Design and Implementation of a Compact 90° Waveguide Twist With Machining Tolerant Layout

We report on a novel compact wideband 90° twist with performance tolerant to small geometry variation and hence improved manufacturability through direct milling. The experimental verification shows 44% fractional bandwidth with return loss better than 20 dB over the 140-220 GHz band. The performance, compactness, and tolerance to manufacturing inaccuracy make it very suitable for use in various waveguide systems from microwave to millimeter-wave range.