Development of broadband phase shifter using slotted substrate integrated waveguide structure

This paper presents a novel broadband phase shifter that makes use of non-radiating longitudinal slots in the broad wall of a substrate integrated waveguide. The design concept is built up on different propagation constants of the TE₁₀ mode and quasi-TEM mode, which are the fundamental modes of substrate integrated waveguides and our proposed slotted substrate integrated waveguides, respectively. The proposed method is then validated by both theory and experiments. In this work, a 90 degree phase shifter is designed and implemented over a broad bandwidth from 21 GHz to 28 GHz. Measured results agree well with simulated results. It is shown that our proposed phase shifter has features of wideband, low insertion loss, and easy to fabricate.