for advanced millimeter-wave applications is presented. It consists of few lengths of constant-curvature bends, properly designed in order to obtain enhanced matching conditions, without matching elements. Comparisons between the proposed bends and the uniform ones are reported, showing that the formers exhibit a better return loss. Measurements on a Ka-band prototype, in its operative condition, and a worst-case analysis on a W-band design, confirm the high electrical performances also in presence of significant manufacturing uncertainties.