Novel ridged waveguide differential phase shifter for satellite application

Abstract

A compact differential phase shifter structure that exhibits both full-band operation and easy mechanical manufacture is presented. It consists of a rectangular waveguide loaded with single ridge sections terminated by a unique H-plane step widening to standard waveguide dimensions. Two prototypes of 90º and 180º differential phase shifters with reference to an empty waveguide of the same length were designed and tested for the WR75 waveguide band. In both cases the differential phase shifter exhibits a maximum measured phase error of ±2.5º and ±3.5º respectively, with return losses better than 24 dB and insertion losses lower than 0.06 dB over a >40% bandwidth, which represents state-of-the-art achievement for non-dielectric loaded waveguide circuits. Furthermore, this structure is well suited for H-plane millimetre-wave integration.