Substrate-integrated waveguide phase shifter with rod-loaded artificial dielectric slab

A substrate-integrated waveguide (SIW) broadband phase shifter is presented and studied. The phase shift mechanism is based on the synthesis of an artificial dielectric slab using an array of metallic rods in the middle of a SIW. This technique enables a large phase shift within a compact size and enhances the density of integration. As an example, 45° and 90° phase shifters are designed and showcased on a single-layer substrate at a centre frequency of 26 GHz. The amplitude imbalance between the two paths is also avoided while the phase error is less than 5° over a frequency band of 20-32 GHz or around 46% relative bandwidth. The measured return loss is found to be better than 12 dB over the whole frequency band.