Design of broad band SIW couplers with 45° and 90° phase difference

This paper presents a Substrate Integrated Waveguide (SIW) directional coupler with required phase-difference at the output ports. In order to verify the feasibility of this design method, a 45° and a 90° SIW coupler are designed, simulated and optimized. The results of simulations have shown the great performances over a broad operational bandwidth.